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

'Body discarded' is a genuine behavioral disclosure—it tells the caller the response will contain only the HTTP status. However, with no annotations provided, the description carries the full burden, and it fails to disclose that most of the 9 parameters are themselves discarded after shape/length checks, what happens when multiple parameters are supplied, or any authentication/rate-limit context.

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 two-sentence description is front-loaded and wastes few words. However, the brevity crosses from efficient into under-specified territory—critical details about output shape, parameter relationships, and scope are absent, so the description reads more like an abbreviation than a well-structured definition.

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 tool with 9 optional parameters, no output schema, and no annotations, a 12-word description is inadequate for correct invocation. An agent cannot determine which parameter drives the 'HTTP status' response, what the returned status is based on when inputs are discarded, or whether the tool validates a URL or merely echoes a checklist result.

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 each of the 9 parameters already documented with a type and a usage note (e.g., 'discarded after the shape check'). Per the rubric, high schema coverage sets the baseline at 3, and the description does not need to compensate. The description itself maps to no specific parameter, but that is acceptable given the schema's completeness.

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 verb and resource ('HTTP status for a public library docs URL') and adds a distinctive behavioral note about discarding the body. However, it is vague about what 'public library docs' means, and it does not differentiate the tool from overlapping siblings like fetch-status, web-fetch, or browser-url-ok, which also deal with URL status. The 9-parameter schema (city, json, timezone, query) suggests a broader scope than the description implies.

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?

No guidance is provided on when to use this tool versus alternatives. The sibling list contains highly overlapping tools (fetch-status, normalize-url, validate-json, web-fetch), and the description gives no selection criteria, no exclusions, and no conditions under which this tool should be preferred.

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