feat: record client name in telemetry. (#1208)

The changes in the PR intercepts the name of the MCP client right after
server initialization, coverts it into one of the existing enum values,
and append it with the telemetry request.

Note that the client name is unset if there is no client connected yet.
This means the server_start event won't have a client name.

Tested with gemini-cli.

---------

Co-authored-by: Yulun Zeng <yulunz@chromium.org>

Author: yulunz

src/index.ts

@@ -57,6 +57,13 @@ export async function createMcpServer(
     return {};
   });
 
+  server.server.oninitialized = () => {
+    const clientName = server.server.getClientVersion()?.name;
+    if (clientName) {
+      clearcutLogger?.setClientName(clientName);
+    }
+  };
+
   let context: McpContext;
   async function getContext(): Promise<McpContext> {
     const chromeArgs: string[] = (serverArgs.chromeArg ?? []).map(String);

src/telemetry/ClearcutLogger.ts

@@ -10,7 +10,12 @@ import {logger} from '../logger.js';
 
 import type {LocalState, Persistence} from './persistence.js';
 import {FilePersistence} from './persistence.js';
-import {type FlagUsage, WatchdogMessageType, OsType} from './types.js';
+import {
+  McpClient,
+  type FlagUsage,
+  WatchdogMessageType,
+  OsType,
+} from './types.js';
 import {WatchdogClient} from './WatchdogClient.js';
 
 const MS_PER_DAY = 24 * 60 * 60 * 1000;
@@ -31,6 +36,7 @@ function detectOsType(): OsType {
 export class ClearcutLogger {
   #persistence: Persistence;
   #watchdog: WatchdogClient;
+  #mcpClient: McpClient;
 
   constructor(options: {
     appVersion: string;
@@ -53,6 +59,18 @@ export class ClearcutLogger {
         clearcutForceFlushIntervalMs: options.clearcutForceFlushIntervalMs,
         clearcutIncludePidHeader: options.clearcutIncludePidHeader,
       });
+    this.#mcpClient = McpClient.MCP_CLIENT_UNSPECIFIED;
+  }
+
+  setClientName(clientName: string): void {
+    const lowerName = clientName.toLowerCase();
+    if (lowerName.includes('claude')) {
+      this.#mcpClient = McpClient.MCP_CLIENT_CLAUDE_CODE;
+    } else if (lowerName.includes('gemini')) {
+      this.#mcpClient = McpClient.MCP_CLIENT_GEMINI_CLI;
+    } else {
+      this.#mcpClient = McpClient.MCP_CLIENT_OTHER;
+    }
   }
 
   async logToolInvocation(args: {
@@ -63,6 +81,7 @@ export class ClearcutLogger {
     this.#watchdog.send({
       type: WatchdogMessageType.LOG_EVENT,
       payload: {
+        mcp_client: this.#mcpClient,
         tool_invocation: {
           tool_name: args.toolName,
           success: args.success,
@@ -76,6 +95,7 @@ export class ClearcutLogger {
     this.#watchdog.send({
       type: WatchdogMessageType.LOG_EVENT,
       payload: {
+        mcp_client: this.#mcpClient,
         server_start: {
           flag_usage: flagUsage,
         },
@@ -99,6 +119,7 @@ export class ClearcutLogger {
         this.#watchdog.send({
           type: WatchdogMessageType.LOG_EVENT,
           payload: {
+            mcp_client: this.#mcpClient,
             daily_active: {
               days_since_last_active: daysSince,
             },

src/telemetry/types.ts

@@ -75,6 +75,7 @@ export enum McpClient {
   MCP_CLIENT_UNSPECIFIED = 0,
   MCP_CLIENT_CLAUDE_CODE = 1,
   MCP_CLIENT_GEMINI_CLI = 2,
+  MCP_CLIENT_OTHER = 3,
 }
 
 // IPC types for messages between the main process and the

tests/telemetry/ClearcutLogger.test.ts

@@ -54,6 +54,24 @@ describe('ClearcutLogger', () => {
     });
   });
 
+  describe('setClientName', () => {
+    it('appends mapped mcp_client to payload', async () => {
+      const logger = new ClearcutLogger({
+        persistence: mockPersistence,
+        appVersion: '1.0.0',
+        watchdogClient: mockWatchdogClient,
+      });
+
+      logger.setClientName('gemini-cli-mcp-client');
+      await logger.logServerStart({headless: true});
+
+      assert(mockWatchdogClient.send.calledOnce);
+      const msg = mockWatchdogClient.send.firstCall.args[0];
+      assert.strictEqual(msg.type, WatchdogMessageType.LOG_EVENT);
+      assert.strictEqual(msg.payload.mcp_client, 2); // 2 is MCP_CLIENT_GEMINI_CLI
+    });
+  });
+
   describe('logServerStart', () => {
     it('logs flag usage', async () => {
       const logger = new ClearcutLogger({