screenshot

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

Without annotations, the description partially discloses behavior by stating it returns a PNG image, implying a read-only operation. However, it does not explicitly mention non-destructiveness, authentication needs, rate limits, or any side effects. The lack of such detail reduces trust, but the core behavior is clear enough for a simple capture.

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

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

The description is a single sentence that front-loads the action verb and resource. Every word serves a purpose: 'Capture', 'screenshot', 'webpage', and the return value. It wastes no space, making it easy to parse quickly.

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

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

Given the tool has 5 parameters and no output schema, the description provides minimal context beyond 'returns a PNG image'. It does not explain the format (e.g., base64), the effect of parameters, or any edge cases. For a simple tool this is adequate but not comprehensive; missing details like timeout or error handling reduce completeness.

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

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

Input schema coverage is 100%, so parameters are fully described structurally. The description adds no extra meaning beyond the schema. Baseline 3 is appropriate since the description does not need to compensate for missing schema details, but it also does not enhance parameter understanding.

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

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

The description clearly states the tool captures a screenshot of a webpage, which is a specific verb+resource. It distinguishes from siblings like 'accessibility_audit' or 'lighthouse_audit' that perform different tasks. The addition of 'for design issues, layout problems, and UI quality' provides context without conflating with similar tools like 'responsive_screenshots'.

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

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

The description provides no guidance on when to use this tool versus alternatives like 'responsive_screenshots', 'compare_screenshots', or 'lighthouse_audit'. There is no mention of prerequisites, when to avoid, or which sibling is better for specific scenarios. This leaves the agent without decision criteria.

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