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

The description adds several behavioral details beyond the annotations: recentCoverage is always null and why, the requirement for the people API scope, and English fallback for untranslated fields. These are useful and not present in the annotations, which already declare readOnlyHint and destructiveHint. The explanation of the null field is particularly informative.

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 concise, with three sentences that front-load the core purpose. The first sentence establishes the main function, and subsequent sentences provide necessary caveats (null field, auth, language). There is no unnecessary repetition or filler, and it is well-structured for quick scanning.

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 presence of an output schema and annotations, the description is fairly complete. It covers the main purpose, an important behavioral caveat (recentCoverage null), auth requirements, and language fallback. It does not cover error scenarios or rate limits, but for a simple get operation with an output schema, these are minor omissions. The description is sufficient for an agent to call the tool 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?

The schema has 50% coverage: lang has a description, while id does not. The description adds context by indicating that id identifies a person with aliases folded in, and it reinforces the lang behavior by stating English is the fallback. However, it does not significantly expand on parameter formats or constraints beyond the schema, so it only partially compensates for the missing id description.

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 that the tool returns one person with all spelling variants folded into them, covering identity and aliases. It distinguishes itself from the sibling people_list by focusing on a single resource, and the verb is implied as 'get' based on the name and context. It is specific and not tautological.

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 for retrieving a single person's details, but it does not explicitly state when to use this tool versus alternatives like people_list. It mentions a required API scope as a prerequisite, but no direct guidance on selection criteria. The name and sibling context suggest the intended use, but the description lacks explicit 'when to use' or 'when not to use' statements.

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