Capture Windows screen

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

The description discloses that it captures a PNG image, but does not specify how the image is returned (e.g., base64 encoding, file path, or direct data). The annotations already cover read-only, idempotent, and non-destructive behavior, so the description adds limited behavioral insight beyond the omission of return format.

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 consists of two succinct sentences with no wasted words. The first sentence states the purpose and output format, the second provides usage guidance. Every sentence earns its place.

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 simple tool with one parameter, no output schema, and comprehensive annotations, the description covers purpose, usage context, and parameter meaning. It lacks precise output format specification, but is otherwise complete enough for an agent to use correctly.

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 description compensates by explaining the two enum values ('primary display' and 'full virtual desktop'). However, it does not mention the default value ('virtual') or provide additional details about the parameter's behavior when omitted.

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 specific verb 'capture' and resource 'primary display or full virtual desktop', and specifies the output format 'PNG image'. It also distinguishes from sibling tools like 'list_windows' by framing it for graphical actions.

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 advises using the tool 'before and after graphical actions to locate controls and verify outcomes', providing clear context. It does not explicitly mention alternatives or when not to use it, but the guidance is sufficient for typical scenarios.

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