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

No annotations are provided, so the description carries the behavioral disclosure burden. It discloses a key behavior: only the HTTP status is returned and the body is discarded, which prevents an agent from expecting page content. It does not mention error behavior, redirects, timeouts, or the fact that the schema contains many mutually exclusive hint modes, so the disclosure is useful but incomplete.

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 two short sentences with no filler: the purpose is front-loaded, and the key behavioral caveat ('Body discarded') follows immediately. Every word earns its place, and the structure is easily scannable by an agent.

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?

With nine optional parameters, no annotations, and no output schema, the description is under-specified for the full tool surface. It explains one mode (library docs URL) but not the other hint modes implied by city, json, feed, zone, or query, and it gives no details about status/error formats. The schema mitigates parameter documentation, but the description alone is not complete enough for reliable selection across the tool's full scope.

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?

All nine parameters have schema descriptions (100% coverage), so the baseline is 3 and the description does not need to restate them. The description adds no additional meaning about which parameter to choose; it only mentions URLs, while the schema itself documents city, json, feed, zone, query, and the rest. Thus the description does not go beyond the schema in parameter semantics.

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 states a concrete operation: return the HTTP status for a public library docs URL, and notes that the body is discarded. It is not a tautology and it is distinguishable from generic siblings like fetch-status or web-fetch by the 'public library docs URL' scope. However, the schema exposes nine unrelated parameters (city, json, feed, zone, query), so the stated purpose is narrower than the actual input surface, preventing 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 use when the agent needs an HTTP status for a public library docs URL and does not need the response body. It does not explicitly state when to prefer this tool over fetch-status, browser-url-ok, or web-fetch, nor does it give exclusions. The guidance is therefore mostly implicit rather than explicit.

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