# Claude 2

> Source: https://aiwiki.ai/wiki/claude_2
> Updated: 2026-06-24
> Categories: AI Models, Anthropic, Large Language Models
> From AI Wiki (https://aiwiki.ai), a free encyclopedia of artificial intelligence. Quote with attribution.

Claude 2 is a large language model released by [Anthropic](/wiki/anthropic) on July 11, 2023, the second major version of the company's [Claude](/wiki/claude) family of conversational AI systems and the first Claude model offered directly to the general public through a free beta chat interface at claude.ai. [1][2][3] It carried a 100,000 token context window (about 75,000 words, the length of a short novel), scored 71.2% on the Codex HumanEval Python coding test, and reached 76.5% on the multiple-choice section of the US bar exam. [1][4] Compared with the earlier [Claude 1](/wiki/claude_1) (specifically the Claude 1.3 release), Claude 2 reported gains in coding, mathematics, and reasoning while keeping the 100,000 token context window introduced in the prior generation. [1][4]

## Background

Anthropic, founded in 2021 by former [OpenAI](/wiki/openai) staff including siblings Dario and Daniela Amodei, had released the first version of Claude in March 2023. That model was available only to a limited set of approved partners and business customers, not to ordinary users. [2][5] Claude 2 followed about four months later. Anthropic described it less as a ground-up rebuild than as a refinement of its predecessor: TechCrunch characterized the system as "a tweaked version of Claude 1.3," the product of roughly two years of work rather than a wholly new architecture. [4]

The release landed in the middle of an intense period of competition among chatbot makers, with OpenAI's GPT-4 and Google's Bard already in the market. Anthropic counted Google among its investors, and press coverage framed Claude 2 as part of the broader contest between OpenAI's backers and Google. [3][6]

## How large is Claude 2's context window?

Claude 2 accepts prompts of up to 100,000 tokens, the same limit as Claude 1.3. [1][4] Anthropic put the figure plainly in its announcement: "You can now input up to 100K tokens in each prompt, which means that Claude can work over hundreds of pages of technical documentation or even a book." [1] In practical terms that allowed users to submit on the order of 75,000 words at once, roughly the length of a novel such as The Great Gatsby, so the model could read through long documents, technical manuals, or transcripts in a single pass. [1][4] Output was shorter: the model could generate up to about 4,000 tokens, on the order of 3,000 words, in one response. [4] TechCrunch noted that the underlying system could in principle handle around 200,000 tokens, but that this was not enabled at launch. [4]

Anthropic positioned Claude 2 for written tasks including summarization, search, question answering, and coding, and the claude.ai interface accepted uploaded files such as PDFs (up to five files in a single chat) so users could ask questions about their contents. [1][3][7] The model was trained on a mix of public web data, licensed third-party datasets, and data voluntarily supplied by users, with training data extending into early 2023. [4][8]

## How did Claude 2 perform on benchmarks?

Anthropic published a set of exam and benchmark results comparing Claude 2 against Claude 1.3. The headline figures were a higher score on the multiple-choice portion of the US bar exam and a large jump on a Python coding test. [1][4] The company also reported standardized-test percentiles on the GRE.

| Evaluation | Claude 2 | Claude 1.3 |
| --- | --- | --- |
| Bar exam, multiple-choice section | 76.5% | 73.0% |
| Codex HumanEval (Python coding) | 71.2% | 56.0% |
| GSM8K (grade-school math) | 88.0% | 85.2% |
| GRE reading and writing | above 90th percentile | not reported |
| GRE quantitative reasoning | near the median applicant | not reported |

Sources: Anthropic's announcement and model card, with the bar exam, HumanEval, and GSM8K comparisons also reported by TechCrunch. [1][4][8]

The coding result drew the most attention, since the move from 56.0% to 71.2% on Codex HumanEval represented the clearest single-metric improvement over the previous generation. [1][4] Several outlets read the combination of these scores and the long context window as evidence that Claude 2 had moved into the same competitive tier as OpenAI's GPT-3.5 and GPT-4 systems. [6]

## When and where did Claude.ai launch?

Before Claude 2, access to Claude had been gated to selected businesses and developers. With this release Anthropic opened a public beta chat experience at claude.ai, free to use, initially restricted to users in the United States and the United Kingdom, with wider availability promised later. [1][3] This was the debut of the consumer-facing claude.ai web product that the company continued to develop in later years.

Developers could also reach Claude 2 through Anthropic's API. The company said API pricing was unchanged from Claude 1.3; TechCrunch put the rate at roughly 4.65 cents to generate about 1,000 words. [1][4] A faster, lower-cost sibling model, [Claude Instant](/wiki/claude_instant), remained available for lighter workloads alongside the larger Claude 2. The free public beta predated Anthropic's paid consumer subscription, [Claude Pro](/wiki/claude_pro), which the company introduced in September 2023. [9]

## How does Constitutional AI keep Claude 2 safe?

Anthropic trained Claude 2 with the same broad safety approach used across the Claude line, combining reinforcement learning from human feedback with the company's [Constitutional AI](/wiki/constitutional_ai) method, in which the model critiques and revises its own outputs against a written set of principles rather than relying solely on human-labeled examples of harmful content. [5][10] The technique was one of the features that Anthropic and the press used to distinguish Claude from competing systems. [6]

On safety metrics, Anthropic said internal red-teaming found Claude 2 was "2x better at giving harmless responses" than Claude 1.3. [1][4] The company was candid that the model was not infallible: like other large language models it could still produce confabulations, reflect bias, make factual errors, and be coaxed past its guardrails. [5]

## Reception

Coverage generally treated Claude 2 as a credible challenger to ChatGPT rather than a clear leader. CNBC noted that Anthropic was opening its technology to consumers for the first time, shortly after raising substantial funding. [3] TIME and others walked readers through how to use the new chatbot and how its capabilities compared with GPT-4 and Bard, with particular interest in the 100,000 token context window, which exceeded what most rivals then offered to typical users. [6][11] The free price of the beta, against the paid tiers required for the most capable competing models, was a recurring talking point. [6]

## What changed in Claude 2.1?

Anthropic released an incremental update, [Claude 2.1](/wiki/claude_2_1), on November 21, 2023. That version doubled the context window to 200,000 tokens (roughly 150,000 words, or over 500 pages of text), added system prompts and a beta tool-use feature, and reduced hallucination rates: Anthropic reported "a 2x decrease in false statements compared to our previous Claude 2.0 model." [12][13] Access to the full 200,000 token window was reserved for paying Claude Pro subscribers at launch. [13]

## What replaced Claude 2?

The Claude 2 series was superseded in March 2024 by the third generation, led by [Claude 3 Opus](/wiki/claude_3_opus), which moved the family to a new three-tier lineup (Haiku, Sonnet, Opus) and added image understanding. [2][14] Anthropic said the mid-tier Claude 3 Sonnet was "2x faster than Claude 2 and Claude 2.1" with higher intelligence, while Claude 3 Opus showed "a twofold improvement in accuracy" over Claude 2.1 on challenging open-ended questions. [14] Later Anthropic generations, including Claude 3.5, Claude 4, and the Opus 4.x line, continued from that lineup.

## References

1. Anthropic, "Claude 2," July 11, 2023. [https://www.anthropic.com/news/claude-2](https://www.anthropic.com/news/claude-2)
2. "Claude (language model)," Wikipedia. [https://en.wikipedia.org/wiki/Claude_(language_model)](https://en.wikipedia.org/wiki/Claude_(language_model))
3. Hayden Field, "Anthropic, an OpenAI rival, opens Claude 2 AI chatbot to the public," CNBC, July 11, 2023. [https://www.cnbc.com/2023/07/11/anthropic-an-openai-rival-opens-claude-2-ai-chatbot-to-the-public.html](https://www.cnbc.com/2023/07/11/anthropic-an-openai-rival-opens-claude-2-ai-chatbot-to-the-public.html)
4. Kyle Wiggers, "Anthropic releases Claude 2, the second generation of its AI chatbot," TechCrunch, July 11, 2023. [https://techcrunch.com/2023/07/11/anthropic-releases-claude-2-the-second-generation-of-its-ai-chatbot/](https://techcrunch.com/2023/07/11/anthropic-releases-claude-2-the-second-generation-of-its-ai-chatbot/)
5. "Anthropic," Wikipedia. [https://en.wikipedia.org/wiki/Anthropic](https://en.wikipedia.org/wiki/Anthropic)
6. "What to Know About Claude 2, Anthropic's Rival to ChatGPT," TIME, July 18, 2023. [https://time.com/6295523/claude-2-anthropic-chatgpt/](https://time.com/6295523/claude-2-anthropic-chatgpt/)
7. Roger Montti, "Anthropic Launches Claude 2 With 100K Context Windows And File Uploads," Search Engine Journal, July 11, 2023. [https://www.searchenginejournal.com/anthropic-launches-claude-2-with-100k-context-windows-file-uploads/491412/](https://www.searchenginejournal.com/anthropic-launches-claude-2-with-100k-context-windows-file-uploads/491412/)
8. Anthropic, "Model Card and Evaluations for Claude Models," 2023. [https://www.anthropic.com/claude-2-model-card](https://www.anthropic.com/claude-2-model-card)
9. Kyle Wiggers, "Anthropic launches a paid plan for its AI-powered chatbot," TechCrunch, September 7, 2023. [https://techcrunch.com/2023/09/07/anthropic-launches-a-paid-plan-for-its-ai-powered-chatbot/](https://techcrunch.com/2023/09/07/anthropic-launches-a-paid-plan-for-its-ai-powered-chatbot/)
10. Anthropic, "Claude's Constitution," May 9, 2023. [https://www.anthropic.com/news/claudes-constitution](https://www.anthropic.com/news/claudes-constitution)
11. Anthropic, "Introducing Claude 2.1," November 21, 2023. [https://www.anthropic.com/news/claude-2-1](https://www.anthropic.com/news/claude-2-1)
12. Roger Montti, "Anthropic Introduces Claude 2.1 With 200K Context Window," Search Engine Journal, November 21, 2023. [https://www.searchenginejournal.com/anthropic-introduces-claude-2-1-with-200k-context-window/501907/](https://www.searchenginejournal.com/anthropic-introduces-claude-2-1-with-200k-context-window/501907/)
13. Anthropic, "Introducing Claude 2.1," November 21, 2023. [https://www.anthropic.com/news/claude-2-1](https://www.anthropic.com/news/claude-2-1)
14. Anthropic, "Introducing the next generation of Claude," March 4, 2024. [https://www.anthropic.com/news/claude-3-family](https://www.anthropic.com/news/claude-3-family)