Take Screenshot

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

The description discloses that the tool returns image with metadata and explains the trade-offs between PNG and JPEG formats. Since annotations are absent, the description carries the full burden. It does not mention any potential side effects or performance impacts.

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 extremely concise with only three sentences, no filler words, and front-loaded with the core purpose. Every sentence adds value.

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 description lacks details about return format (the schema has no output schema), but given the tool's simplicity and rich parameter descriptions, it is nearly complete. No mention of potential errors or performance impacts.

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 description adds significant meaning beyond the schema by explaining the purpose of each parameter (e.g., quality reduces file size, max_width resizes to reduce file size). Schema coverage is 100%, but the description provides high-level guidance.

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 what the tool does (capture a screenshot of the device screen) and what it returns (image with metadata). It also distinguishes between PNG and JPEG formats, giving specific guidance for AI analysis use cases.

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 advises when to use certain parameters (e.g., format='jpeg' for reducing file size for AI analysis), but does not explicitly mention when not to use this tool or compare it with sibling tools like 'record_screen' or 'verify_screen'.

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