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

Annotations indicate readOnlyHint=true and destructiveHint=false, and the description adds valuable context: it's hosted by the platform, requires no platform credentials but uses prepaid credits, and deals with non-confidential official data. It also clarifies data privacy aspects (LGPD). This goes beyond the annotation hints, though it doesn't detail side effects or error behaviors.

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 (four short sentences in Portuguese) and front-loads the main purpose early. No wasted words, but it could be even more streamlined. It's well-structured and to the point.

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 lack of an output schema and zero parameter descriptions, the description should explain the tool's behavior more thoroughly. It fails to explain what the query returns, how the certificate parameters are used, or any prerequisites (e.g., having prepaid credits). The absence of such details makes it incomplete for an agent to use effectively.

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?

Schema coverage is 0% (no parameter descriptions). The description does not explain any of the six parameters (pkcs12_cert, pkcs12_pass, ignora_lidas, etc.). It adds no meaning to the parameters, leaving the agent with only names (some in Portuguese) and no hint of formatting or purpose. This is a major 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 states a specific verb ('consulta' - query) and resource ('Caixa Postal' - postal box) on an official source, which is clear. It distinguishes the tool from generic siblings by naming the specific domain (ECAC, Brazilian official sources). However, it doesn't specify the exact nature of the returned data (e.g., messages or receipts), so it's slightly below a perfect 5.

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?

No explicit guidance on when to use this tool versus alternatives. It mentions the context (official sources, paid via prepaid credit) but does not state when not to use it or compare with sibling tools. The usage is only implied by the description.

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