feat(agent-core): add thinkingLevel to compaction telemetry (#954)

Report the effective thinking effort (off/low/medium/high/xhigh/max) on
compaction_finished, compaction_failed, and micro_compaction_finished events.
The value matches the thinking level applied to the compaction provider, so we
can analyze how thinking mode affects compaction token usage, duration, and
failures.

packages/agent-core/src/agent/compaction/full.ts

@@ -344,6 +344,7 @@ export class FullCompaction {
         compactedCount: result.compactedCount,
         retryCount,
         round,
+        thinkingLevel: this.agent.config.thinkingLevel,
         ...usage,
         ...data,
       });
@@ -357,6 +358,7 @@ export class FullCompaction {
         duration: Date.now() - startedAt,
         round,
         retryCount,
+        thinkingLevel: this.agent.config.thinkingLevel,
         errorType: error instanceof Error ? error.name : 'Unknown',
       });
       if (isKimiError(error) && error.code === ErrorCodes.AUTH_LOGIN_REQUIRED) throw error;

packages/agent-core/src/agent/compaction/micro.ts

@@ -90,6 +90,7 @@ export class MicroCompaction {
         cutoff: nextCutoff,
         message_count: history.length,
         cache_age_ms: cacheAgeMs,
+        thinkingLevel: this.agent.config.thinkingLevel,
       });
     }
   }

packages/agent-core/test/agent/compaction/full.test.ts

@@ -240,6 +240,7 @@ describe('FullCompaction', () => {
         duration: expect.any(Number),
         compactedCount: 6,
         retryCount: 0,
+        thinkingLevel: 'off',
         inputOther: 520,
         output: 8,
         inputCacheRead: 0,
@@ -1589,6 +1590,7 @@ describe('FullCompaction', () => {
 
   it('preserves thinking effort when compacting after provider context overflow', async () => {
     let callCount = 0;
+    const records: TelemetryRecord[] = [];
     const providerThinkingEfforts: Array<Parameters<GenerateFn>[0]['thinkingEffort']> = [];
     const generate: GenerateFn = async (provider, _system, _tools, _history, callbacks) => {
       callCount += 1;
@@ -1612,7 +1614,7 @@ describe('FullCompaction', () => {
       }
       throw new Error(`Unexpected generate call ${String(callCount)}`);
     };
-    const ctx = testAgent({ generate });
+    const ctx = testAgent({ generate, telemetry: recordingTelemetry(records) });
     ctx.configure({
       provider: CATALOGUED_PROVIDER,
       modelCapabilities: CATALOGUED_MODEL_CAPABILITIES,
@@ -1626,6 +1628,13 @@ describe('FullCompaction', () => {
 
     expect(callCount).toBe(3);
     expect(providerThinkingEfforts).toEqual(['high', 'high', 'high']);
+    expect(records).toContainEqual({
+      event: 'compaction_finished',
+      properties: expect.objectContaining({
+        source: 'auto',
+        thinkingLevel: 'high',
+      }),
+    });
   });
 
   it('compacts provider overflow when model context size is unknown', async () => {

packages/agent-core/test/agent/compaction/micro.test.ts

@@ -482,6 +482,7 @@ describe('MicroCompaction', () => {
       truncatedToolResultTokensAfter: expect.any(Number),
       tokensBefore: expect.any(Number),
       tokensAfter: expect.any(Number),
+      thinkingLevel: 'off',
     });
     expect(numberProperty(event, 'truncatedToolResultTokensBefore')).toBeGreaterThan(
       numberProperty(event, 'truncatedToolResultTokensAfter'),