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

With no annotations, the description carries the full burden. It does disclose one important behavior—the response body is discarded—so the agent knows not to expect page content. But it is silent on response shape, error behavior, and whether this is a safe read-only operation.

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 short sentences, front-loaded with the core function and a key result constraint, with no filler. It is appropriately brief, even though the missing usage context is penalized in other dimensions.

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?

The tool has 9 optional parameters, no required parameters, no output schema, and no annotations, but the description only covers one URL-status scenario. It does not explain what to do with the other parameters (city, feed, host, json, path, zone, query) or what exactly is returned, leaving the definition incomplete for correct invocation.

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%, so each parameter is already documented. The description adds only a slight contextual association between 'public library docs URL' and the url parameter; it does not meaningfully explain the many optional parameters or how they interact.

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 names a specific resource ('public library docs URL') and a specific result ('HTTP status'), and adds a scope-limiting trait ('Body discarded'). It is clearly more informative than a tautology, though it doesn't explicitly differentiate from sibling URL-status tools such as fetch-status or browser-url-ok.

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?

Use is implied: if an agent needs the HTTP status of a public library docs URL, this tool is a candidate. However, the description gives no when-not-to-use guidance or alternatives, and the broad nine-parameter schema makes it unclear when this tool should be chosen over similar URL-check siblings.

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