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

With readOnlyHint and idempotentHint already covering the safety profile, the description adds real behavioral context beyond annotations: the meaning of each status value (pendente/paga/cancelada/expirada), the negative scope that the copy-and-paste Pix code and QR are NOT returned, and the account-bound visibility limit. These directly prevent a caller from expecting payloads it will never get.

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 front-loaded with what the tool returns, then explains status values, then the negative scope — a logical progression with no filler. It is denser than strictly necessary (the creation-path caveat appears twice) but each clause carries information.

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?

No output schema exists, and the description compensates by defining every status value and explicitly naming what is omitted from the response (copia-e-cola, QR). For a one-parameter read tool, an agent has everything needed to call it and interpret the result correctly.

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% with a single well-documented `id` parameter, so the schema does the heavy lifting. The description restates the id's provenance (panel or POST /api/v2/creditos), which the schema already states, adding no new syntax or format detail. Baseline 3 is appropriate.

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 — retrieves the state of a Pix credit charge by its `id` — with enough specificity (credit charge, connected account) that it is unmistakably distinct from the vehicle-data siblings. It stops short of naming a sibling to route away from, but no sibling covers this domain, so the ambiguity risk is low.

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?

Explicitly states the precondition that the charge must have been created outside this server (panel or POST /api/v2/creditos) and adds the exclusion 'sem ferramenta MCP para CRIAR cobrança', telling the agent this tool cannot create anything. That is exactly the when-to-use / when-not / no-alternative guidance an agent needs.

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