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

Annotations already establish the read-only, idempotent, non-destructive, closed-world profile, and the description adds meaningful behavior on top: the two query modes, that the call is free, and the null-semantics rule ('a null `familia` or `termos` means the CNAE is not in the dictionary yet; an alert by CNPJ does not use it'). This is exactly the kind of beyond-annotations context the dimension rewards.

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 front-loaded with the core capability and then branches cleanly into the no-`q` and with-`q` behaviors. It is slightly dense with parenthetical asides (examples, the CNPJ-alert caveat), but every sentence carries information rather than 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?

With no output schema, the description does its part by naming the returned fields (description, family, coverage indicators) and explaining the null-value case. For a 2-parameter, optional-input read tool this is close to complete, though pagination/ordering behavior around `limite` is not described.

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%, so both `q` and `limite` are already documented, and the description's explanation of `q` (prefix or word) largely restates the schema. The prefix example `1412-6/01` adds a useful format cue, but `limite` is not addressed and no syntax beyond the schema is given, so the baseline of 3 holds.

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 a specific verb and resource: it returns search-term suggestions for economic activity codes (CNAE), enriched with description, family and coverage indicators. It is clear what the tool does, though it never names or contrasts a sibling tool (e.g., consulta_sugerir), so sibling differentiation is left to inference.

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?

It explicitly spells out the two operating modes: without `q` it lists the most-registered-supplier activities, with `q` it searches by code prefix or description word. That is strong context for invoking it, but it stops short of stating when to prefer this tool over alternatives or any prerequisites/exclusions.

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