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

Annotations already provide readOnlyHint=true and idempotentHint=true, but the description goes beyond by disclosing payment mechanics (prepaid credit), data nature (public access, not private), and legal responsibility (LGPD, controller role). This adds meaningful behavioral context that is not available from the structured annotations alone.

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 concise, with the main purpose stated upfront, followed by essential operational details (hosting, credentials, payment, data scope, LGPD). Every sentence adds value, and the structure is logical: function → access method → data nature → legal responsibility. No 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?

Given the tool has 10 parameters, no output schema, and no parameter descriptions, the description does a good job of explaining the overall behavior and return value (similarity score). It also covers access, cost, and legal context. However, it does not explain the 'completo' parameter or provide details about error handling or response format, which would enhance completeness for an agent selecting this 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 schema has 0% description coverage, so the description must compensate. It names the key data fields: CPF, name, birth, address. This covers most of the 10 parameters implicitly (Address, City, State, PostCode fall under 'endereço'). However, the 'completo' boolean parameter is not explained, leaving a gap in understanding for a param that could alter the behavior of the query.

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 function: 'Compara os dados informados de uma pessoa no Brasil' and 'retorna o grau de similaridade com o cadastro.' The verb+resource structure is specific and distinguishes this tool from the sibling tools like authenticate, connect, or marketplace, which have completely 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?

The description provides clear context for use: it mentions the tool is hosted by the platform, requires no credentials, and charges prepaid credit. It also clarifies that it accesses public data and addresses LGPD compliance. However, it does not explicitly state when not to use the tool or contrast it with alternative tools, but given the sibling list, no direct alternative exists.

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