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

With no annotations, the description must carry the full behavioral burden. It only mentions 'Body discarded,' which is a minor detail. It doesn't disclose side effects, permissions, error behavior, or what the HTTP status means. No information about the tool's actual execution beyond that.

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 extremely short, but that is under-specification, not conciseness. For a tool with 9 parameters and no annotations, a single sentence is inadequate. The structure offers no progressive disclosure—no headers or breakdown of behavior.

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 tool's complexity (9 optional parameters, no output schema, no annotations), the description is woefully incomplete. It doesn't explain the purpose beyond a vague 'library docs' phrase, doesn't cover the parameters, and gives no sense of return values or failure modes. An agent cannot confidently call this tool.

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 schema documents each parameter, but the description completely ignores them and doesn't explain how they relate to the stated purpose. The mismatched parameters (city, zone, json) are not tied to 'library docs URL,' so the description adds confusion rather than clarity. It doesn't help an agent understand which parameter to use.

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 says 'HTTP status for a public library docs URL' but the schema includes 9 unrelated parameters (city, timezone, JSON, etc.) with no connection to library docs. This is misleading—an agent would be confused about what the tool actually does. It fails to define a clear scope matching the schema.

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 on when to use this tool versus any of the 28 siblings like fetch-status, web-fetch, or normalize-url. The description gives no context, exclusions, or alternatives. An agent has no basis to select this tool over others.

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