- run_tests.py: ThreadPoolExecutor runs N tests concurrently within a suite - Each testcase has its own session_id so parallel is safe - Engine tests: fixed asyncio.new_event_loop() for thread safety - Usage: python tests/run_tests.py testcases --parallel=3 - Wall time reduction: ~3x for testcases (15min → 5min with parallel=3) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>