AI agents use cancel_payment_token to commit financial operations through Z Zero — usually the final step of a payment, billing, or trading workflow. A call moves real money.
| Parameter | Type | Required | Description |
|---|---|---|---|
token | string | Yes | The payment token to cancel |
reason | string | Yes | Reason for cancellation, e.g. 'Price mismatch: checkout shows $20 but token is $15' |
Parameters from the server's own tool schema.
This tool triggers a financial reversal (instant refund) and cancels a payment token on a real payment system. While cancelling an unused token is a relatively safe operation, it directly interacts with financial instruments and initiates a refund, placing it firmly in the Financial category. Misuse could disrupt legitimate payment flows or trigger unintended refunds.
From the tool's definition 'Cancel unused token and refund instantly' — the tool performs a financial operation (refund) and cancels a payment token tied to real single-use Visa cards
Risk signalsHandles credentials or secrets (token)
Attacks that exploit this kind of access
Cancel unused token and refund instantly. Use when user cancels the purchase or to free up a card slot. It is categorised as a Financial tool in the Z Zero MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
cancel_payment_token accepts 2 parameters: token, reason. Required: token, reason. The full parameter table on this page comes from the server's own tool schema.
Register the Z Zero MCP server in PolicyLayer and add a rule for cancel_payment_token: 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 Z Zero. Nothing to install.
cancel_payment_token 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 cancel_payment_token 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 cancel_payment_token. 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.
cancel_payment_token is provided by the Z Zero MCP server (z-zero-mcp-server). 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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