screenshot

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

With no annotations, the description must disclose all behavioral traits. It reveals that the tool returns an image and a scale factor, and explains how to use the scale factor for coordinate mapping. It does not mention potential permissions (e.g., screen recording) or image format, but the key behavioral nuance is covered.

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 sentences, front-loading the action and providing essential detail efficiently. No extraneous words.

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?

The tool is low-complexity. Although there is no output schema, the description adequately explains the return values (image and scale factor) and their usage. It lacks details on image format or resolution, but this is not critical for basic usage.

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 'app' is well-documented in the schema (100% coverage). The description adds no additional meaning beyond the schema description, so baseline score of 3 is appropriate.

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 'Take a screenshot of the entire screen or a specific app window', specifying the action and resource. It distinguishes from sibling tools (none are screenshot-related).

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 explains when to use the optional 'app' parameter ('If omitted, captures full screen'), providing clear conditional usage. No explicit exclusions or alternatives are given, which is acceptable for a simple tool.

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