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Playwright MCP на Render

Разверните Playwright MCP на Render в один клик. Получите размещённый сервер MCP с headless-Chromium, которым ваши ИИ-инструменты могут управлять по HTTP — без локальной установки браузера и без npx на каждой машине.

Deploy to Render

https://github.com/user-attachments/assets/0f31c279-f2e0-431f-a854-560677bd800c5

Что он делает

Playwright MCP — это сервер Model Context Protocotol, который позволяет LLM открывать настоящий браузер, переходить по страницам, кликать, вводить текст и читать страницы через структурированные accessibility-снимки (не скриншоты). Обычно он запускается локально через npx @playwright/mcp. Этот шаблон вместо этого запускает его как единый веб-сервис Render, таk что любой MCP-клиент может подключаться к общему HTTP -URL.

Это тонкая обёртка над официальным образом mcr.microsoft.com/playwright/mcp (headless Chromium уже встроен) — без измений исходного кода. Обёртка добавляет флаги, которые нужны Render (--headless, --no-sandbox, плюс --port и --allowed-hosts из окружения) and небolш گуз с beaer-токеном перед сервером, потом у that Prote. У Playwright MCP нет Auth Authentcation.

Аутентификация по умолчанию. Playwright MCP не имеет встроенной аутентификацией в HTTP -режиме and предоставляет инстумент, эквеваленt RCE, поэтому этот шаблон не публикует его прямой. Запросы обязаны содержать Authorization: Bearer $MCP_TOKEN; Render генерирует этот токен for you in deploy.

For full list of инстументов, options config файлав и настройки клиентов см. upstream Readme.

Related MCP server: Playwright MCP

Архитектура

Оdin веб-сервис Render заускает официальный обрас PlayWright MCP за шлузом с beaer-токеном. MCP-клиент говорит по Streamable HTTP с /mcp на TLS-еrmинирующем еdge Render; шлю3 проверяet токен and переeжет запрос к MCP-серуver on loopback, котorый правит headless Chromium in the same container and return accessability snapshot.

┌─────────────┐   HTTPS /mcp    ┌────────────────────────────────────────────────┐
│  MCP client │ ──────────────► │ Render web service  (Docker, standard plan)    │
│ (Claude,    │  + Bearer       │                                                │
│  Cursor, …) │    token        │  render-entrypoint.sh                          │
│             │                 │    │ reads PORT, allowed hosts                 │
│             │  Streamable     │    ▼                                           │
│             │ ◄────────────── │  render-auth-proxy.mjs   :$PORT  (public)      │
└─────────────┘   snapshots     │    │ 401 unless the Bearer token matches       │
                                │    ▼                                           │
                                │  node /app/cli.js  127.0.0.1:8931  (loopback)  │
                                │    │                                           │
                                │    ▼                                           │
                                │  headless Chromium  (baked into base image)    │
                                └────────────────────────────────────────────────┘

Из чего соstavlenа «дедploy а»:

Fайл

Роль

render.yaml

Blueprint. Описивает единstvenный Docker-веб-сервис, его план/регион, перменную orкужения PORT и сгенер ensuring MCP_TOKEN. Именно его читает правая Deploy.

Dockerfile.render

Тонкая обёртка над mcr.microsoft.com/playwright/mcp (headless CHrom um already baked in). Adds only entry-int and auth gate — no browser loading and no source.

render-entrypoint.sh

Read PORT, вычесляет значение allowed-hosts, then launches exec the auth gate with a MCP-server bound to loopback.

render-auth-proxy.mjs

Pid 1. He has only Net.js with standard library, no dependencies: reject any request without Authorization: Bearer $MCP_TOKEN, с-ограничивает reattempts подбоora, and remaining прохоживае на 127.0.0.1:8931, supervises the MCP-server, держить публичный порт закрытымым поka серurvн doesn't accept соъединения, and forwards SIGTERM.

render-auth-limiter.mjs

Лимит скорости шка, removed separately because this is the only piece with a state that is worth testing in isolation: a fixed window with a maximum number of failed auth,counted across all clients. Importted by proxy так that Dockerfile must keep it too.

render-smoke-test.sh

Собирает обрат и проверяет обёртку end to end: без MCP_TOKEN отказается, без of header — 401, after repeated unfortunate headers — 429, correct handshake and настоящий like a browser tool with a correct token, чистый SIGTERM. CI kick it off at every pull request.

[.env.example](./. env.example)

Документируест те же параметры для local run of the container.

Ключевые своййства:

  • **Тонкая обёртка, не форк. The version of the MCP is fixed in skripDockerfile; update of thист on одне строка tag (см. Обновление Playсros MCP).

  • Нет базы даных, ничего.** to fill in. Единственный секret MCP_TOKEN creates Render in the deploy time. Браузер preserve Upstream's default permanent profile, так that logins are preserved through haа requests for в "life of the instance — sufficiently for "сервера", only perceive him, и именно that this suppose "темплайт" (см. Configuration).

  • Auth and fail-to-lock. The gate is added by this template, not earlier. If MCP TOKEN unset container does not started, поэтому no such config, при котором server accessible anonymous (см. Security).

Preconditions

Для deployment are needed:

  • Аккаунт Render, registration is free; service and уer works on платном типа instanses standard (see [Run «Deploy»(#deploy)).

  • GitHub-аккаунт to сделать fork of repository (кнопка Deploy читает render.yaml из repository, owned by you).

Никаки API keeys or strangers. Only one secret, MCP_TOKEN, you generated during deployment — you need only copy it to your MCP-client (см. Запурить).

Also run locally (optional — ** см. Run local):

  • Docker with buildkit (Docker Desptop 4.x+, or Doker Engine 23+). Dockerfile.render uses # yakti directive and COPY --chmod, both are Buildicket features.

  • MCP-client that can туренте прино, е.g. Claude Code, Cersor) or just curl.

You do not required Node.js, Playwright, or local Chromium — базовый обраs includes it all.

Deploy

  1. Нажмите Deploy to Renndre выше and vice versus in naск.

  2. Render preposes render.yaml and provisioned edin **Docker-web service (playwright-mcp) on standard plan.

  3. Pодите, until deploy no live. Ваш сервисях по адресу https://<your-service>.onrender.com/mcp.

  4. Cкопируйте MCP_TOKEN со one page Environment in Dashboard — Render generated for it. Ваш MCP client must send it as Authorization: Bearer <token> (см. Испольова. Пользования ion); without no every query get 401.

  5. Read Securекть before sent what-либо sensing at в neго. Tокен is единственный barring между internet and the code execution in this contein—apply as password — and outside secure в меру.

**Javerage hopping. Headless chromium OOOMs on placed with free/staterTariff (512 МВ), because this is what Blueprint means — standard (2 GB). Set the size only after you sure in your workload often footprint.

Using приложения

Van их

**Pприложение из launch. "Notable any MCP client on /mcp endpoint вашего service, sending MCP_TOKEN as a bearer token. Например, in Claude Code:

claude mcp add --transport http playwright https://<your-service>.onrender.com/mcp \
  --header "Authorization: Bearer <your-MCP_TOKEN>"

...

Else can записать him my enable "client config:

{
  "mcpServers": {
    "playwright": {
      "url": "https://<your-service>.onrender.com/mcp",
      "headers": {
        "Authorization": "Bearer <your-MCP_TOKEN>"
      }
    }
  }
}

**Starting at 401, then on a МCP клиенте — missing headers or token does not match the current value in Dashboard.

**Then ask you to the assistant to see sites from: *"Open example.com and tell me the title of the page and the heading of the main во ходный heading"` He will call your server computer MCP tools and return result.

Unlock недодимо run

**Lockal

** Вопnote, no do it not. If you need to change render-entrypoint.sh and see the effect before push.

git clone https://github.com/render-examples/playwright-mcp-render.git
cd playwright-mcp-render
cp .env.example .env          # then set MCP_TOKEN, e.g. to `openssl rand -hex 32`
docker build -f Dockerfile.render -t playwright-mcp-render .
docker run --rm --env-file .env -p 10000:10000 playwright-mcp-render

Когда гоументов, container prints upstream's own oracle Listening on …, and decrease for first line [аuth] Bearer-token gate listening … — в exactly this order: the "node" between —the public port closed until the server behind it has accept conesso. A [starter] line above outputit with an https:// URL — this scheme for the deployed server; local, use hart//.) Check server with MCP-handshake — Запомine the token from the .env, then the header below will resolve:

curl -sS -X POST http://localhost:10000/mcp \
  -H "Authorization: Bearer $MCP_TOKEN" \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"curl","version":"1"}}}'

Вы should receive serverInfo — block with name Playwright; Remove Authorization header — and get 401. Direct client to http://localhost:10000/mcp — the same as to deployed URL.

MCP_TOKEN is the only variable which you need to specify — container immediately stopped without it. The rest .env — RENDER_DETERAL_HOSTNAME is absent outside Render, so the entrypoint already** additionally falls over PORT=10000 and stored **--allowed-hosts *.

**Ppreta skip Docker run the continuously? The upstream server running the same: npx @playwright/mcp@lastest --port 10000 — note this resolves to best that npm published in this snapshot, not the image tag fixed snapshot, and there in it no auth gate (this is snap appendix). That path does not the same at Render, that why you need to check modifications in container before «закрутив».

Configuring

All is set in render.yaml; .env.example dкомент the same options for local running.

Переменная

По умолчанию

На academе "задала"

PORT

``10000`

Порт, for which the authproxy is binding; Render routes to it.

MCP_TOKEN

генер.

**Обязателен. Bearer-token, which each query must have. The container without no will not be started. Rotate: измените значения (или нажмите Generate again) in Dashboardt and update it in clients.

UPSTREAM_PORT

10000

Loopback-port, on which the MCP after server is listening. requires TemporaryIf is conflicting deliver the container.

Произвите, но что-то помешато переводу. Пожалуйста, повторите запрос.

Available Tools

23 tools
browser_clickB
Destructive

Perform click on a web page

NameRequiredDescriptionDefault
buttonNoButton to click, defaults to left
targetYesExact target element reference from the page snapshot, or a unique element selector
elementNoHuman-readable element description used to obtain permission to interact with the element
modifiersNoModifier keys to press
doubleClickNoWhether to perform a double click instead of a single click

TDQS

B3.2/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false and destructiveHint=true, indicating the tool mutates state and can be destructive. The description adds no further behavioral disclosure, such as possible navigation or permission requirements. It does not contradict annotations, but provides no value 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.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence with no filler. However, it is terse and omits useful context that could be added without bloat, such as the requirement for a snapshot target. It is appropriately sized but not front-loaded with any distinguishing information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity (5 parameters, no output schema), the description alone is minimally sufficient because the schema fully describes parameters. However, it lacks context about return values, when to use click vs other actions, and potential side effects. The schema covers parameter semantics, so a score of 3 is appropriate.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with every parameter documented (e.g., target is 'Exact target element reference from the page snapshot, or a unique element selector'). The description itself adds no additional parameter meaning, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Perform click') and the resource ('web page'), which is specific enough. However, it does not differentiate from sibling interaction tools like browser_hover or browser_drag; the agent must infer that 'click' is a distinct action without additional context. It is unambiguous about the core operation but lacks detail on the target element requirement.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

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. It does not mention prerequisites such as needing a page snapshot to obtain a valid target, nor does it contrast with browser_hover or browser_drag. An agent receives no context for tool selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_closeB
Destructive

Close the page

NameRequiredDescriptionDefault

No parameters

TDQS

B3.3/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotation already indicates destructiveHint=true, so the agent knows the action is destructive. The description simply repeats that by saying 'close' without adding any extra context about side effects (e.g., whether it closes just the current tab, loses unsaved state, or affects other tabs). It does not contradict the annotation, but it adds no new behavioral information.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise, using only three words. It communicates the essential action and target without any fluff, making it easy to parse and understand quickly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simplicity of the tool (no parameters, no output schema), the description is functional but lacks completeness. It leaves open the scope of 'close'—does it close the current page/tab, or the entire browser? In a context with sibling tools like browser_tabs, this ambiguity could be problematic. More detail would improve it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There are no parameters, so the schema coverage is trivially complete at 100%. The description does not need to explain any parameter semantics, and the baseline score of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Close the page' clearly states the action (close) and the resource (page), making it unambiguous. It is distinct from sibling tools like browser_navigate or browser_snapshot, so an agent can easily identify it.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

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. It does not mention potential alternatives (e.g., using browser_tabs to manage multiple pages) or any conditions that would make closing appropriate. The context is minimal and leaves the decision entirely to the agent.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_console_messagesB
Read-only

Returns all console messages

NameRequiredDescriptionDefault
allNoReturn all console messages since the beginning of the session, not just since the last navigation. Defaults to false.
levelYesLevel of the console messages to return. Each level includes the messages of more severe levels. Defaults to "info".info
filenameNoFilename to save the console messages to. If not provided, messages are returned as text.

TDQS

B3.3/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate readOnlyHint true and destructiveHint false, so the description adds no conflicting side-effect information. It does not elaborate on behavior such as saving to a file, but that is covered by parameter descriptions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single clear sentence with no redundancy, front-loading the verb and object.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only tool with full schema coverage, the description is adequate, though it omits explicit use-case guidance and output format details beyond what the schema provides.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with detailed parameter descriptions, so the tool description itself does not add meaning beyond the schema, but no parameter meaning is missing.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description uses a specific verb 'Returns' and identifies the resource 'console messages' with scope 'all', making the tool's purpose clear and distinct from sibling tools such as network request retrieval.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives like browser_network_requests or browser_snapshot, nor does it mention filtering or filename-saving scenarios.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_dragA
Destructive

Perform drag and drop between two elements

NameRequiredDescriptionDefault
endTargetYesExact target element reference from the page snapshot, or a unique element selector
endElementNoHuman-readable target element description used to obtain the permission to interact with the element
startTargetYesExact target element reference from the page snapshot, or a unique element selector
startElementNoHuman-readable source element description used to obtain the permission to interact with the element

TDQS

A3.6/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate destructiveHint=true and readOnlyHint=false, so the destructive nature is covered. The description adds no extra behavioral context such as side effects on the DOM or event firing, but it does not contradict the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence that front-loads the action and provides the core information without any irrelevant detail.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple action with well-described parameters and no output schema, the description is mostly complete. It does not mention any return values or wait behavior, but the lack of output schema makes this acceptable. It could have added a note about the order of start and end parameters, but the parameter names and descriptions handle that.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% with all four parameters described. The tool description adds no additional parameter semantics beyond what the schema already provides, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action (perform drag and drop) and the resource (between two elements), distinguishing it from sibling tools like browser_click, browser_hover, and browser_drop. It is specific and unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description does not provide any guidance on when to use this tool versus alternatives. It does not mention conditions such as needing to move an element or triggering drag-and-drop events, nor does it reference sibling tools like browser_drop or browser_click.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_dropA
Destructive

Drop files or MIME-typed data onto an element, as if dragged from outside the page. At least one of "paths" or "data" must be provided.

NameRequiredDescriptionDefault
dataNoData to drop, as a map of MIME type to string value (e.g. {"text/plain": "hello", "text/uri-list": "https://example.com"}).
pathsNoAbsolute paths to files to drop onto the element.
targetYesExact target element reference from the page snapshot, or a unique element selector
elementNoHuman-readable element description used to obtain permission to interact with the element

TDQS

A4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already convey destructive and non-read-only behavior, so the description does not need to repeat that. The description adds useful semantic context about simulating an external drag, but does not disclose any side effects beyond the basic drop action.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, focused sentence that concisely explains both the action and the key parameter requirement. No filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description, combined with the detailed schema and annotations, provides enough information to invoke the tool correctly. There is no output schema, so return-value details are not required, and the parameter permission explanation is handled by the 'element' field description.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

All parameters have clear schema descriptions. The tool description adds an important cross-parameter constraint that at least one of 'paths' or 'data' must be provided, which is not otherwise expressed in the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action: dropping files or MIME-typed data onto an element. It uses a specific verb and resource, and distinguishes itself from in-page drag operations by specifying 'as if dragged from outside the page'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives a useful usage constraint ('At least one of paths or data must be provided') and hints at external drag context, but it does not explicitly name sibling tools or state when to prefer this over browser_file_upload or browser_drag.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_evaluateB
Destructive

Evaluate JavaScript expression on page or element

NameRequiredDescriptionDefault
targetNoExact target element reference from the page snapshot, or a unique element selector
elementNoHuman-readable element description used to obtain permission to interact with the element
filenameNoFilename to save the result to. If not provided, result is returned as text.
functionYes() => { /* code */ } or (element) => { /* code */ } when element is provided

TDQS

B3.2/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already flag destructiveHint=true and readOnlyHint=false, so the agent knows this can modify state. The description adds minimal context beyond that—it mentions 'on page or element' but doesn't warn about the power of arbitrary JS execution or potential side effects. Since the annotation covers the destructive nature, the description's lack of extra detail keeps it at a baseline 3.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single, clear sentence with no redundant words. The action is front-loaded and easy to parse. This is appropriately concise for a tool whose parameter details are already in the schema.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given that this tool executes arbitrary JavaScript with destructive potential, the description is too sparse. It doesn't mention that the function can modify the page, that results can be saved to a file (though schema covers it), or that there is a separate unsafe variant (browser_run_code_unsafe) that might be more appropriate for certain tasks. The description lacks the context an agent needs to safely and correctly use this tool, especially when annotations already warn about destructiveness but the description provides no additional guidance.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all four parameters are documented in the schema itself. The description does not add any meaning beyond what the schema provides—it doesn't elaborate on the function syntax, target usage, or filename behavior. With high schema coverage, the baseline is 3, and the description contributes nothing extra.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'Evaluate' and the resource 'JavaScript expression on page or element', making the core purpose obvious. However, it doesn't distinguish from the sibling browser_run_code_unsafe, which might also execute code, so it loses a point for not differentiating between similar tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus alternatives like browser_run_code_unsafe or when to avoid it. No context about prerequisites (e.g., page must be loaded) or scenarios that favor this tool over others. The description simply states the action without any usage direction.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_file_uploadB
Destructive

Upload one or multiple files

NameRequiredDescriptionDefault
pathsNoThe absolute paths to the files to upload. Can be single file or multiple files. If omitted, file chooser is cancelled.

TDQS

B3.4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already indicate destructive behavior and non-read-only semantics, so the description does not need to restate those. However, the description does not mention side effects beyond uploading, such as navigating away, opening or cancelling a file chooser, or potential overwrite behavior, though the parameter description partially covers the cancellation case.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise and free of filler. Every word contributes meaning, and the parameter description adds necessary details without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter tool with no output schema, the description and parameter comment cover the essential input and basic behavior. However, it does not describe what happens after the upload, what success or failure looks like, or how this fits into the broader browser automation workflow, leaving some practical context missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema only defines an array of strings, but the parameter description adds important meaning: paths must be absolute, multiple files are allowed, and omitting the parameter cancels the file chooser. This goes beyond the raw schema and helps an agent use the parameter correctly.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Upload') and the resource ('files'), and specifies 'one or multiple'. It does not explicitly state the destination or context, but the tool name and sibling set make the browser file-upload intent sufficiently clear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to use this tool versus alternatives such as browser_drop or other browser interaction tools. It also does not mention prerequisites like whether the file chooser must already be open or how paths should be formatted beyond 'absolute'.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_fill_formB
Destructive

Fill multiple form fields

NameRequiredDescriptionDefault
fieldsYesFields to fill in

TDQS

B3.2/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare readOnlyHint=false and destructiveHint=true, so the write and potentially destructive nature is covered. The description adds the 'multiple form fields' detail but does not disclose additional behavior such as overwriting values or submitting the form.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single clear sentence with no redundant words or boilerplate. It is appropriately short and easy to parse, though it sacrifices deeper context for brevity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The rich schema fully documents the nested field objects, including target references, type-specific value behavior, and permission-related element descriptions. Combined with the read-only and destructive annotations, the description is sufficient for correct invocation; only alternative-selection guidance is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%: the fields array and its nested target, name, type, value, and element properties all have descriptive text. The description itself does not add parameter-level meaning beyond what the schema already provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Fill multiple form fields' clearly identifies the action and resource, and the word 'multiple' helps distinguish it from single-field tools like browser_type. It does not explicitly contrast with sibling tools, but the core purpose is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided for when to use this tool instead of alternatives such as browser_type, browser_select_option, or browser_click. The term 'multiple' implies batch usage, but there is no explicit when-to-use or exclusion context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_handle_dialogC
Destructive

Handle a dialog

NameRequiredDescriptionDefault
acceptYesWhether to accept the dialog.
promptTextNoThe text of the prompt in case of a prompt dialog.

TDQS

C2.2/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations indicate readOnlyHint=false and destructiveHint=true, covering the main safety aspect. However, the description adds no detail about side effects, such as submitting a form or canceling a prompt, beyond what the parameter names imply. It does not clearly disclose the consequences of accepting or rejecting.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness2/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely short and lacks necessary detail, making it under-specified. It is terse but not informative enough to guide an agent effectively, similar to a placeholder like 'Process'.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema or additional context is provided. The description does not explain what happens after handling the dialog, how the parameters interact, or any post-conditions. This is insufficient for an agent to fully understand the tool's behavior.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with clear descriptions for both 'accept' (boolean) and 'promptText' (string for prompt dialogs). The description does not add extra meaning, but the schema already provides adequate parameter semantics, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose3/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Handle a dialog' identifies the action and resource but is vague. It does not specify the type of dialog (alert, confirm, prompt) or the precise effect, though the 'accept' parameter implies accept/dismiss. It is distinct from sibling tools, but the purpose is under-specified.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines1/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided about when to use this tool, such as after a dialog appears or in contrast to other browser actions. The description gives no context for the appropriate situation.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_hoverA
Destructive

Hover over element on page

NameRequiredDescriptionDefault
targetYesExact target element reference from the page snapshot, or a unique element selector
elementNoHuman-readable element description used to obtain permission to interact with the element

TDQS

A3.6/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate readOnlyHint=false and destructiveHint=true, so the description doesn't need to re-state them. The description adds no extra behavioral detail about side effects (e.g., triggering JavaScript events, potential menu changes). With annotations present, the bar is lower, but there's still room for more transparency about outcomes.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise—six words, no redundancy, and perfectly focused on the action. It follows a clear verb-object structure with no extra fluff, making it easy to parse and understand.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple interaction tool, the description, alongside the parameter schema and annotations, is adequate. It lacks details on return values (but no output schema exists) and does not mention any prerequisites or setup. Given the simplicity, it covers essential context without being overlong.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Both parameters (target and element) have descriptions in the schema, achieving 100% coverage. The tool description does not add further meaning beyond the schema; it simply restates the action. Since schema coverage is complete, a baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

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 target (element on page). It distinguishes itself from sibling tools like click, drag, and type by specifying the hover action. However, it lacks detail about what the hover does (e.g., showing tooltips or hover menus), but the core purpose is clear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no explicit guidance on when to use hover versus other interactions. While it's intuitive that hover is for mouse-over actions, the description doesn't mention edge cases or alternative tools (e.g., use click for activating, hover for previews). It provides minimal implicit usage context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_navigateC
Destructive

Navigate to a URL

NameRequiredDescriptionDefault
urlYesThe URL to navigate to

TDQS

C2.7/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description does not elaborate on side effects such as discarding the current page, waiting for load, or handling errors. While annotations indicate destructiveHint=true, the description adds no extra context about the navigation behavior beyond the literal action.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, direct sentence with no unnecessary words. It is appropriately sized for the simple action, though it could benefit from some additional context without becoming verbose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description lacks important context such as whether navigation waits for page load, how errors are reported, or the impact on the current browsing session. Given the tool modifies state (as indicated by destructiveHint), more context about the navigation behavior would be expected.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema fully describes the only parameter 'url' with the same text as the description. Since schema coverage is 100%, the description adds no additional meaning or constraints (e.g., format, absolute vs. relative) beyond what is already in the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action 'Navigate to a URL' with a specific resource. It distinguishes from sibling tools like browser_navigate_back by implying forward navigation to a new URL, though it could be more explicit about the effect on the current page.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines1/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool over alternatives. It does not mention scenarios where browser_navigate is preferred over browser_navigate_back or other navigation methods, nor any prerequisites or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_navigate_backA
Destructive

Go back to the previous page in the history

NameRequiredDescriptionDefault

No parameters

TDQS

A3.7/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description and annotations are consistent; destructiveHint is true, matching the navigation action which changes the current page. The description adds minimal behavioral context beyond the annotations, but does not contradict them. It does not mention potential side effects like what happens if there is no history or whether it affects new tabs.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, concise sentence with no redundant wording. It directly states the action and target without unnecessary detail, which is ideal for a tool with no parameters.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple, parameterless tool, the description is largely complete. It communicates the essential operation. It could be improved by noting the behavior when there is no previous history entry, but the given context is sufficient for most use cases.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so the description does not need to explain parameter semantics. The empty input schema is fully covered by the lack of parameters, making this baseline appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action: 'Go back to the previous page in the history.' It identifies the resource (browser history) and the direction (back), making the core purpose unambiguous. It does not explicitly differentiate from sibling tools like browser_navigate or browser_tabs, but the meaning is clear enough in context.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when to use the tool: when the user wants to go back to the previous page in history. However, it provides no explicit guidance on when not to use it, such as when a direct URL navigation via browser_navigate would be more appropriate, or what to do if no prior history exists.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_network_requestA
Read-only

Returns full details (headers and body) of a single network request, or a single part if part is set. Use the number from browser_network_requests.

NameRequiredDescriptionDefault
partNoReturn only this part of the request. Omit to return full details.
indexYes1-based index of the request, as printed by browser_network_requests.
filenameNoFilename to save the result to. If not provided, output is returned as text.

TDQS

A4.2/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false, covering safety. The description adds that it returns headers and body and can filter to a part, but does not elaborate on output structure or edge cases. Given annotation coverage, a 3 is appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with no redundant wording. The main purpose is front-loaded, the part option is explained, and the source of the index is given. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only retrieval tool with full schema coverage and annotations, the description is sufficient. It explains the return type (full details or part) and the index source. It lacks explicit output format details, but the enum values for 'part' are self-explanatory.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with descriptions for all parameters, so the schema already documents them. The description adds critical value by explaining that 'index' comes from browser_network_requests, which is not in the schema, enhancing clarity.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool returns full details of a single network request, with an optional 'part' parameter to narrow down. It distinguishes from the sibling tool browser_network_requests by referencing its index, making the purpose unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The instruction 'Use the number from browser_network_requests' explicitly guides when to use this tool—after obtaining a listing. It does not explicitly mention alternatives or exclusions, but the context is clear enough for an agent to decide.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_network_requestsA
Read-only

Returns a numbered list of network requests since loading the page. Use browser_network_request with the number to get full details.

NameRequiredDescriptionDefault
filterNoOnly return requests whose URL matches this regexp (e.g. "/api/.*user").
staticYesWhether to include successful static resources like images, fonts, scripts, etc. Defaults to false.
filenameNoFilename to save the network requests to. If not provided, requests are returned as text.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds valuable context about the temporal scope ('since loading the page') and the numbered list format, which goes beyond annotations without contradicting them.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two concise sentences with no redundancy. The primary action is front-loaded, and the companion tool reference is placed efficiently at the end. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description tells the agent what the tool returns (a numbered list) and how to proceed for details. Since there is no output schema, this is essential. It does not describe potential error cases or edge scenarios, but for a read-only list tool with strong schema coverage, it is sufficiently complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

All three parameters have schema descriptions covering 100% of the input schema. The tool description does not add any additional meaning to the parameters themselves, so the baseline of 3 applies; it neither enhances nor detracts from what the schema already provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it returns a numbered list of network requests since page load, and explicitly differentiates from the sibling tool browser_network_request by instructing to use that tool for details. This is a specific verb+resource with a clear scope.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives an explicit usage pattern: first call this tool to get a list, then use browser_network_request with the number for full details. This is clear guidance on when to use it versus its companion, though it does not mention any other alternatives or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_press_keyB
Destructive

Press a key on the keyboard

NameRequiredDescriptionDefault
keyYesName of the key to press or a character to generate, such as `ArrowLeft` or `a`

TDQS

B3.2/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description does not mention any side effects, such as triggering keyboard events or potential destructive behavior. The annotations indicate destructiveHint: true, but the description adds no additional behavioral context beyond that.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise — a single sentence that directly conveys the action. No unnecessary information or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple action with a single well-defined parameter, the description is adequate. It lacks mention of when to use this tool (e.g., for shortcuts or navigation keys) but is otherwise complete for basic invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The parameter 'key' is fully described in the schema with examples, and schema coverage is 100%. The description adds minimal extra meaning ('on the keyboard') but doesn't clarify key formats or special keys, which is already covered by the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action (press) and the resource (key on the keyboard). It is distinct from broader actions like navigate or click, though it does not explicitly differentiate from browser_type (typing) or browser_click (clicking).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus its siblings (e.g., browser_type for text entry or browser_click for mouse actions). The description lacks any contextual cues for choosing this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_resizeB
Destructive

Resize the browser window

NameRequiredDescriptionDefault
widthYesWidth of the browser window
heightYesHeight of the browser window

TDQS

B3.1/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description does not disclose any behavioral traits beyond the bare action. Annotations already indicate it is not read-only and is destructive, but the description adds no extra context about side effects like layout reflows or potential viewport changes.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, short declarative sentence with no unnecessary words. It is perfectly concise and well-structured for the simple action it describes.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple tool, the description is adequate, but it lacks any extra context such as units (e.g., pixels), constraints, or when resizing might be appropriate. Given the simplicity and schema coverage, it is minimally complete but not rich.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already provides descriptions for both parameters (width and height), achieving 100% coverage. The description adds no additional meaning about the parameters, so it stays at the baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action (resize) and the resource (browser window), making it distinct from sibling tools like navigate or click. However, it lacks any nuance about whether it resizes the viewport or the entire window, but the core purpose is clear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided about when to use this tool versus alternatives. It does not mention scenarios like adjusting viewport for responsive testing or any conditions that would make it preferable to other navigation tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_run_code_unsafeA
Destructive

Run a Playwright code snippet. Unsafe: executes arbitrary JavaScript in the Playwright server process and is RCE-equivalent.

NameRequiredDescriptionDefault
codeNoA JavaScript function containing Playwright code to execute. It will be invoked with a single argument, page, which you can use for any page interaction. For example: `async (page) => { await page.getByRole('button', { name: 'Submit' }).click(); return await page.title(); }`
filenameNoLoad code from the specified file. If both code and filename are provided, code will be ignored.

TDQS

A3.9/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and openWorldHint=true, so the description's 'Unsafe: executes arbitrary JavaScript in the Playwright server process and is RCE-equivalent' adds specific severity and mechanism beyond the generic flags. This enhances transparency without contradicting annotations, though it could also mention side effects or sandboxing if any.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence that packs purpose and a crucial warning. It front-loads the action and immediately follows with the risk, maximizing information density with zero filler. Excellent structure.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (arbitrary code execution) and the lack of an output schema, the description does not mention the return value or error behavior. The example in the code parameter shows a return, but that's in the schema. For an advanced tool, this is a notable gap, but the core purpose and danger are clear. A 3 reflects the missing return semantics and operational details.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema covers 100% of parameters with detailed descriptions, including the precedence rule for code vs filename. The tool description adds no additional parameter meaning beyond the schema, so a baseline of 3 is appropriate. The schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action: 'Run a Playwright code snippet.' It specifies the resource (Playwright code) and immediately flags the critical distinction from siblings with 'Unsafe: executes arbitrary JavaScript ... RCE-equivalent.' This unambiguous verb+resource plus the danger label leaves no ambiguity about what the tool does and separates it from all other browser tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives a strong warning about safety ('Unsafe', 'RCE-equivalent') but does not explicitly state when to use it versus alternatives. It implies it's for advanced custom logic, but there is no direct 'use this only if...' or mention of safer alternatives. The warning serves as a caution but not a full usage guide.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_select_optionB
Destructive

Select an option in a dropdown

NameRequiredDescriptionDefault
targetYesExact target element reference from the page snapshot, or a unique element selector
valuesYesArray of values to select in the dropdown. This can be a single value or multiple values.
elementNoHuman-readable element description used to obtain permission to interact with the element

TDQS

B3.4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate destructive=true, so the description does not contradict that. But the description adds no further behavioral detail (e.g., side effects on the page). With annotations present, the bar is lower, and the description is neutral.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence with no redundant words. It is well-structured and to the point.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple and the schema covers all parameters. The description is short but sufficient for a basic understanding. It does not specify whether values are labels or values, but that is a minor omission given the context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with clear parameter descriptions for target and values. The tool description itself does not explain parameters beyond what the schema already provides, so it adds no extra semantic value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action (select) and the target (option in a dropdown), distinguishing it from more general actions like click or type. However, it does not explicitly contrast with sibling tools, so it misses a bit of distinction.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

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. It does not mention when selecting is appropriate or when other actions (e.g., click, type) might be preferred.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_snapshotB
Read-only

Capture accessibility snapshot of the current page, this is better than screenshot

NameRequiredDescriptionDefault
boxesNoInclude each element's bounding box as [box=x,y,width,height] in the snapshot. Coordinates are viewport-relative, in CSS pixels (Element.getBoundingClientRect)
depthNoLimit the depth of the snapshot tree
targetNoExact target element reference from the page snapshot, or a unique element selector
filenameNoSave snapshot to markdown file instead of returning it in the response.

TDQS

B3.3/5.0
Behavior3/5

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 'capture' but no further behavioral detail beyond what annotations convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence. The phrase 'this is better than screenshot' adds some comparative value but could be considered slightly extraneous.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema and the description does not explain what format the snapshot takes, how parameters like depth or target affect the result, or what kind of accessibility information is included. This leaves important context missing for an agent deciding whether and how to call the tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema covers all 4 parameters with descriptions, so the baseline is 3. The description does not add any additional parameter meaning or usage notes beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a clear action ('capture') and object ('accessibility snapshot of the current page'), and distinguishes itself from screenshot with a comparative remark, though 'better than screenshot' is somewhat vague.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives minimal guidance by saying 'better than screenshot', but does not explicitly state when to use this tool over alternatives like browser_evaluate or browser_console_messages, nor when 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.

browser_tabsA
Destructive

List, create, close, or select a browser tab.

NameRequiredDescriptionDefault
urlNoURL to navigate to in the new tab, used for new.
indexNoTab index, used for close/select. If omitted for close, current tab is closed.
actionYesOperation to perform

TDQS

A3.5/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is known. However, the description adds no behavioral context beyond what the schema provides (e.g., index omission for close closes current tab is in schema). No mention of side effects like tab switching or browser-level changes.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence that efficiently lists all supported actions. It is front-loaded with verbs and avoids unnecessary words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has multiple actions and a required action parameter. The description lists the actions but does not explain action-specific requirements (e.g., URL required for new, index for close/select) or edge cases like closing the last tab. Given the schema covers parameter details, the description is adequate but not rich. With no output schema, the agent must infer return values from the action.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% with each parameter having a description (url, index, action with enum). The tool description adds no parameter-level detail, so it does not go beyond schema. Baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose with specific verbs (list, create, close, select) and a specific resource (browser tab). It distinguishes from siblings like browser_close (closes the entire browser) and browser_navigate (navigates current tab) by focusing on tab operations.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage through the list of actions but provides no explicit when-to-use guidance or exclusions. Given siblings like browser_close (closes the entire browser) and browser_navigate (navigates current tab), an agent might benefit from explicit differentiation, but the actions themselves are clear enough that usage is implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_take_screenshotA
Read-only

Take a screenshot of the current page. You can't perform actions based on the screenshot, use browser_snapshot for actions.

NameRequiredDescriptionDefault
typeYesImage format for the screenshot. Default is png.png
scaleYesImage resolution scale. "css" produces a screenshot sized in CSS pixels (smaller, consistent across devices). "device" produces a high-resolution screenshot using device pixels (larger, accounts for the device pixel ratio). Default is css.css
targetNoExact target element reference from the page snapshot, or a unique element selector
elementNoHuman-readable element description used to obtain permission to interact with the element
filenameNoFile name to save the screenshot to. Defaults to `page-{timestamp}.{png|jpeg}` if not specified. Prefer relative file names to stay within the output directory.
fullPageNoWhen true, takes a screenshot of the full scrollable page, instead of the currently visible viewport. Cannot be used with element screenshots.

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already indicate read-only and non-destructive behavior. The description adds useful context beyond annotations by clarifying that screenshots are not suitable for interaction and that browser_snapshot should be used for actions. This is helpful but not extensive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise and well-structured: two sentences that front-load the core purpose and immediately follow with a crucial usage caveat. There is no unnecessary verbosity or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simple nature of the tool and the rich schema annotations, the description is largely complete. It could mention that screenshots are for visual inspection, but the title and schema fill most gaps. The explicit distinction from browser_snapshot adds important context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema description coverage is 100%, so the baseline is 3. The description itself does not add parameter details, but the schema already provides clear explanations for each parameter, including enums, defaults, and constraints.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action: 'Take a screenshot of the current page.' It also distinguishes itself from browser_snapshot by explicitly noting that screenshots cannot be used for actions, which helps differentiate it from a key sibling tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It provides explicit when-not-to-use guidance by stating 'You can't perform actions based on the screenshot, use browser_snapshot for actions.' This directly names the alternative tool and the condition for choosing it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_typeB
Destructive

Type text into editable element

NameRequiredDescriptionDefault
textYesText to type into the element
slowlyNoWhether to type one character at a time. Useful for triggering key handlers in the page. By default entire text is filled in at once.
submitNoWhether to submit entered text (press Enter after)
targetYesExact target element reference from the page snapshot, or a unique element selector
elementNoHuman-readable element description used to obtain permission to interact with the element

TDQS

B3/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotation destructiveHint=true and readOnlyHint=false already signal that this tool can modify state, so the description does not contradict that. However, the main description adds no additional behavioral context beyond the annotations, such as whether typing overwrites existing content or triggers page events. The parameter descriptions do mention key-handler triggering and Enter submission, but the main description itself stays shallow.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, focused sentence with no filler or repetition. It front-loads the verb and object, making the tool's primary purpose immediately obvious.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with several closely related siblings (fill_form, press_key, click), the description is too thin to fully orient an agent. It lacks any mention of when typing is appropriate, how the target is resolved, or what side effects to expect, so the agent must rely on parameter descriptions and external context to make a confident choice.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3 because the input schema already documents all five parameters. The main description, 'Type text into editable element,' adds no meaning beyond the schema's parameter descriptions, which already define text, slowly, submit, target, and element clearly enough.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a clear action ('Type text') and a clear target ('editable element'), which distinguishes it from many sibling tools at a high level. It is slightly vague about whether 'editable element' includes textareas, contenteditable regions, or only input fields, but the core purpose is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines1/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to prefer this tool over sibling tools such as browser_fill_form or browser_press_key. It does not mention exclusions, prerequisites, or scenarios where typing would be inappropriate, leaving the agent to infer usage from the tool name alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

browser_wait_forA
Read-only

Wait for text to appear or disappear or a specified time to pass

NameRequiredDescriptionDefault
textNoThe text to wait for
timeNoThe time to wait in seconds
textGoneNoThe text to wait for to disappear

TDQS

A3.9/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds behavioral detail beyond the readOnlyHint by explaining that it waits for text appearance/disappearance or a time delay. However, it does not specify what happens if multiple parameters are provided or if none are provided, so behavior 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.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence that front-loads the core action and conditions. It contains no unnecessary words and is easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple wait tool with no output schema, the description covers the main use cases, but it omits edge cases such as default behavior when no parameters are supplied, timeout behavior, or error conditions. These gaps make it only partially complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema descriptions already cover each parameter individually, and the tool description mostly restates them. It does not clarify the relationship between text, textGone, and time (e.g., whether they are mutually exclusive or combinable), so minimal semantic value is added beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool waits for a condition: text to appear, text to disappear, or a specified time to pass. This distinguishes it from sibling tools like click, navigate, or type, and its purpose is immediately understandable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when to use the tool (when waiting for page state or a delay), but it does not explicitly state when to prefer this over alternatives or how to choose among text, textGone, and time parameters. It provides functional guidance but lacks explicit usage conditions.

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.

  1. 23 tool updatesv0.0.77
    • First observedbrowser_click
    • First observedbrowser_close
    • First observedbrowser_console_messages
    • First observedbrowser_drag
    • First observedbrowser_drop
    • First observedbrowser_evaluate
    • First observedbrowser_file_upload
    • First observedbrowser_fill_form
    • First observedbrowser_handle_dialog
    • First observedbrowser_hover
    • First observedbrowser_navigate
    • First observedbrowser_navigate_back
    • First observedbrowser_network_request
    • First observedbrowser_network_requests
    • First observedbrowser_press_key
    • First observedbrowser_resize
    • First observedbrowser_run_code_unsafe
    • First observedbrowser_select_option
    • First observedbrowser_snapshot
    • First observedbrowser_tabs
    • First observedbrowser_take_screenshot
    • First observedbrowser_type
    • First observedbrowser_wait_for

TDQS

B3.2/5.0

Scored across 23 tools

Disambiguation5/5

Each tool serves a distinct browser automation purpose: navigation, actions (click, hover, drag), input (type, press_key, fill_form), page inspection (snapshot, screenshot, network/console), and session management (tabs, resize, close). No two tools overlap in function; even similar tools like browser_evaluate and browser_run_code_unsafe are clearly separated by context (page vs server).

Naming Consistency5/5

All 23 tools follow the consistent pattern of 'browser_' prefix followed by a lowercase snake_case verb or verb phrase (e.g., browser_navigate, browser_network_requests). The naming is uniform, descriptive, and predictable, making it easy to infer tool behavior from the name alone.

Tool Count3/5

At 23 tools, the count falls in the 16–25 range, which feels heavy per calibration. However, the domain of browser automation is inherently broad, and each tool addresses a specific action or inspection need. Still, the number exceeds the typical well-scoped 3–15 range, meriting a borderline score.

Completeness4/5

The toolset covers core browser workflows comprehensively: navigation (navigate, back), user input (click, type, press_key, select_option, fill_form), page diagnostics (snapshot, screenshot, console, network), and browser management (tabs, resize, close). Minor gaps exist (e.g., no explicit 'reload' or 'go forward' tool), but these can be handled via browser_evaluate or browser_navigate, so the surface is largely complete.

Maintenance

ActivityStale
ResponsivenessNo issues

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