What is Constitutional AI?
TL;DR
Anthropic's approach of giving AI a set of ethical principles — a 'constitution' — to guide safe, value-aligned behavior.
Constitutional AI: Definition & Explanation
Constitutional AI is an AI safety and alignment methodology developed by Anthropic. It works by providing the AI model with a predefined set of ethical principles (a 'constitution') and training it to self-evaluate and self-correct in accordance with those principles. While traditional RLHF requires large numbers of human labelers, Constitutional AI has the AI itself critique and improve its responses against the constitution, achieving safety more efficiently and at scale. In January 2026, Anthropic published Claude's new constitution — 'Claude's Guidelines Spec' — announcing a shift from a rules-based approach to 'reason-based alignment' that includes the rationale (Why) behind each principle. This methodology has improved Claude's ability to make appropriate judgments in novel situations, marking an important milestone in AI safety research.