Pay an x402 invoice by signing and broadcasting a TRX transfer to the invoice address, then verifying the payment with the facilitator. x402 (Coinbase + Cloudflare HTTP 402 standard) is the protocol AI agents use to pay APIs per call. Use this when you receive an invoice_id from a paywalled servi...
Part of the MERX - TRON Resource Exchange MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents use pay_invoice to initiate financial transactions through MERX - TRON Resource Exchange. Financial operations involve real money and are irreversible once processed. Intercept blocks financial tools by default, requiring explicit human approval with transaction-level limits to prevent unauthorised spending.
pay_invoice moves real money. Without a policy, an autonomous agent could initiate transactions that drain accounts or exceed budgets. Intercept blocks financial tools by default, requiring human-in-the-loop approval with configurable spending limits per transaction and per time window.
Financial tools involve real money. Block by default and require explicit human approval before enabling.
tools:
pay_invoice:
rules:
- action: deny
reason: "Requires human approval"See the full MERX - TRON Resource Exchange policy for all 66 tools.
Agents calling financial-class tools like pay_invoice have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Financial risk category across the catalogue. The same policy patterns (deny, require_approval) apply to each.
pay_invoice is one of the critical-risk operations in MERX - TRON Resource Exchange. For the full severity-focused view — only the critical-risk tools with their recommended policies — see the breakdown for this server, or browse all critical-risk tools across every MCP server.
Pay an x402 invoice by signing and broadcasting a TRX transfer to the invoice address, then verifying the payment with the facilitator. x402 (Coinbase + Cloudflare HTTP 402 standard) is the protocol AI agents use to pay APIs per call. Use this when you receive an invoice_id from a paywalled service or another agent. REQUIRES: TRON_PRIVATE_KEY in env (use set_private_key first) AND a valid invoice_id from create_invoice or x402 challenge response. The transfer is signed locally — your private key never leaves the MCP process.. It is categorised as a Financial tool in the MERX - TRON Resource Exchange MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Add a rule in your Intercept YAML policy under the tools section for pay_invoice. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the MERX - TRON Resource Exchange MCP server.
pay_invoice 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 pay_invoice rule in your Intercept 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 Intercept 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.
pay_invoice is provided by the MERX - TRON Resource Exchange MCP server (merx-mcp). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic policy on every MCP tool call. Per-identity grants. Full audit log.