read_screenshot

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

The description discloses the quadrants and color extraction behavior. With no annotations, it covers the core behavior but omits details like output format, error handling, or read-only guarantee. It adds some transparency but not comprehensive.

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?

Two sentences with no redundancy. The first sentence states what the tool does, the second provides use case. Every word 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 explains the input and core operation, but lacks explicit output format details (e.g., structure of returned colors). With no output schema, the description could be more precise about the return value.

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 coverage is 100% for the single parameter, but the description adds meaning by explaining how the parameter is used (split into quadrants, compute colors). This goes beyond the schema description which only says 'Base64-encoded PNG screenshot.'

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 tool analyzes a screenshot by splitting into quadrants and returning dominant colors. It differentiates from the sibling 'analyze_screenshot' by specifying the method, making the purpose 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 says 'Useful for visual reasoning about what's on screen,' which implies appropriate usage contexts. However, it does not explicitly contrast with siblings like 'analyze_screenshot' or mention when not to use this tool.

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