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

Annotations are minimal (readOnlyHint=false, no other hints). The description adds 'ATO FISCAL REAL' implying legal/fiscal significance and requires 'allow_writes' which hints at authorization. It does not, however, disclose side effects (e.g., irreversibility, impact on subsequent operations). Given the lack of annotations, the description carries some burden but provides only partial transparency.

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 exceptionally concise: one line, two sentences at most. The key information (action, target, timing, and requirement) is delivered upfront without repetition or fluff. Every word adds value, and the 'ATO FISCAL REAL' prefix immediately signals importance.

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 sparse annotations, this tool description leaves significant gaps. It does not explain the effect of closing an MDF-e, whether it is reversible, what responses to expect, or how the parameters interact. For a write operation with legal implications, more context is needed (e.g., confirmation, error handling, consequences). The description is too brief for a tool with these characteristics.

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 three parameters: ids, account, empresa_id, but the description only mentions 'por id' which maps to 'ids'. It does not clarify the purpose or format of 'account' or 'empresa_id', and schema coverage is 0%. The description adds minimal value beyond what the schema already shows, and for an unannotated schema, it should explain the parameters more thoroughly.

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 action: 'encerra um ou mais MDF-e (por id) após o fim da viagem' (closes one or more MDF-e by id after the trip ends). The verb is specific ('encerra') and the resource is clear (MDF-e). It also emphasizes 'ATO FISCAL REAL' which sets it apart from mere utility. While it doesn't explicitly contrast with siblings like 'cancelar' or 'emitir', the phrase 'após o fim da viagem' provides a distinct context, making it distinguishable.

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 explicit context: 'após o fim da viagem' (after the end of the trip) indicates when to use it. It also states a prerequisite: 'Exige allow_writes + mdfe_tenant_id', which is essential for invocation. However, it does not mention when not to use it or suggest alternatives, so it falls short of a 5.

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