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

Annotations already declare read-only and idempotent behavior. The description adds billing model (prepaid credit), access method (no platform credentials), and LGPD compliance responsibilities, which provide valuable operational context beyond the booleans.

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?

The description is three sentences, front-loading the purpose before legal and billing details. It's relatively concise, though the hosting/credential phrase could be tightened without losing meaning.

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 read-only query tool with four self-explanatory parameters and no output schema, the description covers purpose, source, costs, and legal responsibilities well. The only gap is the lack of parameter usage details, but overall it's sufficient for a simple tool.

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?

With 0% schema description coverage and no parameter explanations in the description, it fails to compensate for the missing parameter documentation. Though parameter names like 'numero_certidao' and 'ano' are self-explanatory to Portuguese speakers, the description provides zero elaboration on expected formats or relationships.

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?

The description clearly states this tool validates/consults CNDT from an official TST source, using specific verb 'consulta' and resource 'CNDT'. It distinguishes itself from generic sibling tools like 'authenticate' and 'connect' by covering a concrete, domain-specific operation.

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?

It clarifies when to use the tool by mentioning no platform credentials are needed and that it's pay-per-query with prepaid credit, setting practical usage context. However, it doesn't explicitly name alternatives or exclusion criteria, though no competing data-query tool exists among siblings.

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