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

The phrase 'HEAD' and 'status only' usefully signals a read-only operation that does not retrieve content, which matters because no annotations are provided. However, it does not disclose redirect handling, error behavior, timeout behavior, or the fact that the many non-URL parameters appear to be discarded or ignored. The safety profile is only partially transparent.

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 sentence with no filler, and the core constraint 'status only' is stated directly and front-loaded. It is appropriately concise for what it attempts to express.

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 no output schema and no annotations, the description should clarify what 'status' means and how the nine optional parameters relate to the operation; it does neither. The URL-only phrasing leaves the purpose of ref, city, feed, json, zone, and query unexplained, making the definition insufficient for reliable 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 coverage is 100%, so the input schema already documents each of the nine parameters individually; the description adds no parameter-level meaning. The mismatch between the URL-centric description and the heterogeneous schema is not addressed, but the baseline holds because the schema itself is complete.

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 HTTP verb (HEAD), a resource class ('public URL'), and an output scope ('status only'), so the core action is clear. However, the input schema contains nine heterogeneous optional parameters such as ref, city, feed, json, and zone, which the description never acknowledges. This makes the tool's full purpose ambiguous despite the clear URL-focused phrasing.

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?

The description gives no guidance about when to choose fetch-status over sibling tools like web-fetch, browser-url-ok, playwright-url-ok, or normalize-url. It implies a public URL HEAD check but provides no exclusions, prerequisites, or alternative-selection conditions.

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