Touchpoint

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

No annotations provided, so description carries full burden. It explains cropping behavior and defaults, but omits safety profile (read-only status), image format/encoding details, resolution behavior, or whether captures include cursor/popups. No mention of side effects or permissions.

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?

Well-structured with clear visual hierarchy: purpose statement first, usage logic second, then parameter definitions. No redundant text; every line provides unique information not found in the schema titles.

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?

Adequate for inputs given the Args section compensates for poor schema coverage, but incomplete regarding output. With no output schema, the description should specify image format (PNG/JPEG), encoding (base64 vs binary), or file handling. Title is also null, though the name 'screenshot' compensates.

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?

With 0% schema description coverage, the Args section successfully documents all 5 parameters with specific semantics (e.g., padding adds 'Extra pixels', monitor is '0-indexed'). Minor gap: mutual exclusivity of targeting parameters (app vs window_id vs element_id) is implied by 'Specify one parameter' but not explicitly enforced or explained.

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?

Clear verb ('Capture') and resource ('screen') with output format specified ('return an image'), distinguishing it from sibling interaction tools like 'click' or 'type_text'. However, it does not explicitly differentiate from other retrieval tools like 'get_element' or 'windows'.

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?

Provides explicit guidance on argument selection: 'With no arguments, captures the full desktop. Specify one parameter to crop to a specific target.' This clearly defines the two primary usage modes. Lacks explicit 'when not to use' alternatives.

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