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

With no annotations, the description carries the full behavioral burden. It usefully discloses the per-call price ($0.10), which no structured field covers, but says nothing about authentication, rate limits, failure behavior for an invalid CNPJ, or whether the call is read-only — leaving meaningful gaps for a billed lookup operation.

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, zero filler. The payload contents are front-loaded and the cost caveat follows immediately; nothing needs to be cut.

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 single-parameter lookup with no output schema, the description sketches the return content (registration data, signals, health score), which is helpful. However, with no annotations at all it should also cover side effects, error handling, and billing semantics to be fully complete — those are missing.

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?

Only one parameter and schema description coverage is 100%, so the schema already fully documents the CNPJ format (numeric or alphanumeric, formatted or not). The description adds nothing about the parameter, which is the expected baseline when the schema does the work.

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 resource (Brazilian company dossier) and enumerates its payload: registration data, signals, and health score. The phrase 'in one call' implicitly distinguishes it from the piecemeal siblings get_company and get_company_score, though it never names them explicitly.

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?

Usage is only implied: an agent can infer this is the aggregated option versus the narrower get_company/get_company_score, and the stated price ($0.10) is a decision input. There is no explicit when-to-use, when-not-to-use, or routing statement tying it to the sibling tools.

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