Lookup Brazilian Company (CNPJ)

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, openWorldHint=true. Description adds that data is from Receita Federal but does not disclose additional behavioral traits like rate limits, data freshness, or error handling. No contradictions.

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?

Single sentence with front-loaded purpose, followed by return fields and source. No wasted words. Efficient and clear.

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 simple single-parameter lookup with an output schema (not shown), the description lists key return fields. It lacks info on pagination or status codes, but these are minor given the tool's simplicity and good annotations. Mostly complete.

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 has 1 parameter with 100% coverage, including format and return info. Tool description mentions '14-digit CNPJ tax ID' but adds no new meaning beyond schema. 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?

Description uses specific verb 'Look up' and resource 'Brazilian company by CNPJ', and lists return fields (name, address, CNAE, etc.). It clearly distinguishes from other gov.brasilapi tools (e.g., banks, CEP) and other business-lookup tools on the server.

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?

Description states it returns official Receita Federal data, implying use for Brazilian company info. However, it does not explicitly mention when to use vs alternatives (e.g., other business lookup tools) or exclude cases like inactive companies.

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