apply_promo_code_to_cart

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

No annotations are provided, so the description carries the behavioral burden. It discloses that the operation modifies the cart, associates the code with a facility and sub-basket, requires an authenticated session, and returns success or error. It does not mention potential replacement of an existing promo code or idempotency, but the core behavior and side effect (applying to cart) are clearly communicated.

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 short, front-loaded, and contains no fluff. Each sentence contributes: what the tool does, how the promo is associated, what the response returns, and the authentication requirement.

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 low-complexity mutating tool with three fully documented parameters and no output schema, the description provides enough operational context: action, target, association details, success/error behavior, and session requirement. A more complete description could mention behavior when a promo is already applied, but the current version is sufficient for safe invocation.

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 documents all three parameters with examples and 100% coverage, so the description does not need to add much. It reinforces the context for facilityServiceId and subBasketType, but does not add substantially new semantic meaning beyond the schema.

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 uses a specific verb ('Applies') and identifies the exact resource ('promotional/discount code' to the 'authenticated user's cart on Carrefour France'). It also clarifies the association with a facility/service and sub-basket type, making it clearly distinct from read-only sibling tools like get_advantage_codes or get_cart.

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 clear context for use: applying a promo code to a cart, with an explicit authentication requirement. It does not explicitly name alternatives or when-not-to-use cases, but the context is sufficient to guide selection among the sibling tools.

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