fix(mcp-http-server): default host to 127.0.0.1, not all interfaces (#1918)

Author: ycjcl868

packages/agent-infra/mcp-http-server/README.md

@@ -40,7 +40,7 @@ await startSseAndStreamableHttpMcpServer({
 | Parameter | Type | Description |
 |-----------|------|-------------|
 | `port` | `number` | Port to listen on (default: 8080) |
-| `host` | `string` | Host to bind to (default: '::') |
+| `host` | `string` | Host to bind to (default: '127.0.0.1') |
 | `stateless` | `boolean` | Enable stateless mode for streamable HTTP (default: true) |
 | `middlewares` | `MiddlewareFunction[]` | Custom Express middlewares |
 | `routes` | `RoutesConfig` | Custom route configuration |

packages/agent-infra/mcp-http-server/src/startServer.ts

@@ -259,7 +259,7 @@ export async function startSseAndStreamableHttpMcpServer(
     },
   );
 
-  const HOST = host || '::';
+  const HOST = host || '127.0.0.1';
   const PORT = Number(port || process.env.PORT || 8080);
 
   return new Promise((resolve, reject) => {

packages/agent-infra/mcp-http-server/tests/startServer-server.test.ts

@@ -148,7 +148,7 @@ describe('MCP Server HTTP Server Tests', () => {
       );
 
       const transport = new SSEClientTransport(
-        new URL(`http://localhost:${port}/sse`),
+        new URL(`http://127.0.0.1:${port}/sse`),
       );
 
       await client.connect(transport);
@@ -371,7 +371,7 @@ describe('MCP Server HTTP Server Tests', () => {
 
     it('should handle health check endpoint via custom middleware', async () => {
       const response = await fetch(
-        `http://localhost:${customMiddlewarePort}/health`,
+        `http://127.0.0.1:${customMiddlewarePort}/health`,
       );
 
       expect(response.status).toBe(200);
@@ -440,7 +440,7 @@ describe('MCP Server HTTP Server Tests', () => {
       });
 
       try {
-        const response = await fetch(`http://localhost:${middlewarePort}/mcp`, {
+        const response = await fetch(`http://127.0.0.1:${middlewarePort}/mcp`, {
           method: 'POST',
           headers: { 'Content-Type': 'application/json' },
           body: JSON.stringify({
@@ -530,7 +530,7 @@ describe('MCP Server HTTP Server Tests', () => {
 
       try {
         const response = await fetch(
-          `http://localhost:${statefulTestPort}/mcp`,
+          `http://127.0.0.1:${statefulTestPort}/mcp`,
           {
             method: 'POST',
             headers: {

packages/agent-infra/mcp-servers/browser/src/index.ts

@@ -68,7 +68,7 @@ program
   .option('--headless', 'run browser in headless mode, headed by default')
   .option(
     '--host <host>',
-    'host to bind server to. Default is localhost. Use 0.0.0.0 to bind to all interfaces.',
+    'host to bind server to. Default is 127.0.0.1 (loopback). Use 0.0.0.0 to bind to all interfaces.',
   )
   // .option('--ignore-https-errors', 'ignore https errors')
   // .option(

packages/agent-infra/mcp-servers/commands/README.md

@@ -120,8 +120,8 @@ npx @agent-infra/mcp-server-commands --port 8089
 ```
 
 You can use one of the two MCP Server remote endpoint:
-- Streamable HTTP(Recommended): `http://127.0.0.1::8089/mcp`
-- SSE: `http://127.0.0.1::8089/sse`
+- Streamable HTTP(Recommended): `http://127.0.0.1:8089/mcp`
+- SSE: `http://127.0.0.1:8089/sse`
 
 
 And then in MCP client config, set the `url` to the SSE endpoint:
@@ -130,7 +130,7 @@ And then in MCP client config, set the `url` to the SSE endpoint:
 {
   "mcpServers": {
     "commands": {
-      "url": "http://127.0.0.1::8089/sse"
+      "url": "http://127.0.0.1:8089/sse"
     }
   }
 }
@@ -143,7 +143,7 @@ And then in MCP client config, set the `url` to the SSE endpoint:
   "mcpServers": {
     "commands": {
       "type": "streamable-http", // If there is MCP Client support
-      "url": "http://127.0.0.1::8089/mcp"
+      "url": "http://127.0.0.1:8089/mcp"
     }
   }
 }

packages/agent-infra/mcp-servers/commands/src/index.ts

@@ -20,7 +20,7 @@ program
   .option('--cwd <cwd>', 'current working directory')
   .option(
     '--host <host>',
-    'host to bind server to. Default is localhost. Use 0.0.0.0 to bind to all interfaces.',
+    'host to bind server to. Default is 127.0.0.1 (loopback). Use 0.0.0.0 to bind to all interfaces.',
   )
   .option('--port <port>', 'port to listen on for SSE and HTTP transport.')
   .action(async (options) => {

packages/agent-infra/mcp-servers/filesystem/src/index.ts

@@ -25,7 +25,7 @@ program
   )
   .option(
     '--host <host>',
-    'host to bind server to. Default is localhost. Use 0.0.0.0 to bind to all interfaces.',
+    'host to bind server to. Default is 127.0.0.1 (loopback). Use 0.0.0.0 to bind to all interfaces.',
   )
   .option('--port <port>', 'port to listen on for SSE and HTTP transport.')
   .action(async (options) => {