Brazil Bank Lookup

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

Since no annotations are provided, the description carries the full burden for behavioral disclosure. It honestly states that it looks up data and returns specific fields, and it mentions the external source 'BrasilAPI'. However, it does not describe behavior on invalid/unknown COMPE codes, possible lack of results, formatting requirements, or any rate limits, which leaves some behavioral uncertainty.

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 compact and well-structured: the first sentence states the core action, followed by return fields, a use case, and the data source. Every sentence earns its place with no redundancy or filler.

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?

This is a simple one-parameter lookup tool with an output schema, and the description covers the parameter, the return fields, and the intended use case. It omits edge-case behavior like not-found handling, but for the simplicity of this tool and the presence of an output schema, it is nearly 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?

The schema only defines 'code' as a string with no further description, so the parameter semantics rely entirely on the description. The description explains what a COMPE code is and provides concrete examples, adding real meaning beyond the bare schema. It could also specify whether leading zeros or numeric formatting are expected, which keeps it from a 5.

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 opens with a specific verb and resource: 'Look up a Brazilian bank by its COMPE code', which immediately tells an agent what the tool does. The examples '1 = Banco do Brasil, 341 = Itaú' further ground the resource and clearly differentiate it from sibling tools like brazil_company_lookup, which target a different entity type.

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 phrase 'Useful to resolve the institution behind a payment or a bank slip' provides a clear, practical context for when to invoke the tool. It does not explicitly state when not to use it or name alternative sibling tools, so it stops short of a 5.

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