Capture Screenshot

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

Describes cropping behavior (element), full_page vs viewport, and that full_page is ignored when element is set. Annotations provide safety hints; description adds valuable context beyond them.

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?

Efficient two-sentence summary plus well-structured parameter list. No wasted words; front-loaded with main purpose.

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?

Fully covers all parameters, usage guidance, and behavioral nuances. No missing information for a screenshot capture 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?

All three parameters are explained in detail: name as filename label, element for cropping with reference to click_what syntax, full_page behavior and interaction with element. Adds meaning despite 0% schema coverage.

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 'Capture a screenshot' with specific modes (full viewport, full page, one element), distinguishing it from sibling tools like screenshot_diff.

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?

Explicitly states when to use: for visual evidence or before/after pairs, and mentions alternative tools (record_bug, screenshot_diff).

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