Add HTTP transport fallback for non-standard MCP servers #180
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Add support for multiple HTTP transport types with fallback: - Try streamable HTTP first (SDK StreamableClientTransport) - Fall back to SSE (SDK SSEClientTransport) - Fall back to plain JSON-RPC over HTTP (manual implementation) This ensures compatibility with safeinputs and other non-standard HTTP MCP servers. Co-authored-by: lpcox <15877973+lpcox@users.noreply.github.com>
- Skip SDK transports when custom headers are provided (they don't support headers) - This fixes safeinputs and similar backends that require authentication - Format code with gofmt Co-authored-by: lpcox <15877973+lpcox@users.noreply.github.com>
- Add nil check for session in SDK method wrappers to prevent panics - Extract callSDKMethod to eliminate code duplication - Improve defensive programming Co-authored-by: lpcox <15877973+lpcox@users.noreply.github.com>
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[WIP] Fix gateway handling of safeinputs backend HTTP server
Add HTTP transport fallback for non-standard MCP servers
Jan 12, 2026
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@copilot please fix thesel linting issues run golangci-lint
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Remove unused lastErr variable assignments. The variable was being assigned on lines 196 and 207 but overwritten before use. Now we directly use err in the final error message since it contains the last error from the final transport attempt. Co-authored-by: lpcox <15877973+lpcox@users.noreply.github.com>
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Multi-Transport HTTP MCP Backend Support - COMPLETE ✓
Problem Solved
The gateway now properly handles different types of HTTP MCP servers, including safeinputs which uses a non-standard JSON-RPC 2.0 over HTTP implementation.
Implementation Summary
File Modified:
internal/mcp/connection.go(229 additions, 46 deletions)Key Changes:
Added HTTPTransportType enum to track transport in use:
HTTPTransportStreamable- for 2025-03-26 specHTTPTransportSSE- for 2024-11-05 specHTTPTransportPlainJSON- for non-standard implementationsEnhanced NewHTTPConnection with smart fallback logic:
Added transport-specific connection functions:
tryStreamableHTTPTransport()- Uses SDK's StreamableClientTransporttrySSETransport()- Uses SDK's SSEClientTransporttryPlainJSONTransport()- Manual HTTP POST implementationRefactored SendRequestWithServerID:
Added callSDKMethod helper:
Defensive programming:
Test Results
Compatibility
What This Enables
💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.