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

No annotations are provided, so the description must disclose behavioral traits. It mentions compression/diff and bounding boxes but does not specify side effects, return format, or error conditions. For a capture tool, it lacks details like whether it saves files or returns data.

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?

Very concise, two sentences, front-loaded with main purpose. Could be more efficient by avoiding repetition of 'screenshot' but overall well-structured.

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 11 parameters, no output schema, and no annotations, the description is incomplete. It does not explain return values, error handling, or the meaning of 'element bounding boxes'. Insufficient for a complex 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 91%, most parameters have descriptions. The description adds no extra meaning beyond the schema; it only groups parameters by action (capture vs annotate), which is already clear from parameter descriptions. 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?

The description states the tool does screen capture and annotation, with brief elaboration on two actions: capture with compression/diff and annotate with element bounding boxes. It is clear but does not use a explicit verb+resource format.

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?

No guidance on when to use this tool versus siblings like ui or device. No exclusions or alternatives mentioned. The description only implies usage for screenshots.

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