Anthropic appears to be working on new models under the names Claude Sonnet 4 and Opus 4. These models are likely to be by far the most advanced LLMs the company has developed to date.
References to “Claude 4,” “Claude Sonnet 4,” and “Claude Opus 4” were discovered in web configuration files recently updated by Anthropic. The references found contain warnings such as “Not intended for production use” and “strict rate limits.” This indicates that the models are still in the R&D phase. There are also features such as “show_raw_thinking,” an indication that users may be able to better examine Claude’s thought process than is the case with OpenAI’s o3, for example.
In February, Anthropic launched its latest and most powerful LLM, Claude 3.7 Sonnet. This model already offered improved reasoning capabilities, allowing users to determine how long Claude could think before giving an answer. With the Claude 4 series, Anthropic appears to be further developing these capabilities. However, Anthropic CEO Dario Amodei has repeatedly stated that the “reasoning” step is not an explicit, separate phase within Claude, but operates on a spectrum. In other words, a quick answer requires little reasoning, while a longer answer may contain multiple steps of thinking that other AI players characterize as discrete “reasoning.”
Evolution of Anthropic’s models
Anthropic has proven itself to be a contender with competitors such as OpenAI and Google in the relevant AI benchmarks. Last year, the company launched Claude 3.5 Sonnet, which outperformed competitors such as OpenAI and Google on various benchmarks. This was followed at the end of 2024 by an update under the same name (3.5 Sonnet), which again achieved impressive results. With the introduction of Claude 3.7 Sonnet earlier this year, Anthropic took another step forward.
Anthropic CEO Dario Amodei has indicated in the past that the naming of Claude models is an indication of the progress made. A full Claude 4 series could therefore represent a significant leap forward.
Event coming up
On May 22, Anthropic is organizing a “Code with Claude” event, as BleepingComputer notes. It is still unclear whether the company will introduce the new models at this event. However, the timing could indicate an announcement or demonstration of the new capabilities of Claude 4, although this may only be a sneak peek.