Screenshot

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description does not need to restate safety. It does add the context that the capture target is the 'selected display', implying dependence on an external selection state. However, it does not disclose what the screenshot produces (e.g., file path, clipboard) or any other side effects, which would add value.

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 a single, six-word sentence with no unnecessary words. It is front-loaded with the action and target, making it maximally 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?

For a zero-parameter tool with safety annotations, the description is nearly complete: it states the action and object. The only notable omission is the return format or output behavior, but with no output schema and an obvious name, this is a minor gap. Overall, an agent can confidently invoke this tool based on the description.

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?

There are zero parameters, so the baseline is 4. The phrase 'selected display' clarifies that the tool operates on a pre-selected display rather than taking a parameter, which adds meaning beyond the empty schema. No parameter details are needed.

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 uses a specific verb, 'Capture', and a specific resource, 'the selected display', making the tool's function immediately clear. No sibling tool handles screenshots, so it stands apart without needing explicit differentiation. It is a genuine statement of function, not a tautology.

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 implies usage by naming the action and target, but it does not explicitly state when to use this tool versus alternatives or mention any prerequisites like prior display selection. There are no direct screenshot siblings, so alternatives are not needed, but the lack of any explicit when-to-use guidance leaves it to inference.

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