describe_region

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

No annotations are provided, so the description carries the full burden. It discloses the crop-then-describe behavior and the detect() sequencing, but says nothing about the vision-provider dependency, latency/cost implications of provider selection, or what the response looks like. It's adequate but notably incomplete for an unannotated tool.

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 tightly written sentences: the action first, then the workflow placement. Zero waste and well front-loaded.

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 4-param tool with no output schema, the description conveys the essential behavior and the trigger condition, and 'describe that region in detail' implies a text return. It could briefly note the return type (a textual description) to fully close the gap without an output schema.

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 description coverage is 100%, with bbox format, image path, prompt, and provider enum all documented in the schema. The description adds no parameter-level detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb+resource ('crop an image and describe that region'), clearly distinct from sibling detect() which only locates objects. It doesn't explicitly contrast with the generic describe() sibling, but the bounding-box framing makes the difference inferable.

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?

Explicitly positions the tool in a workflow: 'Use this after detect() to zoom in on specific objects.' This gives clear usage context and names the preceding step. It lacks when-not guidance (e.g., when to use plain describe instead), so it falls short of a 5.

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