AI agents use zap to commit financial operations through MCP Money — usually the final step of a payment, billing, or trading workflow. A call moves real money.
Zaps are Lightning Network payments in the Nostr ecosystem. This tool moves real monetary value to another party, which is irreversible once broadcast. Misuse by an AI agent could result in unauthorized financial transfers. The server context ('provide AI agents money functionalities via Nostr and Cashu') and sibling tools like 'pay' and 'deposit' confirm this is a financial transaction tool.
From the tool's definition "Send a zap to a user" — a 'zap' is a Bitcoin/Lightning Network micropayment sent via the Nostr protocol, directly moving funds to another user.
Documented attack patterns abuse exactly the kind of access zap gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Money, and nothing reaches the server without passing your rules. This is the rule we recommend for zap:
{
"version": "1",
"default": "deny",
"tools": {
"zap": {
"deny_if": [
{
"conditions": [],
"on_deny": "Requires human approval."
}
]
}
}
}Any call to zap is blocked until a human approves it. The rest of the server keeps working.
Free to start. No card required.
Send a zap to a user. It is categorised as a Financial tool in the MCP Money MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the MCP Money MCP server in PolicyLayer and add a rule for zap: 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 MCP Money. Nothing to install.
zap 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 zap 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 zap. 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.
zap is provided by the MCP Money MCP server (pablof7z/mcp-money). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Money, 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.
6 MCP Money tools catalogued and risk-classified — across an index of 43,000+ MCP servers.