Screenshot

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

No annotations are provided, so the description carries the full burden. It does add one genuinely useful behavioral fact ('Returns an image the model can see'), but says nothing about permissions, the trusted/CDP toggle semantics, timeout behavior, or how quality/format affect the 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?

Three tight sentences, no filler, with the capture scopes front-loaded and the flag behaviors following. Every sentence earns its place.

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?

With 13 parameters, no annotations, and no output schema, the description is only minimally sufficient. It usefully notes the image return value (which compensates for the missing output schema) but does not cover the majority of the parameters, leaving real gaps for a tool of this complexity.

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 only 46% and there are 13 parameters. The description adds meaning for grid, annotate, fullPage, and implicitly ref/selector, but leaves tabId, frameId, format, quality, timeout, trusted, maxWidth, and maxHeight undocumented in both schema and description.

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 ('Capture') and resource ('viewport, full page, or one element'), and the three capture scopes are clearly itemized. It does not, however, distinguish itself from the sibling 'snapshot' tool, which an agent could reasonably confuse with a visual capture.

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 explains what the annotate and grid flags do, which implies when to use them, but gives no guidance on when to choose screenshot over 'snapshot' or any other sibling. Usage is implied rather than stated, with no when-not conditions.

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