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

Annotations already communicate that the operation is read-only, idempotent, and non-destructive functioning. The description adds value by specifying that it queries the BAN and returns coordinates plus INSEE code, and by flagging the arrondissement-vs-commune nuance. It does not discuss rate limits or pagination, but these are less material given the read-only hints.

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?

Two sentences carry the full functional description and the placement guidance with zero waste. The core purpose is front-loaded, and the caveat about INSEE/arrondissement codes is placed where it matters most—right after the primary call instruction.

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 geocoding look-up with no output schema, the description covers what the tool returns (coordinates and INSEE code), when to call it, and the critical Paris/Lyon/Marseille edge case. The input schema covers all parameter details, so nothing needed for correct invocation is missing.

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%, so the schema already documents both parameters and their valid ranges. The description reinforces the meaning of 'requete' ('adresse ou nom de commune') but adds no additional semantic detail beyond the schema, so the baseline 3 is appropriate.

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 states a specific action ('Résout une adresse ou un nom de commune en coordonnées et en code INSEE') and names the data source (Base Adresse Nationale). It also distinguishes this tool from the sibling set by explaining that other tools operate on INSEE codes, which clarifies its unique role.

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?

It explicitly instructs when to invoke this tool: 'À appeler en premier quand la question porte sur un lieu'. It also explains why this is necessary—other tools work on INSEE codes, and Paris/Lyon/Marseille are represented by arrondissement codes—giving the agent a concrete decision rule.

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