Claude 2 competed directly with ChatGPTOpenAI's conversational chat product — brought large language models to hundreds of millions of users. and GPTGenerative Pre-trained Transformer — OpenAI's family of large language models from GPT-1 through GPT-5.-4 on reasoningStep-by-step logical thinking in AI models — chain-of-thought before answering hard problems. and long documents — analyzing entire books or codebases in one prompt. It expanded AnthropicAn AI safety company — creators of the Claude family of language models.'s APIApplication programming interface — a defined way for programs to talk to each other or to a service. and consumer chat products before the Claude 3 family arrived.

Claude 2 made long-context LLMs a mainstream product feature.

It validated 100K-token windows for legal, research, and code review workflows.