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

Annotations already mark readOnlyHint=false and destructiveHint=false. The description adds behavioral context beyond that: it states the title reopens and is not deleted, and that it's the way to correct errors. No contradiction with annotations, and it adds value by clarifying the mutation's scope and reversibility.

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 compact and front-loaded with the main action, then adds key differentiations and parameter guidance. Every sentence carries meaning with no redundancy or 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?

Core usage is well covered, but the 'account' parameter is left unexplained and there is no hint about the response or side effects. For a mutation with no output schema, this is a noticeable gap, though the primary guidance is solid.

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 description coverage is 0%, so the description must explain parameters. It explains codigo_baixa and codigo_baixa_integracao clearly, but omits the 'account' parameter entirely. This partial coverage is helpful but leaves one of three parameters unexplained.

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 explicitly states it cancels a payment (baixa) of an accounts payable and clarifies it does not delete the title, distinguishing it from omie_delete_payable. The verb 'CANCELA' and resource are specific and 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?

It gives explicit usage guidance: cancels a payment and corrects a wrong write-off, and tells when to use alternatives (omie_delete_payable for deletion, omie_settle_payable for re-issuing). It also specifies which parameter to provide (codigo_baixa or codigo_baixa_integracao), leaving no ambiguity about when and how to use it.

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