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

With no annotations, the description carries full burden for behavioral disclosure. It only says 'HEAD a public URL and return status only' and omits any mention of side effects, rate limits, auth, failure behavior, or the fact that it also validates non-URL shapes. The lack of transparency is compounded by the parameter mismatch.

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 sentence with no fluff. The core action and output are front-loaded. It is maximally concise, though brevity here sacrifices completeness.

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 has 9 optional parameters and no output schema, yet the description explains only one narrow use case. It fails to explain what 'status' means, how to use the other parameters, what shape checks are performed, or why those parameters exist. This is grossly incomplete for an agent to call the tool correctly.

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 each parameter already has a description. The tool description adds nothing about how parameters relate or how they are used. The schema descriptions themselves are terse but adequate; the baseline of 3 is appropriate since the schema does the heavy lifting.

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 'HEAD a public URL and return status only' names a specific verb and resource, but the schema includes nine unrelated optional parameters (city, feed, json, path, zone, query) described as 'discarded after the shape check'. This mismatch means the description does not accurately cover the tool's actual scope, making it misleading about what the tool does.

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 on when to use this tool versus the many siblings (web-fetch, browser-url-ok, normalize-url, etc.). The phrase 'return status only' implies a narrow use case, but it never names alternatives or exclusions, leaving the agent to infer the appropriate context.

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