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

Annotations already indicate readOnly, idempotent, non-destructive behavior, and the description reinforces this with 'consulta'. It adds useful context beyond annotations: no platform credentials are required, queries are paid with prepaid credit, the data is public/non-confidential, and the client bears LGPD responsibility. It does not contradict the 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 front-loaded with the primary purpose and then provides relevant operational and legal context (hosting, credentials, prepaid credit, public data, LGPD). It is somewhat dense but not bloated; each sentence contributes meaningful information.

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 two-parameter query tool, the description covers purpose, official source, cost, authentication, and privacy obligations. However, with no output schema and no parameter explanations, the agent is left uncertain about what the response looks like and how to supply the CPF/CNPJ. It is usable but not fully 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?

The schema provides only `cpf` and `cnpj` strings with no descriptions and 0% schema coverage. The description does not mention these parameters, their formats, whether one or both can be supplied, or any validation rules. The property names are somewhat self-explanatory, but the description adds none of the needed semantic detail.

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 opens with 'SEFAZ SP: Certidão Negativa de Débitos, consulta em fonte oficial', clearly identifying the exact resource (SEFAZ SP negative debt certificate) and the query action ('consulta'). It is easily distinguished from the generic sibling tools like authenticate, marketplace, and 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?

There is no explicit guidance on when to use this tool vs. alternatives, nor any exclusions or alternative suggestions. The description provides operational context (hosted, no credentials, prepaid credit, LGPD) but does not tell the agent when this tool is the appropriate choice among possible SEFAZ or certificate-related options.

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