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

The annotations already declare read-only, idempotent, and non-destructive behavior; the description adds the risk-relevant details that the tool is official, paid per consultation, hosted by the platform, and returns public rather than confidential data. This is useful beyond the annotations, though there is no mention of response format, errors, rate limits, or output structure.

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, dense sentence that leads with the tool purpose and then adds the key implementation and compliance details. It avoids redundant examples, boilerplate, or repeated schema information, so every clause carries meaningful signal.

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 single-parameter read-only consultation tool, the description covers purpose, source, cost, and confidentiality reasonably well. The major gap is that it does not define the input format or mention the expected output, and there is no output schema to compensate for that.

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?

There is only one parameter, `nfce`, and the schema description coverage is 0%. The description does not tell the agent what format to use, such as a 44-digit NFC-e access key, a sanitized key, a URL, or some other identifier; it only provides the general NFC-e context, so it fails to fully compensate for the missing schema documentation.

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 that this tool performs a SEFAZ RJ NFC-e consultation using an official source, giving the agent a concrete verb and resource. It does not explain exactly what 'Completa' returns or explicitly distinguish itself from siblings, but the sibling set is unrelated, so the main purpose is still clear.

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 explains operational context: no platform credentials are needed, each query uses prepaid credit, and the data is the same official data available to citizens. It does not provide explicit when-not-to-use guidance or alternative tool names, but for a simple query tool this contextual clarity is enough.

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