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

Annotations already provide readOnlyHint=true, so the read-only safety is covered. The description adds behavioral nuance: results are returned as frozen at addition, price age can be assessed via `pricedAt` and `expiresAt`, and stale data should be re-quoted. This goes beyond the annotations without contradicting them.

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?

Two compact sentences with no wasted words. The first sentence states purpose and core behavior; the second adds freshness indicators and routes to an alternative. Information is front-loaded and immediately usable.

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?

For a single-parameter read-only tool with no output schema, the description explains the return semantics (frozen cart, `pricedAt`, `expiresAt`) and provides a fallback action. It omits error behavior and full response shape, but the key facts an agent needs are present.

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 covers the single parameter `cartId` with a detailed capability warning, so schema coverage is 100%. The tool description adds no information about the parameter itself; it only refers to output fields, which matches the baseline 3 for fully documented schemas.

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 ('Renvoie') and resource ('le panier'), and adds the key scoping constraint 'tel que FIGÉ à l’ajout' (frozen at addition). This clearly differentiates it from quote_product and other sibling tools by highlighting that reading does not re-quote.

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?

Explicitly instructs when to use an alternative: 'au-delà, re-cotez avec quote_product' (beyond the expiry, re-quote with quote_product). It also establishes the tool's role as a frozen read with no re-quotation, giving the agent a clear decision rule.

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