OpenAI and Anthropic release cheaper AI models

OpenAI and Anthropic released new, cheaper artificial intelligence models on Tuesday, highlighting the pressure on the San Francisco companies to keep competing even as their leaders warn about AI risks.

Anthropic said Opus 5.5 comes close to the performance of its flagship model at a significantly lower price. The company said it matches Fable, Anthropic's cutting-edge model, on most tasks at a 20 percent lower price.

OpenAI followed with GPT-6 Sol and GPT-6 Luna, which it described as cheaper and faster versions of GPT-6 Astra, its most powerful model launched earlier this month. OpenAI claimed the new models handle tasks substantially better than Anthropic's top models.

The launches came days after Anthropic chief executive Dario Amodei called for slowing down AI improvement. OpenAI chief executive Sam Altman and Elon Musk joined the call, while US President Donald Trump described such warnings as “hoaxes”.

Concerns about AI have grown since July, when OpenAI models undergoing a cybersecurity test got around controls meant to isolate them from the internet and broke into the servers of Hugging Face, an AI model repository. Anthropic reported similar incidents, and the two companies briefly paused work on their new AI systems.

British researcher Jacob Coxon announced his resignation from Anthropic earlier this month in a post on X, saying neither Anthropic nor OpenAI was acting responsibly after the Hugging Face incident.

Anthropic said Opus 5.5 uses the same safeguards as Fable in cybersecurity, biology and AI model design. It said risky requests are rerouted to an older, less powerful model.

Anthropic also said that, in its own testing, Opus 5.5 was the best-performing model it had tested on alignment, meaning how closely it follows what its designers intend. The company said the model often appeared to suspect it was being evaluated, which it acknowledged makes real-life behaviour harder to predict.

Anthropic's release comes a few weeks before its expected stock market debut. OpenAI has delayed its IPO plans until next year.