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

Beyond the annotations (readOnly, idempotent, non-destructive), the description discloses important behaviors: it is hosted by the platform, requires no platform credentials, is paid per query via prepaid credit, queries official Brazilian sources, and states the client's LGPD data controller responsibilities. This adds substantial operational and legal context not available from annotations.

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 relatively compact and front-loads the core purpose, but it contains redundancy (repeating the official source concept) and the LGPD clause adds length. Still, each sentence contributes useful context about payment, credentials, and legal responsibility.

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?

There is no output schema, so the description should clarify what the response contains (e.g., the certificate content or status). It also omits guidance on whether cpf, cnpj, or both are needed for the query. While annotations cover safety, the practical usage and return format remain underspecified for a moderate-complexity 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?

The input schema has two parameters (cpf, cnpj) with 0% description coverage, and the description does not explain their purpose, which one is required, or whether both can be provided. The tool name implies a CND lookup, but the agent is left guessing how to populate the parameters, especially since neither is marked as required.

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 explicitly states the tool performs a query for a 'Certidão Negativa de Débitos' (Negative Debt Certificate) from Blumenau city hall, using an official source. This specific verb+resource clearly distinguishes it from sibling tools like authenticate or report_bug.

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 description provides clear context for when to use this tool (consulting a CND from Blumenau) and adds operational details (no platform credentials required, prepaid credit payment). However, it does not explicitly state when not to use it or mention alternatives, though no direct alternatives exist among siblings.

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