screenshot

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

Annotations already declare readOnlyHint=true, so the safety bar is low. The description usefully adds the pixel-to-CSS-px mapping behavior, but does not disclose default image format, what happens when 'save' is used, or how multiple candidate elements are resolved.

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?

Two short sentences with no filler; the core capability is stated first and the coordinate-mapping caveat follows immediately.

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 no output schema, the description leaves the return value only implicit ('Screenshot' implies an image) and does not say what is captured when ref/text/selector are omitted versus combined. Adequate for a tool whose parameters are well documented, but not fully self-contained.

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 86%, so the baseline is 3. The description earns a bump by explaining the 'scale' parameter's meaning in operational terms (one image pixel = one CSS px at the default), which is the least obvious parameter in the set.

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?

Names a specific verb+resource ('Screenshot of the client') and clarifies scope: whole client or a single element. It is distinguishable from the DOM-oriented 'snapshot'/'query' siblings, though the description never explicitly contrasts them.

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?

Gives a concrete usage rule: at default scale, image coordinates can be fed to click/hover as x/y. That implies when this tool is useful (visual grounding before clicking), but there is no explicit guidance on when to prefer screenshot over snapshot, or what to do when scale is not 1.

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