{"version":"2.0.31","anchor":"startup-performance-profiling","canonical_anchor":"startup-performance-profiling","heading":"Startup Performance Profiling","tier":null,"area":null,"scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.0.31\/e\/startup-performance-profiling","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.0.31","markdown":"### Startup Performance Profiling\n\n**What:** Optional profiling system to measure Claude Code's startup performance and memory usage across initialization phases.\n\n**How to use:**\n\n`# Enable startup profiling CLAUDE_CODE_PROFILE_STARTUP=1 claude # The profiling report will automatically display after startup showing: # - Time elapsed at each checkpoint (absolute and delta) # - Memory usage (RSS and heap) at each checkpoint # - Total startup time` **Details:**\n\n- Tracks 30+ checkpoints throughout the startup sequence\n- Records both timing (via Node.js `perf_hooks`) and memory metrics\n- Zero overhead when disabled (default)\n- Useful for diagnosing slow startup issues or investigating performance regressions\n- **Evidence**: `o5()` at line 3881, `RB9()` at line 3891, `B80()` at line 3919, profiler initialization in `aqA` at line 3926"}