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. It only states the action without disclosing output format, file saving behavior, or whether it captures the full viewport or only the visible area. This is minimal behavioral information.

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 sentence with no extraneous words, making it highly concise. However, it is also under-specified, so while structure is clean, the content is exceptionally brief.

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 lack of annotations, output schema, and parameter explanation, the description is insufficient. An agent cannot predict what the tool returns (e.g., an image path, base64 string) or how to interpret the result.

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 single parameter max_width is not mentioned in the description, and schema coverage is 0%. The agent cannot infer what max_width controls (e.g., resizing the screenshot) or how the default is applied.

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 'Screenshot' and names the resource 'current iPhone Safari viewport', clearly distinguishing it from sibling tools like navigation and text entry. It is unambiguous and concise.

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?

No guidance is provided on when to use screenshot versus alternatives like snapshot or page_source. The description lacks any context on scenarios where this tool is preferred, leaving the agent without decision criteria.

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