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

With no annotations, the description must disclose behavior, and it does reveal the HEAD method and public-URL constraint. However, it never explains how the other eight schema parameters (ref, city, json, path, zone, query, etc.) affect behavior or what a returned 'status' looks like; the schema's own parameter descriptions ('normalize or cite', 'discarded after the shape check') point to behavior not covered by the description.

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 one-sentence description is front-loaded and free of filler, with the verb in the first word. It is appropriately terse for a simple status-check tool, though the brevity hides the complexity of the nine-parameter schema.

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?

No output schema and no annotations mean the description must specify return format and scope; 'status only' does not say whether the result is an HTTP code, a string, or an object. It also does not address the nine optional parameters, zero-required behavior, or sibling alternatives, so the definition is incomplete for reliable 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 baseline is 3, but the description adds no useful parameter guidance and even seems inconsistent with the schema: the `url` parameter is described as 'HTTPS URL to normalize or cite,' not as a URL to HEAD, and it is unclear whether `feed` or `host` are alternatives or irrelevant. An agent cannot reliably choose which parameter to populate.

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 action (HEAD) and a precise result ('status only'), so an agent can see this is a lightweight URL status check. It does not, however, distinguish this tool from sibling URL tools like web-fetch, browser-url-ok, or playwright-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?

'Return status only' implies the tool is for lightweight checks where the response body is not needed, but there is no explicit when-to-use guidance, no alternatives named, and no exclusions such as 'use web-fetch for full content.' This is implied usage at best.

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