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

Although annotations already declare it read-only, open-world, idempotent and non-destructive, the description adds non-obvious behavior: it fetches linked pages to check they load and separately probes for llms-full.txt. That discloses real network side effects beyond the annotation set.

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?

Front-loaded with the purpose and criteria, followed by action guidance and the alternative. Dense but every clause carries information; the inline list of format checks is long but directly useful for interpreting results.

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?

An output schema exists so return values need no explanation, and annotations cover the safety profile. What remains — validation criteria, draft mode, and the sibling fallback — is fully covered, leaving nothing an agent needs to call it correctly.

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 params are documented, but the description adds genuine meaning by explaining the draft-validation scenario for 'text' rather than merely restating that it replaces the live file. The url param's example is left to the schema.

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?

States a specific verb (validate) and resource (llms.txt), and enumerates the exact rules checked (text serving, single H1, > summary, ## sections, size, link liveness). It names the sibling generate_llms_txt as the fallback, so an agent can distinguish it from its neighbors without opening schemas.

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?

Gives explicit when-to-use guidance for the optional text parameter ('Pass text to validate a draft before uploading it') and a clear alternative path ('If the site has none, use generate_llms_txt'). Both the draft workflow and the missing-file case are routed unambiguously.

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