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

Annotations already declare readOnlyHint=true and idempotentHint=true, covering the safety profile. The description adds context about accepted ID formats and the scope of returned data, but it does not disclose error behavior, rate limits, or dependency on external factors. This is adequate but not beyond what annotations provide.

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 dense sentence enumerating all the returned data, followed by a clear identifier instruction. Every phrase adds information, and it is front-loaded with the core content. It is long but not verbose, though it could be broken into two sentences for easier 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 an output schema exists and annotations cover read-only/idempotent behavior, the description is sufficient for an agent to know what it returns and how to call it. It does not mention failure modes or edge cases (e.g., codes not found), but the presence of an output schema fills in the return structure. Overall, the description is complete enough for correct invocation in the common case.

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% with a short description of the 'id' parameter. The tool description adds concrete examples ('01.511.01.0' and 'tanger') that clarify the accepted formats, providing extra value beyond the schema's generic wording. This nudges it above the baseline 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 returns a wide array of data for a single commune (names, type, populations, borders, arrondissements), and specifies the identifier types. It is unambiguous about the resource and scope, but it does not explicitly name sibling tools or contrast with them, so it falls short of a 5.

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 explains how to identify the commune (HCP code, digits, or slug) but gives no guidance on when to use this tool versus alternatives like list_communes, commune_at, or get_unit. There is no mention of use cases, prerequisites, or exclusions, so the agent is left to infer situational appropriateness from the name alone.

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