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

Annotations only cover the read-only/idempotent profile; the description adds substantial context beyond them: API-key requirement, polling rate limit, the 'final' terminal flag, and per-status semantics with an explicit safety directive ('never pay again'). This is exactly the behavioral detail annotations cannot carry.

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?

Front-loads the API-key requirement and the core purpose, then enumerates status meanings compactly. It reads as a dense list but nearly every clause carries actionable meaning; slightly terse transitions between status tokens keep it from a 5.

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?

With no output schema, the description carries the full burden of explaining return values and does so: terminal/final behavior, success fields (pix_e2e, recipient_name, recipient_document, receipt_url), and failure semantics. An agent has everything needed to interpret and act on the response.

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 coverage is 100% and the single payment_id parameter is fully documented in the schema, which already states it is returned by lunium_pay_pix_with_usdt. The description adds no format or edge-case detail beyond that, so the baseline 3 applies.

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?

States a specific verb and resource ('The state of a payment from lunium_pay_pix_with_usdt'), tying it directly to the sibling that creates the payment. An agent can distinguish this polling/status tool from the pay tool and from the other PIX tools without opening the schema.

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?

Gives concrete operational guidance ('Poll at most every 10-15 seconds') and tells the agent what to do per status, including 'never pay again' for falhou_apos_envio and 'tell the user it is being checked' for revisao. It does not explicitly name alternatives like lunium_verify_pix_payment, so it falls short of a full when-to-use/when-not statement.

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