IBKR TWS MCP Server

# CancelledError Troubleshooting Guide ## Current Issue When calling `ibkr_connect` through the MCP protocol, you're getting: ``` CancelledError("Cancelled via cancel scope...") ``` ## What This Means **CancelledError** is different from the previous "Future attached to different loop" error. This error means: - The MCP session cancelled the request before it completed - The connection to TWS is taking too long - OR TWS isn't running/accepting connections ## Changes Made to Fix ### 1. Reduced Timeout ✅ Changed connection timeout from 10s to 5s to avoid MCP session cancellation: ```python # Old: timeout=10 seconds await self.ib.connectAsync(host, port, clientId=client_id, timeout=10) # New: timeout=5 seconds with 8s overall timeout await asyncio.wait_for( self.ib.connectAsync(host, port, clientId=client_id, timeout=5), timeout=8.0 ) ``` ### 2. Better Error Messages ✅ Added specific handling for: - `asyncio.TimeoutError` - Connection takes too long - `asyncio.CancelledError` - Request cancelled by MCP client - Other exceptions - Generic connection failures ### 3. Created Diagnostic Tool ✅ **`test_tws_connection.py`** - Test TWS connection directly (outside MCP): ```bash # Test with default settings (TWS Live on 7496) uv run python test_tws_connection.py # Test with custom port (TWS Paper) uv run python test_tws_connection.py --port 7497 # Test IB Gateway uv run python test_tws_connection.py --port 4001 ``` ## Debugging Steps ### Step 1: Test TWS Connection Directly ```bash # This bypasses the MCP layer to test if TWS is reachable uv run python test_tws_connection.py ``` **Expected outcomes:** - ✅ **Success** → TWS is running and accepting connections (problem is in MCP layer) - ❌ **Timeout** → TWS not running or wrong port - ❌ **Connection Refused** → TWS not listening on that port ### Step 2: Check TWS Configuration In TWS/IB Gateway: 1. Go to: **Edit → Global Configuration → API → Settings** 2. Verify: - ✅ "Enable ActiveX and Socket Clients" is checked - ✅ "Socket Port" shows the correct port: - TWS Live: 7496 - TWS Paper: 7497 - IB Gateway Live: 4001 - IB Gateway Paper: 4002 - ✅ "Allow connections from localhost only" (unless using remote) 3. **Restart TWS after any changes** ### Step 3: Check Your .env File ```bash # Check current settings cat .env ``` Should contain: ```env TWS_HOST=127.0.0.1 TWS_PORT=7496 # Or 7497 for paper trading TWS_CLIENT_ID=1 ``` ### Step 4: Test Through MCP After verifying TWS is working with the diagnostic tool: 1. Start the MCP server: ```bash uv run python main.py ``` 2. Connect via Claude Desktop or MCP Inspector 3. Call `ibkr_connect` tool ## Common Issues & Solutions ### Issue: "Connection timeout" **Cause:** TWS not running or wrong port **Solution:** - Start TWS/IB Gateway - Verify port number matches your TWS settings - Use diagnostic tool to test: `uv run python test_tws_connection.py` ### Issue: "Connection refused" **Cause:** TWS not listening on that port **Solution:** - Check TWS API settings (see Step 2 above) - Verify port number in .env matches TWS configuration - Try different port (7496 vs 7497) ### Issue: "Connection cancelled" (CancelledError) **Cause:** MCP session timeout or client disconnection **Solution:** - Connection is taking too long (see timeout issue above) - OR TWS is slow to respond (start TWS earlier) - Try the diagnostic tool to verify TWS is responsive ### Issue: Still getting event loop errors **Cause:** Not using ib_async library **Solution:** - Verify `uv pip list | grep ib-async` shows version 2.0.1 - Not `ib-insync` - Run `uv sync` to reinstall dependencies ## Port Reference | Application | Mode | Port | |-------------|------|------| | TWS | Live | 7496 | | TWS | Paper | 7497 | | IB Gateway | Live | 4001 | | IB Gateway | Paper | 4002 | ## Next Steps 1. **Run the diagnostic tool:** ```bash uv run python test_tws_connection.py ``` 2. **If diagnostic succeeds:** - TWS connection works ✅ - Problem is in MCP layer - Try restarting the MCP server - Check MCP client timeout settings 3. **If diagnostic fails:** - Fix TWS configuration (see Step 2) - Verify correct port - Ensure TWS is running - Check firewall settings ## Files Modified - ✅ `src/tws_client.py` - Reduced timeout, better error handling - ✅ `tests/unit/test_tws_client.py` - Updated test expectations - ✅ `test_tws_connection.py` - NEW diagnostic tool ## Status - [x] Migrated to ib_async (fixes event loop errors) - [x] Reduced connection timeout (5s) - [x] Added better error messages - [x] Created diagnostic tool - [ ] **NEED TO TEST**: Run diagnostic tool with TWS - [ ] **NEED TO TEST**: Test via MCP after diagnostic passes