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

With no annotations, the description carries the behavioral burden; it does disclose the HTTP method (HEAD), the public nature of the URL, and the restricted output. However, it fails to acknowledge that the input schema contains many unrelated parameters documented as discarded, which is a significant behavioral ambiguity.

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 with no filler or repeated information. Every word contributes to stating what the tool does.

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 output schema, and no annotations, so the description alone is not enough. It doesn't state which parameter is actually used, what the returned status looks like, or how to handle the discarded parameters, leaving an agent to guess.

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 the baseline is 3. The description adds the operation (HEAD) applied to a URL, but it doesn't explicitly identify `url` as the only effective parameter or explain the role of the other eight optional fields, and the schema's `url` description ('normalize or cite') conflicts with the described use.

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 verb ('HEAD'), a resource ('a public URL'), and an output ('return status only'), making the core purpose clear. It is distinguishable from siblings like web-fetch or browser-url-ok by the emphasis on HEAD and status-only, though it doesn't explicitly name them.

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 statement of when to use fetch-status versus alternatives such as web-fetch, browser-url-ok, or normalize-url, and no exclusions or conditions. The only implicit signal is that status-only HEAD requests belong here, which is weak guidance.

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