Merge branch 'main' into add-tests

Author: olaservo

CONTRIBUTING.md

@@ -7,7 +7,7 @@ Thanks for your interest in contributing! This guide explains how to get involve
 1. Fork the repository and clone it locally
 2. Install dependencies with `npm install`
 3. Run `npm run dev` to start both client and server in development mode
-4. Use the web UI at http://127.0.0.1:5173 to interact with the inspector
+4. Use the web UI at http://127.0.0.1:6274 to interact with the inspector
 
 ## Development Process & Pull Requests
 

README.md

@@ -30,7 +30,7 @@ npx @modelcontextprotocol/inspector -e KEY=value -e KEY2=$VALUE2 node build/inde
 npx @modelcontextprotocol/inspector -e KEY=$VALUE -- node build/index.js -e server-flag
 ```
 
-The inspector runs both a client UI (default port 5173) and an MCP proxy server (default port 3000). Open the client UI in your browser to use the inspector. You can customize the ports if needed:
+The inspector runs both an MCP Inspector (MCPI) client UI (default port 6274) and an MCP Proxy (MCPP) server (default port 6277). Open the MCPI client UI in your browser to use the inspector. (These ports are derived from the T9 dialpad mapping of MCPI and MCPP respectively, as a mnemonic). You can customize the ports if needed:
 
 ```bash
 CLIENT_PORT=8080 SERVER_PORT=9000 npx @modelcontextprotocol/inspector node build/index.js

bin/cli.js

@@ -7,7 +7,7 @@ import { fileURLToPath } from "url";
 const __dirname = dirname(fileURLToPath(import.meta.url));
 
 function delay(ms) {
-  return new Promise((resolve) => setTimeout(resolve, ms));
+  return new Promise((resolve) => setTimeout(resolve, ms, true));
 }
 
 async function main() {
@@ -61,8 +61,8 @@ async function main() {
     "cli.js",
   );
 
-  const CLIENT_PORT = process.env.CLIENT_PORT ?? "5173";
-  const SERVER_PORT = process.env.SERVER_PORT ?? "3000";
+  const CLIENT_PORT = process.env.CLIENT_PORT ?? "6274";
+  const SERVER_PORT = process.env.SERVER_PORT ?? "6277";
 
   console.log("Starting MCP inspector...");
 
@@ -73,42 +73,40 @@ async function main() {
     cancelled = true;
     abort.abort();
   });
-
-  const server = spawnPromise(
-    "node",
-    [
-      inspectorServerPath,
-      ...(command ? [`--env`, command] : []),
-      ...(mcpServerArgs ? [`--args=${mcpServerArgs.join(" ")}`] : []),
-    ],
-    {
-      env: {
-        ...process.env,
-        PORT: SERVER_PORT,
-        MCP_ENV_VARS: JSON.stringify(envVars),
-      },
-      signal: abort.signal,
-      echoOutput: true,
-    },
-  );
-
-  const client = spawnPromise("node", [inspectorClientPath], {
-    env: { ...process.env, PORT: CLIENT_PORT },
-    signal: abort.signal,
-    echoOutput: true,
-  });
-
-  // Make sure our server/client didn't immediately fail
-  await Promise.any([server, client, delay(2 * 1000)]);
-  const portParam = SERVER_PORT === "3000" ? "" : `?proxyPort=${SERVER_PORT}`;
-  console.log(
-    `\n🔍 MCP Inspector is up and running at http://127.0.0.1:${CLIENT_PORT}${portParam} 🚀`,
-  );
-
+  let server, serverOk;
   try {
-    await Promise.any([server, client]);
-  } catch (e) {
-    if (!cancelled || process.env.DEBUG) throw e;
+    server = spawnPromise(
+      "node",
+      [
+        inspectorServerPath,
+        ...(command ? [`--env`, command] : []),
+        ...(mcpServerArgs ? [`--args=${mcpServerArgs.join(" ")}`] : []),
+      ],
+      {
+        env: {
+          ...process.env,
+          PORT: SERVER_PORT,
+          MCP_ENV_VARS: JSON.stringify(envVars),
+        },
+        signal: abort.signal,
+        echoOutput: true,
+      },
+    );
+
+    // Make sure server started before starting client
+    serverOk = await Promise.race([server, delay(2 * 1000)]);
+  } catch (error) {}
+
+  if (serverOk) {
+    try {
+      await spawnPromise("node", [inspectorClientPath], {
+        env: { ...process.env, PORT: CLIENT_PORT },
+        signal: abort.signal,
+        echoOutput: true,
+      });
+    } catch (e) {
+      if (!cancelled || process.env.DEBUG) throw e;
+    }
   }
 
   return 0;

client/bin/cli.js

@@ -15,5 +15,19 @@ const server = http.createServer((request, response) => {
   });
 });
 
-const port = process.env.PORT || 5173;
-server.listen(port, () => {});
+const port = process.env.PORT || 6274;
+server.on("listening", () => {
+  console.log(
+    `🔍 MCP Inspector is up and running at http://127.0.0.1:${port} 🚀`,
+  );
+});
+server.on("error", (err) => {
+  if (err.message.includes(`EADDRINUSE`)) {
+    console.error(
+      `❌  MCP Inspector PORT IS IN USE at http://127.0.0.1:${port} ❌ `,
+    );
+  } else {
+    throw err;
+  }
+});
+server.listen(port);

client/package.json

@@ -18,7 +18,7 @@
     "dev": "vite",
     "build": "tsc -b && vite build",
     "lint": "eslint .",
-    "preview": "vite preview",
+    "preview": "vite preview --port 6274",
     "test": "jest --config jest.config.cjs",
     "test:watch": "jest --config jest.config.cjs --watch"
   },

client/src/App.tsx

@@ -49,7 +49,7 @@ import { DEFAULT_INSPECTOR_CONFIG } from "./lib/constants";
 import { InspectorConfig } from "./lib/configurationTypes";
 
 const params = new URLSearchParams(window.location.search);
-const PROXY_PORT = params.get("proxyPort") ?? "3000";
+const PROXY_PORT = params.get("proxyPort") ?? "6277";
 const PROXY_SERVER_URL = `http://${window.location.hostname}:${PROXY_PORT}`;
 const CONFIG_LOCAL_STORAGE_KEY = "inspectorConfig_v1";
 

client/src/components/Sidebar.tsx

@@ -8,6 +8,7 @@ import {
   Github,
   Eye,
   EyeOff,
+  RotateCcw,
   Settings,
 } from "lucide-react";
 import { Button } from "@/components/ui/button";
@@ -375,8 +376,17 @@ const Sidebar = ({
 
           <div className="space-y-2">
             <Button className="w-full" onClick={onConnect}>
-              <Play className="w-4 h-4 mr-2" />
-              Connect
+              {connectionStatus === "connected" ? (
+                <>
+                  <RotateCcw className="w-4 h-4 mr-2" />
+                  {transportType === "stdio" ? "Restart" : "Reconnect"}
+                </>
+              ) : (
+                <>
+                  <Play className="w-4 h-4 mr-2" />
+                  Connect
+                </>
+              )}
             </Button>
 
             <div className="flex items-center justify-center space-x-2 mb-4">

client/src/components/ToolsTab.tsx

@@ -226,7 +226,11 @@ const ToolsTab = ({
                         </div>
                       ) : (
                         <Input
-                          type={prop.type === "number" ? "number" : "text"}
+                          type={
+                            prop.type === "number" || prop.type === "integer"
+                              ? "number"
+                              : "text"
+                          }
                           id={key}
                           name={key}
                           placeholder={prop.description}
@@ -235,7 +239,8 @@ const ToolsTab = ({
                             setParams({
                               ...params,
                               [key]:
-                                prop.type === "number"
+                                prop.type === "number" ||
+                                prop.type === "integer"
                                   ? Number(e.target.value)
                                   : e.target.value,
                             })

package-lock.json

@@ -12,6 +12,7 @@ import {
   StdioClientTransport,
   getDefaultEnvironment,
 } from "@modelcontextprotocol/sdk/client/stdio.js";
+import { Transport } from "@modelcontextprotocol/sdk/shared/transport.js";
 import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
 import express from "express";
 import { findActualExecutable } from "spawn-rx";
@@ -98,12 +99,14 @@ const createTransport = async (req: express.Request) => {
   }
 };
 
+let backingServerTransport: Transport | undefined;
+
 app.get("/sse", async (req, res) => {
   try {
     console.log("New SSE connection");
 
-    let backingServerTransport;
     try {
+      await backingServerTransport?.close();
       backingServerTransport = await createTransport(req);
     } catch (error) {
       if (error instanceof SseError && error.code === 401) {
@@ -182,17 +185,17 @@ app.get("/config", (req, res) => {
   }
 });
 
-const PORT = process.env.PORT || 3000;
-
-try {
-  const server = app.listen(PORT);
+const PORT = process.env.PORT || 6277;
 
-  server.on("listening", () => {
-    const addr = server.address();
-    const port = typeof addr === "string" ? addr : addr?.port;
-    console.log(`Proxy server listening on port ${port}`);
-  });
-} catch (error) {
-  console.error("Failed to start server:", error);
+const server = app.listen(PORT);
+server.on("listening", () => {
+  console.log(`⚙️ Proxy server listening on port ${PORT}`);
+});
+server.on("error", (err) => {
+  if (err.message.includes(`EADDRINUSE`)) {
+    console.error(`❌  Proxy Server PORT IS IN USE at port ${PORT} ❌ `);
+  } else {
+    console.error(err.message);
+  }
   process.exit(1);
-}
+});