diff_openapi

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

Annotations already cover read-only, idempotent, non-destructive and open-world, so the safety profile is settled. The description adds value beyond that by disclosing the returned classification scheme (breaking/warning/non-breaking/info) and the `breaking` and `semver` result fields, which is exactly the extra context needed for a diff tool. It doesn't explain how the five optional source parameters interact or conflict, but that is largely the schema's job.

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?

Three short sentences with the purpose front-loaded, then result semantics, then an example – no filler. Minor cost from the inline backticked field names reading slightly clipped, but nothing wasteful.

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?

There is no output schema, and the description appropriately compensates with the shape of the result (change severities, `breaking`, `semver`). The remaining gap is that all five parameters are optional, and the description never states that at least one base/revision source pair must be supplied or what precedence applies.

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% with per-parameter descriptions, so the baseline is 3. The description rises above that by demonstrating a specific parameter pairing (revision_path together with base_git_ref) that shows how to build a git-ref comparison, which the schema alone does not convey.

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 and resource: 'Compare two OpenAPI 3.x documents', and follows with the semantics of the change categories it produces. That mostly separates it from the sibling validate_openapi, though it never says so explicitly.

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?

Adds one concrete usage scenario ('Typical use after editing a spec: revision_path="openapi.yaml", base_git_ref="main"') which implicitly shows the main workflow. It never mentions when not to use it or why to pick it over validate_openapi/validate_json_schema, so the routing decision is left to inference.

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