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

The description notes that the body is discarded, but with no annotations it does not disclose external network behavior, error cases, redirects, rate limits, or side effects.

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 a concise two-sentence statement with no wasted words, though it lacks any structured elaboration.

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?

Given the nine-parameter schema and overlapping sibling tools, the description omits essential context such as which parameter is the primary input, what the response looks like, and how failures are reported.

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?

Although every parameter has a description, most descriptions are irrelevant to fetching a URL (e.g., 'Git ref name', 'City name', 'IANA timezone name'), and the url parameter is described as 'normalize or cite' rather than fetch; all parameters are optional, so the required input is unclear.

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 and resource ('HTTP status and content type for a public URL'), but the input schema includes many unrelated optional fields, leaving the actual fetch target ambiguous.

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 prefer this tool over sibling tools such as fetch-status, browser-url-ok, or normalize-url; the only implicit use case is needing status/content type and not the body.

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