change_plan

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It openly states the write scope ('Escopo write') and the timing semantics (immediate vs scheduled, proration), which are genuine behavioral traits. It does not cover reversibility or failure behavior, but the core mutating nature and scheduling nuances are disclosed.

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 a single compact sentence that front-loads the core purpose and packs in the timing/proration behavior without waste. It is appropriately sized for the tool.

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?

Given the tool has 3 parameters, no output schema, and no annotations, the description provides solid behavioral context but leaves the semantics of the parameters (especially keep_coupon) and the return/confirmation behavior undocumented. It is adequate but has clear gaps an agent would need filled.

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%, so the description must compensate for the undocumented parameters, but it does not explain any of them. offer_slug's expected format is unknown, and keep_coupon — an optional boolean — is entirely unexplained, leaving an agent to guess its meaning when calling the tool.

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 states a specific verb and resource ('Troca o plano de uma assinatura') and adds precise behavioral detail: immediate upgrade with proration versus scheduled downgrade/cycle change. This clearly distinguishes it from its sibling cancel_plan_change, leaving no ambiguity about what the tool does.

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 conveys context by explaining that upgrades take effect immediately with proration while downgrades/cycle changes are scheduled, which helps an agent decide when calling this tool is appropriate. However, it never names an alternative tool or an explicit when-not-to-use condition, leaving the trade-off against siblings like cancel_plan_change to inference.

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