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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It discloses the HEAD method and status-only return, but it fails to reveal that the tool actually performs diverse shape checks — the schema shows 9 heterogeneous inputs (city, zone, json, query, etc.) many marked 'discarded after the check' — which is behavior far beyond 'HEAD a public URL.' This mismatch is a significant transparency gap.

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?

At eight words, the description is extremely terse, but for a tool with nine parameters this reads as under-specification rather than disciplined conciseness. Critical information about the multi-parameter shape-check behavior and return semantics is omitted to the point of misleading brevity.

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?

Given nine parameters, no annotations, no output schema, and 28 siblings, the description is far from complete. It does not explain the return format (no output schema), the purpose of the non-URL parameters, or how it differs from the four-plus URL-checking siblings. An agent cannot confidently invoke this tool correctly based on the description alone.

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%, which normally warrants a baseline 3. However, the description states the tool heads a URL, while only one of the nine parameters (url) relates to that purpose. The other eight parameters (city, zone, json, path, query, etc.) are inconsistent with the stated purpose, and the description does nothing to reconcile this or clarify how they factor into the call.

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 specific verb (HEAD), resource (public URL), and return value (status only). It is clear and compact, and the HTTP HEAD verb distinguishes it from content-fetching tools. However, it does not explicitly differentiate from URL-related siblings like browser-url-ok, playwright-url-ok, or web-fetch, so it gets a 4 rather than 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?

No guidance is given on when to use this tool versus the many URL-adjacent siblings (browser-url-ok, playwright-url-ok, web-fetch, normalize-url, inspect-robots). There is no when-to-use, no exclusions, and no mention of prerequisites such as URL reachability. The intended usage must be inferred entirely from the terse description.

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