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

With no annotations, the description must carry the behavioral burden. It does disclose 'Body discarded,' which tells agents the tool returns only status and no body. But it omits other relevant behavior such as whether it performs a network fetch, handling for the diverse params, 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 two sentences and wastes no words; 'HTTP status' and 'Body discarded' are front-loaded. It is appropriately short, but the brevity comes at the cost of failing to resolve the mismatch with the 9-parameter schema, so it is not a 5.

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 output schema, and no annotations, a single-sentence description is incomplete. It does state the broad return type (HTTP status), but it never explains how the parameters relate to the operation, what constitutes a valid call, or what distinguishes this from sibling URL 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%, and each parameter already has its own note (e.g., 'discarded after the check'). The description adds no parameter meaning beyond that baseline, and its 'library docs URL' focus doesn't explain the unrelated parameters like city, zone, or feed. 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 names a specific resource ('public library docs URL') and result ('HTTP status'), so agents can guess the core purpose. However, it doesn't distinguish this tool from URL-status siblings like fetch-status, browser-url-ok, or web-fetch, and the broad 9-parameter schema (city, json, zone, etc.) doesn't align with the narrow description.

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 guidance on when to use this tool versus alternatives, and no exclusions or calling context. The phrase 'public library docs URL' implies a niche, but it doesn't state when an agent should pick this over other URL-checking tools.

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