Claude 2

Claude 2, released July 11, 2023, was the first Claude anyone could simply sign up and use. It launched alongside claude.ai as a public beta in the US and UK, ending the waitlist-and-API-key period that had kept Claude 1 to a narrow developer audience. It carried a 100K-token context window — roughly 75,000 words — which at the time was the largest available from any major AI lab and made whole-book and whole-codebase prompting a mainstream idea rather than a research demo.

Anthropic pitched it on measured gains over Claude 1.3: 71.2% on Codex HumanEval, up from 56.0%; 88.0% on GSM8K; 78.5% on MMLU; and 76.5% on the multistate bar exam. Those were respectable rather than record-setting figures next to GPT-4, and Claude 2's real significance was distribution — it put Anthropic in front of consumers four months after GPT-4 shipped, and set up the context-window expansion that arrived with Claude 2.1 in November.