feat: proxy support

README.md

@@ -135,6 +135,20 @@ To bypass authentication, or to emit custom headers on all requests to your remo
       ]
 ```
 
+* To enable an outbound HTTP(S) proxy for mcp-remote, add the `--enable-proxy` flag. When enabled, mcp-remote will use the proxy settings from common environment variables (for example `HTTP_PROXY`, `HTTPS_PROXY`, and `NO_PROXY`).
+
+```json
+    "args": [
+      "mcp-remote",
+      "https://remote.mcp.server/sse",
+      "--enable-proxy"
+    ],
+    "env": {
+      "HTTPS_PROXY": "http://127.0.0.1:3128",
+      "NO_PROXY": "localhost,127.0.0.1"
+    }
+```
+
 * To ignore specific tools from the remote server, add the `--ignore-tool` flag. This will filter out tools matching the specified patterns from both `tools/list` responses and block `tools/call` requests. Supports wildcard patterns with `*`.
 
 ```json

package.json

@@ -33,7 +33,8 @@
   "dependencies": {
     "express": "^4.21.2",
     "open": "^10.1.0",
-    "strict-url-sanitise": "^0.0.1"
+    "strict-url-sanitise": "^0.0.1",
+    "undici": "^7.12.0"
   },
   "devDependencies": {
     "@modelcontextprotocol/sdk": "^1.17.3",

src/lib/utils.ts

@@ -14,6 +14,7 @@ import fs from 'fs'
 import { readFile, rm } from 'fs/promises'
 import path from 'path'
 import { version as MCP_REMOTE_VERSION } from '../../package.json'
+import { fetch, setGlobalDispatcher, RequestInit, EnvHttpProxyAgent } from 'undici'
 
 // Global type declaration for typescript
 declare global {
@@ -642,6 +643,13 @@ export async function parseCommandLineArgs(args: string[], usage: string) {
     log('Debug mode enabled - detailed logs will be written to ~/.mcp-auth/')
   }
 
+  const enableProxy = args.includes('--enable-proxy')
+  if (enableProxy) {
+    // Use env proxy
+    setGlobalDispatcher(new EnvHttpProxyAgent())
+    log('HTTP proxy support enabled - using system HTTP_PROXY/HTTPS_PROXY environment variables')
+  }
+
   // Parse transport strategy
   let transportStrategy: TransportStrategy = 'http-first' // Default
   const transportIndex = args.indexOf('--transport')