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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does disclose that the body is discarded, which is useful for an agent deciding whether this tool provides enough information. However, it does not describe the return format, whether the URL is fetched over the network, or any 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 only 11 words across two sentences and front-loads the action. It is free of filler, but its brevity sacrifices a useful pointer to the relevant parameter.

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?

For a tool with 9 optional parameters, no annotations, and no output schema, this description is under-specified. An agent cannot tell whether to use url, city, feed, json, or another field, nor what the returned HTTP status looks like. The mismatch between the narrow description and the broad schema leaves a significant gap.

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 input schema already documents all 9 parameters. The description adds no param-specific meaning and never indicates which parameter applies to 'lib-docs-hint'; it only mentions 'URL' generically, leaving the other 8 parameters unexplained in context.

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 concrete outcome—HTTP status for a URL—and notes that the body is discarded, so it is not a pure tautology. However, 'public library docs URL' is vague and does not distinguish this tool from siblings like fetch-status or browser-url-ok. The schema also lists 9 unrelated parameters, so the description does not clarify the tool's actual scope.

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 explicit guidance about when to use this tool versus siblings such as fetch-status, normalize-url, or web-fetch. 'Body discarded' is a hint that the body is not returned, but it is not a clear when-to-use or when-not-to-use statement.

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