topai_headless_screenshot

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, and the closing sentence largely restates those ('Stateless, read-only, idempotent'). The genuinely additive detail is the 'public webpage' constraint, which implies pages behind auth cannot be rendered, but this is not spelled out and no return-shape or failure behavior is described.

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, front-loaded with purpose then routing guidance, with no filler. The trailing 'Stateless, read-only, idempotent rendering' sentence is largely redundant with the annotations already attached to the tool, which is the only waste.

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

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

For a three-parameter read-only tool with no output schema, the description covers purpose, routing, and the public-URL constraint adequately. It does signal the return is metadata/dimensions rather than raw image bytes, but does not explain how a caller retrieves the actual image, leaving a modest gap.

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

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

Schema description coverage is 100%, so the schema already documents url, format, and full_page, including the enum values and defaults. The description only echoes the viewport/full-page distinction, adding no format, size, or URL-syntax detail beyond the schema; baseline 3 applies.

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 ('Renders a public webpage in a serverless headless browser') and names what it returns (viewport or full-page screenshot metadata and dimensions). It explicitly distinguishes itself from the sibling topai_web_to_markdown, so an agent can route correctly 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 explicit when-to-use ('visual layout inspection, UI verification, or image capture of a live URL') and when-not-to-use ('only need the textual content') with the exact alternative named and a quantified reason (90% bandwidth/token savings). Nothing is left to inference.

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