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

With no annotations, the description carries the full burden and does disclose the method (HEAD), the scope (public URL), and the limited return value. But the input schema exposes many optional parameters (city, path, json, etc.) whose relationship to the HEAD call is unexplained, and redirect/error behavior is not covered.

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?

A single, front-loaded sentence with no filler. Every word earns its place and the core action is immediately clear.

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?

For a tool with no output schema, no annotations, and 9 optional parameters, the description is thin: it does not specify the exact format of the returned status, does not state that `url` is effectively required despite the schema listing 0 required parameters, and does not say what happens if multiple parameters are supplied. Still, the common 'HEAD a URL' path is reasonably clear.

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 tool description adds the key clue that `url` is the actual target of the HEAD request, but it does not clarify why the other eight optional parameters exist or whether url is effectively required.

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 uses a specific verb ('HEAD'), names the resource ('public URL'), and specifies the narrow output ('status only'). This clearly distinguishes it from content-fetching siblings like web-fetch and from boolean URL checks like browser-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?

It clearly implies the tool is for when only an HTTP status is needed, not page content. However, it does not explicitly name alternatives or state when not to use it, so it stops short of the top score.

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