Summary
When using MCP SuperAssistant with SSE (http://localhost:3006/sse), the proxy repeatedly crashes after reconnects.
Environment
- MCP SuperAssistant: 0.6.0 (Chrome Web Store)
- Proxy command:
npx @srbhptl39/mcp-superassistant-proxy@latest --config /Users/<user>/projects/mcpsuperassistant/config.json --outputTransport sse
- OS: macOS
Steps to Reproduce
- Start proxy with SSE transport
- Open supported chat site and connect extension to
http://localhost:3006/sse
- Connection toggles between connected/disconnected and tools remain empty (0/0)
- Reconnect occurs, then proxy crashes
Actual Behavior
- Extension becomes unstable (
SSE error: Failed to fetch)
- Proxy exits with error and restarts if wrapped by auto-restart script
Proxy Error
Error: Already connected to a transport. Call close() before connecting to a new transport, or use a separate Protocol instance per connection.
at Server.connect (.../node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:217:19)
at .../node_modules/@srbhptl39/mcp-superassistant-proxy/dist/gateways/configToSse.js:78:22
Additional Notes
- Reproducible consistently
- Looks like reconnect path reuses protocol/server transport incorrectly for concurrent/new SSE sessions
- This prevents stable tool listing and usage in browser
Summary
When using MCP SuperAssistant with SSE (
http://localhost:3006/sse), the proxy repeatedly crashes after reconnects.Environment
npx @srbhptl39/mcp-superassistant-proxy@latest --config /Users/<user>/projects/mcpsuperassistant/config.json --outputTransport sseSteps to Reproduce
http://localhost:3006/sseActual Behavior
SSE error: Failed to fetch)Proxy Error
Additional Notes