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

Beyond the annotations (readOnly, idempotent, non-destructive), the description adds significant behavioral context: it is hosted, requires no credentials, is paid per consultation, accesses only public data, and designates the client as LGPD controller. This fully discloses the operation's nature and data source.

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 two sentences and front-loaded with the core action. It then adds operational and legal details without unnecessary fluff, though the LGPD clause is slightly wordy but still relevant.

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 consultation tool with strong annotations, the description covers the main purpose, payment model, and data public nature. The main gap is the undocumented 'completo' parameter and lack of return format, but the essential required parameter (CPF) is clearly present, so the tool can be invoked correctly.

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 has no descriptions, and the description explicitly ties the CPF parameter to the query input. However, it completely ignores the 'completo' boolean parameter, leaving its purpose ambiguous. Thus, it partially compensates for the schema's 0% coverage.

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 the tool verifies if a person appears in the CEAF registry using CPF, using a specific verb (Verifica) and resource. This distinguishes it from sibling tools like authenticate or connect, which serve different purposes.

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 provides context on how to use the tool: hosted, no credentials, pay-per-query with prepaid credit. However, it does not explicitly mention when not to use it or name alternatives, so it slightly misses the full guideline bar.

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