Listar gateways de cartão (chaves públicas)

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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds value by explaining the security reason for not exposing card charging and specifying that it returns public keys (publishable keys). 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 a single, well-structured sentence in Portuguese. It includes the core purpose, the type of data returned, and an important security note. Every word serves a purpose, with no redundancy.

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 no output schema, the description adequately explains what the tool returns (list of gateways with publishable keys). It also provides context about the account and security. For a simple listing tool with no parameters, the description is complete.

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?

There are zero parameters, so the description does not need to explain them. The baseline for 0 parameters is 4, and the description appropriately mentions the account context (ZuckPay) implicitly. No additional parameter info is needed.

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 tool lists available card gateways with their publishable keys, specifying the scope (ZuckPay account) and types (Stripe international and/or national BRL card). It distinguishes itself from siblings by being a read-only listing tool, not involved in charging or creating payments.

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 explicitly states the tool is read-only and advises against using it for direct card charging due to PCI security; it directs users to use ZuckPay's hosted checkout instead. This provides clear when-to-use and when-not-to-use guidance, with a named alternative.

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