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

No annotations are provided, so the description carries the full burden. It discloses the HEAD method and that it returns status only, which implies a read-only operation. However, it does not mention behavior like redirect handling, timeout behavior, error responses, or that it only works on public URLs (which is stated but not elaborated). It does not contradict any annotation, but it is minimal.

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 a single, front-loaded sentence that states the core action and output. It is appropriately concise and avoids fluff. However, given the tool's complexity (9 parameters), it might be too terse, but it is not bloated and gets to the point immediately.

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 9 parameters, no output schema, and no annotations, the description is insufficient. It does not explain what 'status' means (e.g., HTTP status code), how the other parameters affect the operation, or what happens when multiple parameters are provided. The description covers only the URL case, leaving the tool's full behavior unexplained. An agent cannot confidently invoke it for non-URL parameters based on this description.

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?

The schema covers all 9 parameters with descriptions, so the baseline is 3, but the description does not explain how the non-URL parameters (ref, city, feed, host, json, path, zone, query) relate to the HEAD request. It says 'HEAD a public URL' which only aligns with the 'url' parameter. The schema descriptions indicate these are for shape checks and are discarded, but the tool description does not clarify that the tool actually validates various inputs and returns a status. This mismatch reduces clarity.

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 clearly states a specific verb (HEAD), a resource (public URL), and the result (status only). It differentiates from siblings like web-fetch (which fetches content) and browser-url-ok (which likely checks availability). The phrase 'status only' also clarifies the output scope, making the purpose 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?

There is no explicit guidance on when to choose this tool over alternatives. The description implies that if you need only a status, this is suitable, but it does not name sibling tools like web-fetch or browser-url-ok or state when not to use it. For a tool with many similar siblings, this is a significant omission.

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