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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description does not need to repeat safety. It adds value by disclosing that the cadastre URL is returned 'quand elle existe' (when it exists), a conditional behavior, and by stating the precedence ('use first'). This enriches the agent's understanding beyond the annotations.

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 two sentences, front-loaded with the action and input, and every phrase earns its place. It includes the return fields, the conditional URL, and the usage context with zero fluff.

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 simple one-parameter search tool with no output schema, the description covers the input method, the output fields, and the usage context. It does not mention potential multiple matches or error handling, but given the tool's simplicity and the annotations covering safety, it is sufficiently complete for an agent to invoke 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 description coverage is 100%, and the schema already describes the 'query' parameter with an example. The description reiterates 'par nom ou code postal' but does not add new syntax or format details beyond the schema. Per the rubric, baseline 3 is appropriate when the schema fully documents parameters and the description provides no extra semantics.

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 a specific verb ('Recherche'), the resource ('commune française'), and the input method ('par nom ou code postal'). It also lists the output (INSEE code, coordinates, cadastre URL) and explicitly differentiates it from siblings by noting that the INSEE code is required for get_commune_stats. This is a precise, non-tautological purpose.

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 includes explicit guidance: 'À utiliser en premier quand on ne connaît que le nom d'une ville' (use first when only the name is known). It also implicitly advises that the returned INSEE code feeds into get_commune_stats, indicating a typical workflow. However, it does not explicitly mention when not to use it (e.g., if the INSEE code is already known), so it falls short of a 5.

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