AI agents use refund_charge to commit financial operations through Tru — usually the final step of a payment, billing, or trading workflow. A call moves real money.
| Parameter | Type | Required | Description |
|---|---|---|---|
charge_id | string | Yes | The charge request ID to refund |
amount_cents | integer | — | Amount to refund in cents. If omitted, refunds the full charge amount. |
Parameters from the server's own tool schema.
Refunds commit financial obligations and move money; this is the Financial category. Severity is high because a misused refund tool could refund arbitrary charges, causing revenue loss and customer confusion, though the impact is bounded to existing charges rather than unlimited financial exposure. Confidence is high given explicit financial language in name and description.
From the tool's definition Tool name 'refund_charge' and description 'Refund a charge' directly indicate moving money back to customers. Description specifies it 'Supports full or partial refunds' on 'charges that have been successfully paid', confirming financial obligation reversal.
Attacks that exploit this kind of access
Refund a charge. Supports full or partial refunds. Only works on charges that have been successfully paid. It is categorised as a Financial tool in the Tru MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
refund_charge accepts 2 parameters: charge_id, amount_cents. Required: charge_id. The full parameter table on this page comes from the server's own tool schema.
Register the Tru MCP server in PolicyLayer and add a rule for refund_charge: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Tru. Nothing to install.
refund_charge is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the refund_charge rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for refund_charge. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
refund_charge is provided by the Tru MCP server (tru-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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