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

With no annotations, the description carries the full burden. It transparently states that only a HEAD request is made and only status is returned, but it does not describe error behavior, timeout handling, or whether any content is ever fetched, leaving some 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, focused sentence with no redundant wording. It directly communicates the core operation and output in a concise manner.

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 description is too minimal for the tool's complexity. It does not explain the nine parameters, many of which appear irrelevant, nor does it describe output format, error conditions, or how it relates to the sibling URL-checking tools. An agent would likely be uncertain about which parameters are actually needed.

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 descriptions cover all parameters, so the baseline is 3. However, the tool description adds no parameter-level meaning, and several schema descriptions (e.g., url 'to normalize or cite', ref 'discarded after shape check') seem unrelated to a HEAD status check, creating confusion rather than 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 the action (HEAD request), the target (public URL), and the output (status only), which distinguishes it from tools that fetch full content. However, it does not explicitly mention why this tool exists relative to its many sibling network-checking tools.

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 about when to prefer this tool over alternatives like web-fetch, browser-url-ok, or normalize-url. The phrase 'return status only' implies a use case but does not explicitly state conditions or compare with siblings.

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