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

The annotations already carry the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), so the bar for additional disclosure is correctly lower. The description adds genuinely useful provenance by naming the public sources (DVF, Filosofi, DGFiP, INSEE) and framing the output as 'chiffres publiés', which tells an agent the data is official published data whose availability may depend on publication. Nothing here contradicts 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 compact: a front-loaded enumeration of the returned figures followed by sources and use-case guidance. Every element earns its place, though the long list of outputs makes the sentence slightly dense rather than glossy.

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?

With a single parameter and no output schema, the description compensates by enumerating the return fields in detail (prices, rent, tax, population, neighbours), which is effectively the missing output schema. Edge cases like communes lacking published data or how to compare two communes with one accepted parameter are unaddressed, but those are minor given the simple, lookup-style tool and annotation-covered safety.

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%: the single parameter 'commune' already has a description ('Nom de commune, adresse ou code INSEE : « Rennes », « 35238 »'). The description adds no additional meaning beyond what the schema already states, so the baseline score of 3 applies. A sentence specifying accepted input formats would push this higher.

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 a specific verb and resource ('Rend les chiffres publiés d'une commune française') and then enumerates the exact outputs: median property purchase price per square metre for houses and apartments, estimated listing rent, median standard of living, property tax rate, population and bordering communes. This precise itemization clearly distinguishes it from siblings such as 'cherche_adresse' or 'classement_taxe_fonciere'.

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 gives explicit use cases: 'À utiliser pour situer une commune, comparer deux communes ou répondre à « combien coûte l'immobilier à … »'. This is clear contextual guidance. However, it never names any sibling as the alternative for ranking or rent-control questions, so exclusion is left implicit, and 'comparer deux communes' sits awkwardly with a single-parameter schema.

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