Screenshot

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

The description significantly extends beyond the readOnlyHint annotation by explaining behavior such as returning a file path by default, forcing a path with raw=True, generating Haiku text with describe, auto-setting camera from annotation_id, and the meaning of zoom/angles/supersample. It does not contradict the annotation and provides valuable operational context.

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 compact and front-loaded with the core action, then follows with a dense but organized reference of parameters. Every sentence contributes, though the line-packed formatting is somewhat cryptic; still, it's appropriately sized for a tool with 16 parameters.

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 the tool's complexity (16 params, no output schema), the description covers nearly all behavioral aspects: output modes, camera options, framing controls, highlight syntax, and annotation handling. Minor gaps exist (e.g., exact return format/path details), but the description is substantially complete for a tool of this scope.

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?

Although schema coverage is 100%, the description adds key semantic value by explaining syntactic shorthand (e.g., 'ex,ey,ez', '_=skip', 'paths[:#RRGGBB]'), the relationship between describe and raw, and how annotation_id auto-configures camera. These details are not in the schema and help an agent invoke parameters correctly.

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 opens with 'Capture screenshot (file path)'—a specific verb+resource pairing that clearly states the tool's purpose. It goes on to describe the two primary output modes (file path or Haiku description), which distinguishes it from all sibling tools that are unrelated to image 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 gives clear context on how to use the tool, including camera modes, angle presets, zoom semantics, and framing options. It doesn't explicitly name alternatives because no sibling tool serves a similar function, but the extensive parameter guidance makes its intended use evident.

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