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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds that these vocabularies feed filters, which is useful behavioral context, but it doesn't disclose what happens when `q` is omitted (list all?) or the shape of results.

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 tight sentences with zero filler, front-loading the purpose before the search instruction. It could be marginally sharper by stating the implied use case explicitly, but it is well-sized.

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 two-parameter lookup with no output schema, the description covers what the tool is and how to search, but omits what a call returns (code/label lists?) and the no-`q` fallback behavior, leaving an agent to infer the result format.

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 description coverage is 100% and the enum is fully documented, so the schema carries parameter meaning. The description restates the three vocabulary values and mentions text search via `q`, matching the schema without adding format or matching semantics (e.g., substring vs prefix).

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 names a specific resource (reference vocabularies for filters) and enumerates the three vocabularies (cnae, municipio, natureza), plus the search action via q. It's clear what the tool does, though it doesn't explicitly differentiate itself from potential siblings like search, suggest, or ia_filters.

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?

Saying the vocabularies are 'for the filters' implies this tool is used to discover valid filter values, and it notes how to search with `q`. However, there is no explicit when-to-use vs alternatives guidance, no statement of when not to use it, and no routing to sibling lookup tools.

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