Create line change metrics (#12299)

Author: jerop

docs/cli/telemetry.md

@@ -539,10 +539,6 @@ Measures tool usage and latency.
     - `decision` (string: "accept", "reject", "modify", or "auto_accept", if
       applicable)
     - `tool_type` (string: "mcp" or "native", if applicable)
-    - `model_added_lines` (Int, optional)
-    - `model_removed_lines` (Int, optional)
-    - `user_added_lines` (Int, optional)
-    - `user_removed_lines` (Int, optional)
 
 - `gemini_cli.tool.call.latency` (Histogram, ms): Measures tool call latency.
   - **Attributes**:
@@ -586,6 +582,12 @@ Counts file operations with basic context.
     - `extension` (string, optional)
     - `programming_language` (string, optional)
 
+- `gemini_cli.lines.changed` (Counter, Int): Number of lines changed (from file
+  diffs).
+  - **Attributes**:
+    - `function_name`
+    - `type` ("added" or "removed")
+
 ##### Chat and Streaming
 
 Resilience counters for compression, invalid chunks, and retries.

packages/core/src/telemetry/loggers.test.ts

@@ -786,12 +786,16 @@ describe('loggers', () => {
 
     const mockMetrics = {
       recordToolCallMetrics: vi.fn(),
+      recordLinesChanged: vi.fn(),
     };
 
     beforeEach(() => {
       vi.spyOn(metrics, 'recordToolCallMetrics').mockImplementation(
         mockMetrics.recordToolCallMetrics,
       );
+      vi.spyOn(metrics, 'recordLinesChanged').mockImplementation(
+        mockMetrics.recordLinesChanged,
+      );
       mockLogger.emit.mockReset();
     });
 
@@ -888,10 +892,6 @@ describe('loggers', () => {
           success: true,
           decision: ToolCallDecision.ACCEPT,
           tool_type: 'native',
-          model_added_lines: 1,
-          model_removed_lines: 2,
-          user_added_lines: 5,
-          user_removed_lines: 6,
         },
       );
 
@@ -900,6 +900,19 @@ describe('loggers', () => {
         'event.name': EVENT_TOOL_CALL,
         'event.timestamp': '2025-01-01T00:00:00.000Z',
       });
+
+      expect(mockMetrics.recordLinesChanged).toHaveBeenCalledWith(
+        mockConfig,
+        1,
+        'added',
+        { function_name: 'test-function' },
+      );
+      expect(mockMetrics.recordLinesChanged).toHaveBeenCalledWith(
+        mockConfig,
+        2,
+        'removed',
+        { function_name: 'test-function' },
+      );
     });
     it('should log a tool call with a reject decision', () => {
       const call: ErroredToolCall = {

packages/core/src/telemetry/loggers.ts

@@ -63,6 +63,7 @@ import {
   recordTokenUsageMetrics,
   recordApiResponseMetrics,
   recordAgentRunMetrics,
+  recordLinesChanged,
 } from './metrics.js';
 import { isTelemetrySdkInitialized } from './sdk.js';
 import type { UiEvent } from './uiTelemetry.js';
@@ -118,15 +119,22 @@ export function logToolCall(config: Config, event: ToolCallEvent): void {
     success: event.success,
     decision: event.decision,
     tool_type: event.tool_type,
-    ...(event.metadata
-      ? {
-          model_added_lines: event.metadata['model_added_lines'],
-          model_removed_lines: event.metadata['model_removed_lines'],
-          user_added_lines: event.metadata['user_added_lines'],
-          user_removed_lines: event.metadata['user_removed_lines'],
-        }
-      : {}),
   });
+
+  if (event.metadata) {
+    const added = event.metadata['model_added_lines'];
+    if (typeof added === 'number' && added > 0) {
+      recordLinesChanged(config, added, 'added', {
+        function_name: event.function_name,
+      });
+    }
+    const removed = event.metadata['model_removed_lines'];
+    if (typeof removed === 'number' && removed > 0) {
+      recordLinesChanged(config, removed, 'removed', {
+        function_name: event.function_name,
+      });
+    }
+  }
 }
 
 export function logToolOutputTruncated(

packages/core/src/telemetry/metrics.test.ts

@@ -94,6 +94,7 @@ describe('Telemetry Metrics', () => {
   let recordFlickerFrameModule: typeof import('./metrics.js').recordFlickerFrame;
   let recordExitFailModule: typeof import('./metrics.js').recordExitFail;
   let recordAgentRunMetricsModule: typeof import('./metrics.js').recordAgentRunMetrics;
+  let recordLinesChangedModule: typeof import('./metrics.js').recordLinesChanged;
 
   beforeEach(async () => {
     vi.resetModules();
@@ -136,6 +137,7 @@ describe('Telemetry Metrics', () => {
     recordFlickerFrameModule = metricsJsModule.recordFlickerFrame;
     recordExitFailModule = metricsJsModule.recordExitFail;
     recordAgentRunMetricsModule = metricsJsModule.recordAgentRunMetrics;
+    recordLinesChangedModule = metricsJsModule.recordLinesChanged;
 
     const otelApiModule = await import('@opentelemetry/api');
 
@@ -348,6 +350,53 @@ describe('Telemetry Metrics', () => {
     });
   });
 
+  describe('recordLinesChanged metric', () => {
+    const mockConfig = {
+      getSessionId: () => 'test-session-id',
+      getTelemetryEnabled: () => true,
+    } as unknown as Config;
+
+    it('should not record lines added/removed if not initialized', () => {
+      recordLinesChangedModule(mockConfig, 10, 'added', {
+        function_name: 'fn',
+      });
+      recordLinesChangedModule(mockConfig, 5, 'removed', {
+        function_name: 'fn',
+      });
+      expect(mockCounterAddFn).not.toHaveBeenCalled();
+    });
+
+    it('should record lines added with function_name after initialization', () => {
+      initializeMetricsModule(mockConfig);
+      mockCounterAddFn.mockClear();
+      recordLinesChangedModule(mockConfig, 10, 'added', {
+        function_name: 'my-fn',
+      });
+      expect(mockCounterAddFn).toHaveBeenCalledWith(10, {
+        'session.id': 'test-session-id',
+        'installation.id': 'test-installation-id',
+        'user.email': 'test@example.com',
+        type: 'added',
+        function_name: 'my-fn',
+      });
+    });
+
+    it('should record lines removed with function_name after initialization', () => {
+      initializeMetricsModule(mockConfig);
+      mockCounterAddFn.mockClear();
+      recordLinesChangedModule(mockConfig, 7, 'removed', {
+        function_name: 'my-fn',
+      });
+      expect(mockCounterAddFn).toHaveBeenCalledWith(7, {
+        'session.id': 'test-session-id',
+        'installation.id': 'test-installation-id',
+        'user.email': 'test@example.com',
+        type: 'removed',
+        function_name: 'my-fn',
+      });
+    });
+  });
+
   describe('recordFileOperationMetric', () => {
     const mockConfig = {
       getSessionId: () => 'test-session-id',

packages/core/src/telemetry/metrics.ts

@@ -24,6 +24,7 @@ const API_REQUEST_LATENCY = 'gemini_cli.api.request.latency';
 const TOKEN_USAGE = 'gemini_cli.token.usage';
 const SESSION_COUNT = 'gemini_cli.session.count';
 const FILE_OPERATION_COUNT = 'gemini_cli.file.operation.count';
+const LINES_CHANGED = 'gemini_cli.lines.changed';
 const INVALID_CHUNK_COUNT = 'gemini_cli.chat.invalid_chunk.count';
 const CONTENT_RETRY_COUNT = 'gemini_cli.chat.content_retry.count';
 const CONTENT_RETRY_FAILURE_COUNT =
@@ -72,11 +73,6 @@ const COUNTER_DEFINITIONS = {
       success: boolean;
       decision?: 'accept' | 'reject' | 'modify' | 'auto_accept';
       tool_type?: 'native' | 'mcp';
-      // Optional diff statistics for file-modifying tools
-      model_added_lines?: number;
-      model_removed_lines?: number;
-      user_added_lines?: number;
-      user_removed_lines?: number;
     },
   },
   [API_REQUEST_COUNT]: {
@@ -116,6 +112,15 @@ const COUNTER_DEFINITIONS = {
       programming_language?: string;
     },
   },
+  [LINES_CHANGED]: {
+    description: 'Number of lines changed (from file diffs).',
+    valueType: ValueType.INT,
+    assign: (c: Counter) => (linesChangedCounter = c),
+    attributes: {} as {
+      function_name?: string;
+      type: 'added' | 'removed';
+    },
+  },
   [INVALID_CHUNK_COUNT]: {
     description: 'Counts invalid chunks received from a stream.',
     valueType: ValueType.INT,
@@ -454,6 +459,7 @@ let apiRequestLatencyHistogram: Histogram | undefined;
 let tokenUsageCounter: Counter | undefined;
 let sessionCounter: Counter | undefined;
 let fileOperationCounter: Counter | undefined;
+let linesChangedCounter: Counter | undefined;
 let chatCompressionCounter: Counter | undefined;
 let invalidChunkCounter: Counter | undefined;
 let contentRetryCounter: Counter | undefined;
@@ -621,6 +627,21 @@ export function recordFileOperationMetric(
   });
 }
 
+export function recordLinesChanged(
+  config: Config,
+  lines: number,
+  changeType: 'added' | 'removed',
+  attributes?: { function_name?: string },
+): void {
+  if (!linesChangedCounter || !isMetricsInitialized) return;
+  if (!Number.isFinite(lines) || lines <= 0) return;
+  linesChangedCounter.add(lines, {
+    ...baseMetricDefinition.getCommonAttributes(config),
+    type: changeType,
+    ...(attributes ?? {}),
+  });
+}
+
 // --- New Metric Recording Functions ---
 
 /**