Add CLI and config file support

.gitignore

@@ -1,7 +1,11 @@
 .DS_Store
-node_modules
+node_modules/
+*-workspace/
 server/build
 client/dist
 client/tsconfig.app.tsbuildinfo
 client/tsconfig.node.tsbuildinfo
 .vscode
+bin/build
+cli/build
+test-output

README.md

@@ -21,13 +21,13 @@ You can pass both arguments and environment variables to your MCP server. Argume
 npx @modelcontextprotocol/inspector build/index.js arg1 arg2
 
 # Pass environment variables only
-npx @modelcontextprotocol/inspector -e KEY=value -e KEY2=$VALUE2 node build/index.js
+npx @modelcontextprotocol/inspector -e key=value -e key2=$VALUE2 node build/index.js
 
 # Pass both environment variables and arguments
-npx @modelcontextprotocol/inspector -e KEY=value -e KEY2=$VALUE2 node build/index.js arg1 arg2
+npx @modelcontextprotocol/inspector -e key=value -e key2=$VALUE2 node build/index.js arg1 arg2
 
 # Use -- to separate inspector flags from server arguments
-npx @modelcontextprotocol/inspector -e KEY=$VALUE -- node build/index.js -e server-flag
+npx @modelcontextprotocol/inspector -e key=$VALUE -- node build/index.js -e server-flag
 ```
 
 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:
@@ -59,6 +59,36 @@ The MCP Inspector supports the following configuration settings. To change them,
 
 These settings can be adjusted in real-time through the UI and will persist across sessions.
 
+The inspector also supports configuration files to store settings for different MCP servers. This is useful when working with multiple servers or complex configurations:
+
+```bash
+npx @modelcontextprotocol/inspector --config path/to/config.json --server everything
+```
+
+Example server configuration file:
+
+```json
+{
+  "mcpServers": {
+    "everything": {
+      "command": "npx",
+      "args": ["@modelcontextprotocol/server-everything"],
+      "env": {
+        "hello": "Hello MCP!"
+      }
+    },
+    "my-server": {
+      "command": "node",
+      "args": ["build/index.js", "arg1", "arg2"],
+      "env": {
+        "key": "value",
+        "key2": "value2"
+      }
+    }
+  }
+}
+```
+
 ### From this repository
 
 If you're working on the inspector itself:
@@ -83,6 +113,57 @@ npm run build
 npm start
 ```
 
+### CLI Mode
+
+CLI mode enables programmatic interaction with MCP servers from the command line, ideal for scripting, automation, and integration with coding assistants. This creates an efficient feedback loop for MCP server development.
+
+```bash
+npx @modelcontextprotocol/inspector --cli node build/index.js
+```
+
+The CLI mode supports most operations across tools, resources, and prompts. A few examples:
+
+```bash
+# Basic usage
+npx @modelcontextprotocol/inspector --cli node build/index.js
+
+# With config file
+npx @modelcontextprotocol/inspector --cli --config path/to/config.json --server myserver
+
+# List available tools
+npx @modelcontextprotocol/inspector --cli node build/index.js --method tools/list
+
+# Call a specific tool
+npx @modelcontextprotocol/inspector --cli node build/index.js --method tools/call --tool-name mytool --tool-arg key=value --tool-arg another=value2
+
+# List available resources
+npx @modelcontextprotocol/inspector --cli node build/index.js --method resources/list
+
+# List available prompts
+npx @modelcontextprotocol/inspector --cli node build/index.js --method prompts/list
+
+# Connect to a remote MCP server
+npx @modelcontextprotocol/inspector --cli https://my-mcp-server.example.com
+
+# Call a tool on a remote server
+npx @modelcontextprotocol/inspector --cli https://my-mcp-server.example.com --method tools/call --tool-name remotetool --tool-arg param=value
+
+# List resources from a remote server
+npx @modelcontextprotocol/inspector --cli https://my-mcp-server.example.com --method resources/list
+```
+
+### UI Mode vs CLI Mode: When to Use Each
+
+| Use Case                 | UI Mode                                                                   | CLI Mode                                                                                                                                             |
+| ------------------------ | ------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- |
+| **Server Development**   | Visual interface for interactive testing and debugging during development | Scriptable commands for quick testing and continuous integration; creates feedback loops with AI coding assistants like Cursor for rapid development |
+| **Resource Exploration** | Interactive browser with hierarchical navigation and JSON visualization   | Programmatic listing and reading for automation and scripting                                                                                        |
+| **Tool Testing**         | Form-based parameter input with real-time response visualization          | Command-line tool execution with JSON output for scripting                                                                                           |
+| **Prompt Engineering**   | Interactive sampling with streaming responses and visual comparison       | Batch processing of prompts with machine-readable output                                                                                             |
+| **Debugging**            | Request history, visualized errors, and real-time notifications           | Direct JSON output for log analysis and integration with other tools                                                                                 |
+| **Automation**           | N/A                                                                       | Ideal for CI/CD pipelines, batch processing, and integration with coding assistants                                                                  |
+| **Learning MCP**         | Rich visual interface helps new users understand server capabilities      | Simplified commands for focused learning of specific endpoints                                                                                       |
+
 ## License
 
 This project is licensed under the MIT License—see the [LICENSE](LICENSE) file for details.

bin/cli.js

@@ -1,57 +1,34 @@
 #!/usr/bin/env node
-
-import { resolve, dirname } from "path";
+import { Command } from "commander";
+import fs from "node:fs";
+import path from "node:path";
+import { dirname, resolve } from "path";
 import { spawnPromise } from "spawn-rx";
 import { fileURLToPath } from "url";
-
 const __dirname = dirname(fileURLToPath(import.meta.url));
-
+function handleError(error) {
+  let message;
+  if (error instanceof Error) {
+    message = error.message;
+  } else if (typeof error === "string") {
+    message = error;
+  } else {
+    message = "Unknown error";
+  }
+  console.error(message);
+  process.exit(1);
+}
 function delay(ms) {
   return new Promise((resolve) => setTimeout(resolve, ms, true));
 }
-
-async function main() {
-  // Parse command line arguments
-  const args = process.argv.slice(2);
-  const envVars = {};
-  const mcpServerArgs = [];
-  let command = null;
-  let parsingFlags = true;
-
-  for (let i = 0; i < args.length; i++) {
-    const arg = args[i];
-
-    if (parsingFlags && arg === "--") {
-      parsingFlags = false;
-      continue;
-    }
-
-    if (parsingFlags && arg === "-e" && i + 1 < args.length) {
-      const envVar = args[++i];
-      const equalsIndex = envVar.indexOf("=");
-
-      if (equalsIndex !== -1) {
-        const key = envVar.substring(0, equalsIndex);
-        const value = envVar.substring(equalsIndex + 1);
-        envVars[key] = value;
-      } else {
-        envVars[envVar] = "";
-      }
-    } else if (!command) {
-      command = arg;
-    } else {
-      mcpServerArgs.push(arg);
-    }
-  }
-
+async function runWebClient(args) {
   const inspectorServerPath = resolve(
     __dirname,
     "..",
     "server",
     "build",
     "index.js",
   );
-
   // Path to the client entry point
   const inspectorClientPath = resolve(
     __dirname,
@@ -60,43 +37,38 @@ async function main() {
     "bin",
     "cli.js",
   );
-
   const CLIENT_PORT = process.env.CLIENT_PORT ?? "6274";
   const SERVER_PORT = process.env.SERVER_PORT ?? "6277";
-
   console.log("Starting MCP inspector...");
-
   const abort = new AbortController();
-
   let cancelled = false;
   process.on("SIGINT", () => {
     cancelled = true;
     abort.abort();
   });
-  let server, serverOk;
+  let server;
+  let serverOk;
   try {
     server = spawnPromise(
       "node",
       [
         inspectorServerPath,
-        ...(command ? [`--env`, command] : []),
-        ...(mcpServerArgs ? [`--args=${mcpServerArgs.join(" ")}`] : []),
+        ...(args.command ? [`--env`, args.command] : []),
+        ...(args.args ? [`--args=${args.args.join(" ")}`] : []),
       ],
       {
         env: {
           ...process.env,
           PORT: SERVER_PORT,
-          MCP_ENV_VARS: JSON.stringify(envVars),
+          MCP_ENV_VARS: JSON.stringify(args.envArgs),
         },
         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], {
@@ -108,13 +80,138 @@ async function main() {
       if (!cancelled || process.env.DEBUG) throw e;
     }
   }
-
-  return 0;
 }
-
-main()
-  .then((_) => process.exit(0))
-  .catch((e) => {
-    console.error(e);
-    process.exit(1);
+async function runCli(args) {
+  const projectRoot = resolve(__dirname, "..");
+  const cliPath = resolve(projectRoot, "cli", "build", "index.js");
+  const abort = new AbortController();
+  let cancelled = false;
+  process.on("SIGINT", () => {
+    cancelled = true;
+    abort.abort();
   });
+  try {
+    await spawnPromise("node", [cliPath, args.command, ...args.args], {
+      env: { ...process.env, ...args.envArgs },
+      signal: abort.signal,
+      echoOutput: true,
+    });
+  } catch (e) {
+    if (!cancelled || process.env.DEBUG) {
+      throw e;
+    }
+  }
+}
+function loadConfigFile(configPath, serverName) {
+  try {
+    const resolvedConfigPath = path.isAbsolute(configPath)
+      ? configPath
+      : path.resolve(process.cwd(), configPath);
+    if (!fs.existsSync(resolvedConfigPath)) {
+      throw new Error(`Config file not found: ${resolvedConfigPath}`);
+    }
+    const configContent = fs.readFileSync(resolvedConfigPath, "utf8");
+    const parsedConfig = JSON.parse(configContent);
+    if (!parsedConfig.mcpServers || !parsedConfig.mcpServers[serverName]) {
+      const availableServers = Object.keys(parsedConfig.mcpServers || {}).join(
+        ", ",
+      );
+      throw new Error(
+        `Server '${serverName}' not found in config file. Available servers: ${availableServers}`,
+      );
+    }
+    const serverConfig = parsedConfig.mcpServers[serverName];
+    return serverConfig;
+  } catch (err) {
+    if (err instanceof SyntaxError) {
+      throw new Error(`Invalid JSON in config file: ${err.message}`);
+    }
+    throw err;
+  }
+}
+function parseKeyValuePair(value, previous = {}) {
+  const parts = value.split("=");
+  const key = parts[0];
+  const val = parts.slice(1).join("=");
+  if (val === undefined || val === "") {
+    throw new Error(
+      `Invalid parameter format: ${value}. Use key=value format.`,
+    );
+  }
+  return { ...previous, [key]: val };
+}
+function parseArgs() {
+  const program = new Command();
+  const argSeparatorIndex = process.argv.indexOf("--");
+  let preArgs = process.argv;
+  let postArgs = [];
+  if (argSeparatorIndex !== -1) {
+    preArgs = process.argv.slice(0, argSeparatorIndex);
+    postArgs = process.argv.slice(argSeparatorIndex + 1);
+  }
+  program
+    .name("inspector-bin")
+    .allowExcessArguments()
+    .allowUnknownOption()
+    .option(
+      "-e <env>",
+      "environment variables in KEY=VALUE format",
+      parseKeyValuePair,
+      {},
+    )
+    .option("--config <path>", "config file path")
+    .option("--server <n>", "server name from config file")
+    .option("--cli", "enable CLI mode");
+  // Parse only the arguments before --
+  program.parse(preArgs);
+  const options = program.opts();
+  const remainingArgs = program.args;
+  // Add back any arguments that came after --
+  const finalArgs = [...remainingArgs, ...postArgs];
+  // Validate that config and server are provided together
+  if (
+    (options.config && !options.server) ||
+    (!options.config && options.server)
+  ) {
+    throw new Error(
+      "Both --config and --server must be provided together. If you specify one, you must specify the other.",
+    );
+  }
+  // If config file is specified, load and use the options from the file. We must merge the args
+  // from the command line and the file together, or we will miss the method options (--method,
+  // etc.)
+  if (options.config && options.server) {
+    const config = loadConfigFile(options.config, options.server);
+    return {
+      command: config.command,
+      args: [...(config.args || []), ...finalArgs],
+      envArgs: { ...(config.env || {}), ...(options.e || {}) },
+      cli: options.cli || false,
+    };
+  }
+  // Otherwise use command line arguments
+  const command = finalArgs[0] || "";
+  const args = finalArgs.slice(1);
+  return {
+    command,
+    args,
+    envArgs: options.e || {},
+    cli: options.cli || false,
+  };
+}
+async function main() {
+  process.on("uncaughtException", (error) => {
+    handleError(error);
+  });
+  try {
+    const args = parseArgs();
+    if (args.cli) {
+      runCli(args);
+    } else {
+      await runWebClient(args);
+    }
+  } catch (error) {
+    handleError(error);
+  }
+}
+main();