mcp-proxy

# mcp-proxy > A Rust bidirectional MCP proxy supporting SSE and Streamable HTTP transports with OAuth. ## Features - **Multiple transports**: SSE and Streamable HTTP - **OAuth authentication**: Full OAuth flow with automatic token refresh - **Bidirectional proxy**: Connect remote servers to local clients or expose local servers remotely - **Fast and lightweight**: Built in rust for performance ## Usage ### Installing ```bash # from crates.io cargo install rmcp-proxy # from github cargo install --git https://github.com/stephenlacy/mcp-proxy ``` ### Building ```bash cargo build --release ``` ### Running The proxy can operate in two modes: #### 1. Remote Client Mode Connect to a remote MCP server and expose it as a local stdio server. Supports both SSE and Streamable HTTP transports with automatic detection. **Transport Detection**: - URLs containing `/sse` → Uses SSE transport - All other URLs → Uses Streamable HTTP transport - Override with `--transport` flag ##### Basic Examples ```bash # Streamable HTTP mcp-proxy http://localhost:9090/mcp/instances_abc123 # SSE transport mcp-proxy http://localhost:8080/sse mcp-proxy --transport sse http://localhost:8080/events # Specific mcp-proxy --transport streamable-http http://localhost:9090/api ``` ##### Using with Claude or Cursor ```json { "mcpServers": { "my-remote-server": { "command": "mcp-proxy", "args": ["http://example.com/mcp/instances_abc123"] }, "sse-server": { "command": "mcp-proxy", "args": ["--transport", "sse", "http://example.com/sse"] } } } ``` #### 2. Local Server Mode Connect to a local MCP server via stdio and expose it as a remote server. Supports both SSE and Streamable HTTP endpoints. ```bash # Expose as SSE server mcp-proxy --port 8080 -- your-command --arg1 value1 --arg2 value2 mcp-proxy --port 8080 python mcp_server.py mcp-proxy --port 8080 -- npx -y @modelcontextprotocol/server-everything # Or http+streamable mcp-proxy --port 9090 --transport streamable-http -- python mcp_server.py mcp-proxy --port 8080 -e KEY VALUE -e ANOTHER_KEY ANOTHER_VALUE -- your-command ``` ### Authentication Management #### Clearing Auth Cache If you encounter authentication issues, clear the auth cache: ```bash # Clear all auth data mcp-proxy reset # Or manually delete the directory rm -rf ~/.mcp-auth ``` ### Command Line Options ```bash # Transport selection --transport <TRANSPORT> # sse, streamable-http, or auto (default: auto) # Server mode options --port <PORT> # Port for local server mode (default: random) --host <HOST> # Host to bind to (default: 127.0.0.1) # Environment variables (server mode) -e, --env <KEY> <VALUE> # Set environment variable --pass-environment # Pass through all environment variables # Headers (client mode) -H, --headers <KEY> <VALUE> # Add custom headers # Reset auth mcp-proxy reset # Clear all stored auth data ``` ### Logging > The upstream rmcp crate dumps noisy logs unfortunately Control log verbosity with the `RUST_LOG` environment variable: ```bash # Minimal logging RUST_LOG=error mcp-proxy http://example.com/mcp RUST_LOG=debug mcp-proxy http://example.com/mcp RUST_LOG=info mcp-proxy http://example.com/mcp ``` ### Library Usage ```rust use rmcp_proxy::{ sse_client::run_sse_client, streamable_http_client::run_streamable_http_client, StreamableHttpClientConfig, SseClientConfig }; // Streamable HTTP client let config = StreamableHttpClientConfig { url: "http://example.com/mcp/instances_abc123".to_string(), headers: HashMap::new(), }; run_streamable_http_client(config).await?; // SSE client let config = SseClientConfig { url: "http://example.com/sse".to_string(), headers: HashMap::new(), }; run_sse_client(config).await?; ``` ## License MIT