setup_payment · LetsFG MCP: Risk & Policy

WHAT IT DOES

What setup_payment does on LetsFG

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

WHY IT NEEDS A POLICY

Why setup_payment needs a policy

This tool attaches a payment card to a user profile, which is a financial action — it establishes the payment instrument used for future financial transactions (flight bookings). While attaching the card itself may not immediately move money, it is a prerequisite financial setup action that enables charges.

From the tool's definition Attach a payment card (required before booking). Free to attach. Only needs to be called once.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

setup_payment Approval-gated

Any call to setup_payment 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": {
    "setup_payment": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

GATE THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about setup_payment

What does the setup_payment tool do? +

Attach a payment card (required before booking). Free to attach. Only needs to be called once. It is categorised as a Financial tool in the LetsFG MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on setup_payment? +

Register the LetsFG MCP server in PolicyLayer and add a rule for setup_payment: 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 LetsFG. Nothing to install.

What risk level is setup_payment? +

setup_payment 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 setup_payment? +

Yes. Add a rate_limit block to the setup_payment 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 setup_payment completely? +

Set action: deny in the PolicyLayer policy for setup_payment. 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 setup_payment? +

setup_payment is provided by the LetsFG MCP server (letsfg/letsfg). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.