computer.screenshot

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

With no annotations, the description carries the burden of disclosing behavior. It clearly explains that default mode returns only coordinate metadata to save tokens, and that 'image' mode returns a short-term base64 screenshot. It also explains the window parameter's behavior when omitted.

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, front-loaded sentence that conveys all essential information without fluff. Every clause adds value regarding mode, default behavior, and token efficiency.

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 two-parameter tool with no output schema, the description covers the key behavioral aspects: default metadata return, image mode for base64, and window optionality. The token-saving rationale adds helpful 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?

Schema coverage is 100%, providing baseline expectations. The description adds value by explaining the mode enum's behavior (only 'image' returns base64) and the window parameter's semantics when omitted (returns up to 20 windows), which the schema does not detail.

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 screenshots of a dedicated desktop window on demand, with a specific verb and resource. It does not explicitly differentiate from sibling tools like computer.inspect or computer.state, but the name and description make the primary purpose clear.

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 for on-demand screenshots but does not provide explicit guidance on when to use this tool versus alternatives. Sibling tools are not mentioned, so the agent must infer context.

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