{
  "jsonrpc": "2.0",
  "id": "a2a-test-001",
  "method": "tools/call",
  "params": {
    "name": "run_agent_to_agent_test",
    "arguments": {
      "rail_key": "packetops",
      "idempotency_key": "a2a-mcp-packetops-001",
      "payment_reference": "agent_test_ref_mcp_packetops_001"
    }
  }
}