screenshot

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does well by explaining the visual output behavior when 'withLabels' is used (color-coding by element role), which goes beyond the basic screenshot functionality. However, it doesn't mention potential side effects, performance implications, or error conditions.

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 perfectly structured and concise. It starts with the core purpose, then presents options in a clear bulleted format, and provides specific details about the color-coding system. Every sentence earns its place with no wasted words, and information is front-loaded appropriately.

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?

For a tool with 3 parameters, 100% schema coverage, but no annotations or output schema, the description does quite well. It explains the tool's purpose, parameter usage, and visual output behavior. The main gap is lack of information about return values or error handling, but given the context, it's reasonably complete.

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?

The schema description coverage is 100%, so the baseline would be 3. However, the description adds significant value by explaining the practical meaning of parameters: 'ref' screenshots specific elements, 'fullPage' captures scrollable areas, and 'withLabels' shows interactive element labels with detailed color-coding. This provides context beyond the schema's technical descriptions.

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's purpose with 'Capture page screenshot' - a specific verb+resource combination. However, it doesn't explicitly differentiate from sibling tools like 'snapshot' or 'browser_search_snapshot', which might have overlapping functionality. The purpose is clear but lacks sibling differentiation.

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 implied usage guidance through the 'Options' section, explaining what each parameter does. However, it doesn't explicitly state when to use this tool versus alternatives like 'snapshot' or provide clear exclusions. The guidance is present but not comprehensive about tool selection.

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