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

With no annotations, the description must carry the behavioral burden; 'Body discarded' is a useful, non-obvious disclosure that only the status is meaningful, and 'HTTP status' clarifies the output. But it does not address error behavior, how status is determined, whether network access is used, or what happens when different or multiple params are supplied.

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 terse sentences with no filler; the most important behavioral caveat ('Body discarded') is stated immediately, and every phrase earns its place.

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 combination of nine optional parameters, no annotations, and no output schema needs more than a one-line description. An agent cannot tell how to invoke the library-docs-URL use case, what the returned status looks like, or why the schema includes city/feed/json/zone/query parameters; the per-parameter schema descriptions do not connect these to the tool's stated purpose.

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 coverage is 100%, so the baseline is 3; the schema already describes each parameter. The tool description adds almost nothing about parameter semantics beyond implying the 'url' field is the relevant one, and with nine optional parameters it does not clarify whether they are alternatives, combinations, or unrelated.

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 identifies a concrete output ('HTTP status') and a specific resource ('public library docs URL'), and it adds a meaningful behavioral note ('Body discarded'), so the basic operation is understandable. It does not name or differentiate against close siblings such as fetch-status or browser-url-ok, so it misses the top score; the broad nine-parameter schema also muddies which input is actually relevant.

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 when-to-use guidance, no mention of alternatives, and no exclusion such as 'for general URLs use fetch-status instead.' The only inference is from the narrow phrasing 'public library docs URL,' which is not enough to route an agent reliably among the sibling tools.

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