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

Annotations already declare the mutation profile (readOnly=false, destructive=true, idempotent=false, openWorld=true), so the bar is lower. The description adds two genuinely useful facts beyond them: the mandatory client-approval gate and that the price is recalculated server-side (so the final price may differ from the quote). It still does not say what happens on failure, whether a booking can be duplicated, or how confirmation is signalled.

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 the action, then the precondition, then the price caveat. Nothing is redundant and no sentence could be dropped without losing meaning.

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 13-parameter mutation with nested objects and no output schema, the description covers the invocation gate well but says almost nothing about the return (other than the price being recalculated), nor about failure or refund/cancel paths. The payment-mode outcomes (payment link for en_ligne) live only in the schema, so the high-level behaviour described is thinner than the tool's complexity warrants.

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 77% and the schema documents the enums, formats, and nested client object thoroughly, so the structured data does the heavy lifting. The description only reinforces the accord_client precondition already stated in the schema. Per the coverage rule, baseline 3 is appropriate.

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?

« Enregistre la reservation pour le client » states a specific verb (enregistrer) and resource (reservation), and the reference to calculer_prix identifies the sibling this tool depends on versus the read-side lire_reservation / lister_vehicules. An agent can tell what this tool does and where it sits in the flow without opening the 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?

The description gives an explicit gating rule: call ONLY after calculer_prix and after the client's explicit approval of the recap. That is a concrete when-to-use ordering constraint with a hard precondition (accord_client), not an implied one. The only gap is that it doesn't name alternatives to use instead, but the prerequisite already rules them out.

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