get_screenshot

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

No annotations are provided, so the description carries full burden. It mentions the tool returns an image but doesn't disclose critical behavioral traits like whether this requires device permissions, if it works on locked screens, what image format is returned, or potential side effects (e.g., screen flash).

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 brief and front-loaded with the core purpose in the first sentence. The second sentence about returns is somewhat redundant but not excessive. It could be slightly more efficient by combining both ideas into one sentence.

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 tool that captures device screenshots with no annotations and no output schema, the description is insufficient. It doesn't explain the return format (e.g., image type, encoding), error conditions, or prerequisites like screen state requirements, leaving significant gaps for an agent to use it correctly.

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 0 parameters with 100% schema description coverage, so no parameter documentation is needed. The description appropriately doesn't discuss parameters, earning a high baseline score for not adding unnecessary information.

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 ('takes a screenshot') and the resource ('of the device'), making the purpose immediately understandable. However, it doesn't differentiate from sibling tools like 'get_screen_info' or 'get_screen_xml' that also retrieve screen-related data, preventing a perfect score.

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 provides no guidance on when to use this tool versus alternatives. With siblings like 'get_screen_info' (for metadata) and 'get_screen_xml' (for UI structure), there's no indication of when a screenshot is preferred over other screen-related tools.

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