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

With no annotations, the description carries the full burden. It does disclose the key behavioral trait that the response body is discarded, and implies read-only network behavior. However, it omits details about redirects, timeouts, auth requirements, error behavior, or rate limits, so transparency is only partial.

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?

Two short sentences with zero filler. The core outcome is front-loaded, and the important 'body discarded' caveat follows immediately. This is an appropriately sized definition for its core promise.

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 complete for a simple single-URL fetch, but the schema accepts nine unrelated optional parameters (ref, city, json, zone, query, etc.) with no tool-level explanation of how they relate to the fetch operation. With no output schema and no annotations, an agent cannot confidently determine which parameter to supply or what the response will look like beyond status and content type.

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 structured schema already documents all nine parameters. The description itself adds no parameter-level meaning beyond pointing at URLs. Baseline 3 is appropriate because 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 clearly states the operation: returning HTTP status and content type for a public URL, with the body discarded. This is a specific verb+resource and helps distinguish from content-grabbing fetchers, though it does not explicitly distinguish it from the sibling fetch-status tool.

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 use this tool versus fetch-status, browser-url-ok, playwright-url-ok, normalize-url, or citation. 'Body discarded' implies the tool is not for content retrieval, but no explicit exclusions or alternative routing are provided.

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