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

With no annotations the description carries the full burden, and it does disclose a meaningful behavioral trait: the per-record credit cost. However it says nothing about rate limits, required auth, pagination behavior, or what happens on a zero-result search, leaving notable gaps for a registry-query tool.

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?

A single sentence front-loads the resource and data source, then the query dimension and return fields, with the cost note appended. No 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?

For a four-parameter registry search with no output schema, the description usefully enumerates the returned fields and cost model, and the schema covers the parameters. But without annotations or an output schema, more should be said about pagination semantics and result limits than is present.

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%, so keyword, status enum, max_items (up to 250, default 25), and start_page are all documented in the schema. The description adds only that keyword is a company name, 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?

States a specific verb and resource ('Search the Brazil company registry (CNPJ / Receita Federal data) by company name') and lists the returned fields (name, CNPJ, status, link). It clearly reads as the search variant of the sibling run_br_companies, though it never names that sibling 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?

There is no when-to-use/when-not guidance and no mention of the non-search sibling run_br_companies or when to prefer a direct lookup over a keyword search. The only usage-relevant signal is the billing note ('1 point per returned record'), which is cost, not routing.

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