payment_create · Starling Bank MCP: Risk & Policy

WHAT IT DOES

What payment_create does on Starling Bank

AI agents use payment_create to commit financial operations through Starling Bank — usually the final step of a payment, billing, or trading workflow. A call moves real money.

WHY IT NEEDS A POLICY

Why payment_create needs a policy

This tool initiates a financial payment from the user's Starling Bank account to a payee. Moving money is a Financial category action — the highest severity — and misuse could result in unauthorized transfers of funds that may be difficult or impossible to reverse.

From the tool's definition 'payment_create' and 'Create a payment to an existing payee'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

payment_create Approval-gated

Any call to payment_create is blocked until a human approves it. The rest of the server keeps working.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "payment_create": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Starling Bank, so you can run agents against it safely.

FAQ

Questions about payment_create

What does the payment_create tool do? +

Create a payment to an existing payee. It is categorised as a Financial tool in the Starling Bank MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on payment_create? +

Register the Starling Bank MCP server in PolicyLayer and add a rule for payment_create: 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 Starling Bank. Nothing to install.

What risk level is payment_create? +

payment_create is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit payment_create? +

Yes. Add a rate_limit block to the payment_create 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.

How do I block payment_create completely? +

Set action: deny in the PolicyLayer policy for payment_create. 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.

What MCP server provides payment_create? +

payment_create is provided by the Starling Bank MCP server (starling-bank-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.