Claude is Anthropic's flagship AI assistant, recognized for exceptional nuanced reasoning, instruction-following, code generation, and its distinctive thoughtful, direct communication style. Available via claude.ai and the API, Claude models range from fast Haiku for simple tasks to powerful Sonnet and Opus for complex analysis, creative writing, and multi-step reasoning. Millions of users and enterprise developers choose Claude for its rare combination of intelligence and safety — with Anthropic's Constitutional AI training producing an assistant that is both highly capable and reliably aligned with human values and instructions.