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

Annotations already cover readOnly, idempotent and non-destructive, so the bar is lower, and the description still adds real value: it names the not_found error behavior and restricts scope to "produit public" (no private/non-public matches). It does not describe the shape or size of the returned detail payload, which is the remaining gap.

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?

Three short sentences, front-loaded with what it does, then when to use it, then the error contract and read-only note. No filler and nothing redundant with the schema or annotations.

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 should indicate what comes back; it gestures at "détails complets", "déclinaisons" and "disponibilité", enough to set expectations, plus the not_found failure mode. Rich annotations cover the safety profile, so this is nearly complete for a two-parameter lookup 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 coverage is 100%, so baseline would be 3, but the description adds provenance for `id` (it must come from search_catalog/lookup_catalog) and clarifies the id may refer to a product or a variant, which the schema's single line only hints at. The optional `context` object is left entirely to the schema, which documents it adequately.

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 specific verb and resource ("Récupère les détails complets d'UN produit") and scopes it to a single product by identifier, explicitly capitalizing UN to distinguish it from list/search behavior. It names the sibling tools as the source of the id, so an agent can separate it from search_catalog and lookup_catalog without opening either schema.

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?

Explicit trigger given: "À utiliser lorsque le client souhaite les détails, les déclinaisons ou la disponibilité d'un produit précis." It also states the prerequisite (id obtained via search_catalog or lookup_catalog), which is the exact routing an agent needs to reach this tool.

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