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

With no annotations, the description carries the full burden of behavioral disclosure. It states the output includes addresses and coordinates, but says nothing about whether the CEP must exist, what happens for invalid or malformed inputs, whether results are limited, or whether this is a read-only lookup. Some behavioral expectation can be inferred from the name, but the description does not explicitly disclose limits or error behavior.

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 compact single sentence in Portuguese that states the resource and the key output fields. It is appropriately sized for the tool's simplicity, though it could be slightly more explicit about the action (e.g., 'looks up' or 'returns').

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 simple single-parameter tool, the description covers the main purpose but lacks usage context relative to siblings and does not mention return details beyond the presence of addresses and coordinates. A slightly fuller sentence naming the output shape or behavior for invalid CEPs would make it 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 has 100% description coverage for the single parameter, documenting that 'cep' is an 8-digit string with or without hyphen. The description adds no further parameter meaning beyond noting that addresses and coordinates are returned for that CEP. Baseline 3 is appropriate because the schema already provides complete parameter documentation.

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 that the tool returns addresses for a CEP along with latitude and longitude. It clearly identifies the resource (Brazilian postal code) and the type of output (addresses plus geocoordinates). It does not differentiate among sibling tools, though the specificity is sufficient to understand its core purpose.

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?

There is no guidance on when to use this tool versus its siblings. Sibling names such as 'buscar', 'raio', and 'vizinhanca' suggest related geolocation or search tools, but the description does not explain when cep is the right choice or what types of queries fall outside its scope.

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