Chrome Bridge
Chrome Bridge is an MCP server that connects Claude Code to a real Chrome browser via a local WebSocket bridge, providing ~60 specialized tools for web automation, testing, and analysis.
Navigation & Tab Management
Navigate to URLs, create/close/activate/reload tabs, go back/forward
List all open tabs and frames (main + iframes) for targeting nested content
Interaction & Form Control
Click, type, hover, press keys, scroll, drag-and-drop, upload files
Batch-fill entire forms and submit in one call; dismiss cookie banners, overlays, and JS dialogs
DOM Inspection & Manipulation
Read page content as text, HTML, or accessibility tree
Query/modify DOM elements, inject CSS, highlight elements, watch mutations, measure spacing
Find text with context and list all actionable elements (buttons, links, inputs)
JavaScript Execution & Debugging
Run arbitrary JS in the page, read console logs, list event listeners
Monitor network requests (XHR/fetch/all), WebSocket connections, export as HAR
Get performance metrics and Core Web Vitals (CLS, LCP, FCP, TTFB)
Network Mocking & Control
Block, redirect, stub, or modify request/response headers (survives reloads)
Make HTTP requests using the user's session cookies; set HTTP auth credentials
Visual & Responsive Testing
Take viewport, element, or full-page stitched screenshots
Visual regression: save baselines and compare with pixel-diff highlighting
Resize viewport, set zoom, emulate color scheme/reduced motion/print, override geolocation
Audits
Accessibility audit (alt text, ARIA, contrast, form labels, heading hierarchy)
SEO audit (title/description, canonical, Open Graph, JSON-LD)
Security headers audit (CSP, HSTS, clickjacking protection)
Check links for broken URLs, detect unused CSS
Structured Data Extraction
Extract HTML tables as JSON with server-side row filtering
Extract repeated structured data (cards, lists) with field mappings in one call
State, Storage & Session Management
Read/write/delete localStorage, sessionStorage, and cookies
Save/restore named session fixtures (e.g. logged-in state), save pages as MHTML
List and wait for file downloads
Automation & CI
Wait for elements, JS conditions, navigations, or network idle
Assert page conditions (existence, visibility, text, URL) with polling
Record sessions as replayable JSONL files and replay via CLI without a model
Launch a dedicated headless Chromium instance with an ephemeral profile for isolated CI runs
Chrome Bridge
An MCP server that gives Claude Code your real, logged-in Chrome — measured 2.75× fewer turns and 2.28× lower cost than the official "Claude in Chrome" extension on a form-filling task, with ~3× the toolset and no paid plan.
63 web-development tools (navigation, DOM inspection, visual regression, audits, network mocking) over a local WebSocket bridge, plus a headless instance for CI. Self-hosted, local-only.

Quickstart
Requires Node.js 18+ and Chrome 135+.
git clone git@github.com:frsorrentino/chrome-bridge.git
cd chrome-bridge && ./install.shOpen
chrome://extensions, enable Developer mode, click Load unpacked, select theextension/folder.Restart Claude Code.
Then ask for something like "open localhost:3000, run an accessibility audit
and find the Sign Up button": Claude Code calls navigate,
accessibility_audit and find_text. Because navigate already returns
element refs, click(ref="n1") follows with no discovery turn in between.
On ChromeOS/Crostini install from the Chrome Web Store instead: an unpacked extension is dropped on every reboot, because the container isn't mounted when Chrome starts.
install.sh registers the MCP server with --scope user. To do it by hand:
claude mcp add --scope user chrome-bridge node /path/to/server/index.js.
For execute_js, enable Allow user scripts in chrome://extensions →
Chrome Bridge → Details (on Chrome 135-137, enable Developer Mode instead).
Related MCP server: OpenBrowser
Why Chrome Bridge?
Chrome Bridge | Claude in Chrome | Chrome DevTools MCP | Playwright MCP | |
ChromeOS / Crostini | Yes (real host) | No | Container only | Container only |
Tools | 63 (34 core) | ~20 | ~50 | 23 core (71 total) |
Requires paid plan | No | Yes (Pro+) | No | No |
Network mocking | Yes (stub/headers) | No | No | Yes |
Visual regression | Yes ( | No | No | No |
Audits (a11y/SEO/sec) | Yes (full suite) | No | Partial | No |
Headless / CI | Yes | No | Yes | Yes |
GIF / video | No | Yes | Partial | No |
Breakpoints / heap | No | No | Yes | No |
It wins on round trips, not payload size: short element refs instead of the
screenshot-and-click loop, fill_form filling N fields in one call, table
filtering done server-side. Per single turn it actually costs slightly more.
The full benchmark — method, every raw run including the unfavourable ones, and what the harness can't measure — is in docs/EFFICIENCY.md.

Using it
Beyond the MCP tools, two lanes keep work away from the model entirely.

CLI — batch operations, piped through grep or jq before anything reaches
the context:
chrome-bridge navigate --url https://example.com
chrome-bridge read_console --level error | head -20
chrome-bridge assert --selector "#success" --text "Done"
chrome-bridge replay --file ./recordings/login.jsonlLaunch mode — a dedicated Chromium instance with an ephemeral profile, for isolated sessions or CI:
node server/index.js --launch --headlessPair it with session_record + replay for smoke tests with no model in the
loop. In launch mode execute_js falls back to new Function when the
user-script toggle isn't available.
Tools
63 in total, in seven groups. Only core (34 tools) loads by default; the rest
are opt-in via --caps.

Group | N | What's in it |
Core & Navigation | 9 | tabs, windows, |
Interaction | 11 |
|
DOM & Inspection | 11 |
|
Debugging & Network | 9 |
|
Visual & Responsive | 7 |
|
Audits | 6 | a11y, SEO, security headers, links, |
State, Storage & Files | 9 | storage, fixtures, MHTML, recording, |
Every tool, with the notes that matter: docs/TOOLS.md.
How it works

Claude Code <--stdio--> MCP Server <--WebSocket :8765--> Chrome Extension
(server/) (extension/, MV3)The Node.js server handles the protocol and tool logic; the MV3 extension
executes commands through Chrome APIs. User scripts (execute_js) run via
chrome.userScripts.execute().
Configuration and security
Environment variables, each with a matching CLI flag:
Variable | Default | Notes |
|
| |
|
|
|
| unset | Required on both |
|
|
|
The bridge binds loopback, accepts extension connections only from a
chrome-extension:// origin, and — when a token is set — requires it on both
handshakes. Without one, any local process could act as a relay and reach
execute_js inside your authenticated browser session. Secondary MCP instances
connect via loopback and are acknowledged with relay_init_ok, so a foreign
process holding the port fails fast instead of timing out per command.
What is not protected: page content reaches the model unfiltered, so a
hostile page's text is untrusted input. get_storage, session_fixture, HAR
exports and screenshots are not redacted and may carry cookies, tokens or
personal data. Don't point the automation at pages holding secrets you wouldn't
paste into a chat.
Troubleshooting
Symptom | Cause / fix |
| Extension disabled, or its port differs from the server's. The error names the actual host/port; check them in the popup (⚙). |
Port 8765 already in use | Expected: a second MCP session becomes a relay and shares the one bridge. Set |
| Something else owns the port. Free it or change |
| Enable Allow user scripts in |
| The page was opened before the extension, "Capture console & metrics" is off, or the page isn't injectable ( |
Screenshot times out | On ChromeOS a fully occluded window stops producing frames; captures fail after 10s. Bring the window forward. |
Commands work, then stop | The MV3 service worker restarted and in-memory state (network log, diff baselines, HTTP auth) was reset. Re-run the monitoring call. |
Extension dropped on every ChromeOS reboot | Install from the Web Store instead of Load unpacked. |
Tool missing from the list | It's in an opt-in group. Check |
Documentation
docs/TOOLS.md — all 63 tools, by group
docs/EFFICIENCY.md — the benchmark and the design behind it
bench/RESULTS.md — raw runs and inclusion rule
Tests
npm test (Chrome-free, ~22s) · npm run test:e2e (needs Chrome and a
connected extension) · npm run measure (schema cost).
License
MIT
Available Tools
63 toolsaccessibility_auditARead-onlyIdempotent
A11y audit: missing alt, empty links, heading hierarchy, ARIA, contrast (approximate), form labels.
| Name | Required | Description | Default |
|---|---|---|---|
| scope | No | Limit scope (CSS selector) | |
| checks | No | Subset to run; fewer checks means a shorter answer | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. Description adds that contrast check is approximate, but does not disclose output format or other behavioral details.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Single concise line; no wasted words. Could be slightly more structured but effective.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema, description should explain what the tool returns (e.g., list of issues). It only lists checks, leaving output ambiguity. Incomplete for a multi-check audit tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema covers 100% parameters. Description adds natural language meaning to the checks parameter by listing specific issues (e.g., 'missing alt' for images), going beyond schema enums.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Description states verb 'audit' and resource 'accessibility', listing specific checks (alt, links, headings, ARIA, contrast, forms). Distinct from sibling tools like seo_audit and check_links.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance on when to use this tool over alternatives. No mention of prerequisites or context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
assertARead-onlyIdempotent
Assert a page condition, polling until timeout: element exists/visible (optionally with count or containing text), text on page, tab url/title. Patterns: substring, or "/…/" for regex. Recorded flows replay it as a test.
| Name | Required | Description | Default |
|---|---|---|---|
| url | No | Tab url pattern | |
| text | No | In the element (with selector) or anywhere on the page | |
| count | No | Exact match count for selector | |
| state | No | attached means present in the DOM, visible also requires a rendered box | attached |
| title | No | Tab title pattern | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| timeout | No | Max ms to wait for the condition before failing | |
| selector | No | Element the assertion is about; ">>>" pierces shadow DOM |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and idempotentHint=true. The description adds behavioral context about polling timeout and pattern syntax, which is valuable beyond annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with no wasted words. The core functionality and pattern syntax are conveyed efficiently.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given 8 parameters and no output schema, the description covers main conditions, patterns, and replay context. It lacks explicit return behavior but is otherwise sufficient.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so parameters are already well-described. The description adds minimal extra meaning, only summarizing condition types and pattern styles. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: to assert page conditions (element existence/visibility, text, URL/title) with polling until timeout. It distinguishes from siblings by focusing on assertion rather than observation or waiting.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies use for assertions but does not provide explicit guidance on when to use this tool versus alternatives like wait_for or query_dom. No exclusions or comparison with siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
check_linksARead-onlyIdempotent
Check page links for broken URLs, verified server-side (no CORS limits, real HTTP status).
| Name | Required | Description | Default |
|---|---|---|---|
| scope | No | same-origin skips third-party links, which are the slow ones | all |
| format | No | lines is compact; json keeps per-link status and timing | lines |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| timeout | No | Per-link ms | |
| selector | No | CSS selector; ">>>" pierces shadow DOM. Restricts which links are collected | a[href] |
| max_links | No | Cap on links fetched: each one is a real HTTP request |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate read-only and non-destructive behavior. The description adds that verification is server-side with no CORS limits and real HTTP status, which provides useful context beyond annotations but does not disclose potential rate limits or error handling.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, well-structured sentence that immediately conveys the tool's purpose. Every word earns its place with no unnecessary information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the 6 parameters and no output schema, the description is quite minimal. It does not explain what constitutes a 'broken' link (e.g., 4xx, 5xx, timeouts) or how results are returned (lines/json), though the schema provides some clues. More detail would improve completeness.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% and adequately documents each parameter. The description does not add extra meaning or usage guidance for parameters beyond what the schema provides, thus baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool checks page links for broken URLs, verified server-side. This distinguishes it from client-side link checks and other diagnostic tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies this tool is for server-side link verification, but does not explicitly state when to use it over sibling tools like 'accessibility_audit' or 'get_status.' No exclusions or alternatives mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
clickA
Click an element, by CSS selector or by a ref (n1, n2…) from get_interactives or navigate. Fires a real pointer sequence, so it can submit, open a dialog or navigate away — use wait_after to let that settle. Not idempotent, and a click that triggers a native confirm() blocks the bridge: install handle_dialogs first.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | No | From get_interactives, e.g. "n3" | |
| count | No | 2 emits dblclick after the two clicks, which is what selects a word or opens an editor | |
| force | No | Click even if occluded | |
| button | No | right opens the page context menu instead of activating the element | left |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| selector | No | CSS selector; ">>>" pierces shadow DOM. Ignored when ref is given | |
| wait_after | No | Settle before returning: navigation waits for a page load, networkidle for quiet traffic | none |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Discloses that it fires a real pointer sequence, can submit/dialog/navigate, is not idempotent, and that confirm() blocks the bridge. Adds significant value beyond annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two packed sentences with zero wasted words; front-loaded with purpose and targeting.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Thorough coverage of parameters and behavioral traits; no output schema but that is acceptable. Minor gap: does not mention return value (if any), but not essential for selection.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Adds meaningful details for count (dblclick), button (context menu), selector (ignored with ref), and wait_after (settle behavior), all beyond the schema descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states 'Click an element' with two targeting methods (CSS selector or ref), distinguishing it from sibling tools like hover or press_key.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides context for when to use wait_after and handle_dialogs, but does not explicitly state when not to use this tool or compare to alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
clipboardBIdempotent
Read or write the system clipboard (text). Activates the tab first.
| Name | Required | Description | Default |
|---|---|---|---|
| text | No | For write | |
| action | Yes | write takes text; read returns the current clipboard contents | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Description states the tool can write to clipboard, but annotation idempotentHint=true implies the operation is safe to retry without side effects. Writing is typically not idempotent, creating a contradiction. The description adds 'activates the tab first' but is undermined by the inconsistency.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, efficient sentence that conveys the core purpose and a key behavior (tab activation). No redundant or unnecessary words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description does not mention return values for read operations or error handling. With no output schema, the user is left uninformed about what the tool returns on read. The tab_id parameter behavior is explained in schema but not reinforced in description.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the baseline is 3. The description does not add any additional meaning beyond what the schema already provides for the three parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb 'read or write' and the resource 'system clipboard (text)', and adds a specific behavioral detail 'activates the tab first'. It uniquely identifies the tool among siblings, as no other sibling tool mentions clipboard operations.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No explicit guidance on when to use this tool versus alternatives. The description implies clipboard interaction but does not mention when-not or suggest alternative tools for similar tasks (e.g., using type_text for paste).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
create_tabA
Open a new tab, optionally at a URL, and make it the implicit target of later commands in this session. Each call creates another tab: reuse a tab_id or navigate() to move an existing one instead of piling up tabs.
| Name | Required | Description | Default |
|---|---|---|---|
| top | No | Window y (new_window) | |
| url | No | URL to open (default: new tab page) | |
| left | No | Window x on the virtual desktop (new_window) | |
| width | No | Window width px (new_window) | |
| active | No | false opens the tab in the background, leaving the current one focused | |
| height | No | Window height px (new_window) | |
| new_window | No | Open in a fresh window instead of a tab; with left/top it lands on the chosen monitor |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses that the new tab becomes 'the implicit target of later commands in this session' and that each call creates another tab, behaviors not captured by the annotations. This provides critical context about statefulness and side effects beyond the structured hints.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, front-loaded with the primary action and followed by a practical usage tip. Every sentence contributes value with no redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description is fully self-contained for a state-changing tool: it explains the action, the session-wide implication, and the fallback to navigate(). It does not explicitly state the return value, but the mention of 'reuse a tab_id' implies a tab identifier is returned, which is sufficient given the tool's simplicity and the comprehensive schema.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the baseline is 3. The description adds minimal parameter-specific meaning beyond the schema, merely mentioning the optional URL, which is already documented. It does not introduce new information about parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('Open') and resource ('new tab'), clearly distinguishing this from navigation tools. It explicitly contrasts with navigate(), stating 'reuse a tab_id or navigate() to move an existing one instead of piling up tabs.'
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides explicit usage guidance: it tells the agent that each call creates a new tab and recommends reusing a tab_id or using navigate() to move an existing tab, preventing tab accumulation. This addresses when to use the tool versus alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
dismiss_overlaysAIdempotent
Dismiss cookie banners/modal overlays: OneTrust, Cookiebot, Usercentrics, then generic heuristic. Idempotent.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Description complements annotations by detailing the specific overlay dismissal approach (vendor-specific plus heuristic). Annotations already mark destructiveHint false and idempotentHint true, and description reinforces idempotency, adding valuable context without contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences pack the essential information: what it does, which overlays it targets, and idempotency. No wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the simple input schema, annotations covering safety and idempotency, and the focused purpose, the description is fully adequate. No output schema needed for this straightforward action.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with a clear description for tab_id. The tool description adds the non-obvious default behavior: omitted means last tab navigated or active tab, which is helpful beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Description clearly states the tool dismisses cookie banners/modal overlays, listing specific vendor patterns (OneTrust, Cookiebot, Usercentrics) and a generic heuristic. This sets it apart from sibling tools that interact with page elements in other ways.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly mentions idempotency, signaling safe repeated use. Implicitly suggests use when overlays block interaction. No explicit when-not-to-use or alternatives, but context is clear given sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
drag_and_dropA
Drag an element onto another. html5 = DragEvent+DataTransfer; pointer = pointer/mouse events (sortable libraries).
| Name | Required | Description | Default |
|---|---|---|---|
| mode | No | Which event family to emit, since libraries listen to different ones | html5 |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| source_selector | Yes | Element to drag; ">>>" pierces shadow DOM | |
| target_selector | Yes | Drop target; ">>>" pierces shadow DOM |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate non-destructive behavior. The description adds the event family implementation detail but does not disclose other behavioral traits like timing, side effects (e.g., element reordering), or error scenarios.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, well-structured sentence with no filler. Every word adds meaning, and the semicolon effectively separates the general action from mode specifics.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the complexity of drag-and-drop (source, target, modes, frames, tabs) and no output schema, the description is adequate but thin. It does not explain return values, waiting behavior, or what constitutes a successful drop.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
All 5 parameters have schema descriptions (100% coverage), so the tool description's role is diminished. However, it adds valuable context for the 'mode' parameter by explaining the difference between html5 and pointer events, which goes beyond the schema's 'which event family to emit'.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Description clearly states the action ('Drag an element onto another') and distinguishes by specifying two event families (html5 vs pointer). This verb+resource structure is specific and distinct from sibling tools like click or hover.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
While the description explains when to use each mode ('html5 = DragEvent+DataTransfer; pointer = pointer/mouse events'), it lacks explicit guidance on when not to use this tool or alternative approaches. No prerequisites or exclusions are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
element_screenshotARead-onlyIdempotent
Screenshot cropped to one element (PNG), scrolled into view first. Read-only. The cheapest image in the set, because it carries only the box you asked for: a component, a chart, a table cell.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| selector | Yes | CSS selector; ">>>" pierces shadow DOM. The element is scrolled into view first |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adding to the annotations (readOnlyHint, destructiveHint, idempotentHint), the description discloses scrolling behavior, format (PNG), and performance profile (cheapest). No contradictions between description and annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two concise sentences, front-loading key information: purpose, action, and performance. Every word adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple, well-annotated, single-element screenshot tool with no output schema, the description covers all essential aspects: what it does, how it behaves (scroll), and why to use it (cheapest). Complete for agent decision-making.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with both parameters described. The description adds no new semantic information beyond the schema; it repeats 'scrolled into view' which is already in the schema. Baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it takes a screenshot of a single element, cropped to that element, and scrolled into view. It explicitly distinguishes from siblings by calling itself the cheapest image, which differentiates it from full-page or screenshot tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides context about when to use this tool by highlighting cost/performance (cheapest) and scope (single element). It implies this is for minimal images, but does not explicitly state when not to use or list alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
emulate_mediaAIdempotent
Make the page believe it runs in a different environment, until reset or reload: prefers-color-scheme, prefers-reduced-motion, print mode (matchMedia override + CSS) and navigator.userAgent/platform. user_agent only changes what page JS reads — the request header is a separate thing, set it with network_rules(action=modify_header, header="User-Agent"). Pair with viewport_resize to emulate a device.
| Name | Required | Description | Default |
|---|---|---|---|
| reset | No | Remove all emulations | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| printMode | No | Make print media queries match, without opening a print dialog | |
| user_agent | No | Overrides navigator.userAgent and appVersion in the page (not the HTTP header) | |
| colorScheme | No | Value reported to prefers-color-scheme queries | |
| reducedMotion | No | Value reported to prefers-reduced-motion queries |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses key behavioral traits beyond annotations: the emulation is temporary (until reset or reload), and it details the scope of userAgent override (only page JS, not HTTP header). Annotations indicate idempotentHint=true and destructiveHint=false, which are consistent. No contradictions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is concise (two sentences) and front-loaded with the primary purpose. Every sentence adds value: first sentence defines the tool and lists overrides; second sentence clarifies a common confusion (userAgent vs header) and suggests a pairing. No wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the complexity (6 parameters, no output schema), the description covers the main functionality, scope (until reset/reload), and relevant sibling tools. It does not explicitly describe the reset parameter's effect or return values, but these are handled by the schema. Overall it provides sufficient context for an agent to understand and invoke the tool correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so baseline is 3. The description adds context about the overall effect (e.g., 'print mode' overrides matchMedia) and relationships to other tools, but does not provide additional meaning for individual parameters beyond the schema descriptions. It adds moderate value but not significant per-parameter detail.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: making the page believe it runs in a different environment, listing specific overrides (prefers-color-scheme, prefers-reduced-motion, print mode, userAgent/platform). It distinguishes from sibling tools like network_rules for user-agent headers and suggests pairing with viewport_resize for device emulation.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides explicit guidance on when to use alternatives (e.g., network_rules for modifying the User-Agent HTTP header) and suggests pairing with viewport_resize for device emulation. However, it does not explicitly mention when to use the reset parameter or when the tool is not appropriate.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
execute_jsADestructive
Run JavaScript in the page (MAIN world). Requires the extension's "Allow user scripts" toggle; errors explain setup if disabled.
| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes | JS evaluated in the page; the value of the last expression is returned | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| max_length | No | Max output chars |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate destructive and non-readonly behavior. The description adds important context about MAIN world execution and the permission toggle, complementing annotations without contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Extremely concise two sentences: first sentence states core purpose, second sentence adds essential setup requirement. No wasted words, every sentence earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Covers core purpose and setup requirement well. Schema already documents that the return value is the last expression result. Could mention async behavior, but overall sufficiently complete given the tool's simplicity.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
All parameters are fully documented in the schema with 100% coverage. The description adds no additional semantics beyond what the schema provides, meeting the baseline expectation.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool runs JavaScript in the MAIN world of the page, using specific verb 'run' and resource 'JavaScript in the page', distinguishing it from similar sibling tools that may operate in other contexts.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides a clear precondition (requires 'Allow user scripts' toggle) and a helpful note about error messages explaining setup if disabled. However, it does not explicitly compare with alternative tools like query_dom or modify_dom.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
extractARead-onlyIdempotent
Read repeated non-tabular structures — product cards, list items, search results — as one record per item: item_selector matches the repeating block, fields map output names to selectors relative to it. Read-only, deterministic, parsed server-side from the main-document HTML.
| Name | Required | Description | Default |
|---|---|---|---|
| fields | Yes | field name → {selector, attr} | |
| format | No | lines is compact; json keeps one object per record | lines |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| save_to | No | Absolute path: write the records as JSON there and return the path instead of the content | |
| max_items | No | Cap on records returned, in document order | |
| max_length | No | Max output chars | |
| item_selector | Yes | CSS selector matching each item |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds useful context: deterministic, parsed server-side from main-document HTML. This adds value beyond annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, well-structured sentence that front-loads the purpose. Every part adds value with no wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (7 params, nested object, no output schema), the description covers the core usage and behavioral context. It lacks explicit mention of defaults or output format, but schema descriptions fill that gap.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with descriptions for all 7 parameters. The description adds a general pattern explanation but does not provide details beyond the schema. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool reads repeated non-tabular structures as records per item, with specific examples (product cards, list items, search results). It distinguishes from siblings like extract_table by specifying 'non-tabular'.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies when to use (non-tabular structures) and hints at alternatives (extract_table for tables), but does not explicitly state when not to use or list alternatives. The context is clear enough.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
extract_tableARead-onlyIdempotent
Read a real as JSON: thead cells become keys, each row an object. Read-only. Only for tabular markup — where filters rows server-side, so one matching row out of 1500 costs a few hundred bytes instead of the whole document. row_count is the table total, match_count how many rows passed the filter.
| Name | Required | Description | Default |
|---|---|---|---|
| index | No | Which table to take when the selector matches several, 0-based | |
| where | No | {column: substring} rows must match, case-insensitive contains. Key "any" matches any cell. | |
| offset | No | Skip N rows of the (filtered) set before applying max_rows. | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| columns | No | Return only these columns per row. | |
| max_rows | No | Max rows returned to you (output cap). | |
| selector | No | The table to read; ">>>" pierces shadow DOM | table |
| scan_rows | No | Max rows materialized in-page to scan/filter; raise for very large tables. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false; description reinforces with 'Read-only' and adds details on filtering behavior and row counts, providing extra context beyond annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three concise sentences front-load the core purpose, add efficiency context, and describe key filtering behavior with zero wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema, the description compensates by mentioning output fields. It covers main usage patterns and performance considerations, though interaction between offset and row limits could be clearer.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema covers all parameters with descriptions, but the description adds value by explaining the filtering logic of `where` (case-insensitive contains, 'any' key) and hints at output fields like `row_count` and `match_count` not in schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Description clearly states it reads a table as JSON with specific structure, and the scope 'Only for tabular markup' distinguishes it from generic DOM queries or page reading.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly says 'Only for tabular markup' and highlights efficiency benefits of server-side filtering, but does not explicitly state when not to use or name alternative tools for non-tabular data.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
fill_formAIdempotent
Batch fill form fields with React-compatible events. Handles input, select, checkbox, radio, and textarea.
| Name | Required | Description | Default |
|---|---|---|---|
| fields | Yes | {selector, value} pairs | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| wait_after | No | Settle before returning: navigation waits for a page load, networkidle for quiet traffic | none |
| submit_selector | No | Submit button to click after filling |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds value beyond annotations by specifying that events are 'React-compatible', indicating synthetic event dispatch. It also lists handled element types. Annotations already denote idempotency (idempotentHint=true) and non-destructive nature (destructiveHint=false). No contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise: two sentences totaling ~15 words. It front-loads the verb 'fill' and quickly covers scope. No superfluous information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (5 parameters, batch operation) and lack of output schema, the description omits details about return values, error handling for missing fields, or effect of submit_selector. It's minimally adequate but not fully comprehensive.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%. The description does not elaborate on individual parameters beyond what the schema already provides. The mention of 'React-compatible events' is general context, not parameter-specific, so the description adds minimal meaning beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: batch filling form fields with React-compatible events. It specifies the supported element types (input, select, checkbox, radio, textarea), distinguishing it from siblings like type_text for single-field input.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides no guidance on when to use fill_form versus alternatives like type_text or click. It does not mention efficiency trade-offs or appropriateness for single-field vs. multi-field scenarios.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
find_textARead-onlyIdempotent
Find text on the page: parent selector, context, visibility, position per match. Attaches nearby interactive elements (with refs for click/type_text/hover) for the first visible match.
| Name | Required | Description | Default |
|---|---|---|---|
| text | Yes | Literal text to find, not a regex | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| max_results | No | Cap on matches returned, in document order | |
| case_sensitive | No | Match case exactly |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds behavioral details about attaching nearby interactive elements with refs for interaction. This is valuable context beyond annotations, though it does not cover edge cases like no match found.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two concise sentences, front-loaded with the core purpose, followed by an important behavioral detail. No wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema, the description adequately explains the return values (parent selector, context, visibility, position, interactive elements). It covers the main aspects but could be more explicit about the list of matches and behavior when no match is found.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so parameters are well-described in the schema. The description does not add additional meaning or usage hints for parameters beyond what the schema provides. The mention of 'parent selector, context, visibility, position' refers to output, not parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool finds text on a page and specifies what it returns: parent selector, context, visibility, position per match, and attached interactive elements for the first visible match. This is specific and distinguishes it from sibling tools like query_dom or get_interactives.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for finding text and obtaining interactive elements, but it lacks explicit guidance on when to use this versus alternatives like query_dom. No when-not-to-use conditions or prerequisites are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
full_page_screenshotARead-onlyIdempotent
Full-page capture by scrolling: stitched segments of ~2 viewports (≤1568px, top→bottom), or one image per viewport with stitch=false. Read-only, but expensive: each segment costs ~2.7k image tokens, so only the first max_segments are returned and the rest need segment_offset. On a long page, reading the text you actually need is cheaper by an order of magnitude — prefer read_page, extract or find_text unless the layout itself is the question.
| Name | Required | Description | Default |
|---|---|---|---|
| delay | No | ms between captures (min 500, Chrome quota) | |
| stitch | No | false = one image per viewport | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| max_scrolls | No | Cap on scroll steps: a taller page is captured only up to here | |
| max_segments | No | Images returned, from the top (each ≈2.7k image tokens); raise or use segment_offset for the rest | |
| segment_offset | No | Skip the first N segments |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Describes expensive token cost, segment limit, scrolling process, and Chrome quota for delay, adding context beyond read-only and idempotent annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Front-loaded with main action, then details; every sentence adds value without unnecessary words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Comprehensive for a complex tool: explains return behavior, cost, pagination, and when to avoid use, despite no output schema.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema covers all parameters with descriptions, but description adds meaningful context like Chrome quota for delay and cost implications for max_segments.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Clearly defines as full-page capture via scrolling with stitching, distinguishing from single-viewport screenshot and cheaper text-reading tools like read_page.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly advises preferring read_page, extract, or find_text unless layout is needed, and explains cost and segment retrieval behavior.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_framesARead-onlyIdempotent
List frames (main + iframes) with frameId, parent, URL — for the frame_id parameter of DOM tools.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is clear. The description adds that the tool lists frames with specific fields, which is consistent with annotations and not contradictory.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single 16-word sentence that is front-loaded with the verb 'List' and resource. Every word adds value; no fluff.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple listing tool with one optional parameter and no output schema, the description covers the purpose, output structure, and usage context. It is complete enough for an agent to understand and use the tool correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% for the single parameter tab_id, and the description does not add any additional semantics or details about the parameter beyond what the schema already provides. Baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states 'List frames (main + iframes) with frameId, parent, URL', specifying the verb (List), resource (frames), and output fields. It distinguishes from siblings like get_tabs by targeting frame IDs for DOM tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly says 'for the frame_id parameter of DOM tools', indicating when to use this tool (to get frame IDs for DOM operations). It does not mention when not to use or list alternatives, but the usage context is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_interactivesARead-onlyIdempotent
List actionable elements (buttons, links, inputs, [role], [onclick]) with ready-to-use CSS selector, label, position, flags. Prefer this over dumping HTML to discover selectors.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Max elements returned; raise it on a dense page | |
| scope | No | Limit search (CSS selector) | |
| format | No | lines is compact; json adds full attributes per element | lines |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| visible_only | No | false also lists elements hidden or scrolled out of view |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint, idempotentHint, and destructiveHint. The description adds behavioral context by detailing what elements are considered actionable (buttons, links, inputs, roles, onclick) and that it returns selectors, labels, positions, and flags. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Only two sentences, both front-loaded with the tool's purpose and key benefit. No wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With full schema coverage, no output schema, and annotations, the description provides sufficient context about what the tool returns and when to use it. It could mention return format (lines/json) but the schema already covers that.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with all parameters described. The description does not add parameter-specific meaning beyond the schema, but the overall usage context helps. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Description clearly states it lists actionable elements (buttons, links, etc.) with ready-to-use CSS selectors, labels, positions, and flags. It distinguishes itself from sibling tools by recommending preference over dumping HTML.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly advises to prefer this tool over dumping HTML to discover selectors, providing clear usage guidance. Could be strengthened by mentioning conditions where alternatives are better, but it's still helpful.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_page_infoARead-onlyIdempotent
Get page metadata: meta tags, scripts, stylesheets, links, and forms
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so safety and idempotency are clear. Description adds specific metadata types, but no additional behavioral context (e.g., network requests, performance impact).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Single sentence with no wasted words, clearly front-loading the purpose. Highly concise.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Description lists the output components (meta tags, scripts, etc.), providing sufficient context for an agent to understand what will be returned, even without an output schema. Could mention return format but not critical.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with clear descriptions for both parameters. The description does not add extra parameter information beyond the schema, so baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Clearly states verb and resource: 'Get page metadata' and lists specific items (meta tags, scripts, stylesheets, links, forms). Distinguishes from siblings like query_dom (broader) and get_interactives (interactive elements).
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No explicit guidance on when to use this tool versus alternatives. Among many sibling tools, no context is provided for selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_performanceARead-onlyIdempotent
Navigation timing, paint metrics, JS heap size and per-resource load times, as measured since the current document loaded. Read-only, no reload triggered — numbers are only meaningful once loading has settled, so on a page still fetching wait for network idle first. Covers how fast the document arrived, not the layout-shift and interaction metrics that accumulate afterwards.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark readOnlyHint, idempotentHint, destructiveHint; the description adds that no reload is triggered and explains when numbers are meaningful, adding context beyond annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Concise, front-loaded with key behavior, and every sentence adds value with no waste.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
No output schema, but description hints at return types (timing, metrics, heap size); could specify format but complete enough given annotations and complexity.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with a clear parameter description for tab_id; the tool description does not repeat parameter info, which is acceptable as schema covers it.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description explicitly states it provides 'Navigation timing, paint metrics, JS heap size and per-resource load times', clearly distinguishing it from sibling tools like 'web_vitals' which cover layout-shift and interaction metrics.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
It advises waiting for network idle before using, and contrasts with metrics that accumulate after loading, providing clear guidance on when and why to use this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_statusARead-onlyIdempotent
Check bridge status: extension connection, server mode (primary/relay), port, version
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint, idempotentHint, destructiveHint. Description adds minimal extra context beyond listing fields.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Single sentence, no waste, front-loaded with purpose.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a zero-parameter status check, the description adequately lists key fields. Could elaborate on field meanings or possible values.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
No parameters in schema (100% coverage). Description lists output fields, adding value beyond empty schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states 'Check bridge status' and lists specific fields (extension connection, server mode, port, version). This distinguishes it from sibling browser automation tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Implies usage for checking bridge status, but no explicit when-to-use or when-not-to-use compared to sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_storageARead-onlyIdempotent
Read localStorage, sessionStorage or cookies of the current origin (type=all for every one). Read-only. Cookies come with domain, path, expiry and the httpOnly/secure flags, so this also answers whether a session cookie is present — write them back with set_storage, or snapshot a logged-in state with session_fixture.
| Name | Required | Description | Default |
|---|---|---|---|
| type | No | all returns the three together | all |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, destructiveHint, etc. Description adds specifics about cookie details (domain, path, expiry, flags) and confirms read-only nature. Consistent and adds value.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, front-loaded with verb and resource. No wasted words; each sentence contributes purpose and detail.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
No output schema, but description mentions cookie structure. For a simple read tool, it sufficiently covers behavior and output shape. Adequate given the tool's simplicity.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema has 100% description coverage. Description adds context for 'type' (all returns three together) and 'tab_id' default behavior, complementing the schema well.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Description clearly states the tool reads localStorage, sessionStorage, or cookies of the current origin. It differentiates from siblings set_storage and session_fixture by mentioning write and snapshot operations.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides context on when to use, e.g., checking for session cookies, and hints at alternatives. Lacks explicit when-not-to-use but offers good guidance overall.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_tabsARead-onlyIdempotent
List every open tab with id, url, title and active flag. Read-only. Use it to find a tab_id when the implicit target (last navigated tab, else the active one) is not the tab you mean. include_windows adds the windows themselves with their position, size, state and type — what you need before moving or tiling anything, and the only way to tell which monitor a window is on.
| Name | Required | Description | Default |
|---|---|---|---|
| include_windows | No | Also return the windows with bounds, state, type and tab count |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false; the description reinforces with 'Read-only' and adds behavioral detail about listing every open tab and the include_windows effect on window attributes. No contradictions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences that front-load the core function and then expand on usage and the optional parameter. Every sentence earns its place; no fluff.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's low complexity (one optional parameter, no output schema), the description provides all necessary return fields, usage guidance, and safety context, making it fully self-contained.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Though schema covers include_windows at 100%, the description adds meaning by explaining why you'd set it (before moving/tiling, to identify monitor) and what it returns (position, size, state, type), going beyond the schema's 'bounds, state, type and tab count'.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb 'List' with a clear resource 'every open tab' and enumerates the exact fields returned (id, url, title, active flag). This distinguishes it from sibling tools like get_frames or get_page_info.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly states when to use: 'Use it to find a tab_id when the implicit target (last navigated tab, else the active one) is not the tab you mean.' Also guides the include_windows option for moving/tiling and determining monitor placement, giving practical context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
handle_dialogsAIdempotent
Auto-accept/dismiss future JS dialogs (alert/confirm/prompt), logging them. reset restores native dialogs and returns the log.
| Name | Required | Description | Default |
|---|---|---|---|
| action | No | accept/dismiss auto-answer future dialogs; reset restores native behaviour | accept |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| prompt_text | No | Returned by window.prompt on accept |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations provide idempotentHint=true, and the description adds logging behavior and the reset functionality. It discloses that dialogs are auto-handled and logged, but does not detail the log format or potential side effects like interference with user interaction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two sentences, concise, and front-loaded with the primary action. Every sentence adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple tool with clear schema and annotations, the description and schema together fully explain the tool's capabilities. The log return is mentioned, and optional parameters are covered.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
All three parameters have descriptions in the schema (100% coverage), so the description adds minimal extra value beyond what the schema already provides. The description mentions logging and reset but not parameter-specific details.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly specifies the tool auto-accepts or dismisses future JS dialogs (alert/confirm/prompt) and logging them, with a reset option. It uniquely identifies the resource and action among sibling tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for dialog handling but does not explicitly state when to use this tool vs alternatives or when not to use it. No context on prerequisites or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
highlight_elementsAIdempotent
Outline every element matching a selector with a coloured overlay, to see on a screenshot what a selector actually caught. Each call clears the overlays left by the previous one instead of stacking them, and remove=true clears without adding. The overlays are injected DOM nodes: a reload or a navigation drops them, and they sit above the page without altering its layout or its own styles.
| Name | Required | Description | Default |
|---|---|---|---|
| color | No | Any CSS color for the overlay label | rgba(255,0,0,0.3) |
| label | No | Show tag.class (WxH) label | |
| border | No | CSS border shorthand, e.g. "2px solid red" | 2px solid red |
| remove | No | Remove previously injected highlights instead of adding | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| selector | No | CSS selector; ">>>" pierces shadow DOM. Every match is outlined |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations, the description adds crucial behavioral details: overlays are injected DOM nodes, reload/navigation drops them, and they sit above the page without altering layout or styles. This enriches the agent's understanding of side effects and persistence, fully leveraging the annotation context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is concise (3 sentences) and front-loads the core purpose in the first sentence. Each subsequent sentence adds valuable behavioral context without redundancy. Minor improvement would be reordering to place usage context earlier, but overall very effective.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema and 6 parameters, the description covers the main behavior, clearing mechanism, and lack of permanence. It does not explain return values, but for a visual feedback tool, this is acceptable. Slightly more context on what happens after highlighting (e.g., can it be removed via remove=true) is already included.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema has 100% coverage with descriptions for all 6 parameters. The tool description does not add new parameter details beyond summarizing the overall behavior, which is appropriate. Baseline 3 is correct as the schema already provides sufficient parameter semantics.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool outlines every element matching a selector with a coloured overlay, using a specific verb ('outline') and resource ('elements matching a selector'). It distinguishes itself from sibling tools by focusing on visual highlighting for selector verification, not DOM modification.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains when to use the tool: 'to see on a screenshot what a selector actually caught'. It also clarifies call behavior (clears previous overlays) and the effect of remove=true. However, it does not explicitly state when not to use it or compare with alternatives among siblings, slightly lowering the score.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
hoverAIdempotent
Hover over an element (mouseenter/mouseover), by CSS selector or ref.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | No | From get_interactives | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| selector | No | CSS selector; ">>>" pierces shadow DOM. Triggers CSS and JS hover handlers |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds value beyond annotations by stating that hover triggers CSS and JS hover handlers. Annotations already provide idempotentHint=true and destructiveHint=false, so this context is useful.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Single sentence, front-loaded with the verb and resource, no wasted words. Highly concise.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple hover action with no output schema, the description adequately covers the tool's behavior. It mentions the triggered events, which is sufficient. No major gaps.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already documents parameters. The description adds minor context ('by CSS selector or ref' and events triggered), but not significant beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the action (hover) and the resource (element by CSS selector or ref), and it distinguishes from sibling tools like click and type_text.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No explicit guidance on when to use this tool over alternatives, such as click or type_text. The description does not mention conditions or prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
http_authAIdempotent
Set/clear credentials for HTTP Basic/Digest auth dialogs (browser-wide, in-memory only).
| Name | Required | Description | Default |
|---|---|---|---|
| action | Yes | set installs credentials for HTTP auth prompts; clear removes them | |
| password | No | Required for action=set; kept in memory, never written to disk | |
| username | No | Required for action=set |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations provide basic hints (readOnlyHint=false, destructiveHint=false, idempotentHint=true). The description adds valuable context: credentials are stored in-memory only, browser-wide. This is consistent with annotations and improves understanding beyond them.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single sentence that captures verb, resource, scope, and key constraints. No wasted words, front-loaded with the core action.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema, the description adequately covers purpose, scope, and parameter dependencies. It could mention that credentials apply to all requests (global) or note potential security considerations, but for a simple set/clear tool, it is largely complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with clear descriptions for all three parameters. The description reinforces the action enum and indicates username/password are required for action=set. This adds marginal clarity, but the schema already does the heavy lifting.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the action (set/clear), the resource (credentials for HTTP Basic/Digest auth dialogs), and the scope (browser-wide, in-memory only). It is specific and distinct from sibling tools, which are unrelated to auth.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage context ('for HTTP Basic/Digest auth dialogs'), providing clear context. It does not explicitly mention when not to use or alternatives, but the context is sufficiently narrow given the diverse sibling list.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
http_requestADestructive
HTTP request sent from the browser, so it carries the session cookies of the logged-in user: fetches URLs a plain server-side request would get a login page for (invoices, authenticated JSON, CSV exports). Text bodies are returned inline (capped by max_length); with save_to the bytes are written to that path instead, which is how you read a PDF — Chrome renders PDFs in a viewer no content script can reach, so read_page returns nothing on a PDF tab.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | Absolute URL. Cookies are sent for its origin | |
| body | No | Request body (POST/PUT/PATCH) | |
| method | No | HEAD fetches headers only, without the body | GET |
| headers | No | Extra request headers | |
| save_to | No | Absolute path: write the response bytes here instead of returning them (PDF, images, archives) | |
| max_length | No | Max chars of body returned inline |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate destructiveHint true and readOnlyHint false, but the description adds critical context: the request carries browser cookies, text bodies are capped by max_length, and save_to writes bytes to a path. It explains why read_page fails on PDFs. No contradictions with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single paragraph that front-loads the key feature (carries session cookies) and provides necessary details without redundancy. Every sentence adds value, though it could be slightly more structured for readability.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description addresses authentication and binary content handling effectively, but lacks details on response structure (e.g., status codes, headers) and error behavior. Given the tool's complexity and no output schema, more context on return types and possible failures would improve completeness.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with descriptions for all 6 parameters. The description adds semantic value by explaining how max_length and save_to interact (text vs. binary) and the effect of method HEAD as noted in schema. This goes beyond the schema's attribute descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states the tool makes HTTP requests from the browser, carrying session cookies, which distinguishes it from server-side requests. It explicitly mentions fetching authenticated content like invoices and JSON, and explains the use of save_to for binary files such as PDFs, differentiating from read_page.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description clearly explains that the tool carries session cookies, making it suitable for authenticated content. It provides explicit guidance on using save_to for binary content like PDFs instead of read_page. However, it does not explicitly list when to avoid using this tool or compare with other tools beyond the PDF scenario.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
inject_cssAIdempotent
Inject a CSS rule into the page. Stays until the next navigation or reload, and re-injecting the same id replaces it rather than stacking. Affects only what is rendered — the stylesheet of the site is untouched.
| Name | Required | Description | Default |
|---|---|---|---|
| css | Yes | One or more CSS rules, as they would appear in a stylesheet | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds significant behavioral context beyond annotations: lifetime (until navigation/reload), idempotency (re-inject replaces), and non-destructive nature (stylesheets untouched). Annotations already indicate idempotent=true and destructive=false, but description enriches with concrete details.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three concise, front-loaded sentences with no redundancy. Each sentence adds essential information: purpose, behavioral details, and scope. Excellent efficiency.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity and the presence of detailed parameter schema, the description covers all necessary aspects: what it does, how it behaves (lifetime, idempotency), and its non-destructive nature. No missing essentials.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with adequate descriptions for both parameters. The description does not add new parameter-level information beyond what's in the schema. The mention of 'same id' in the description implies an identifier not present in the parameters, which could cause confusion but does not directly affect parameter semantics.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb 'inject' and the resource 'CSS rule into the page'. It distinguishes this tool from siblings like modify_dom or execute_js by focusing specifically on CSS injection.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains persistence ('stays until next navigation') and idempotency ('re-injecting the same id replaces it'). It also clarifies it only affects rendered content, not the site's stylesheet. However, it does not explicitly state when not to use it or mention alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
list_event_listenersARead-onlyIdempotent
List addEventListener registrations since page load: counts by type + recent entries.
| Name | Required | Description | Default |
|---|---|---|---|
| type | No | e.g. "click" | |
| limit | No | Max listeners returned, from the top of the match list | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds context beyond annotations by specifying 'since page load', which limits the scope. Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, which are consistent. No contradictions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise with no wasted words. It is front-loaded with the verb and resource, then succinctly describes the output structure.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema, the description compensates by indicating the output format (counts by type + recent entries). However, it could elaborate on what constitutes 'recent entries' or any limits. Overall, it is sufficiently complete for a non-complex tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
All three parameters are fully described in the schema (100% coverage). The description does not add significant new meaning beyond what the schema provides, so baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: listing addEventListener registrations since page load, with specifics on output (counts by type and recent entries). This distinguishes it from other sibling tools like query_dom or get_interactives.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for inspecting event listeners, but does not explicitly state when to use this tool versus alternatives, nor does it provide conditions or exclusions. Some guidance would improve clarity.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
manage_downloadsBRead-onlyIdempotent
List downloads, start one, or wait for the newest to finish. Files land in the browser Downloads folder, not on the server. action=download reports the download's real state rather than just an id: with Chrome set to ask where to save each file, saveAs:false is overridden and it comes back as waiting_for_user — every byte fetched, no destination chosen, and nothing will move until someone picks one.
| Name | Required | Description | Default |
|---|---|---|---|
| url | No | What to download (action=download); sent with the session cookies of its origin | |
| limit | No | Max download entries returned, newest first | |
| action | Yes | download fetches with the browser cookie jar and reports the real state; wait_for_complete blocks until the newest finishes | |
| timeout | No | Max ms (wait_for_complete) | |
| filename | No | Relative path inside the Downloads folder (action=download) |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description contradicts the annotations: it says 'start one' (action=download) which has side effects (creates a file in the Downloads folder), while annotations declare readOnlyHint=true, implying no side effects. Although the description richly describes the saveAs behavior, the contradiction is a serious issue.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is three sentences long, front-loaded with the main purpose, and each sentence provides relevant detail. It is concise without being terse, though the technical depth might be slightly heavy for a quick scan.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool has 5 parameters and no output schema. The description explains the trickiest part (download state) but does not describe the return format for list or wait_for_complete, nor does it mention timeout/limit behaviors beyond what the schema already states. This leaves some gaps for an agent to fully understand expected outputs.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema descriptions cover all parameters, but the description adds crucial nuance beyond the schema, particularly for action=download: it explains that it reports the real download state and details the waiting_for_user behavior under saveAs prompts. This adds value beyond the structured field descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states the tool's purpose with specific verbs: 'List downloads, start one, or wait for the newest to finish.' It clearly identifies the resource (downloads) and the three distinct operations, distinguishing it from sibling browser automation tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives context ('Files land in the browser Downloads folder, not on the server') but does not explicitly state when to use this tool over alternatives, nor does it mention any exclusions or alternative tools. The usage context is implied but not fully explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
measure_spacingARead-onlyIdempotent
Measure the gap, overlap and distance in CSS pixels between two elements, with their margins and paddings. Read-only. Values come from the current layout, so zoom and viewport size change them: set_zoom(1) and a fixed viewport_resize make results comparable across runs.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| selector1 | Yes | First element; distances are measured from its box | |
| selector2 | Yes | Second element; ">>>" pierces shadow DOM |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Describes dependency on zoom and viewport, advising use of set_zoom(1) and fixed viewport_resize for consistency. Adds behavioral context beyond readOnlyHint and idempotentHint annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with no wasted words. Front-loaded with purpose, followed by behavioral context. Efficient and well-structured.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Covers purpose, parameters implicitly, and behavioral context. Missing output description (no output schema), but otherwise sufficiently complete for a measurement tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema descriptions already cover parameters (100% coverage). Description adds minor detail about shadow DOM piercing for selector2, but does not significantly enhance meaning beyond schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Clearly specifies the verb 'measure' and the resource 'gap, overlap and distance in CSS pixels between two elements'. Distinguishes from sibling tools like query_dom.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Implies use for layout measurement but lacks explicit guidance on when to use vs alternatives or when not to use. Suggests using set_zoom and viewport_resize for comparability.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
modify_domAIdempotent
Change an element in the live DOM: setAttribute, removeAttribute, addClass, removeClass, setStyle, setTextContent. Nothing is persisted — the next reload restores the page as the server sends it. For styling many elements at once inject_css is one call instead of N.
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Attribute name | |
| value | No | Attribute value, style declaration, or text, per action | |
| action | Yes | setStyle takes a CSS declaration in value; addClass/removeClass take className | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| selector | Yes | CSS selector; ">>>" pierces shadow DOM. Only the first match is changed | |
| className | No | Class to add or remove (addClass/removeClass) |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate idempotent and non-destructive. Description adds transparency that changes are not persisted across reloads and that only the first match is modified. No contradictions with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two concise sentences plus a one-sentence alternative recommendation. No redundant information; every sentence adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the 7 parameters fully described in the schema, no output schema, and annotations providing safety profile, the description adequately covers core functionality and persistence behavior. Could enhance by contrasting with query_dom for read-only access.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with descriptive parameter names and descriptions. The description does not add additional context beyond the schema, so baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool changes an element in the live DOM, enumerates specific actions (setAttribute, removeAttribute, etc.), and contrasts with inject_css for bulk styling. It differentiates itself from sibling tools like inject_css.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly states when to use inject_css instead for many elements, providing clear guidance. Does not explicitly exclude other scenarios, but the contrast is sufficient for most use cases.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
monitor_networkARead-onlyIdempotent
Monitor network requests. source=page: XHR/fetch hook (installed on first call); source=browser: all requests incl. static assets. format=har exports HAR 1.2.
| Name | Required | Description | Default |
|---|---|---|---|
| clear | No | Clear buffer after read | |
| limit | No | Most recent; buffer 1000 | |
| format | No | har exports HAR 1.2 for external tooling | lines |
| source | No | page sees XHR/fetch only; browser also sees static assets | page |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only and idempotent behavior. The description adds valuable context about the source=page hook being 'installed on first call' and that format=har exports HAR 1.2 for external tooling. No contradictions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with key details front-loaded. No redundant phrases or fluff.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Core behavior and all parameters are documented in schema. Description adds source installation detail and har export purpose. Could briefly describe lines/json output format, but overall sufficient for a monitoring tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema covers 100% of parameters with descriptions. The description adds nuance beyond schema: 'source=page: XHR/fetch hook (installed on first call); source=browser: all requests incl. static assets. format=har exports HAR 1.2.' This helps understanding installation behavior and har purpose.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool monitors network requests and distinguishes between two sources (page vs browser) and three formats (lines, json, har). This specificity differentiates it from sibling tools like http_request or network_rules.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains options but does not explicitly state when to use this tool over alternatives like http_request or network_rules. Usage context is implied but no exclusions or guidance is provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
monitor_websocketARead-onlyIdempotent
Monitor WebSocket connections/messages (500-char previews). Hook installs on first call; earlier connections are missed.
| Name | Required | Description | Default |
|---|---|---|---|
| clear | No | Clear buffer after read | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnlyHint, idempotentHint, etc. The description adds critical behavior beyond annotations: the hook installs on first call and earlier connections are missed, plus the 500-char preview limit. This significantly aids the agent in understanding the tool's runtime behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two concise, front-loaded sentences. No unnecessary words. Every sentence adds value: first sentence defines purpose, second explains important behavioral caveat.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity (2 optional params, no output schema), the description is complete. It explains what it monitors, the preview limitation, and the hook installation nuance. No additional information about return values is needed as the tool likely provides streamed data.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with descriptions for both parameters ('clear' and 'tab_id'). The description does not add further parameter semantics beyond the schema, so baseline 3 is appropriate. The schema descriptions are clear and sufficient.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool monitors WebSocket connections and messages with 500-character previews. It uses a specific verb ('Monitor') and resource ('WebSocket connections/messages'), and distinguishes from sibling tools like monitor_network by focusing on WebSocket traffic.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description includes a key usage guideline: 'Hook installs on first call; earlier connections are missed.' This tells the agent to call early to capture all messages. While it doesn't explicitly list when not to use or alternatives, the context of siblings and the guideline provided is sufficient for correct use.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
move_tabAIdempotent
Move an existing tab into another window (chrome.tabs.move). Nothing is created or closed: the tab keeps its id, history and page state, and this works even on chrome-untrusted:// tabs where creating one is forbidden — verified on a ChromeOS Terminal tab. The destination must be a normal window: moving out of an app or popup window is fine, moving into one is refused with "Tabs can only be moved to and from normal windows". So a ChromeOS Terminal session can be pulled out to its own window (new_window, then position it with viewport_resize) but cannot be merged back into the Terminal window — the closest look is window_type popup: no tab strip, no omnibox, visually a terminal window. An extension cannot create app windows: normal and popup are all Chrome offers.
| Name | Required | Description | Default |
|---|---|---|---|
| top | No | New window y (new_window) | |
| left | No | New window x (new_window) | |
| index | No | Position in the destination window; -1 appends at the end | |
| width | No | New window width px (new_window) | |
| height | No | New window height px (new_window) | |
| tab_id | Yes | Tab to move; get it from get_tabs | |
| window_id | No | Destination window; get_tabs reports windowId for every tab | |
| new_window | No | Extract the tab into a fresh window instead — tabs.move needs an existing window, this does not | |
| window_type | No | new_window only: popup has no tab strip and no omnibox — the terminal-window look for detached chrome-untrusted://terminal tabs | normal |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Despite annotations already flagging mutation (readOnly=false) and non-destructiveness, the description goes far beyond by disclosing that the tab keeps its id/history/page state, works on chrome-untrusted:// tabs, and the exact error message for invalid destinations. This is valuable behavioral context not captured in annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is front-loaded with purpose and every sentence adds relevant detail. However, it is a single dense paragraph with somewhat anecdotal content (e.g., 'verified on a ChromeOS Terminal tab') that could be tightened without losing value. Still, it remains purposeful.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (9 params, no output schema), the description thoroughly covers constraints, error conditions, and a real-world use case. The only notable omission is the return value (what the caller gets after a successful move), but this is partially mitigated by the schema's parameter detail and the clear action-oriented nature of the tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the baseline is 3. The description adds meaningful context for new_window ('tabs.move needs an existing window, this does not') and for window_type (the terminal-window look). All other params are already well-described in the schema, so this extra context pushes it above baseline.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The first sentence immediately states the action: 'Move an existing tab into another window (chrome.tabs.move).' This is a specific verb + resource that distinguishes it from tab creation or tab_action siblings. It further clarifies the non-destructive nature and the new_window option, reinforcing purpose.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly states when not to use it: 'moving into [an app or popup window] is refused'. It also provides an alternative within the tool: 'new_window' for extracting a tab, and suggests 'viewport_resize' for positioning. The ChromeOS Terminal example gives concrete usage context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
network_rulesAIdempotent
Network interception, browser-wide, survives reloads until cleared: block requests, redirect URLs, set/remove request headers, or stub responses with a synthetic body (served by a local helper; from HTTPS pages the stub host must be trustworthy).
| Name | Required | Description | Default |
|---|---|---|---|
| body | No | Response body (action=stub) | |
| action | Yes | list and clear inspect and drop the rules already installed | |
| header | No | Header name for action=modify_header, e.g. "User-Agent" | |
| status | No | action=stub | |
| url_filter | No | declarativeNetRequest urlFilter, e.g. "||example.com/api/*" | |
| content_type | No | action=stub | application/json |
| header_value | No | Omit to remove header | |
| redirect_url | No | Destination for action=redirect | |
| header_target | No | response = strip content-security-policy / x-frame-options, inject CORS | request |
| resource_types | No | Limit the rule to these request types; omitted = all of them |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations show idempotent, not read-only, not destructive. The description adds useful behavioral details: rules survive reloads, stub responses use a local helper, and HTTPS pages require a trustworthy stub host. However, the 'list' and 'clear' actions are omitted from the description, creating a minor gap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single, front-loaded sentence that efficiently conveys scope, persistence, and capabilities. Every word contributes value with no redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Covers core interception capabilities but omits actions 'list' and 'clear', the url_filter parameter, and resource_types. The lack of an output schema is not compensated by description. Adequate but not fully comprehensive for a complex tool with 10 parameters.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the baseline is 3. The description summarizes action types but does not add new meaning or detail beyond the schema (e.g., url_filter, resource_types).
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool intercepts network requests browser-wide, survives reloads, and lists specific actions: block, redirect, set/remove headers, stub responses. This distinguishes it from sibling tools like http_request (single request) and monitor_network (monitoring only).
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for persistent network rule manipulation but does not explicitly contrast with alternatives like monitor_network or http_request. No 'use this for' or 'if you need' guidance is provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
press_keyA
Send a key to the focused element (or to selector, focusing it first) as a real keydown/keypress/keyup sequence, so framework handlers fire. For typing a value use type_text; this is for Enter, Tab, Escape, arrows and shortcuts. Not idempotent: two calls send the key twice.
| Name | Required | Description | Default |
|---|---|---|---|
| alt | No | Hold Alt | |
| key | Yes | e.g. "Enter", "Escape", "Tab", "ArrowDown" | |
| ctrl | No | Hold Control | |
| meta | No | Hold Meta (Command/Windows) | |
| shift | No | Hold Shift | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| selector | No | Target (default: activeElement) |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate non-idempotent (idempotentHint=false) and non-destructive. Description adds that it simulates a real key sequence and focuses the element if a selector is provided. Does not contradict annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, each serving a clear purpose: first explains the action and effect, second provides usage guidance and idempotency warning. No redundant words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Covers key aspects: what the tool does, key sequence, focusing behavior, example keys, and idempotency. No output schema, so return values are not needed. Sufficient for an 8-parameter tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema covers all 8 parameters with descriptions (100% coverage). Description only adds context about focusing when a selector is used, which is already implied. Little additional value beyond schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the action ('Send a key to the focused element') and specifies the key sequence (keydown/keypress/keyup). It distinguishes from type_text for typing values and gives examples like Enter, Tab, Escape, arrows, and shortcuts.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly tells when to use (Enter, Tab, Escape, arrows, shortcuts) and when not ('For typing a value use type_text'). Also warns about non-idempotency: 'Not idempotent: two calls send the key twice'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
query_domARead-onlyIdempotent
Query DOM elements by CSS selector, returning structure, attributes, bounding rect, and computed styles.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Max elements returned, from the top of the match list | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| selector | Yes | CSS selector; ">>>" pierces shadow DOM. Matches all, not just the first | |
| properties | No | Computed styles to include, e.g. ["color"] |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate readOnlyHint=true and idempotentHint=true. The description adds value by stating what is returned (structure, attributes, bounding rect, computed styles), and the schema covers the limit and selector details. No contradictions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence that is front-loaded with the action and key details. No unnecessary words; highly concise.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema, the description adequately hints at the return format (structure, attributes, bounding rect, computed styles). It could mention that results are an array or ordered by DOM order, but it is sufficient for an agent.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the baseline is 3. The description does not add extra meaning beyond the schema; it only mentions the selector in the tool description but not the other parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the action (Query DOM elements by CSS selector) and the return data (structure, attributes, bounding rect, computed styles). It is specific and distinguishes from siblings like get_interactives or modify_dom.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description does not provide explicit guidance on when to use this tool versus others. It implies usage for general DOM querying but does not mention alternatives or exclusions. Given many sibling tools, more context would help.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
read_consoleADestructive
Read console messages captured since page load, incl. uncaught errors and unhandled rejections.
| Name | Required | Description | Default |
|---|---|---|---|
| clear | No | Clear buffer after read | |
| level | No | all merges every level in one chronological list | all |
| limit | No | Most recent; buffer 1000 | |
| format | No | lines is compact; json keeps timestamps and stack traces | lines |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate destructiveHint=true, but the description omits the destructive side effect of clearing the buffer via the 'clear' parameter. It does not elaborate on behavioral traits beyond the annotation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, concise 12-word sentence that efficiently communicates the tool's core function without unnecessary detail.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the presence of 5 parameters and no output schema, the description lacks guidance on output format and does not address the destructive nature of the 'clear' parameter. It is adequate but not fully complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so each parameter is already documented. The description adds no extra meaning or context beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb 'Read' and the resource 'console messages captured since page load', specifying the scope and types included. This uniquely identifies the tool among siblings.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides no guidance on when to use this tool versus alternatives like query_dom or get_status. It lacks any when-to-use or when-not-to-use instructions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
read_pageARead-onlyIdempotent
Read the page as text (default), markdown, raw HTML, or accessibility tree. Read-only. markdown keeps headings, links and tables at a fraction of the HTML cost, and is usually the right middle ground. Expensive on large pages: HTML on a big table costs tens of thousands of tokens for data you then filter anyway — prefer extract_table or extract for tabular and repeated content, and get_interactives to find click targets.
| Name | Required | Description | Default |
|---|---|---|---|
| mode | No | text strips markup, markdown keeps headings/links/tables far cheaper than html, accessibility returns the a11y tree | text |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| save_to | No | Absolute path: write the page there and return the path instead of the content | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| max_length | No | Max output chars |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the tool as read-only and idempotent. The description adds valuable behavioral info: cost warning ('expensive on large pages') and practical advice about token usage for HTML, which annotations do not cover.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is slightly long but highly informative and well-structured: first sentence states purpose, then emphasizes read-only, recommends a mode, and warns about cost with alternatives. Front-loaded with key info.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (multiple output modes, cost implications, alternatives), the description covers all essential aspects: what it does, when to use each mode, what to avoid, and how to use parameters like save_to. No output schema exists, but the description implies return of content or path.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema covers 100% of parameters with descriptions. The description adds semantic value by explaining the trade-offs between modes (e.g., markdown being cheaper than HTML) and suggesting default usage, going beyond mere enum listing.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states 'Read the page as text (default), markdown, raw HTML, or accessibility tree' with a specific verb and resource. It distinguishes from siblings by explicitly naming alternatives like extract_table, extract, and get_interactives.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides explicit guidance: recommends markdown as the 'right middle ground', warns against using HTML on large pages, and directs users to other tools for tabular or repeated content and interactive elements.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
save_pageADestructiveIdempotent
Save the full page (DOM, styles, images) as an MHTML archive file on the server filesystem.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| output_path | Yes | Absolute file path to write (e.g. /tmp/page.mhtml) |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate destructiveHint=true and idempotentHint=true. The description adds that the tool writes an MHTML archive to the server filesystem, which elaborates on the destructive nature but does not detail side effects or required permissions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence that conveys all essential information without redundancy or unnecessary details. It is efficiently front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity, the description adequately covers the operation. However, it omits potential edge cases, such as errors from invalid paths or overwrite behavior, which could be important for proper use.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Input schema coverage is 100%, so the schema already describes both parameters. The description adds no extra semantics beyond the schema, such as the meaning of 'last tab navigated' for tab_id. Therefore, it provides minimal added value.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the action (save), the resource (full page), and the output format (MHTML archive file). It distinguishes from sibling tools like screenshot (image capture) and read_page (content extraction) by specifying the archive format and filesystem destination.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides no guidance on when to use this tool versus alternatives, such as when to prefer save_page over screenshot or get_page_info. No context about prerequisites or exclusions is given.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
screenshotARead-onlyIdempotent
Screenshot of the visible viewport only (PNG), at the current scroll position. Read-only. Activates the tab in the background without stealing window focus, then restores the previous tab. Downscaled to ≤1568px, so fine print may not survive.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| save_to | No | Absolute path: write the PNG there and return the path instead of the content |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds behavioral details beyond annotations: it activates tab in background without stealing focus, restores previous tab, and downscales to ≤1568px. Annotations already indicate read-only, idempotent, non-destructive, so no contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise with three short segments, front-loaded with the core purpose. Every sentence adds unique value without redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool is simple with two optional params and no output schema. The description covers purpose, behavioral constraints, and side effects. It could mention the return format explicitly, but overall it is sufficient for correct agent invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
With 100% schema description coverage, the baseline is 3. The description does not add significant meaning beyond the schema's descriptions for tab_id and save_to; it mainly provides context about the output (PNG) and constraints (downscaling) which are not parameter-specific.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly specifies the tool captures a screenshot of the visible viewport as a PNG at the current scroll position. It distinguishes itself from sibling tools like element_screenshot and full_page_screenshot by explicitly stating 'viewport only' and 'current scroll position'.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description tells when to use (viewport screenshot) and mentions behaviors like background tab activation and downscaling. It does not explicitly state when not to use or compare with alternatives, but the context of sibling tools and the specific constraints provide adequate guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
screenshot_diffAIdempotent
Visual regression: save a named baseline (viewport or element), compare later — returns changed-pixel % and red-highlighted diff image. Baselines are in-memory (lost on service worker restart).
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Baseline id: reuse the same one to compare across runs | default |
| action | Yes | baseline stores, compare measures against it, clear drops baselines | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| selector | No | Capture one element (default viewport) | |
| threshold | No | Per-channel tolerance 0-255 |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare idempotentHint=true and destructiveHint=false, but the description adds critical behavior: baselines are in-memory and lost on service worker restart. This goes beyond annotations and helps the agent understand state persistence.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences efficiently convey purpose, return values, and a key caveat (in-memory baselines). No redundant or filler content; every phrase adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a visual regression tool with 5 parameters and no output schema, the description covers purpose, return format (changed-pixel % and diff image), and critical limitations. It is sufficiently complete for an agent to decide when and how to use it.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Input schema covers all 5 parameters with descriptions, and the description enriches them with additional context (e.g., action enum meanings, default tab_id behavior, threshold range). Schema coverage is 100%, so baseline is 3; the extra context justifies 4.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Description clearly states the tool performs visual regression: saving a named baseline and comparing later, returning changed-pixel percentage and a diff image. It distinguishes from sibling tools like 'screenshot' and 'full_page_screenshot' by specifying visual comparison.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for visual regression testing and mentions the ephemeral nature of baselines (lost on service worker restart). However, it lacks explicit when-not-to-use guidance or direct comparisons with alternative tools, so it's clear but not fully prescriptive.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
scrollA
Scroll. action=to: once to element/coordinates; action=until: repeatedly until element visible, network idle, or no new content (infinite scroll).
| Name | Required | Description | Default |
|---|---|---|---|
| x | No | Absolute horizontal position in px (action=to, without selector) | |
| y | No | Absolute vertical position in px (action=to, without selector) | |
| until | No | no_new_content stops when the page height stops growing | no_new_content |
| action | No | to jumps to a position or element; until scrolls repeatedly to load more | to |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| step_px | No | px per step, default viewport height | |
| behavior | No | instant avoids waiting for smooth-scroll animations | auto |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| offset_y | No | px offset for fixed headers (to) | |
| selector | No | Target (to) or stop element (until=element) | |
| settle_ms | No | Pause ms after each step | |
| max_scrolls | No | Cap on scroll steps, so an infinite feed terminates |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds behavioral context beyond annotations by differentiating the two scroll modes and mentioning conditions like 'network idle' and 'infinite scroll.' However, it does not disclose potential side effects such as triggering lazy loading or the impact of parameters like settle_ms and step_px. Annotations are minimal, so the description carries some burden but is not fully transparent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is concise with two sentences, front-loading the key information about the two actions. The redundant 'Scroll.' at the start is minor. It is well-structured for quick reading, though it could be slightly more informative without sacrificing conciseness.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the complexity (12 parameters, no output schema), the description provides a minimal overview of the two main modes but lacks details on how to use parameters like 'selector', 'offset_y', 'step_px', etc. It is enough for basic understanding but incomplete for advanced usage. The schema descriptions help, but the tool description could be more comprehensive.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so parameters are already documented. The description provides a high-level overview of the 'action' and 'until' parameters, but does not add significant meaning to other parameters like 'x', 'y', 'selector', or 'offset_y'. It clarifies the purpose of the two modes, which is useful, but overall adds limited value beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool scrolls the page and defines the two distinct actions ('to' and 'until') with specific behaviors. However, it could be more explicit about the overall function (e.g., 'Scroll the current page') rather than just 'Scroll.' Distinguishes between modes but not from sibling tools, which are mostly unrelated.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains when to use each action: 'to' for one-time scroll to element/coordinates, 'until' for repeated scrolling until a condition. This provides clear context but does not include explicit when-not or alternatives, though none are obviously needed for a scroll tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
security_headersARead-onlyIdempotent
Audit security headers (CSP, HSTS, XCTO, clickjacking, Referrer/Permissions-Policy, version leaks). Captured from real navigations — reload if unavailable.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate read-only, idempotent, open-world behavior. The description adds valuable context: results depend on real navigations and may require reloading. No contradictions with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, front-loaded with header list, no fluff. Each sentence provides necessary information efficiently.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Lacks description of output format or return values. With no output schema, the description could be more complete, though the tool's simplicity and annotations partially compensate.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with a single parameter tab_id described. The description adds no additional meaning to the parameter, staying at baseline for high coverage.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Description clearly states it audits security headers, listing specific ones like CSP, HSTS, XCTO. The verb 'audit' and explicit header names make purpose unambiguous. No sibling tool has overlapping purpose.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No explicit guidance on when to use this tool over alternatives like accessibility_audit or seo_audit. The note 'reload if unavailable' implies a dependency on navigation but does not provide clear when-to-use context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
seo_auditARead-onlyIdempotent
SEO audit: title/description lengths, canonical, robots, h1 count, Open Graph, Twitter card, JSON-LD validity, hreflang, lang, viewport, favicon
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is clear. The description adds value by listing the specific checks performed, which helps the agent understand what the tool examines.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, concise sentence that front-loads the tool's purpose and lists checks. It wastes no words and is easy to parse.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description lists the checks but omits information about the output format, return structure, or how results are presented. Given the absence of an output schema, this lack of detail could hinder the agent's understanding of what the tool returns.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% for the single optional parameter ('tab_id'). The description does not add additional semantic information beyond what the schema already provides.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool performs an SEO audit and lists specific checks (title/description lengths, canonical, etc.). It uses a specific verb ('audit') and resource ('SEO'), and effectively distinguishes from sibling tools like 'accessibility_audit' and 'check_links'.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage when SEO analysis is needed, but does not explicitly specify when to use this tool versus alternatives (e.g., 'web_vitals', 'accessibility_audit'). No 'when not to use' guidance is provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
session_fixtureADestructiveIdempotent
Snapshot localStorage, sessionStorage and cookies of the current origin into a named fixture on the server, restore one, or list what has been saved. A logged-in state is the usual reason. save overwrites a fixture of the same name without asking; restore writes entries on top of what is already there rather than clearing first, and refuses outright when the tab sits on a different origin than the one recorded — cookies would otherwise attach to the wrong site. name is required except for list.
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Required for save/restore | |
| action | Yes | save snapshots the current origin; restore writes it back | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds significant behavioral context beyond annotations: it states that save overwrites without asking, restore writes on top without clearing first, restore refuses on different origin, and name is required except for list. Annotations already indicate destructiveHint=true and idempotentHint=true, but the description clarifies the specifics.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is three sentences, front-loaded with the primary purpose and common use case. Every sentence provides essential information without redundancy. The structure is efficient and easy to parse.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (3 parameters, no output schema, annotations present), the description covers key behaviors, edge cases (different origin), and default behavior for tab_id. However, it does not describe what the list action returns, which might be helpful for an agent.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with descriptions for all 3 parameters. The description adds further meaning: it explains that name is required except for list, and tab_id omitted means the last navigated tab. It also clarifies the action enum values (save/restore/list). Thus it enriches beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's function: snapshotting localStorage, sessionStorage, and cookies into a named server fixture, restoring one, or listing saved fixtures. It specifically mentions 'A logged-in state is the usual reason,' which distinguishes this from sibling tools like get_storage or set_storage that operate directly on browser storage.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides clear context for when to use the tool (for saving/restoring logged-in states). It also details important behaviors like overwriting without asking for save, writing on top for restore, and refusal on different origin. However, it does not explicitly mention when not to use or provide alternatives, though the context makes it apparent.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
session_recordA
Record the commands of this session as a replayable jsonl file (replay with the CLI: chrome-bridge replay --file ). tab_id is stripped — replays target the tab they navigate.
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Required for start | |
| action | Yes | start begins recording, stop writes the file and returns its path |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate the tool is not read-only and not destructive. The description adds that it writes a JSONL file and strips tab_id. It does not disclose potential side effects like file persistence or session state changes beyond recording.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences provide essential information: recording purpose, CLI replay command, and tab_id behavior. Every sentence earns its place with no fluff.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple two-parameter tool with no output schema, the description covers key behaviors. Minor gaps: no details on return from status/list actions or file location.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, with descriptions for both parameters. The tool description does not add meaningful parameter details beyond what the schema already provides.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it records session commands to a replayable JSONL file. It mentions CLI replay and tab_id stripping. However, it does not explicitly differentiate from sibling tools like session_fixture.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for recording sessions and mentions replay behavior, but does not provide explicit guidance on when to use this tool vs alternatives, nor reasons not to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
set_geolocationAIdempotent
Override navigator.geolocation with fixed coordinates (page-level patch). reset restores native.
| Name | Required | Description | Default |
|---|---|---|---|
| reset | No | Restore the real position and stop overriding | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| accuracy | No | Meters | |
| latitude | No | Decimal degrees, -90 to 90 | |
| longitude | No | Decimal degrees, -180 to 180 |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate idempotentHint=true and readOnlyHint=false, which the description does not contradict. The description adds that it is a page-level patch and that reset restores native behavior, but does not elaborate on persistence or scope beyond the page.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is very concise (two sentences) and front-loaded with the main action. It is efficient but could be slightly more structured with separation of setting and resetting.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With 5 parameters and no output schema, the description is adequate but does not explain the interaction between reset and coordinates, or the temporary/durable nature of the override. It lacks guidance for typical testing scenarios.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already documents all parameters. The description adds minimal extra meaning beyond the schema (e.g., 'reset restores native' is implicit in the reset parameter description).
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the action: override navigator.geolocation with fixed coordinates. It also mentions the reset capability. This distinguishes it from sibling tools, as no other tool handles geolocation.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage (setting coordinates for testing), but does not explicitly state when to use this tool versus alternatives, nor does it provide exclusion criteria or prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
set_storageADestructiveIdempotent
Write, delete or clear a localStorage/sessionStorage key, or a cookie with its path, domain and expiry. action=clear wipes every entry of that type for the origin and cannot be undone — on a site the user is logged into, clearing cookies logs them out. Read the current values first with get_storage.
| Name | Required | Description | Default |
|---|---|---|---|
| key | No | Required for set/delete | |
| path | No | Cookie path (default /) | |
| type | Yes | cookie writes a real cookie, not a storage key | |
| value | No | Required for action=set | |
| action | Yes | clear ignores key and wipes every entry of that type | |
| domain | No | Cookie domain | |
| secure | No | Cookie sent over HTTPS only | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| expires | No | UTC date string (cookie) | |
| sameSite | No | None requires secure=true | |
| http_only | No | Cookie hidden from page JS |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations (destructiveHint=true, idempotentHint=true), the description adds that clearing cookies logs the user out and cannot be undone, giving critical behavioral context for agent decision-making.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two concise sentences with front-loaded core functionality and a critical warning. No wasted words; every sentence adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given 11 parameters with full schema coverage and no output schema, the description covers the main behavior, destructive consequences, and prerequisite (read first). Could mention error conditions or parameter interactions, but sufficient for selection.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
With 100% schema coverage, baseline is 3. The description adds meaning by explaining action=clear wipes all entries of that type and that reading first is advisable, which goes beyond schema descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool writes, deletes, or clears localStorage, sessionStorage, or cookies. It specifies the action, storage type, and parameters like path, domain, and expiry, making it distinct from siblings like get_storage.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description advises reading current values first with get_storage, providing clear context for safe usage. It does not explicitly list when not to use, but the destructive hint and warning about logout imply caution.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
set_zoomAIdempotent
Get or set tab zoom (0.25–5). No factor = read current; reset restores default.
| Name | Required | Description | Default |
|---|---|---|---|
| reset | No | Restore the default zoom for this origin | |
| factor | No | 1 = 100% | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations (idempotentHint=true), the description adds the duality of read/write behavior, the allowed zoom range, and the effect of reset. No contradictions with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, well-structured sentence that front-loads the primary purpose and then details additional behaviors. No unnecessary words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple tool with no output schema, the description covers all parameter behaviors, return modes (read vs set), and the reset option. It is fully self-contained.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
With 100% schema coverage, the description adds extra context: 'No factor = read current' for the factor parameter, and '1 = 100%' clarifies its meaning. The tab_id explanation about default behavior is also included.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's dual purpose (get or set zoom) and specifies the zoom range (0.25–5). It distinguishes itself from siblings by being the only zoom-related tool among many unrelated ones.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains how to use the tool: omit factor to read current zoom, provide factor to set, and use reset to restore default. This provides clear guidance on different usage modes.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
tab_actionADestructive
Tab lifecycle: close, activate (focus), reload (optional cache bypass), back, forward. close discards the tab and anything unsaved in it, and cannot be undone — it may be a tab the user is working in. reload and navigation drop injected CSS, emulations and page hooks. duplicate works where create_tab is forbidden (chrome-untrusted://, verified on a ChromeOS Terminal tab) and lands in the source tab's own window, app windows included — the only way to open a new Terminal session inside the Terminal window. discard replaces the tab id: the result carries the new one, saved ids go stale.
| Name | Required | Description | Default |
|---|---|---|---|
| action | Yes | close cannot be undone; discard frees memory, the tab reloads on focus; reload drops injected CSS and hooks | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| bypass_cache | No | reload only |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description goes well beyond the annotations by detailing that close discards unsaved content and cannot be undone, that reload/navigation drop injected CSS, emulations, and page hooks, and that duplicate has special restrictions (works on chrome-untrusted://, lands in source window). It also discloses that discard replaces the tab id, making saved ids stale. These are substantive behavioral traits not captured by the readOnlyHint/destructiveHint annotations, and there is no contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is front-loaded with a succinct summary of actions, and each sentence conveys unique operational details. The long sentence about duplicate is dense but contains critical, tool-specific facts. It is appropriately sized for a multi-action tool, though it could be slightly tightened without losing value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (9 enum actions, multi-action behavior), the description does a good job covering destructive consequences (close), side effects (reload), edge cases (duplicate), and id-staleness (discard). However, it entirely omits the mute/unmute actions and does not explain back/forward history semantics or return values for other actions, leaving some gaps for an agent relying solely on this description.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema already provides 100% coverage for all three parameters, including enum descriptions for actions and notes on bypass_cache and tab_id. The description adds meaningful extra context not in the schema, such as bypass_cache being 'optional cache bypass,' duplicate's environment restrictions, and discard's id replacement. This elevates it above the baseline 3.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description begins with 'Tab lifecycle' and enumerates specific operations (close, activate, reload, back, forward), making the general purpose clear. It distinguishes duplicate from the sibling create_tab by noting it works where create_tab is forbidden. However, it omits the mute and unmute actions that appear in the enum, and does not contrast back/forward with the navigate sibling, so the full scope is somewhat incomplete.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides explicit guidance for duplicate as an alternative to create_tab and warns that close is irreversible and may affect a tab the user is working in. It also explains side effects of reload/navigation that should inform when to use this tool. It does not, however, offer explicit when-not-to-use guidance for back/forward versus navigate, or for activate/reload in all contexts.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
tile_windowsAIdempotent
Tile Chrome windows over one monitor, splitting its usable area into equal parts that leave no gap. Only Chrome windows: an extension cannot touch other applications. The monitor is chosen by pointing at a window already on it, since the work area is read from a page there — so at least one target window needs a scriptable tab (a chrome:// or chrome-untrusted:// tab cannot provide it). Maximized windows are restored first, because a maximized window accepts bounds and ignores them.
| Name | Required | Description | Default |
|---|---|---|---|
| area | No | Monitor area to fill, when no target window has a scriptable tab to read it from | |
| layout | No | columns splits left to right, rows top to bottom, grid keeps tiles as square as it can | grid |
| padding | No | Px of empty margin kept inside the work area | |
| window_ids | No | Windows to tile; omitted = every normal window on the reference monitor | |
| include_types | No | Window types to include; omitted = normal only | |
| reference_window_id | No | Window whose monitor is used; omitted = the focused one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds behavioral details beyond annotations: maximized windows are restored first because they ignore bounds, and the monitor selection mechanism depends on reading a page from a window. It also explains the limitation of scriptable tabs. This complements the annotations (idempotentHint=true, destructiveHint=false) without contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is three sentences, with the core purpose first, then constraints in the following sentences. No redundant words; every sentence adds information about scope, prerequisites, or edge cases.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (6 parameters, nested area object), the description covers the key behavioral aspects: scope, monitor selection, scriptable tab requirement, and maximized window handling. The schema covers parameter details. It lacks return value info, but no output schema exists and the tool likely returns nothing meaningful. Overall it's sufficient.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
All parameters are documented in the schema with descriptions (100% coverage), so the description doesn't need to repeat them. It does add context that 'area' is used when no target window has a scriptable tab, which relates to the schema description. The baseline of 3 is appropriate since the description adds marginal value beyond schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's function: 'Tile Chrome windows over one monitor, splitting its usable area into equal parts that leave no gap.' It specifies the resource (Chrome windows) and the action (tiling over a monitor), and distinguishes from siblings by noting the extension limitation.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives explicit usage guidance: it only works on Chrome windows ('Only Chrome windows: an extension cannot touch other applications'), and it explains the prerequisite that at least one target window needs a scriptable tab. It also clarifies when to use the 'area' parameter indirectly. No explicit alternative tool is named, but the scope is well-defined.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
type_textAIdempotent
Put text into an input, textarea or contenteditable, by CSS selector or by a ref from get_interactives. Replaces the whole value rather than appending, and assigns through the native setter so React and Vue controlled inputs register the change, then fires input and change. mode=keys instead emits keydown/input/keyup per character, which is what autocomplete and masked fields need — slower, so reach for it only when mode=set leaves the field empty or the dropdown never opens.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | No | From get_interactives, e.g. "n3" | |
| mode | No | set = assign value; keys = per-char events (autocomplete/masked) | set |
| text | Yes | Value to type; empty string clears the field | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| selector | No | CSS selector; ">>>" pierces shadow DOM. Ignored when ref is given | |
| wait_after | No | Settle before returning: navigation waits for a page load, networkidle for quiet traffic | none |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Discloses behavioral traits beyond annotations: replaces whole value, uses native setter so frameworks register changes, fires input/change events, and details key event emission for keys mode. No contradiction with annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=true).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Four sentences, front-loaded with core purpose, then specifics about mode behavior and usage. No filler; every sentence earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given 7 parameters, 2 enums, and no output schema, the description covers key behavioral nuances (mode behavior, event firing). Missing some edge cases like priority of ref over selector (partially in schema) but adequate for selection.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, but description adds value by explaining when to use each mode (set vs keys), notes that selector is ignored if ref given, and clarifies shadow DOM piercing with '>>>'. This supplements schema descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb 'Put text' and the resources 'input, textarea or contenteditable', and specifies two methods: CSS selector or ref from get_interactives. It distinguishes from sibling tools like click and hover by focusing on text input, and the mode detail adds specificity.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly explains when to use 'mode=keys' (for autocomplete/masked fields) vs 'mode=set' (default), including a performance trade-off. However, it does not mention alternatives like fill_form for multiple fields, which would improve guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
unused_cssARead-onlyIdempotent
List CSS selectors matching nothing in the current DOM (approximate; cross-origin sheets unreadable).
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| max_selectors | No | Cap on unused selectors reported: a large stylesheet has thousands |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only and idempotent behavior. The description adds value by disclosing the approximation and the limitation of cross-origin sheets being unreadable, which is helpful for the agent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence that is front-loaded and contains no unnecessary words, earning its place efficiently.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the simple tool with full schema coverage and no output schema, the description covers purpose and limitations. However, it could mention the output format (list of selectors) to be fully complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the baseline is 3. The description does not add any extra meaning about the parameters beyond what the schema provides via their descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb 'List' and the specific resource 'CSS selectors matching nothing in the current DOM', and distinguishes it from siblings like 'query_dom' and 'inject_css' by focusing on unused selectors.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies use for detecting unused CSS rules but does not provide explicit when-to-use or when-not-to-use guidance, nor does it mention alternatives despite many sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
upload_fileA
Set a file on input[type=file] from the server filesystem via DataTransfer (max 10MB).
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes | Absolute path on the server machine | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| selector | Yes | The file input to fill; ">>>" pierces shadow DOM | |
| mime_type | No | Default: inferred from extension |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations are mostly false, so description carries burden. It discloses the DataTransfer mechanism and a 10MB limit, but omits behavior on size exceedance, path errors, or whether it clears existing files. Adequate but not rich.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
One concise sentence with no wasted words. Front-loaded with the action and key details.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema and 4 params fully described in schema, the description adds the 10MB limit and mechanism. Missing error behavior or return value, but complete enough for a straightforward file upload tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema covers 100% of parameters with descriptions. The description adds only the 10MB limit, which is not per-parameter. Baseline 3 achieved; no additional meaning beyond schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool uploads a file from the server filesystem to an input[type=file] via DataTransfer, with a 10MB limit. This is specific and distinct from sibling tools like fill_form or type_text.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for file inputs but does not explicitly state when to use vs alternatives or any exclusions. No 'when not to use' or alternatives mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
viewport_resizeAIdempotent
Resize the Chrome window to a preset (mobile 375x812, tablet 768x1024, desktop 1440x900) or to explicit dimensions. The rendered viewport ends up smaller than what you ask for, by the height of the browser chrome — measure it with execute_js if the exact number matters. width and height each override the corresponding half of the preset, so preset plus width gives a custom width at the preset height. A maximized window on ChromeOS ignores the request.
| Name | Required | Description | Default |
|---|---|---|---|
| top | No | Window y on the virtual desktop | |
| left | No | Window x on the virtual desktop; on multi-monitor this is what picks the screen | |
| state | No | Applied before bounds: a maximized window accepts left/top/width/height and ignores them | |
| width | No | Overrides preset | |
| action | No | get reports the current viewport without resizing anything | set |
| height | No | Overrides preset | |
| preset | No | 375x812, 768x1024, 1440x900 | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses important non-obvious behavior: the rendered viewport is smaller than requested by the browser chrome height, and a maximized window on ChromeOS ignores the request. It also explains the override semantics for width/height. With annotations already declaring idempotentHint and non-destructive, the description adds valuable context beyond the structured fields.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three sentences, each with a purpose: main functionality, viewport nuance, and override semantics plus a platform caveat. Front-loaded with the action, no filler words. Efficient and well-structured.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For an 8-parameter tool with no output schema, the description covers the core behavior, edge cases (browser chrome, ChromeOS maximized), and parameter relationships. Combined with the fully-described schema, it provides enough context for an agent to use the tool correctly. It omits action=get details, but those are in the schema.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema already provides descriptions for all 8 parameters (100% coverage), so the baseline is 3. The description adds meaning by explaining the relationship between presets and overrides ('preset plus width gives a custom width at the preset height') and the viewport vs window distinction, which affects how to interpret width/height. However, it doesn't elaborate on top/left/tab_id, which rely on schema descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description opens with a specific verb+resource: 'Resize the Chrome **window** to a preset ... or to explicit dimensions.' It clearly distinguishes from sibling tools like set_zoom (zoom) and window_layout/tile_windows (window arrangement) by focusing on window size. It also clarifies the window-vs-viewport distinction, which is central to the tool's name.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear context: presets are listed, width/height override preset, and it warns about the ChromeOS maximized window behavior. It mentions using execute_js to measure the exact viewport, which is a cross-reference to a sibling tool. However, it doesn't explicitly state when to prefer this over alternatives or provide exclusion criteria, so it's clear but not explicit about alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
wait_forARead-onlyIdempotent
Block until a condition holds: element (selector in the DOM), function (JS expression turns truthy; needs the "Allow user scripts" toggle), navigation (mode=spa for client-side route changes), network_idle. Polls until timeout — 10s for element and function, 15s for navigation and network_idle — then returns found: false with a reason instead of raising, so a caller that ignores the result silently proceeds as if the wait had succeeded. Read-only: waiting changes nothing on the page.
| Name | Required | Description | Default |
|---|---|---|---|
| mode | No | spa = pushState/popstate/hashchange | load |
| text | No | Literal text to wait for (condition=text), matched case-insensitively | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| idle_ms | No | Quiet period ms (network_idle) | |
| timeout | No | Max ms (default 10000; 15000 navigation/network_idle) | |
| visible | No | Element must also be visible | |
| frame_id | No | Target iframe id from get_frames; omitted = main frame | |
| interval | No | Poll ms, min 50 | |
| selector | No | condition=element; with condition=text it narrows the search to that subtree | |
| condition | Yes | element and text need selector or text; function needs expression | |
| expression | No | JS expression (condition=function) |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations mark it read-only, idempotent, non-destructive. The description reinforces this with 'Read-only: waiting changes nothing on the page' and details the non-raising timeout behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is concise and front-loaded with the main purpose, but the later sentence about timeout behavior could be more structured. Still, every sentence adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the complexity (11 params, condition types), the description covers the key behavioral aspects (timeout, read-only, non-raising). No output schema, but return value is hinted.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the description adds marginal value. It provides context for condition types, default timeouts, and the 'Allow user scripts' toggle, but does not detail all 11 parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description specifies the tool blocks until a condition holds, listing four distinct condition types (element, function, navigation, network_idle). It clearly distinguishes from siblings by focusing on waiting behavior.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains when to use each condition type and what happens on timeout (returns found: false). It lacks explicit when-not-to-use guidance but the context is clear enough.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
watch_domARead-onlyIdempotent
Watch DOM mutations (MutationObserver). First call installs the watcher; later calls read accumulated mutations.
| Name | Required | Description | Default |
|---|---|---|---|
| stop | No | Disconnect observer | |
| clear | No | Clear buffer after read | |
| limit | No | Most recent mutations; buffer 1000 | |
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one | |
| subtree | No | Observe descendants too, not just the matched node | |
| selector | No | Subtree to observe; ">>>" pierces shadow DOM | body |
| childList | No | Report added and removed children | |
| attributes | No | Report attribute changes | |
| characterData | No | Report text content changes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds stateful behavior (install watcher on first call) which contradicts the 'idempotentHint: true' annotation. While it discloses more about usage pattern than annotations alone, the contradiction reduces reliability. Missing details on side effects like buffer limits or callback behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise with two sentences covering the core functionality and phase behavior. No redundant words; essential information is front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
While parameter details are fully covered by the schema, the description lacks information about return format, how mutations are structured, and the lifecycle of the watcher. For a tool with 9 parameters, more behavioral context (e.g., how to stop/clear) would improve completeness.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the description adds no additional meaning beyond the schema. Each parameter's purpose is already clear from the schema, so no extra value from the tool description.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool watches DOM mutations via MutationObserver and explains the two-phase behavior (install then read). It distinguishes itself from siblings like 'query_dom' or 'modify_dom' by specifying the observation pattern.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies the tool is for tracking DOM changes over time but does not explicitly state when to use it versus alternatives like 'get_interactives' or 'execute_js'. No exclusions or prerequisite conditions are provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
web_vitalsARead-onlyIdempotent
Core Web Vitals accumulated since the current document loaded: CLS, LCP, FCP, TTFB, long tasks and an INP approximation. Read-only. Needs the page instrumentation active from before load, so it reports whether it was hooked instead of silently returning zeros — navigate() installs it. Covers user-perceived stability and responsiveness after load, not the load timings themselves.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | Target tab; omitted = last tab navigated in this session, else the active one |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations (readOnlyHint, idempotentHint, destructiveHint), the description adds critical behavioral context: requiring pre-load instrumentation, reporting hook status instead of returning zeros if not installed, and scoping to user-perceived stability after load. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is concise at 4 sentences, front-loading the key metrics in the first sentence, then covering prerequisites and scope. Every sentence adds unique value without redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool has one optional parameter, no output schema, and comprehensive annotations, the description sufficiently covers what the tool returns, its prerequisites, and what it does not cover. No gaps are apparent.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The single parameter tab_id is fully described in the schema (100% coverage), and the description adds no additional meaning beyond what the schema provides. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states that it retrieves Core Web Vitals (CLS, LCP, FCP, TTFB, long tasks, INP approximation) accumulated since document load. It distinguishes itself by noting it covers user-perceived stability and responsiveness after load, not load timings, differentiating from siblings like get_performance.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains the prerequisite that page instrumentation must be active from before load (installed via navigate()), and that it reports whether it was hooked. It clarifies the scope (post-load) and implicitly suggests other tools for load timings, but does not explicitly name alternative tools for when not to use this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
window_layoutADestructiveIdempotent
Save the current window arrangement under a name, restore one, list or delete saved ones. save overwrites a same-named layout without asking. Window ids do not survive a browser restart, so restore recognises windows by the overlap of their tab URLs (same type required) and repositions the best match — windows it cannot recognise are reported, not guessed. Needs extension >= 1.14.0 for window geometry.
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Layout name, required except for list | |
| action | Yes | save snapshots every window; restore repositions the recognised ones |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds substantial behavioral context beyond the annotations: save overwrites without asking, restore uses URL-overlap matching because window IDs don't survive restarts, and unrecognized windows are reported rather than guessed. This fully discloses the tool's quirks and limitations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is compact and front-loaded with the core actions. Every sentence provides value: overwrite behavior, recognition logic, and the version requirement—no filler or redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Despite lacking an output schema, the description covers the essential behaviors and edge cases: overwriting, window ID instability, matching strategy, and version dependency. This is sufficient for an agent to invoke the tool correctly across all actions.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the baseline is 3, but the description adds meaningful semantics: name is required except for list, and action descriptions like 'save snapshots every window' clarify the effect. This goes beyond the simple enum descriptions in the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool saves, restores, lists, or deletes named window arrangements, distinguishing it from sibling tools like tile_windows or move_tab. The verb+resource structure is explicit and specific.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Usage context is implied by the action enum and the description's narrative, but there's no explicit guidance on when to use this tool versus alternatives, nor any exclusions or alternative recommendations. The version requirement is a partial prerequisite note but not a full usage guideline.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections. Dates show when Glama detected each change.
8 tool updates
v1.15.0- Changed
create_tab5 fields changed- added
Input schema / properties / heightAdded value: +{ + "description": "Window height px (new_window)", + "type": "number" +} - added
Input schema / properties / leftAdded value: +{ + "description": "Window x on the virtual desktop (new_window)", + "type": "number" +} - added
Input schema / properties / new_windowAdded value: +{ + "default": false, + "description": "Open in a fresh window instead of a tab; with left/top it lands on the chosen monitor", + "type": "boolean" +} - added
Input schema / properties / topAdded value: +{ + "description": "Window y (new_window)", + "type": "number" +} - added
Input schema / properties / widthAdded value: +{ + "description": "Window width px (new_window)", + "type": "number" +}
- Changed
get_tabs1 field changed- added
Input schema / properties / include_windowsAdded value: +{ + "default": false, + "description": "Also return the windows with bounds, state, type and tab count", + "type": "boolean" +}
- Changed
manage_downloads4 fields changed- changed
Input schema / properties / action / descriptionPrevious value: -"wait_for_complete blocks until the newest download finishes or times out"New value: +"download fetches with the browser cookie jar and reports the real state; wait_for_complete blocks until the newest finishes" - changed
Input schema / properties / action / enumPrevious value: -[ - "list", - "wait_for_complete" -]New value: +[ + "list", + "wait_for_complete", + "download" +] - added
Input schema / properties / filenameAdded value: +{ + "description": "Relative path inside the Downloads folder (action=download)", + "type": "string" +} - added
Input schema / properties / urlAdded value: +{ + "description": "What to download (action=download); sent with the session cookies of its origin", + "type": "string" +}
- Changed
move_tab7 fields changed- added
Input schema / properties / heightAdded value: +{ + "description": "New window height px (new_window)", + "type": "number" +} - added
Input schema / properties / leftAdded value: +{ + "description": "New window x (new_window)", + "type": "number" +} - added
Input schema / properties / new_windowAdded value: +{ + "default": false, + "description": "Extract the tab into a fresh window instead — tabs.move needs an existing window, this does not", + "type": "boolean" +} - added
Input schema / properties / topAdded value: +{ + "description": "New window y (new_window)", + "type": "number" +} - added
Input schema / properties / widthAdded value: +{ + "description": "New window width px (new_window)", + "type": "number" +} - added
Input schema / properties / window_typeAdded value: +{ + "default": "normal", + "description": "new_window only: popup has no tab strip and no omnibox — the terminal-window look for detached chrome-untrusted://terminal tabs", + "enum": [ + "normal", + "popup" + ], + "type": "string" +} - changed
Input schema / requiredPrevious value: -[ - "tab_id", - "window_id" -]New value: +[ + "tab_id" +]
- Changed
tab_action2 fields changed- changed
Input schema / properties / action / descriptionPrevious value: -"close cannot be undone; reload drops injected CSS and page hooks"New value: +"close cannot be undone; discard frees memory, the tab reloads on focus; reload drops injected CSS and hooks" - changed
Input schema / properties / action / enumPrevious value: -[ - "close", - "activate", - "reload", - "back", - "forward" -]New value: +[ + "close", + "activate", + "reload", + "back", + "forward", + "discard", + "mute", + "unmute", + "duplicate" +]
- Added
tile_windows - Changed
viewport_resize3 fields changed- added
Input schema / properties / leftAdded value: +{ + "description": "Window x on the virtual desktop; on multi-monitor this is what picks the screen", + "type": "number" +} - added
Input schema / properties / stateAdded value: +{ + "description": "Applied before bounds: a maximized window accepts left/top/width/height and ignores them", + "enum": [ + "normal", + "maximized", + "fullscreen", + "minimized" + ], + "type": "string" +} - added
Input schema / properties / topAdded value: +{ + "description": "Window y on the virtual desktop", + "type": "number" +}
- Added
window_layout
1 tool update
v1.12.0- Added
move_tab
6 tool updates
v1.11.0- Changed
click2 fields changed- added
Input schema / properties / buttonAdded value: +{ + "default": "left", + "description": "right opens the page context menu instead of activating the element", + "enum": [ + "left", + "right" + ], + "type": "string" +} - added
Input schema / properties / countAdded value: +{ + "default": 1, + "description": "2 emits dblclick after the two clicks, which is what selects a word or opens an editor", + "type": "number" +}
- Changed
extract1 field changed- added
Input schema / properties / save_toAdded value: +{ + "description": "Absolute path: write the records as JSON there and return the path instead of the content", + "type": "string" +}
- Changed
read_page3 fields changed- changed
Input schema / properties / mode / descriptionPrevious value: -"text strips markup, html keeps it (costly), accessibility returns the a11y tree"New value: +"text strips markup, markdown keeps headings/links/tables far cheaper than html, accessibility returns the a11y tree" - changed
Input schema / properties / mode / enumPrevious value: -[ - "text", - "html", - "accessibility" -]New value: +[ + "text", + "markdown", + "html", + "accessibility" +] - added
Input schema / properties / save_toAdded value: +{ + "description": "Absolute path: write the page there and return the path instead of the content", + "type": "string" +}
- Changed
screenshot1 field changed- added
Input schema / properties / save_toAdded value: +{ + "description": "Absolute path: write the PNG there and return the path instead of the content", + "type": "string" +}
- Changed
viewport_resize1 field changed- added
Input schema / properties / actionAdded value: +{ + "default": "set", + "description": "get reports the current viewport without resizing anything", + "enum": [ + "set", + "get" + ], + "type": "string" +}
- Changed
wait_for4 fields changed- changed
Input schema / properties / condition / descriptionPrevious value: -"function needs expression; element needs selector"New value: +"element and text need selector or text; function needs expression" - changed
Input schema / properties / condition / enumPrevious value: -[ - "element", - "function", - "navigation", - "network_idle" -]New value: +[ + "element", + "text", + "function", + "navigation", + "network_idle" +] - changed
Input schema / properties / selector / descriptionPrevious value: -"condition=element"New value: +"condition=element; with condition=text it narrows the search to that subtree" - added
Input schema / properties / textAdded value: +{ + "description": "Literal text to wait for (condition=text), matched case-insensitively", + "type": "string" +}
58 tool updates
v1.10.0- Changed
accessibility_audit2 fields changed- added
Input schema / properties / checks / descriptionAdded value: +"Subset to run; fewer checks means a shorter answer" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
assert4 fields changed- added
Input schema / properties / selector / descriptionAdded value: +"Element the assertion is about; \">>>\" pierces shadow DOM" - added
Input schema / properties / state / descriptionAdded value: +"attached means present in the DOM, visible also requires a rendered box" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / timeout / descriptionAdded value: +"Max ms to wait for the condition before failing"
- Changed
check_links5 fields changed- added
Input schema / properties / format / descriptionAdded value: +"lines is compact; json keeps per-link status and timing" - added
Input schema / properties / max_links / descriptionAdded value: +"Cap on links fetched: each one is a real HTTP request" - added
Input schema / properties / scope / descriptionAdded value: +"same-origin skips third-party links, which are the slow ones" - added
Input schema / properties / selector / descriptionAdded value: +"CSS selector; \">>>\" pierces shadow DOM. Restricts which links are collected" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
click4 fields changed- added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / selector / descriptionAdded value: +"CSS selector; \">>>\" pierces shadow DOM. Ignored when ref is given" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / wait_after / descriptionAdded value: +"Settle before returning: navigation waits for a page load, networkidle for quiet traffic"
- Changed
clipboard2 fields changed- added
Input schema / properties / action / descriptionAdded value: +"write takes text; read returns the current clipboard contents" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
create_tab1 field changed- added
Input schema / properties / active / descriptionAdded value: +"false opens the tab in the background, leaving the current one focused"
- Changed
dismiss_overlays1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
drag_and_drop5 fields changed- added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / mode / descriptionAdded value: +"Which event family to emit, since libraries listen to different ones" - added
Input schema / properties / source_selector / descriptionAdded value: +"Element to drag; \">>>\" pierces shadow DOM" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / target_selector / descriptionAdded value: +"Drop target; \">>>\" pierces shadow DOM"
- Changed
element_screenshot2 fields changed- added
Input schema / properties / selector / descriptionAdded value: +"CSS selector; \">>>\" pierces shadow DOM. The element is scrolled into view first" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
emulate_media4 fields changed- added
Input schema / properties / colorScheme / descriptionAdded value: +"Value reported to prefers-color-scheme queries" - added
Input schema / properties / printMode / descriptionAdded value: +"Make print media queries match, without opening a print dialog" - added
Input schema / properties / reducedMotion / descriptionAdded value: +"Value reported to prefers-reduced-motion queries" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
execute_js3 fields changed- added
Input schema / properties / code / descriptionAdded value: +"JS evaluated in the page; the value of the last expression is returned" - added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
extract3 fields changed- added
Input schema / properties / format / descriptionAdded value: +"lines is compact; json keeps one object per record" - added
Input schema / properties / max_items / descriptionAdded value: +"Cap on records returned, in document order" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
extract_table4 fields changed- added
Input schema / properties / index / descriptionAdded value: +"Which table to take when the selector matches several, 0-based" - added
Input schema / properties / selector / descriptionAdded value: +"The table to read; \">>>\" pierces shadow DOM" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - changed
Input schema / properties / where / descriptionPrevious value: -"Keep only rows where each {column: substring} matches (case-insensitive contains). Use key \"any\" (or when the table has no headers) to match against any cell."New value: +"{column: substring} rows must match, case-insensitive contains. Key \"any\" matches any cell."
- Changed
fill_form3 fields changed- added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / wait_after / descriptionAdded value: +"Settle before returning: navigation waits for a page load, networkidle for quiet traffic"
- Changed
find_text4 fields changed- added
Input schema / properties / case_sensitive / descriptionAdded value: +"Match case exactly" - added
Input schema / properties / max_results / descriptionAdded value: +"Cap on matches returned, in document order" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / text / descriptionAdded value: +"Literal text to find, not a regex"
- Changed
full_page_screenshot2 fields changed- added
Input schema / properties / max_scrolls / descriptionAdded value: +"Cap on scroll steps: a taller page is captured only up to here" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
get_frames1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
get_interactives5 fields changed- added
Input schema / properties / format / descriptionAdded value: +"lines is compact; json adds full attributes per element" - added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / limit / descriptionAdded value: +"Max elements returned; raise it on a dense page" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / visible_only / descriptionAdded value: +"false also lists elements hidden or scrolled out of view"
- Changed
get_page_info2 fields changed- added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
get_performance1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
get_storage2 fields changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / type / descriptionAdded value: +"all returns the three together"
- Changed
handle_dialogs2 fields changed- added
Input schema / properties / action / descriptionAdded value: +"accept/dismiss auto-answer future dialogs; reset restores native behaviour" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
highlight_elements5 fields changed- added
Input schema / properties / border / descriptionAdded value: +"CSS border shorthand, e.g. \"2px solid red\"" - added
Input schema / properties / color / descriptionAdded value: +"Any CSS color for the overlay label" - added
Input schema / properties / remove / descriptionAdded value: +"Remove previously injected highlights instead of adding" - added
Input schema / properties / selector / descriptionAdded value: +"CSS selector; \">>>\" pierces shadow DOM. Every match is outlined" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
hover3 fields changed- added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / selector / descriptionAdded value: +"CSS selector; \">>>\" pierces shadow DOM. Triggers CSS and JS hover handlers" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
http_auth3 fields changed- added
Input schema / properties / action / descriptionAdded value: +"set installs credentials for HTTP auth prompts; clear removes them" - added
Input schema / properties / password / descriptionAdded value: +"Required for action=set; kept in memory, never written to disk" - added
Input schema / properties / username / descriptionAdded value: +"Required for action=set"
- Changed
http_request1 field changed- added
Input schema / properties / method / descriptionAdded value: +"HEAD fetches headers only, without the body"
- Changed
inject_css2 fields changed- added
Input schema / properties / css / descriptionAdded value: +"One or more CSS rules, as they would appear in a stylesheet" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
list_event_listeners2 fields changed- added
Input schema / properties / limit / descriptionAdded value: +"Max listeners returned, from the top of the match list" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
manage_downloads2 fields changed- added
Input schema / properties / action / descriptionAdded value: +"wait_for_complete blocks until the newest download finishes or times out" - added
Input schema / properties / limit / descriptionAdded value: +"Max download entries returned, newest first"
- Changed
measure_spacing3 fields changed- added
Input schema / properties / selector1 / descriptionAdded value: +"First element; distances are measured from its box" - added
Input schema / properties / selector2 / descriptionAdded value: +"Second element; \">>>\" pierces shadow DOM" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
modify_dom6 fields changed- added
Input schema / properties / action / descriptionAdded value: +"setStyle takes a CSS declaration in value; addClass/removeClass take className" - added
Input schema / properties / className / descriptionAdded value: +"Class to add or remove (addClass/removeClass)" - added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / selector / descriptionAdded value: +"CSS selector; \">>>\" pierces shadow DOM. Only the first match is changed" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / value / descriptionAdded value: +"Attribute value, style declaration, or text, per action"
- Changed
monitor_network3 fields changed- added
Input schema / properties / format / descriptionAdded value: +"har exports HAR 1.2 for external tooling" - added
Input schema / properties / source / descriptionAdded value: +"page sees XHR/fetch only; browser also sees static assets" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
monitor_websocket1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
navigate2 fields changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / url / descriptionAdded value: +"Absolute URL, or a path resolved against the current page"
- Changed
network_rules4 fields changed- added
Input schema / properties / action / descriptionAdded value: +"list and clear inspect and drop the rules already installed" - added
Input schema / properties / header / descriptionAdded value: +"Header name for action=modify_header, e.g. \"User-Agent\"" - added
Input schema / properties / redirect_url / descriptionAdded value: +"Destination for action=redirect" - added
Input schema / properties / resource_types / descriptionAdded value: +"Limit the rule to these request types; omitted = all of them"
- Changed
press_key6 fields changed- added
Input schema / properties / alt / descriptionAdded value: +"Hold Alt" - added
Input schema / properties / ctrl / descriptionAdded value: +"Hold Control" - added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / meta / descriptionAdded value: +"Hold Meta (Command/Windows)" - added
Input schema / properties / shift / descriptionAdded value: +"Hold Shift" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
query_dom4 fields changed- added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / limit / descriptionAdded value: +"Max elements returned, from the top of the match list" - added
Input schema / properties / selector / descriptionAdded value: +"CSS selector; \">>>\" pierces shadow DOM. Matches all, not just the first" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
read_console3 fields changed- added
Input schema / properties / format / descriptionAdded value: +"lines is compact; json keeps timestamps and stack traces" - added
Input schema / properties / level / descriptionAdded value: +"all merges every level in one chronological list" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
read_page3 fields changed- added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / mode / descriptionAdded value: +"text strips markup, html keeps it (costly), accessibility returns the a11y tree" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
save_page1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
screenshot1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
screenshot_diff3 fields changed- added
Input schema / properties / action / descriptionAdded value: +"baseline stores, compare measures against it, clear drops baselines" - added
Input schema / properties / name / descriptionAdded value: +"Baseline id: reuse the same one to compare across runs" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
scroll8 fields changed- added
Input schema / properties / action / descriptionAdded value: +"to jumps to a position or element; until scrolls repeatedly to load more" - added
Input schema / properties / behavior / descriptionAdded value: +"instant avoids waiting for smooth-scroll animations" - changed
Input schema / properties / frame_id / descriptionPrevious value: -"action=to only"New value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / max_scrolls / descriptionAdded value: +"Cap on scroll steps, so an infinite feed terminates" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / until / descriptionAdded value: +"no_new_content stops when the page height stops growing" - added
Input schema / properties / x / descriptionAdded value: +"Absolute horizontal position in px (action=to, without selector)" - added
Input schema / properties / y / descriptionAdded value: +"Absolute vertical position in px (action=to, without selector)"
- Changed
security_headers1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
seo_audit1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
session_fixture2 fields changed- added
Input schema / properties / action / descriptionAdded value: +"save snapshots the current origin; restore writes it back" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
session_record1 field changed- added
Input schema / properties / action / descriptionAdded value: +"start begins recording, stop writes the file and returns its path"
- Changed
set_geolocation4 fields changed- added
Input schema / properties / latitude / descriptionAdded value: +"Decimal degrees, -90 to 90" - added
Input schema / properties / longitude / descriptionAdded value: +"Decimal degrees, -180 to 180" - added
Input schema / properties / reset / descriptionAdded value: +"Restore the real position and stop overriding" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
set_storage7 fields changed- added
Input schema / properties / action / descriptionAdded value: +"clear ignores key and wipes every entry of that type" - added
Input schema / properties / http_only / descriptionAdded value: +"Cookie hidden from page JS" - added
Input schema / properties / sameSite / descriptionAdded value: +"None requires secure=true" - added
Input schema / properties / secure / descriptionAdded value: +"Cookie sent over HTTPS only" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / type / descriptionAdded value: +"cookie writes a real cookie, not a storage key" - added
Input schema / properties / value / descriptionAdded value: +"Required for action=set"
- Changed
set_zoom2 fields changed- added
Input schema / properties / reset / descriptionAdded value: +"Restore the default zoom for this origin" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
tab_action2 fields changed- added
Input schema / properties / action / descriptionAdded value: +"close cannot be undone; reload drops injected CSS and page hooks" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
type_text5 fields changed- added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / selector / descriptionAdded value: +"CSS selector; \">>>\" pierces shadow DOM. Ignored when ref is given" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one" - added
Input schema / properties / text / descriptionAdded value: +"Value to type; empty string clears the field" - added
Input schema / properties / wait_after / descriptionAdded value: +"Settle before returning: navigation waits for a page load, networkidle for quiet traffic"
- Changed
unused_css2 fields changed- added
Input schema / properties / max_selectors / descriptionAdded value: +"Cap on unused selectors reported: a large stylesheet has thousands" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
upload_file2 fields changed- added
Input schema / properties / selector / descriptionAdded value: +"The file input to fill; \">>>\" pierces shadow DOM" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
viewport_resize1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
wait_for3 fields changed- added
Input schema / properties / condition / descriptionAdded value: +"function needs expression; element needs selector" - added
Input schema / properties / frame_id / descriptionAdded value: +"Target iframe id from get_frames; omitted = main frame" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
watch_dom6 fields changed- added
Input schema / properties / attributes / descriptionAdded value: +"Report attribute changes" - added
Input schema / properties / characterData / descriptionAdded value: +"Report text content changes" - added
Input schema / properties / childList / descriptionAdded value: +"Report added and removed children" - added
Input schema / properties / selector / descriptionAdded value: +"Subtree to observe; \">>>\" pierces shadow DOM" - added
Input schema / properties / subtree / descriptionAdded value: +"Observe descendants too, not just the matched node" - added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
- Changed
web_vitals1 field changed- added
Input schema / properties / tab_id / descriptionAdded value: +"Target tab; omitted = last tab navigated in this session, else the active one"
2 tool updates
v1.9.0- Changed
emulate_media1 field changed- added
Input schema / properties / user_agentAdded value: +{ + "description": "Overrides navigator.userAgent and appVersion in the page (not the HTTP header)", + "type": "string" +}
- Added
http_request
59 tool updates
v1.8.0- First observed
accessibility_audit - First observed
assert - First observed
check_links - First observed
click - First observed
clipboard - First observed
create_tab - First observed
dismiss_overlays - First observed
drag_and_drop - First observed
element_screenshot - First observed
emulate_media - First observed
execute_js - First observed
extract - First observed
extract_table - First observed
fill_form - First observed
find_text - First observed
full_page_screenshot - First observed
get_frames - First observed
get_interactives - First observed
get_page_info - First observed
get_performance - First observed
get_status - First observed
get_storage - First observed
get_tabs - First observed
handle_dialogs - First observed
highlight_elements - First observed
hover - First observed
http_auth - First observed
inject_css - First observed
list_event_listeners - First observed
manage_downloads - First observed
measure_spacing - First observed
modify_dom - First observed
monitor_network - First observed
monitor_websocket - First observed
navigate - First observed
network_rules - First observed
press_key - First observed
query_dom - First observed
read_console - First observed
read_page - First observed
save_page - First observed
screenshot - First observed
screenshot_diff - First observed
scroll - First observed
security_headers - First observed
seo_audit - First observed
session_fixture - First observed
session_record - First observed
set_geolocation - First observed
set_storage - First observed
set_zoom - First observed
tab_action - First observed
type_text - First observed
unused_css - First observed
upload_file - First observed
viewport_resize - First observed
wait_for - First observed
watch_dom - First observed
web_vitals
TDQS
Most tools have clearly distinct purposes, but some overlap exists (e.g., multiple screenshot and page-reading tools). Descriptions help differentiate, but agents may occasionally select the wrong tool for a task.
Tool names generally follow a verb_noun pattern (e.g., get_status, click), but exceptions like tab_action, viewport_resize, full_page_screenshot, and screenshot_diff break consistency. Conventions are mixed but still readable.
60 tools is excessive for a single MCP server. Many tools (e.g., accessibility_audit, unused_css) are niche and could be separated. The large surface area may overwhelm an agent.
The tool set comprehensively covers browser automation: navigation, interaction, DOM, storage, network, screenshots, performance, accessibility, SEO, and more. No major gaps are apparent for the stated purpose.
Maintenance
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