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 useful behavioral context beyond those hints: no platform credentials are required, each query consumes prepaid credit, the data is non-confidential official information, and the client is the LGPD data controller. It does not cover errors or output format, but the annotation baseline lowers the burden.

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 purpose is front-loaded in the first sentence, and the description is compact. However, the phrase about consulting official sources and agencies largely repeats the 'fonte oficial' point from the first sentence, and the legal/payment context adds necessary information but could be tightened.

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 one-parameter, read-only tool with no output schema, the description covers purpose, hosting, credentials, payment, data sensitivity, and LGPD responsibility. Still, it omits the expected `nfce` input format and gives no indication of what the consultation result contains, leaving a notable completeness gap.

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 one string parameter `nfce` with 0% description coverage. The tool description only mentions NFC-e generically and never explains what value to pass, such as the access key, format, or length. This does not compensate for the lack of schema-level parameter 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 identifies the verb 'consulta' and the resource 'NFC-e' from 'SEFAZ TO', making the purpose understandable. It is specific about the official source but does not explicitly differentiate this tool from sibling alternatives, though no directly competing query sibling appears.

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 gives operational context (prepaid credit, no platform credentials) but does not state when to use this tool versus alternatives, nor any exclusions or prerequisites beyond payment. There is no explicit when/when-not guidance, so the agent must infer usage conditions.

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