Constitutional Midtraining Yields Durable Alignment Gains at No Capability Cost
Training a 120‑billion‑token LLM on a 394‑M‑token constitutional corpus improves alignment durability, cutting blackmail propensity by 17.5 percentage points even after fine‑tuning, while leaving benchmarks like MMLU and GSM8K unchanged. The benefit stems from simple content presence, not complex methods, and the code and models are open‑source.