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

Since annotations only indicate mutation (readOnlyHint=false) and non-destructive (destructiveHint=false), the description adds valuable context: the title returns to open and is not deleted. This goes beyond the annotations, explaining the state change and the non-destructive nature. It is sufficient for a simple cancellation, though it does not mention idempotency or failure modes.

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, using one sentence plus a key note. The action is front-loaded (CANCELA) and the core behavior is stated clearly. It is efficiently written, though the parameter key note could be formatted as a separate line for better clarity—but overall it is appropriately sized with no 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?

For a simple mutation tool with 3 parameters and no output schema, the description covers the primary purpose and the key selection, but it omits the account parameter entirely and does not mention edge cases (e.g., what happens if the receipt is already cancelled or reconciled). The description is adequate for basic usage but incomplete for full operational confidence.

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 explain parameters. It mentions that codigo_baixa or codigo_baixa_integracao act as keys, but it does not clarify their meaning (internal ID vs integration ID) or the role of the 'account' parameter. This is a significant gap; an agent cannot determine how to populate 'account' or the exact semantics of the key fields from the description alone.

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 function: cancel the receipt of an accounts receivable, returning the title to open status. It explicitly distinguishes from deletion (não apaga o título) and matches the sibling omie_cancel_payment but for receipts. The action verb and resource are precise, making the purpose unambiguous.

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 identifies the target operation (canceling a receipt) and provides the key selection (codigo_baixa OR codigo_baixa_integracao), which implies usage context. However, it does not explicitly contrast with siblings like omie_cancel_payment or omie_unreconcile_receipt, so there is no explicit when-not guidance, though the purpose is clear enough for most cases.

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