describe_ui

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

No annotations are provided, so the description carries the full burden of explaining behavior. It only says 'describe a UI screenshot file', which implies a read-only operation but does not explicitly disclose that it is read-only, nor does it mention output format, error handling, or any side effects. The addition of 'on disk' is a minor behavioral detail, but overall it lacks sufficient transparency.

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, consisting of only one short bilingual sentence. It is front-loaded with the verb 'describe' and the resource, and every word contributes to the purpose without any unnecessary fluff.

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 simple, but with no output schema and no annotations, the description should do more to explain the return value or behavior. It does not differentiate from sibling tools that might also handle images, and it omits any indication of what the description looks like (e.g., language, detail level). This makes it incomplete for an agent to confidently invoke.

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 schema description fully covers the single parameter 'image_path' with an absolute path explanation. The tool description adds no further meaning about the parameter, so with high schema coverage, a 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 the tool's purpose with a specific verb ('describe') and resource ('UI screenshot file'), and mentions 'on disk' to indicate local file access. It is distinct from siblings like extract_text or diagnose_error, but does not explicitly contrast with analyze_image, so it falls short of a 5.

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 by specifying a UI screenshot file, but provides no explicit guidance on when to use this tool over alternatives like analyze_image or understand_diagram. There are no exclusions or alternative mentions, making the usage context only implicit.

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