compare_screenshots

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

With no annotations, the description carries the full behavioral burden but only says it 'compares'. It omits the safety profile, whether it is read-only, what happens when no baseline exists, tolerance/matching behavior, and the shape of the result. For a comparison tool with no output schema this is a substantial gap.

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?

A single front-loaded sentence with no filler, so it is structurally clean, but it is under-specified rather than appropriately sized for a three-parameter tool with no supporting docs.

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 no annotations, no output schema, and 0% schema coverage, the definition should do far more work. It gives no return-value meaning, no error behavior, and no parameter documentation, so an agent cannot call it confidently.

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 0%, so the description must compensate, yet it names no parameters. It loosely implies actualPath (the 'screenshot') and baselinePath ('baseline image') but never mentions sessionId or how the three relate, leaving required params undocumented.

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 (compare) and resource (screenshot vs baseline image), enough to distinguish it from the capture-oriented siblings like take_screenshot and screenshot. However, it doesn't clarify where the 'screenshot' comes from (sessionId vs actualPath), leaving a small ambiguity.

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 when-to-use guidance and no alternatives named. There is no indication of when a visual comparison is appropriate versus simply calling take_screenshot, nor any prerequisites such as needing an existing baseline.

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