credito_recarregarTops up prepaid credit: pay once with x402 and get the token that is charged in any API of the house. Returns: { token, saldo_usd, guarde, usar, usar_com_outra_credencial, saldo_em, onde_gastar }
| Name | Required | Description | Default |
|---|---|---|---|
| usd | Yes | Package: 0.1, 1, 5, 10 or 25 dollars. |
Changes observed during successful MCP inspections.
Input schema / properties / usd / descriptionPrevious value: -"1, 5, 10 ou 25"New value: +"Pacote em dólares: 0.1, 1, 5, 10 ou 25."Input schema / properties / usd / enumAdded value: +[
+ 0.1,
+ 1,
+ 5,
+ 10,
+ 25
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds real context beyond the annotations: this is a paid x402 operation whose output is a charge token. But with idempotentHint=false and destructiveHint=false, the risk an agent most needs to know is unstated — that repeating the call spends money again and there is no undo. The cryptic return-key list does not compensate for that missing caution.
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?
Two sentences, front-loaded with the action and payment mechanism. The return-key enumeration is dense but earns its place since there is no output schema; the untranslated keys (guarde, usar, saldo_em) make it harder to parse but it stays compact.
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 one-parameter purchase whose annotations cover the safety profile, the definition covers the payment flow and the return shape, which is the main unknown. The only gap is guidance on repeat invocation and how the returned token is subsequently supplied to other APIs.
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 coverage is 100% and the single 'usd' parameter is fully documented with an enum of 0.1/1/5/10/25. The description adds nothing about the parameter, so the 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 ('Tops up prepaid credit') and adds the mechanism (pay once with x402, receive a token charged across the house's APIs). That distinguishes it from a pure balance read like credito_saldo, but it never names the sibling, so an agent must infer the distinction.
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?
Implies usage ('pay once ... get the token that is charged in any API'), so an agent can infer this is the step before paid calls. However, it gives no explicit when/when-not against credito_saldo, buy_plan, api_access_buy, or billing, all of which sit adjacent to this action.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.