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

With no annotations, the description carries the burden of disclosing behavior; it does state the HTTP method, the public-scope requirement, and that only status is returned. It does not explain how the many non-URL parameters are handled or what happens on redirects or errors, though the schema's parameter notes add some discard behavior.

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 single sentence is concise and front-loaded, but it is under-specified for a tool with nine optional parameters and no output schema. It is not bloated, yet it leaves the agent to discover the schema's full behavior.

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 is complex: nine heterogeneous optional parameters, no annotations, and no output schema. The description only covers URL checking and gives no indication of what statuses are returned, which parameters are valid together, or why city, JSON, timezone, and search query inputs belong in the same schema.

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 schema already documents all nine parameters; the description adds no parameter-level meaning. The schema notes like 'discarded after the check' are helpful, but the description itself does not clarify which parameter or combination should be supplied.

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 concrete HTTP verb (HEAD), a target (public URL), and a narrow output (status only), so the basic action is clear. It does not explicitly distinguish it from siblings like web-fetch or browser-url-ok, and it only describes one of the nine schema parameters.

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 guidance about when to use this tool versus web-fetch, browser-url-ok, normalize-url, or the shape-checking siblings. The phrase 'status only' weakly implies a lightweight check, but it never states when this tool should or should not be chosen.

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