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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description still adds genuine value beyond them: the ordering follows 'l'ordre du comparatif de Sous La Gélule' and prices are normalized to 'prix par mois à quantité égale' — non-obvious semantics an agent could not derive from the annotations or schema.

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?

A single dense sentence with no filler; the resource and the ordering rule are front-loaded. The phrase structure is slightly list-like and lacks a verb, but nothing is redundant.

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 no output schema, the description carries the burden of describing what comes back, and it does list the returned attributes (price per month at equal quantity, shop, price date) plus the ranking basis. What remains unstated — pagination behaviour across ranks and the full meaning of the comparison order — is minor for a read-only ranking tool.

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%, with 'limite' and 'depuis_le_rang' fully documented including defaults and bounds, so the baseline of 3 applies. The description adds nothing about these parameters — notably no mention that the result set is paginated by rank, which is the one place extra meaning would have helped.

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 names the resource ('le classement d'une catégorie') and specifies the ordering basis and the data returned (prix par mois à quantité égale, boutique, date du prix), so the agent knows what it gets back. It is a noun phrase rather than a verb+resource statement and never distinguishes itself from siblings like 'meilleur_choix' or 'chercher_produit', which is the only thing keeping it from a 5.

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?

There is no when-to-use guidance at all — nothing says to call this instead of 'meilleur_choix' for a single recommendation or 'chercher_produit' for lookup. The agent must infer the fit from the noun phrase alone, with no exclusions or preconditions stated.

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