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

Annotations declare idempotentHint=true and destructiveHint=true; the description reinforces idempotency ('Repeating the current choice writes nothing') and adds a trait the annotations do not cover — the choice is per-person ('Each person's choice is kept in the account'). It does not explain the destructiveHint or what side effects occur on first selection.

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 short sentences, zero waste, front-loaded with what the tool does before the idempotency caveat. Every clause earns its place.

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 one-parameter, no-output-schema tool with annotations present, the description covers purpose, the analysis exclusion, per-person scoping, and idempotency. The only omission is any hint about what the operation returns or what destructiveHint implies.

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 coverage is 100% and the single cnpj parameter is fully documented in the schema (14 digits, valid check digit). The description adds no syntax or format detail beyond that, so the baseline 3 is appropriate.

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?

States a specific verb+resource ('Selects a registered company') and immediately scopes it against a neighbour ('it does not run an analysis'), which separates it from analyze_participation. It stops short of naming the sibling explicitly, so the differentiation is implied rather than crisp.

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 exclusion of analysis implies when this tool is the right pick, but there is no explicit when-to-use statement and no alternative named (add_company, remove_company, search_companies are all plausibly confusable). Usage is inferable but not spelled out.

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