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: refund]
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 description adds useful behavioral context beyond the annotations: it explicitly states that the operation 'mexe em dinheiro, irreversível' (touches money, irreversible), and mentions bulk support. However, it also unnecessarily includes behaviors of sibling tools, which dilutes the transparency. The annotations already indicate readOnlyHint=false and idempotentHint=false, so the description's money/irreversibility warning is additive rather than redundant. No contradiction with annotations was found.
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 short, but it contains a long list of actions that are irrelevant to the refund-specific tool, plus an unexplained '[Flattened action: refund]' marker. This extraneous content hurts clarity rather than adding value. A focused description stating 'Refunds Guru transactions irreversibly; supports batch via ids' would be more concise and useful.
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, sparse annotations, and a nested 'data' object in the schema, the description needed to provide more operational context. It does mention irreversibility and batch support, but it omits return value behavior, error conditions, prerequisites, and the meaning of the 'data' and 'account' parameters. The confusing multi-action list further reduces completeness for an AI agent trying to invoke this tool 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?
The input schema has 0% description coverage, so the description must compensate for parameter meaning. It does explain that 'id' is the transaction identifier for refunds and 'ids' enables batch execution, but it leaves 'data' and 'account' completely unexplained. It also ties 'data' to update_buyer in the action list, which is misleading since this tool is for refunds and 'data' may have a different role here. Overall, the parameter semantics are only partially addressed.
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 a generic statement about Guru transaction mutations and then lists five different actions (refund, chargeback, reissue, update_buyer, generate_invoice) without clearly stating that this tool is specifically for refunds. The cryptic '[Flattened action: refund]' is the only hint that the refund action applies here, but it doesn't override the confusion caused by listing sibling actions. The verb 'refund' appears, but the overall purpose is muddled and fails to distinguish this tool from its sibling write tools.
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?
No explicit guidance is given on when to use this tool versus alternatives like guru_transactions_write_chargeback or guru_transactions_write_reissue. The bulk support note ('accepts ids for batched execution') is a usage hint, but there is no exclusionary context or recommendation. The listing of other actions without explaining that they belong to separate tools makes usage guidance more ambiguous.
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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