Fetch a Brazilian company's registry details by CNPJ or Receita Federal URL, returning name, status, registration date, address, and legal form.
Get one company from the Brazil registry (CNPJ / Receita Federal) by registration number or registry URL: name, status, registration date, address and legal form. Flat 5 points per successful run.
| Name | Required | Description | Default |
|---|---|---|---|
| company | Yes | Registration number or registry URL. e.g. 33000167000101 |
Changes observed during successful MCP inspections.
v1.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It usefully discloses the return fields and the cost model ("Flat 5 points per successful run"), which is real behavioral context, but says nothing about auth/prerequisite requirements, error behavior, or rate limits for a call producing one legal record.
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 short clauses, front-loaded with purpose and identifier format before the cost note; nothing is redundant. Tight and readable, though the trailing cost sentence is tangential to selection.
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 lookup with full schema coverage and no output schema, the description compensates by listing the returned fields (name, status, registration date, address, legal form) and the pricing rule. Only auth/prerequisite details and failure behavior are missing, which is minor at this complexity.
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 schema already documents the single parameter ("Registration number or registry URL. e.g. 33000167000101"). The description merely restates the same accepted input forms without adding format details or validation guidance, so baseline 3 applies.
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?
Specific verb+resource: "Get one company from the Brazil registry (CNPJ / Receita Federal) by registration number or registry URL", plus an enumeration of returned fields. The word "one" implicitly signals a single-entity lookup, but it never names run_br_companies_search, the obvious sibling, so true 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?
The phrase "by registration number or registry URL" implies the tool is for looking up a single already-known company, which is usable guidance. However there is no explicit when-to-use vs run_br_companies_search or any when-not/precondition statement, leaving the choice between lookups to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.