screenshot

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

With no annotations provided, the description takes full responsibility for behavioral disclosure. It reveals that screenshots are unfiltered, that actions are rejected if apps are not in the allowlist, and that the returned image is the reference for click coordinates. This adds significant context beyond the schema.

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 four sentences with no redundant information. Every sentence adds value, covering purpose, behavior, and a practical note about coordinate reference. It is front-loaded and efficient.

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 simplicity (one optional param, no output schema), the description covers key aspects: what it does, behavioral constraints, and how the output is used. It explains error conditions and the relevance of the returned image. Minor omissions (e.g., explicit format of non-saved image) are acceptable given the context.

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 schema already provides a detailed description for the single parameter (save_to_disk), achieving 100% coverage. The tool description does not add any extra parameter semantics beyond what's in the schema, so a 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 'Take a screenshot of the primary display', specifying verb and resource. It distinguishes from siblings by noting that screenshots are not filtered and includes context about allowlist rejection, which differentiates it from other tools like cursor_position or mouse_move.

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 guidance on when to use the tool (e.g., for looking at screen) and includes behavioral notes like allowlist rejection and error conditions. However, it does not explicitly contrast with alternatives or state when not to use it.

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