Confirm payment and store credentials. Call this after l402-fetch returns a 402 with a paymentHash — polls the payment server for settlement (up to 30s for human wallet), then stores the credential so the next l402-fetch succeeds. For human wallets, call this immediately after showing the payment...
AI agents use l402-pay to commit financial operations through 402 — usually the final step of a payment, billing, or trading workflow. A call moves real money.
| Parameter | Type | Required | Description |
|---|---|---|---|
method | string | — | Payment method override. Defaults to wallet priority: NWC > Cashu > human. |
invoice | string | — | BOLT-11 invoice to pay. Optional if paymentHash matches a cached challenge from l402-discover. |
macaroon | string | — | Macaroon from the L402 challenge. Optional if paymentHash matches a cached challenge. |
paymentHash | string | — | Payment hash to look up cached challenge from l402-discover. |
Parameters from the server's own tool schema.
This tool irreversibly commits financial transactions on behalf of the AI agent. Even though a human may initiate the payment via wallet, the tool confirms and settles the payment, moving money and creating financial obligations. This is the highest-severity category.
From the tool's definition Tool description states 'Confirm payment and store credentials' and 'polls the payment server for settlement' — this directly commits financial transactions.
Documented attack patterns abuse exactly the kind of access l402-pay gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and 402, and nothing reaches the server without passing your rules. This is the rule we recommend for l402-pay:
{
"version": "1",
"default": "deny",
"tools": {
"l402-pay": {
"deny_if": [
{
"conditions": [],
"on_deny": "Requires human approval."
}
]
}
}
}Any call to l402-pay is blocked until a human approves it. The rest of the server keeps working.
Free to start. No card required.
Confirm payment and store credentials. Call this after l402-fetch returns a 402 with a paymentHash — polls the payment server for settlement (up to 30s for human wallet), then stores the credential so the next l402-fetch succeeds. For human wallets, call this immediately after showing the payment URL to the user. It is categorised as a Financial tool in the 402 MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
l402-pay accepts 4 parameters: method, invoice, macaroon, paymentHash. The full parameter table on this page comes from the server's own tool schema.
Register the 402 MCP server in PolicyLayer and add a rule for l402-pay: 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 402. Nothing to install.
l402-pay 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 l402-pay 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 l402-pay. 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.
l402-pay is provided by the 402 MCP server (402-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from 402, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
11 402 tools catalogued and risk-classified — across an index of 43,000+ MCP servers.