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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, and the description reinforces read-only while adding substantial context beyond annotations: it lists the exact rule data shown (mode, thresholds, welcome stamps, expiration, points settings, style, color, stamp, public signup link). With no output schema, this is exactly the disclosure an agent needs about the return content.

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?

Front-loaded with the core action and then the usage rule; the long enumeration of settings is informative rather than filler. The closing 'Lecture seule' repeats the readOnly annotation and is the only clearly redundant phrase.

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?

No output schema exists, so the description must convey what is returned, and it does so thoroughly by listing the card preview and rule fields. Parameters are schema-documented and safety is annotation-documented, leaving nothing important for an agent to call this tool correctly.

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%, so the meaning of qr, variantes, and tampons_poses is fully documented in the schema. The description only adds the cross-tool note that modifier_carte uses the same setting names, which is useful but does not explain the parameters themselves, so baseline 3 applies.

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 — it shows the loyalty card as customers see it in Apple/Google Wallet — and enumerates the rule fields returned. It also explicitly contrasts with modifier_carte, so an agent can distinguish it from the sibling mutation tool 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?

Gives explicit when-to-use conditions: before any modification, because modifier_carte reuses the same setting names, or when the merchant asks what the card looks like or what its rule is. The alternative is named alongside the condition that selects it.

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