Telemetry: Improve clarity of user prompt event (#967)

5 files changed, 65 insertions, 9 deletions

diff --git a/docs/core/telemetry.md b/docs/core/telemetry.md
index 695eacaf..e6498d3b 100644
--- a/docs/core/telemetry.md
+++ b/docs/core/telemetry.md
@@ -278,7 +278,7 @@ These are timestamped records of specific events.
 - `gemini_cli.user_prompt`: Fired when a user submits a prompt.
 
   - **Attributes**:
-    - `prompt_char_count`
+    - `prompt_length`
     - `prompt` (except if `log_user_prompts_enabled` is false)
 
 - `gemini_cli.tool_call`: Fired for every function call.
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.ts b/packages/cli/src/ui/hooks/useGeminiStream.ts
index 56e87fc3..e17413ef 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.ts
+++ b/packages/cli/src/ui/hooks/useGeminiStream.ts
@@ -188,7 +188,7 @@ export const useGeminiStream = (
         const trimmedQuery = query.trim();
         logUserPrompt(config, {
           prompt: trimmedQuery,
-          prompt_char_count: trimmedQuery.length,
+          prompt_length: trimmedQuery.length,
         });
         onDebugMessage(`User query: '${trimmedQuery}'`);
         await logger?.logMessage(MessageSenderType.USER, trimmedQuery);
diff --git a/packages/core/src/telemetry/loggers.test.ts b/packages/core/src/telemetry/loggers.test.ts
index 283af47a..2153ef48 100644
--- a/packages/core/src/telemetry/loggers.test.ts
+++ b/packages/core/src/telemetry/loggers.test.ts
@@ -7,8 +7,12 @@
 import { logs } from '@opentelemetry/api-logs';
 import { SemanticAttributes } from '@opentelemetry/semantic-conventions';
 import { Config } from '../config/config.js';
-import { EVENT_API_RESPONSE } from './constants.js';
-import { logApiResponse, logCliConfiguration } from './loggers.js';
+import { EVENT_API_RESPONSE, EVENT_USER_PROMPT } from './constants.js';
+import {
+  logApiResponse,
+  logCliConfiguration,
+  logUserPrompt,
+} from './loggers.js';
 import * as metrics from './metrics.js';
 import * as sdk from './sdk.js';
 import { vi, describe, beforeEach, it, expect } from 'vitest';
@@ -86,6 +90,56 @@ describe('loggers', () => {
     });
   });
 
+  describe('logUserPrompt', () => {
+    const mockConfig = {
+      getSessionId: () => 'test-session-id',
+      getTelemetryLogUserPromptsEnabled: () => true,
+    } as unknown as Config;
+
+    it('should log a user prompt', () => {
+      const event = {
+        prompt: 'test-prompt',
+        prompt_length: 11,
+      };
+
+      logUserPrompt(mockConfig, event);
+
+      expect(mockLogger.emit).toHaveBeenCalledWith({
+        body: 'User prompt. Length: 11',
+        attributes: {
+          'session.id': 'test-session-id',
+          'event.name': EVENT_USER_PROMPT,
+          'event.timestamp': '2025-01-01T00:00:00.000Z',
+          prompt_length: 11,
+          prompt: 'test-prompt',
+        },
+      });
+    });
+
+    it('should not log prompt if disabled', () => {
+      const mockConfig = {
+        getSessionId: () => 'test-session-id',
+        getTelemetryLogUserPromptsEnabled: () => false,
+      } as unknown as Config;
+      const event = {
+        prompt: 'test-prompt',
+        prompt_length: 11,
+      };
+
+      logUserPrompt(mockConfig, event);
+
+      expect(mockLogger.emit).toHaveBeenCalledWith({
+        body: 'User prompt. Length: 11',
+        attributes: {
+          'session.id': 'test-session-id',
+          'event.name': EVENT_USER_PROMPT,
+          'event.timestamp': '2025-01-01T00:00:00.000Z',
+          prompt_length: 11,
+        },
+      });
+    });
+  });
+
   describe('logApiResponse', () => {
     const mockConfig = {
       getSessionId: () => 'test-session-id',
diff --git a/packages/core/src/telemetry/loggers.ts b/packages/core/src/telemetry/loggers.ts
index c4f773b4..49a7019a 100644
--- a/packages/core/src/telemetry/loggers.ts
+++ b/packages/core/src/telemetry/loggers.ts
@@ -81,19 +81,21 @@ export function logUserPrompt(
   },
 ): void {
   if (!isTelemetrySdkInitialized()) return;
-  const { prompt, ...restOfEventArgs } = event;
+
   const attributes: LogAttributes = {
     ...getCommonAttributes(config),
-    ...restOfEventArgs,
     'event.name': EVENT_USER_PROMPT,
     'event.timestamp': new Date().toISOString(),
+    prompt_length: event.prompt_length,
   };
+
   if (shouldLogUserPrompts(config)) {
-    attributes.prompt = prompt;
+    attributes.prompt = event.prompt;
   }
+
   const logger = logs.getLogger(SERVICE_NAME);
   const logRecord: LogRecord = {
-    body: `User prompt. Length: ${event.prompt_char_count}`,
+    body: `User prompt. Length: ${event.prompt_length}`,
     attributes,
   };
   logger.emit(logRecord);
diff --git a/packages/core/src/telemetry/types.ts b/packages/core/src/telemetry/types.ts
index f62bd23e..da352862 100644
--- a/packages/core/src/telemetry/types.ts
+++ b/packages/core/src/telemetry/types.ts
@@ -7,7 +7,7 @@
 export interface UserPromptEvent {
   'event.name': 'user_prompt';
   'event.timestamp': string; // ISO 8601
-  prompt_char_count: number;
+  prompt_length: number;
   prompt?: string;
 }