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

Adds substantial context beyond the annotations: a 2 MB size limit, JSON-or-YAML acceptance, per-call pricing (first 25 free, failed calls free), and an explicit 'each call is charged, so repeats are not free' that explains the non-idempotent, costly nature of retries. Also restates the read-only/no-mutation guarantee consistently with readOnlyHint and destructiveHint=false.

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?

Front-loaded with the action and the returned fields, then usage, then an example, then commercial terms. The pricing/permission sentence is long but earns its place because it explains retry cost. Slightly dense as a single paragraph, but no filler.

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?

No output schema exists, yet the description effectively specifies the return payload field-by-field, including the 150-operation truncation cap — the key detail an agent needs to avoid assuming a full listing. Coverage limit, auth/payment route, and safety profile are all present.

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% and the single `url` parameter is documented there. The description still contributes format and constraint meaning ('JSON or YAML, up to 2 MB' and a concrete example value) that the schema does not carry, though it does not say what happens for non-OpenAPI URLs or unreachable hosts.

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 ('Read ... and summarise') and resource (OpenAPI 3 / Swagger 2 document), then enumerates the exact fields returned (title, version, servers, auth schemes, operation counts, paid/deprecated flags, up to 150 operations with method/path/summary/operationId). No sibling tool does this, and the scope is unmistakable.

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?

Gives concrete trigger conditions: 'Use before calling an unfamiliar API, to pick an endpoint, or to compare APIs', plus a worked example URL. It stops short of naming when NOT to use it or a specific alternative, but no sibling overlaps meaningfully.

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