Log the 2 types of loop detection (#4193)

2 files changed, 39 insertions, 3 deletions

diff --git a/packages/core/src/services/loopDetectionService.test.ts b/packages/core/src/services/loopDetectionService.test.ts
index 915bedc0..f0d76166 100644
--- a/packages/core/src/services/loopDetectionService.test.ts
+++ b/packages/core/src/services/loopDetectionService.test.ts
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { describe, it, expect, beforeEach } from 'vitest';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
 import { LoopDetectionService } from './loopDetectionService.js';
 import {
   GeminiEventType,
@@ -12,15 +12,26 @@ import {
   ServerGeminiToolCallRequestEvent,
 } from '../core/turn.js';
 import { ServerGeminiStreamEvent } from '../core/turn.js';
+import { Config } from '../config/config.js';
+import * as loggers from '../telemetry/loggers.js';
+
+vi.mock('../telemetry/loggers.js', () => ({
+  logLoopDetected: vi.fn(),
+}));
 
 const TOOL_CALL_LOOP_THRESHOLD = 5;
 const CONTENT_LOOP_THRESHOLD = 10;
 
 describe('LoopDetectionService', () => {
   let service: LoopDetectionService;
+  let mockConfig: Config;
 
   beforeEach(() => {
-    service = new LoopDetectionService();
+    mockConfig = {
+      getTelemetryEnabled: () => true,
+    } as unknown as Config;
+    service = new LoopDetectionService(mockConfig);
+    vi.clearAllMocks();
   });
 
   const createToolCallRequestEvent = (
@@ -48,6 +59,7 @@ describe('LoopDetectionService', () => {
       for (let i = 0; i < TOOL_CALL_LOOP_THRESHOLD - 1; i++) {
         expect(service.addAndCheck(event)).toBe(false);
       }
+      expect(loggers.logLoopDetected).not.toHaveBeenCalled();
     });
 
     it(`should detect a loop on the TOOL_CALL_LOOP_THRESHOLD-th identical call`, () => {
@@ -56,6 +68,7 @@ describe('LoopDetectionService', () => {
         service.addAndCheck(event);
       }
       expect(service.addAndCheck(event)).toBe(true);
+      expect(loggers.logLoopDetected).toHaveBeenCalledTimes(1);
     });
 
     it('should detect a loop on subsequent identical calls', () => {
@@ -64,6 +77,7 @@ describe('LoopDetectionService', () => {
         service.addAndCheck(event);
       }
       expect(service.addAndCheck(event)).toBe(true);
+      expect(loggers.logLoopDetected).toHaveBeenCalledTimes(2);
     });
 
     it('should not detect a loop for different tool calls', () => {
@@ -91,6 +105,7 @@ describe('LoopDetectionService', () => {
       for (let i = 0; i < CONTENT_LOOP_THRESHOLD - 1; i++) {
         expect(service.addAndCheck(event)).toBe(false);
       }
+      expect(loggers.logLoopDetected).not.toHaveBeenCalled();
     });
 
     it(`should detect a loop on the CONTENT_LOOP_THRESHOLD-th identical content string`, () => {
@@ -99,6 +114,7 @@ describe('LoopDetectionService', () => {
         service.addAndCheck(event);
       }
       expect(service.addAndCheck(event)).toBe(true);
+      expect(loggers.logLoopDetected).toHaveBeenCalledTimes(1);
     });
 
     it('should not detect a loop for different content strings', () => {
@@ -108,6 +124,7 @@ describe('LoopDetectionService', () => {
         expect(service.addAndCheck(event1)).toBe(false);
         expect(service.addAndCheck(event2)).toBe(false);
       }
+      expect(loggers.logLoopDetected).not.toHaveBeenCalled();
     });
   });
 
diff --git a/packages/core/src/services/loopDetectionService.ts b/packages/core/src/services/loopDetectionService.ts
index 57e0980c..c1078f69 100644
--- a/packages/core/src/services/loopDetectionService.ts
+++ b/packages/core/src/services/loopDetectionService.ts
@@ -6,6 +6,9 @@
 
 import { createHash } from 'crypto';
 import { GeminiEventType, ServerGeminiStreamEvent } from '../core/turn.js';
+import { logLoopDetected } from '../telemetry/loggers.js';
+import { LoopDetectedEvent, LoopType } from '../telemetry/types.js';
+import { Config } from '../config/config.js';
 
 const TOOL_CALL_LOOP_THRESHOLD = 5;
 const CONTENT_LOOP_THRESHOLD = 10;
@@ -24,6 +27,11 @@ export class LoopDetectionService {
   private lastRepeatedSentence: string = '';
   private sentenceRepetitionCount: number = 0;
   private partialContent: string = '';
+  private config: Config;
+
+  constructor(config: Config) {
+    this.config = config;
+  }
 
   private getToolCallKey(toolCall: { name: string; args: object }): string {
     const argsString = JSON.stringify(toolCall.args);
@@ -59,7 +67,14 @@ export class LoopDetectionService {
       this.lastToolCallKey = key;
       this.toolCallRepetitionCount = 1;
     }
-    return this.toolCallRepetitionCount >= TOOL_CALL_LOOP_THRESHOLD;
+    if (this.toolCallRepetitionCount >= TOOL_CALL_LOOP_THRESHOLD) {
+      logLoopDetected(
+        this.config,
+        new LoopDetectedEvent(LoopType.CONSECUTIVE_IDENTICAL_TOOL_CALLS),
+      );
+      return true;
+    }
+    return false;
   }
 
   private checkContentLoop(content: string): boolean {
@@ -94,6 +109,10 @@ export class LoopDetectionService {
       }
 
       if (this.sentenceRepetitionCount >= CONTENT_LOOP_THRESHOLD) {
+        logLoopDetected(
+          this.config,
+          new LoopDetectedEvent(LoopType.CHANTING_IDENTICAL_SENTENCES),
+        );
         return true;
       }
     }