Shotlane

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

Annotations cover the safety profile (readOnlyHint, openWorldHint, destructiveHint), so the bar is lower; the description still adds real behavioral context: per-device output contents, the inline side-by-side viewer the user sees, and a cost model ('Uses 1 credit per device'). It doesn't mention latency or failure modes of the check itself, but it adds meaningful disclosure beyond structured fields.

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

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

Purpose is front-loaded in the first sentence, outputs follow, then usage guidance and cost. Four sentences each earn their place, though the viewer and credit notes could be trimmed slightly for efficiency.

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

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

For a read-only check tool with full schema coverage and no output schema, the description supplies everything needed: what it returns, what counts as 'wrong', when to use it, the sibling alternative, and the cost. No material gap remains.

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

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

Schema coverage is 100% and each parameter already carries a description, so the baseline is 3. The description adds value by enumerating what 'what went wrong' means and by implying the per-device cost interacts with the multi-device 'devices' array, helping the agent reason about how many screenshots and credits a call yields.

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

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

States a specific verb+resource ('Check whether a public web page looks right on phone, tablet and desktop') and enumerates concrete outputs (screenshots per device, sideways scrolling, JS errors, failed requests, broken images). It also distinguishes itself from the sibling 'screenshot' tool explicitly, so an agent can route without reading schemas.

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

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

Gives concrete trigger conditions ('when the user asks whether a page looks right, works on mobile or has layout bugs, or after a deploy') and names the alternative sibling with its own selection condition ('To just see a page, including on one device, use screenshot instead'). Explicit when and when-not, with the alternative specified.

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

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds a behavior not present in annotations: querying the balance does not itself consume credits, which is decision-relevant for an agent. It stops short of describing return format or any account scoping caveats.

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

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

Two short sentences, front-loaded with the purpose and followed by the one caveat that matters. No filler, no repetition of the title, no wasted tokens.

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

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

For a no-param, read-only, closed-world tool with annotations covering the safety profile, the description says what is returned (remaining credit count) and that no credits are consumed. The only minor gap is that the response shape (e.g., a bare number vs. a message) is not hinted at, but the stakes are low.

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

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

There are zero input parameters, so the schema cannot be elaborated further and the baseline for an empty schema applies. Nothing in the description is needed or missing on this dimension.

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

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

The description gives a specific verb+resource: 'Show how many Shotlane render credits remain on this account.' The resource (account credit balance) is inherently distinct from the rendering-oriented siblings (html_to_pdf, read_page, screenshot), so an agent can route to it unambiguously.

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

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

Usage is implied by the purpose: call it when you need the remaining credit balance. It adds a useful reassurance ('Does not use credits') that lowers the cost of calling, but names no alternatives or when-not-to-use conditions, so guidance stays at the implied level.

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

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

Annotations already establish readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds genuinely new behavioral context beyond those annotations: rendering happens in headless Chromium, the result is a download link (not inline bytes), and the call consumes 1 credit from the user's account. It stops short of describing failure handling or rate/credit limits for repeated calls.

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

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

Two sentences, zero filler, with the core capability front-loaded and the credit cost as a trailing caveat. Every clause carries information an agent needs.

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

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

For a 7-parameter tool with 71% schema coverage, the description covers the essential contract: what goes in, where rendering happens, and what comes back (a download link), which compensates for the missing output schema. The main remaining gap is the mutual exclusivity of url/html/markdown and any constraints when more than one is supplied.

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

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

Schema coverage is 71%, so most parameters are already documented and the baseline of 3 applies. The description restates the three input modes (HTML, Markdown, URL) but adds no new semantics: it never says they are mutually exclusive, nor does it clarify paper/margin/landscape/page_numbers behavior beyond the schema text.

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

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

The description names a specific verb and output resource: render HTML, Markdown or a URL into a PDF via headless Chromium, returning a download link. That is far more informative than the title alone and is clearly distinguishable from screenshot (image output) and read_page (content extraction), though it never explicitly names those siblings as alternatives.

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

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

Usage is only implied: an agent can infer 'use this when you need a PDF', but there is no statement of when to prefer this over screenshot or read_page, nor any exclusions or prerequisites. The 'Alternatively' framing in the schema hints the three input modes are mutually exclusive, but the description does not confirm or route between them.

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

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

Annotations already cover the safety profile (readOnly, openWorld, non-destructive), so the description's job is to add operational context — and it does: JavaScript is executed in a real browser, title/metadata are included, and it costs 1 account credit. The cost disclosure is genuinely useful and not derivable from annotations; what's missing is any note on failure/timeout behavior for pages that never load.

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

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

Three sentences, each earning its place: capability first, then the differentiator (JS-heavy sites), then the cost warning. No redundancy and the most decision-relevant facts are front-loaded.

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

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

No output schema exists, but the description states the return shape (clean Markdown with title and metadata), so the agent knows what comes back. Cost and JS execution are covered. Minor gaps around truncation and load-failure behavior are partly handled by the max_chars parameter.

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

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

Schema description coverage is 83%, with only include_links undocumented, so the structured data carries most parameter meaning. The description echoes the main_content default behavior ('return its main content') but adds no syntax or format guidance for selector, wait_for_selector, or max_chars. Baseline 3 is appropriate.

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

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

States a specific verb and resource (load a public web page, return main content as Markdown) with the key differentiator of a real browser executing JavaScript. An agent can distinguish this from html_to_pdf (static conversion) and screenshot (image capture) without opening any schema.

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

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

Gives clear selection context: 'Works on single-page apps and JavaScript-heavy sites' plus the word 'public', which implicitly excludes authenticated/private pages. It does not name html_to_pdf or screenshot as the alternatives for static or visual needs, so the routing is implied rather than explicit.

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

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

Annotations already cover readOnly/openWorld/non-destructive, and the description adds meaningful context beyond them: the result is rendered in an inline viewer for the user, the page must be public, and the call costs 1 credit. It does not discuss failure modes (e.g. what happens on unreachable or auth-gated pages) or latency, so not a 5.

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

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

Front-loaded with the core action and output, then routing guidance, then cost. Dense and mostly waste-free, though the device/visual-bug enumeration runs slightly long for what it delivers.

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

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

With no output schema, the description does the needed work by explaining that an image is returned and shown in an inline viewer, and that full-page captures come back as several slices. What's missing is any note on errors or how long captures take, which matters for an open-world network tool.

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

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

Schema coverage is 88%, so most parameters are already documented. The description only adds marginal guidance by pointing at the `device` parameter for iPhone rendering, which the schema already explains in more detail. Baseline 3 is appropriate when the schema carries the weight.

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

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

States a specific verb and resource ('Take a screenshot of a public web page') and the return type ('return it as an image you can look at'). Explicitly contrasts with read_page, so the agent can distinguish it from the closest sibling without opening either schema.

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

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

Gives concrete triggering conditions: user asks for a screenshot, wants to see a page, wants a specific device rendering, or asks about layout/visual bugs/charts/images/deploy rendering. Names the alternative ('For page text, read_page returns Markdown'), which is an explicit when-not-to-use rule.

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