screenshot

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. The description states it captures a screenshot and returns a PNG, but does not disclose behaviors like whether it waits for the window to be ready, what happens if no verified Sky window exists, the resolution/output size, or whether it scrolls/captures the full page. The 'verified' qualifier hints at validation behavior but is never explained.

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?

A single concise sentence conveys purpose and output format with zero wasted words. The qualifier 'only the verified Sky window' is meaningful scoping rather than filler.

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 no output schema, the description is reasonably complete on inputs and format. However, the 'verified' qualifier creates ambiguity about behavioral prerequisites (when is the Sky window considered verified?), and with siblings like 'take_screenshot' and 'read_screen' present, the lack of differentiation leaves the agent unsure which screenshot tool to pick. The tool is simple enough that a 3 is fair, but it could do more to resolve sibling ambiguity.

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 tool has zero parameters and 100% schema coverage (vacuously, since there are no params). With 0 params, the baseline is 4. The description adds the PNG return format detail, which is useful since there is no output schema to convey it.

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 captures a screenshot and returns a PNG image. The qualification 'only the verified Sky window' adds specificity about scope. However, given the existence of sibling tools 'take_screenshot' and 'read_screen', the description does not explicitly distinguish itself from these alternative screenshot-related tools.

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 mentions 'verified Sky window' but does not explain when to use this tool versus the siblings 'take_screenshot' or 'read_screen'. There is no guidance on prerequisites (what does 'verified' mean, when is a Sky window considered verified) or when an alternative should be preferred.

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