consultar_cep

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

With no annotations, the description carries the full burden. It discloses that it uses the external ViaCEP API and accepts two input formats, but it does not mention error behavior, rate limits, or what happens when a CEP is not found. This is partial transparency.

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 purpose, and no wasted words. The second sentence adds necessary input format detail.

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 simple lookup tool with one parameter and no output schema, the description covers the core purpose and input format. It does not describe the return structure or error handling, but the tool is simple enough that the address lookup intent is clear.

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 has no description for the 'cep' parameter (0% coverage), but the description explicitly explains accepted formats with examples: hyphenated (12345-678) and numeric (12345678). This fully compensates for the schema gap and adds clear semantic value.

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 starts with a clear verb and resource: 'Consulta endereço pelo CEP' (looks up address by CEP). It also names the ViaCEP API, making its function distinct from siblings like validar_cep, which validates rather than consults.

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 clearly implies when to use this tool: when you need an address from a CEP. However, it does not explicitly mention alternatives or exclusions, such as 'use validar_cep to validate the CEP format' instead.

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