Explain a check and how to fix it

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

No annotations are provided, so the description carries the full burden. It describes the output behavior (explaining verification, importance, remediation) but does not disclose potential side effects, rate limits, or output structure. The read-only nature is implied but not explicit.

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 a single sentence that is concise and front-loaded with the tool's purpose. Every word is informative, and there is no redundancy or wasted content.

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 description explains what the output contains, compensating for lack of an output schema. However, it could mention the language parameter's role or output format. Given the complexity (two params, no output schema), it is mostly complete.

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?

The input schema covers both parameters (check_id, lang) with descriptions. The tool description does not add extra semantics beyond the schema, such as explaining the impact of the lang parameter or how check_id is used. With 100% schema coverage, baseline is 3.

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 clearly states the tool's action ('explain what it verifies, why it matters, and how to remediate a failure') and resource ('a check id'). It distinguishes from sibling tools: 'check_domain' runs checks, 'list_checks' lists them, while this explains.

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?

The description implies usage context ('Given a check id (see list_checks)') by referencing the sibling tool for obtaining valid IDs. It does not explicitly state when not to use or provide alternatives, but the guidance is clear enough for an agent to understand prerequisites.

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