cancel_subscription

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

With no annotations, the description carries the full burden. It discloses idempotency, terminality, and the 422 error condition for payable Pix QR, plus 'Escopo write' (write scope). This is significant behavioral context, though side effects beyond cancellation (e.g., billing impact) are not mentioned.

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?

A single, compact sentence that conveys the action, key properties (terminal, idempotent), a critical error condition, and scope. No wasted words, and the most important information is front-loaded.

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?

The description covers the core behavior and a key error condition, but is incomplete for an agent: it does not explain the reason parameter, nor does it describe expected responses or side effects beyond cancellation. Given the lack of annotations and output schema, more context is needed 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 schema documents subscription_id (required) and reason (optional), but the description does not mention either. Since schema description coverage is 0%, the description fails to add any meaning to the parameters—particularly the optional reason is left entirely 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 clearly states the action ('Cancela') and resource ('assinatura'), and adds that it is terminal and idempotent. It does not explicitly name a sibling to contrast with, but the action is unambiguous against the read-only sibling tools.

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?

No guidance is given on when to use this tool versus alternatives like change_plan or cancel_plan_change. The description mentions terminality but does not contextualize when cancellation is appropriate or when another tool should be used instead.

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