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

Annotations already mark the tool as read-only and non-destructive, but the description adds substantial behavioral detail beyond that: output values must be passed verbatim, the result includes latitude/longitude intended for aroundLat/aroundLng, and arrondissement postcodes like 69003 resolve to Lyon. This gives the agent a clear model of what the tool does with the input and what it returns.

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 well organized and front-loaded, but it repeats nearly the entire content in both French and English, making it much longer than needed for a one-parameter resolver. While bilingual text can be intentional, the duplication means many sentences do not earn their place in an otherwise compact tool definition.

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?

The description is complete for this tool's complexity: it explains accepted input formats, resolution behavior, the exact output fields to reuse, and how to use coordinates with radiusKm. Since there is no output schema, the description compensates by naming the relevant return values and their intended downstream usage.

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 query parameter with 100% coverage, including examples and arrondissement behavior. The description restates some of this but does not add significant new meaning about the query parameter itself; its extra value is more about how to use the resolved outputs, which belongs to behavior rather than parameter 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 states a precise action: 'Résout un lieu français à partir d'un code postal ou d'un nom de ville' and explains that it returns values to reuse in searches. This makes the tool's resource and purpose unambiguous, and it clearly distinguishes the tool from the search/get siblings by focusing on location resolution as a prerequisite step.

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 explicitly tells when to call the tool: 'À appeler avant toute recherche "près de chez moi"' and explains how to use its outputs for both verbatim city/department values and aroundLat/aroundLng radius searches. It also gives a concrete fallback strategy: use the coordinates when a small town yields nothing. This is strong usage guidance even without naming sibling alternatives.

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