pay_invoice

Pay a BOLT11 Lightning invoice from the agent balance. Returns preimage as proof of payment. REQUIRES AGENT KEY.

SERVERLightning Wallet SOURCElightning-wallet-mcp

Critical RISK CLASS

Category Financial

Parameters 00 required

Recommended Approval-gatedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-lightningfaucet-lightning-wallet-mcp/pay-invoice.md

WHAT IT DOES

What pay_invoice does on Lightning Wallet

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

RISK

Why pay_invoice is rated Critical

This tool directly transfers cryptocurrency from a wallet balance to settle Lightning invoices. Even with authorization checks ('REQUIRES AGENT KEY'), an AI agent with compromised or malicious instructions could drain funds, incur unauthorized financial obligations, or be exploited by third parties to receive payments.

From the tool's definition Tool name 'pay_invoice' combined with description 'Pay a BOLT11 Lightning invoice from the agent balance' explicitly moves money (Bitcoin via Lightning Network). The phrase 'from the agent balance' confirms debit of funds.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs pay_invoice safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Lightning Wallet, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For pay_invoice, this is the rule to start with:

pay_invoice Approval-gated

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

GATE THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Lightning Wallet, apply this rule, and every pay_invoice call is checked against it from then on.

FAQ

Questions about pay_invoice

What does the pay_invoice tool do? +

Pay a BOLT11 Lightning invoice from the agent balance. Returns preimage as proof of payment. REQUIRES AGENT KEY. It is categorised as a Financial tool in the Lightning Wallet MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on pay_invoice? +

Register the Lightning Wallet MCP server in PolicyLayer and add a rule for pay_invoice: 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 Lightning Wallet. Nothing to install.

What risk level is pay_invoice? +

pay_invoice 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 pay_invoice? +

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

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

pay_invoice is provided by the Lightning Wallet MCP server (lightning-wallet-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Lightning Wallet, and thousands of servers like it.

This server

All 45 Lightning Wallet tools → Critical-risk tools on this server →

Across the catalogue

pay_invoice on Bitcoin MCP Server →approve_supplier_invoice on Tripletex MCP Server → All critical-risk MCP tools → The MCP Attack Database →

Guides

Govern MCP payment tools →Human-in-the-loop →Tool call approval →