Lightning Enable MCP

Instructions

Implementation Reference

• python/lightning-enable-mcp/src/lightning_enable_mcp/tools/send_onchain.py:21-129 (handler)

  The main handler function for the `send_onchain` MCP tool. It validates inputs, checks wallet compatibility, performs budget authorization, delegates the actual transaction to the wallet (LND or Strike), records the spend, and formats the result.

  async def send_onchain(
      address: str,
      amount_sats: int,
      wallet: "Union[StrikeWallet, LndWallet, None]" = None,
      budget_service: "BudgetService | None" = None,
  ) -> str:
      """
      Send an on-chain Bitcoin payment to a Bitcoin address.
  
      Supports Strike and LND wallets. The payment is sent from your
      wallet balance.
  
      Args:
          address: Bitcoin address to send to (e.g., bc1q...)
          amount_sats: Amount to send in satoshis
          wallet: Strike or LND wallet instance
          budget_service: BudgetService for spending limits
  
      Returns:
          JSON with payment result including transaction details
      """
      if not address or not address.strip():
          return json.dumps({
              "success": False,
              "error": "Bitcoin address is required"
          })
  
      if amount_sats <= 0:
          return json.dumps({
              "success": False,
              "error": "Amount must be greater than 0 sats"
          })
  
      if not wallet:
          return json.dumps({
              "success": False,
              "error": "Wallet not configured. Set STRIKE_API_KEY or LND_REST_HOST+LND_MACAROON_HEX for on-chain payments."
          })
  
      # Verify it's a supported wallet type
      from ..strike_wallet import StrikeWallet
      from ..lnd_wallet import LndWallet
      if not isinstance(wallet, (StrikeWallet, LndWallet)):
          provider_name = type(wallet).__name__.replace("Wallet", "")
          return json.dumps({
              "success": False,
              "error": f"{provider_name} does not support on-chain payments. Use Strike or LND wallet.",
              "errorCode": "NOT_SUPPORTED",
              "hint": "Set STRIKE_API_KEY or LND_REST_HOST+LND_MACAROON_HEX for on-chain payments."
          })
  
      # Check budget if configured
      if budget_service:
          try:
              budget_result = await budget_service.check_approval_level(amount_sats)
              from ..config import ApprovalLevel
              if budget_result.level == ApprovalLevel.DENY:
                  return json.dumps({
                      "success": False,
                      "error": f"Budget check failed: {budget_result.denial_reason}",
                  })
          except Exception as e:
              logger.warning(f"Budget check failed: {e}")
  
      try:
          result = await wallet.send_onchain(address.strip(), amount_sats)
  
          if not result.success:
              return json.dumps({
                  "success": False,
                  "error": result.error_message,
                  "errorCode": result.error_code,
              })
  
          # Record spend if budget service available
          if budget_service:
              try:
                  total_sats = amount_sats + (result.fee_sats or 0)
                  budget_service.record_spend(total_sats)
                  budget_service.record_payment_time()
              except Exception:
                  pass
  
          provider_name = "LND" if isinstance(wallet, LndWallet) else "Strike"
  
          if result.state == "COMPLETED":
              message = f"On-chain payment of {amount_sats} sats sent to {address}"
          else:
              message = f"On-chain payment initiated (status: {result.state})"
  
          return json.dumps({
              "success": True,
              "provider": provider_name,
              "payment": {
                  "id": result.payment_id,
                  "txId": result.txid,
                  "state": result.state,
                  "amountSats": result.amount_sats,
                  "feeSats": result.fee_sats,
              },
              "message": message,
          }, indent=2)
  
      except Exception as e:
          logger.exception("Error sending on-chain payment")
          return json.dumps({
              "success": False,
              "error": sanitize_error(str(e))
          })