feat: add file change tracking to session metrics (#6094)

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: Jacob Richman <[email protected]>

2 files changed, 77 insertions, 17 deletions

diff --git a/packages/core/src/telemetry/uiTelemetry.test.ts b/packages/core/src/telemetry/uiTelemetry.test.ts
index cd509a8e..a64f839e 100644
--- a/packages/core/src/telemetry/uiTelemetry.test.ts
+++ b/packages/core/src/telemetry/uiTelemetry.test.ts
@@ -108,6 +108,10 @@ describe('UiTelemetryService', () => {
         },
         byName: {},
       },
+      files: {
+        totalLinesAdded: 0,
+        totalLinesRemoved: 0,
+      },
     });
     expect(service.getLastPromptTokenCount()).toBe(0);
   });
@@ -342,9 +346,9 @@ describe('UiTelemetryService', () => {
         ToolConfirmationOutcome.ProceedOnce,
       );
       service.addEvent({
-        ...JSON.parse(JSON.stringify(new ToolCallEvent(toolCall))),
+        ...structuredClone(new ToolCallEvent(toolCall)),
         'event.name': EVENT_TOOL_CALL,
-      });
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
 
       const metrics = service.getMetrics();
       const { tools } = metrics;
@@ -376,9 +380,9 @@ describe('UiTelemetryService', () => {
         ToolConfirmationOutcome.Cancel,
       );
       service.addEvent({
-        ...JSON.parse(JSON.stringify(new ToolCallEvent(toolCall))),
+        ...structuredClone(new ToolCallEvent(toolCall)),
         'event.name': EVENT_TOOL_CALL,
-      });
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
 
       const metrics = service.getMetrics();
       const { tools } = metrics;
@@ -410,9 +414,9 @@ describe('UiTelemetryService', () => {
         ToolConfirmationOutcome.ModifyWithEditor,
       );
       service.addEvent({
-        ...JSON.parse(JSON.stringify(new ToolCallEvent(toolCall))),
+        ...structuredClone(new ToolCallEvent(toolCall)),
         'event.name': EVENT_TOOL_CALL,
-      });
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
 
       const metrics = service.getMetrics();
       const { tools } = metrics;
@@ -426,9 +430,9 @@ describe('UiTelemetryService', () => {
     it('should process a ToolCallEvent without a decision', () => {
       const toolCall = createFakeCompletedToolCall('test_tool', true, 100);
       service.addEvent({
-        ...JSON.parse(JSON.stringify(new ToolCallEvent(toolCall))),
+        ...structuredClone(new ToolCallEvent(toolCall)),
         'event.name': EVENT_TOOL_CALL,
-      });
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
 
       const metrics = service.getMetrics();
       const { tools } = metrics;
@@ -462,13 +466,13 @@ describe('UiTelemetryService', () => {
       );
 
       service.addEvent({
-        ...JSON.parse(JSON.stringify(new ToolCallEvent(toolCall1))),
+        ...structuredClone(new ToolCallEvent(toolCall1)),
         'event.name': EVENT_TOOL_CALL,
-      });
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
       service.addEvent({
-        ...JSON.parse(JSON.stringify(new ToolCallEvent(toolCall2))),
+        ...structuredClone(new ToolCallEvent(toolCall2)),
         'event.name': EVENT_TOOL_CALL,
-      });
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
 
       const metrics = service.getMetrics();
       const { tools } = metrics;
@@ -497,13 +501,13 @@ describe('UiTelemetryService', () => {
       const toolCall1 = createFakeCompletedToolCall('tool_A', true, 100);
       const toolCall2 = createFakeCompletedToolCall('tool_B', false, 200);
       service.addEvent({
-        ...JSON.parse(JSON.stringify(new ToolCallEvent(toolCall1))),
+        ...structuredClone(new ToolCallEvent(toolCall1)),
         'event.name': EVENT_TOOL_CALL,
-      });
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
       service.addEvent({
-        ...JSON.parse(JSON.stringify(new ToolCallEvent(toolCall2))),
+        ...structuredClone(new ToolCallEvent(toolCall2)),
         'event.name': EVENT_TOOL_CALL,
-      });
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
 
       const metrics = service.getMetrics();
       const { tools } = metrics;
@@ -629,4 +633,42 @@ describe('UiTelemetryService', () => {
       expect(spy).toHaveBeenCalledOnce();
     });
   });
+
+  describe('Tool Call Event with Line Count Metadata', () => {
+    it('should aggregate valid line count metadata', () => {
+      const toolCall = createFakeCompletedToolCall('test_tool', true, 100);
+      const event = {
+        ...structuredClone(new ToolCallEvent(toolCall)),
+        'event.name': EVENT_TOOL_CALL,
+        metadata: {
+          ai_added_lines: 10,
+          ai_removed_lines: 5,
+        },
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL };
+
+      service.addEvent(event);
+
+      const metrics = service.getMetrics();
+      expect(metrics.files.totalLinesAdded).toBe(10);
+      expect(metrics.files.totalLinesRemoved).toBe(5);
+    });
+
+    it('should ignore null/undefined values in line count metadata', () => {
+      const toolCall = createFakeCompletedToolCall('test_tool', true, 100);
+      const event = {
+        ...structuredClone(new ToolCallEvent(toolCall)),
+        'event.name': EVENT_TOOL_CALL,
+        metadata: {
+          ai_added_lines: null,
+          ai_removed_lines: undefined,
+        },
+      } as ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL };
+
+      service.addEvent(event);
+
+      const metrics = service.getMetrics();
+      expect(metrics.files.totalLinesAdded).toBe(0);
+      expect(metrics.files.totalLinesRemoved).toBe(0);
+    });
+  });
 });
diff --git a/packages/core/src/telemetry/uiTelemetry.ts b/packages/core/src/telemetry/uiTelemetry.ts
index 8d1b044f..318478aa 100644
--- a/packages/core/src/telemetry/uiTelemetry.ts
+++ b/packages/core/src/telemetry/uiTelemetry.ts
@@ -63,6 +63,10 @@ export interface SessionMetrics {
     };
     byName: Record<string, ToolCallStats>;
   };
+  files: {
+    totalLinesAdded: number;
+    totalLinesRemoved: number;
+  };
 }
 
 const createInitialModelMetrics = (): ModelMetrics => ({
@@ -96,6 +100,10 @@ const createInitialMetrics = (): SessionMetrics => ({
     },
     byName: {},
   },
+  files: {
+    totalLinesAdded: 0,
+    totalLinesRemoved: 0,
+  },
 });
 
 export class UiTelemetryService extends EventEmitter {
@@ -171,7 +179,7 @@ export class UiTelemetryService extends EventEmitter {
   }
 
   private processToolCall(event: ToolCallEvent) {
-    const { tools } = this.#metrics;
+    const { tools, files } = this.#metrics;
     tools.totalCalls++;
     tools.totalDurationMs += event.duration_ms;
 
@@ -209,6 +217,16 @@ export class UiTelemetryService extends EventEmitter {
       tools.totalDecisions[event.decision]++;
       toolStats.decisions[event.decision]++;
     }
+
+    // Aggregate line count data from metadata
+    if (event.metadata) {
+      if (event.metadata['ai_added_lines'] !== undefined) {
+        files.totalLinesAdded += event.metadata['ai_added_lines'];
+      }
+      if (event.metadata['ai_removed_lines'] !== undefined) {
+        files.totalLinesRemoved += event.metadata['ai_removed_lines'];
+      }
+    }
   }
 }