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

The description discloses that only HTTP status and content type are returned and that the body is discarded, which is useful behavioral information. However, there are no annotations and no output schema, so important behavior such as redirects, timeouts, error responses, or authentication requirements is not addressed.

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 two short sentences with no filler or repetition. The core result is front-loaded, and every word contributes to the meaning.

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?

A tool with nine optional parameters, no required fields, no output schema, and no annotations needs more than an eleven-word description. The description does not connect the URL-focused behavior to the rest of the schema or help the agent choose among the many fetch-related sibling tools.

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 applies because the schema already documents each parameter. The description adds little parameter-level meaning and does not clarify why non-URL parameters like city, json, and zone appear alongside the URL-focused description.

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 states a specific action: retrieving HTTP status and content type for a public URL, with the body discarded. It is clear, but it does not distinguish web-fetch from closely related sibling tools such as fetch-status, browser-url-ok, or playwright-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?

No guidance is provided about when to use this tool instead of alternatives. With sibling tools like fetch-status, normalize-url, and inspect-robots available, the agent must infer selection criteria from the name and the short description alone.

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