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

Annotations already declare this as read-only and idempotent, which the description complements by adding important behavioral traits: it is hosted by the platform, requires no credentials, incurs a cost per query, accesses only public official data (not private or confidential), and places LGPD compliance responsibility on the client. These details go well beyond 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 a single concise paragraph that front-loads the main purpose, then adds relevant context (hosting, authentication, cost, data classification, LGPD). Every sentence earns its place without redundancy or fluff.

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 read-only tool with two parameters and no output schema, the description provides sufficient context about purpose, access, cost, and legal compliance. However, it omits explicit guidance on the 'completo' parameter and does not describe the return data structure, which would improve completeness.

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 and completo) with no descriptions (0% schema coverage). The description mentions 'expanded data' but does not explicitly explain the 'completo' boolean parameter or its effect on the response. The only hint is 'além dos dados básicos,' which is too vague to fully clarify the parameter's semantics.

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's purpose: it retrieves expanded registration data (dados cadastrais ampliados) for an individual from their CPF, in addition to basic data. This is a specific resource and action, and it distinguishes itself from the unrelated sibling tools (e.g., authenticate, 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 useful context indicating when to use the tool: it queries public-access official data, requires no credentials, and is paid per query with prepaid credit. It does not explicitly mention alternatives or exclusions, but none of the sibling tools are competitors, so the context is sufficient.

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