refactor: split Claude agent runner entrypoint (#200)

runners/agent-runner/test/compaction-boundary.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { compactBoundaryFromMessage } from '../src/compaction-boundary.js';
+
+describe('compactBoundaryFromMessage', () => {
+  it('extracts compact boundary metadata from SDK system messages', () => {
+    const log = vi.fn();
+
+    const compaction = compactBoundaryFromMessage(
+      {
+        type: 'system',
+        subtype: 'compact_boundary',
+        compact_metadata: {
+          trigger: 'manual',
+          pre_tokens: 1234,
+        },
+      },
+      log,
+    );
+
+    expect(compaction).toEqual({
+      completed: true,
+      trigger: 'manual',
+    });
+    expect(log).toHaveBeenCalledWith(
+      'Compact boundary — trigger=manual pre_tokens=1234',
+    );
+  });
+
+  it('ignores unrelated SDK messages', () => {
+    expect(
+      compactBoundaryFromMessage({ type: 'assistant' }, vi.fn()),
+    ).toBeUndefined();
+  });
+});