feat(client/compression): Log telemetry when compressing chat context. (#6195)

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

@@ -34,6 +34,7 @@ import {
   logUserPrompt,
   logToolCall,
   logFlashFallback,
+  logChatCompression,
 } from './loggers.js';
 import { ToolCallDecision } from './tool-call-decision.js';
 import {
@@ -43,12 +44,15 @@ import {
   ToolCallEvent,
   UserPromptEvent,
   FlashFallbackEvent,
+  makeChatCompressionEvent,
 } from './types.js';
 import * as metrics from './metrics.js';
 import * as sdk from './sdk.js';
 import { vi, describe, beforeEach, it, expect } from 'vitest';
 import { GenerateContentResponseUsageMetadata } from '@google/genai';
 import * as uiTelemetry from './uiTelemetry.js';
+import { makeFakeConfig } from '../test-utils/config.js';
+import { ClearcutLogger } from './clearcut-logger/clearcut-logger.js';
 
 describe('loggers', () => {
   const mockLogger = {
@@ -68,6 +72,45 @@ describe('loggers', () => {
     vi.setSystemTime(new Date('2025-01-01T00:00:00.000Z'));
   });
 
+  describe('logChatCompression', () => {
+    beforeEach(() => {
+      vi.spyOn(metrics, 'recordChatCompressionMetrics');
+      vi.spyOn(ClearcutLogger.prototype, 'logChatCompressionEvent');
+    });
+
+    it('logs the chat compression event to Clearcut', () => {
+      const mockConfig = makeFakeConfig();
+
+      const event = makeChatCompressionEvent({
+        tokens_before: 9001,
+        tokens_after: 9000,
+      });
+
+      logChatCompression(mockConfig, event);
+
+      expect(
+        ClearcutLogger.prototype.logChatCompressionEvent,
+      ).toHaveBeenCalledWith(event);
+    });
+
+    it('records the chat compression event to OTEL', () => {
+      const mockConfig = makeFakeConfig();
+
+      logChatCompression(
+        mockConfig,
+        makeChatCompressionEvent({
+          tokens_before: 9001,
+          tokens_after: 9000,
+        }),
+      );
+
+      expect(metrics.recordChatCompressionMetrics).toHaveBeenCalledWith(
+        mockConfig,
+        { tokens_before: 9001, tokens_after: 9000 },
+      );
+    });
+  });
+
   describe('logCliConfiguration', () => {
     it('should log the cli configuration', () => {
       const mockConfig = {