screen_capture

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It details that the screenshot is captured using .NET System.Drawing from the primary monitor at full resolution, and that it returns PNG base64 data. This is thorough, though it does not mention potential failure modes or permission requirements, which are not critical for a screenshot tool.

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 well-structured, starting with the core action, then return format, use cases, and technical details. It is somewhat lengthy due to the enumeration of use cases, but each sentence provides value. It is appropriately front-loaded with the most important information.

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 one optional parameter and no output schema, the description fully covers the essential context: what it does, how it returns the image, technical background, and the optional save behavior. It leaves no gaps regarding the tool's basic operation and integration with the AI.

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 only parameter, output_path, is fully described in the schema: 'Absolute path to save the screenshot PNG file to disk. If omitted, the screenshot is still captured and returned as base64 image data but not saved to a specific file location.' The description repeats this with 'Optionally save the screenshot to a specific file path on disk' but adds no new meaning beyond the schema, so the baseline score of 3 is appropriate.

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 function with a specific verb and resource: 'Capture a screenshot (screen grab) of the primary monitor on this Windows PC.' This is unambiguous and distinguishable from any sibling tools, which are all unrelated to screenshots.

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 a clear list of use cases: 'see what's currently displayed on screen, debug UI issues in applications, verify visual changes, create visual documentation, or monitor what's showing on the display.' It gives context for when to use the tool but does not explicitly state when not to use it or mention alternatives, which are not needed given the absence of similar tools.

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