screenshot

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

The description does not contradict the readOnlyHint annotation, and it mentions saving a file, which is a mild side effect. However, it does not add significant behavioral context beyond the annotations, such as permissions or edge cases.

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 two concise sentences, front-loading the action and then elaborating on the output. It is well-structured and free of unnecessary detail.

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?

In the absence of an output schema, the description provides sufficient context about the returned data (a downscaled copy plus scale factor). It does not over-explain but covers the essential behavior expected from a screenshot tool.

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 description coverage is 75%, below the 80% threshold, so the description must compensate for the missing parameter details. The description only indirectly references output_path and return_image without explaining parameters like serial or inline_max_px more deeply than the schema.

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 action ('Take a screenshot of the device screen') and specifies the output behavior: saving a full-resolution PNG and returning a downscaled copy inline with scale factor information. This is specific and unambiguous.

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 capturing the screen but does not explicitly state when to use it versus alternatives. No comparative guidance is provided, only the tool's inherent functionality.

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