Mutações em transações Guru (mexe em dinheiro, irreversível). Ações: refund (id, reembolsa); chargeback (id); reissue (id, reemite boleto); update_buyer (id + data); generate_invoice (id, NF-e BR).
[Flattened action: chargeback]
Bulk support: accepts ids for batched execution.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ||
| ids | No | ||
| data | No | ||
| account | No |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The phrase 'mexe em dinheiro, irreversível' clearly warns that this operation moves money and is irreversible, which is important context beyond the annotations. It also adds bulk behavior with 'accepts ids for batched execution'. This does not contradict the annotations since readOnlyHint=false aligns with 'Mutações'.
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 first sentence is a useful front-loaded warning, but the five-action list is unnecessarily broad for a chargeback-specific flattened tool. The '[Flattened action: chargeback]' phrasing is technical and cryptic. The bulk-support sentence is helpful, but overall the description could be much more focused.
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?
The tool has 4 parameters, no output schema, and handles irreversible financial mutations. The description captures the key warning and the id/ids usage, but it omits semantics for 'account' and 'data', does not explain what a successful chargeback returns, and leaves the difference from sibling transaction-write tools implicit.
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 compensate. It partially does by identifying 'id' as the chargeback target and 'ids' for bulk execution. However, 'data' and 'account' remain unexplained, and the action list associates 'data' with update_buyer rather than chargeback, creating ambiguity about whether those parameters are relevant here.
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 opens with generic 'Mutations in Guru transactions' and lists five actions (refund, chargeback, reissue, update_buyer, generate_invoice) before clarifying '[Flattened action: chargeback]'. This dilutes the precise purpose and does not clearly separate this tool from dedicated siblings like guru_transactions_write_refund or guru_transactions_write_reissue.
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?
There is no explicit guidance on when to use this tool versus alternatives. The '[Flattened action: chargeback]' note implies the current scope, but it never states that refunds/reissues/buyer updates/invoices have separate sibling tools, nor does it describe the conditions or prerequisites for issuing a chargeback.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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