capture_image

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

No annotations present, so description fully carries the burden. Discloses inability to drive click/type or read text, and provides size/format constraints. Clearly communicates what the tool cannot do.

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

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

Concise, front-loaded with key factual details. One minor redundancy: 'Do NOT call this to see what is on the page — call view_page instead' could be slightly tighter, but overall no wasted sentences.

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?

Adequate for a simple screenshot tool with no output schema. Provides size limits and use cases. Missing details on return format or error handling, but not critical given its purpose.

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

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

Schema covers 100% of parameters with descriptions. Description adds no further semantics to parameters (full_page, som). Baseline 3 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?

Specific verb ('capture') + resource ('image') with technical details (WebP, max 800px, <100KB). Distinctly contrasts with sibling 'view_page' by stating its limitations.

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

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

Explicitly warns against using for general page visibility, recommends 'view_page' as cheaper alternative (10-30x). Lists three narrow valid use cases and advises 'use view_page' when unsure.

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