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

No annotations are supplied, so the description alone must disclose behavioral traits. It only mentions the output content and never states that the operation is read-only, how invalid codes are handled, what response format is used, or any other operational side effects (e.g., rate limits or prerequisites). The lack of this information is a meaningful gap for an agent invoking the tool.

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 one short, front-loaded sentence that communicates the tool's purpose and the full list of return fields without any filler. Every item in the list is relevant and the structure directly supports agent comprehension.

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?

For a single-parameter read-only lookup with no output schema or nested objects, the description is largely complete because it lists exactly what the agent will receive. It falls short only in not describing error behavior for invalid department codes or the concrete JSON response shape, but it covers the main informational needs for correct invocation.

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 already documents the single parameter 'code' with its type and example values, achieving 100% schema coverage. The description adds context about DMTO rates and the domain, but it does not enrich the meaning of the 'code' parameter itself, so the baseline for full schema coverage applies.

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 opens with 'Retourne' (returns) and lists the exact data fields: nom, région, préfecture, taux DMTO standard/appliqué, hausse 2025, slug. This makes the tool's purpose unmistakable and distinct from siblings calculate_frais_notaire and compare_departements, which involve calculation and comparison rather than simple information retrieval.

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 the tool is used to fetch static department metadata by the list of returned fields, but it does not explicitly state when to prefer it over the sibling tools or when not to use it. No exclusions or alternative routing are provided, so the agent must infer usage from the name and output fields.

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