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

Annotations cover the safety profile (readOnly, idempotent, non-destructive), but the description adds substantial behaviour the annotations do not: result truncation (up to 20 addresses / 20 companies), the `pontos_total` counter field, a 10-per-day network-scoped free quota, and the exact error payload (`free_limit` with `resets_at`). It still doesn't say what happens with a malformed CEP or whether an API key is ever needed.

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?

Three dense sentences, front-loaded with the payload, then limits, then quota behaviour. Every clause conveys information an agent can act on; nothing is padded or repeated from the schema.

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?

With no output schema, the description does the heavy lifting by naming the returned collections, their caps, and the `pontos_total` field, plus quota failure shape. It stops short of describing the structure of an individual address or company record, but it is sufficient to invoke the tool correctly.

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 is a single required parameter with 100% schema description coverage ('CEP with 8 digits'), so the schema already carries the semantics. The description adds no format, normalization, or example detail beyond that baseline.

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?

Clear verb+resource: it retrieves addresses (with CNEFE/IBGE coordinates) and the companies registered at a given CEP. It is specific about the payload, but it never distinguishes itself from near-identical siblings such as `cep`, `consulta_endereco`, `consulta_cnpj`, or `empresas`, so the agent cannot be sure which one to pick.

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?

No statement of when to use this versus `cep` or `consulta_endereco`, and no prerequisites beyond the implicit 'have a CEP'. The only conditional guidance is the post-quota failure mode, not usage routing.

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