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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable context beyond annotations: hosted by the platform, no credentials, pay-per-query pricing, and the public/LGPD data classification. This enriches the behavioral understanding without contradicting 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 three sentences and front-loads the core purpose. The second sentence explains the access/payment model, and the third adds LGPD context. All sentences earn their place; it is concise without being over-stuffed.

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 straightforward lookup tool with no output schema, the description covers the essential aspects: exact purpose, required parameters, authentication requirement (none), cost model, and data sensitivity. It doesn't describe response format or error conditions, but those are not explicitly needed for this simple read operation.

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 0% description coverage, so the description must carry the meaning. It does name the three required parameters (CPF, birth date, tax year) and ties them to the query purpose, but it omits the optional 'completo' parameter and does not explain formats, patterns, or value constraints. This is a partial but not complete compensation for the schema gap.

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 it queries the income tax refund status for an individual using CPF, birth date, and tax year. This specific verb (consulta), resource (situação da restituição do IRPF), and parameter set distinguish it sharply from sibling tools (authenticate, connect, marketplace, etc.).

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 clear context: the tool is hosted on the platform, requires no credentials, is paid per query with prepaid credit, and accesses public data. While it doesn't explicitly name alternative tools or give 'when not to use' exclusions, the context is sufficient to understand when and how to invoke it.

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