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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds real behavioral context: the provenance distinction (measured on DVF sales vs estimated), the arrondissement counting for Paris/Lyon/Marseille, and the rule that missing prices are reported as absent, never guessed. It does not restate annotation fields.

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 core scope is front-loaded in the first clause, followed by routing rules. It is dense but each sentence carries information; the only slight excess is the closing reassurance sentence, which is borderline redundant with the earlier 'jamais deviné' clause.

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?

No output schema exists, so the description deliberately names the return fields (valeur, provenance, millésime, date de reconstruction) and the missing-value behavior. Combined with the explicit routing among siblings, an agent has everything needed to call it 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 documents the commune/INSEE/postal-code forms and the PLM arrondissement notation. The description adds essentially nothing about the parameter beyond that, so the baseline of 3 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?

States a precise verb+resource+scope: reference price per m² for ONE French commune, apartments and houses, explicitly 'et rien d'autre'. It also enumerates the returned facets (valeur, provenance, millésime), so the agent knows exactly what this returns versus the sibling tools.

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?

Gives an explicit inclusion rule ('quand la question porte seulement sur le prix d'une commune') and names each alternative with the condition that selects it: marche_commune for rent/yield/trend/tension, prix_m2_quartiers for neighborhood detail, comparaison_communes for multiple communes.

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