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

Annotations already signal a mutation (readOnlyHint=false, idempotentHint=false), and the description confirms 'Mutações.' It adds bulk execution behavior and the action signature, but it does not disclose side effects, validation behavior, auth/account requirements, or what happens after a coupon is added. No contradiction with annotations.

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 padded with a large action list covering unrelated operations (e.g., cancel, change_plan, set_payment_types) before the relevant add_coupon line. Including the full mutation list for a single flattened action is inefficient and distracts from the tool's actual purpose.

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 mutation tool with no output schema and four parameters including a nested `data` object, the description provides no return-value behavior, no data-payload details, and no account context. Even considering the sibling tool names, the description is too thin for an agent to invoke it correctly beyond guessing `id`.

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 0%, and the description only indicates 'id + data' for add_coupon and 'ids' for bulk. It does not explain the structure of the `data` object, the role of `account`, or the relationship between `id` and `ids`. With four parameters, most parameter semantics remain undocumented.

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 names 'add_coupon (id + data)' and includes the '[Flattened action: add_coupon]' marker, so the operation is identifiable. However, it opens by listing 14 different mutation actions ('Ações: cancel ... change_plan ...') and never states in plain terms that this tool adds a coupon to a subscription, which muddies the purpose.

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?

There is no explicit when-to-use or when-not-to-use guidance. The description lists sibling actions but does not say to prefer this tool for adding coupons and another for removing or canceling. The only usage hint is 'Bulk support: accepts ids for batched execution,' which addresses batching, not tool selection.

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