OpenAI launches GPT-5.6 model family to target Anthropic

OpenAI unveiled its newest family of models on Thursday: GPT-5.6, which comes in three variants — Sol, the workhorse; Terra, an intermediate option; and Luna, the budget-friendly option. The company says GPT-5.6 expands capabilities across enterprise work, coding, and scientific research. Alongside the launch, OpenAI released a new tool called ChatGPT Work, designed as a workplace companion for enterprise teams. The release follows similar launches this week from competitors SpaceXAI and Meta.

The launch seems aimed squarely at OpenAI’s primary rival, Anthropic. OpenAI cites the Artificial Analysis Coding Agent Index, a benchmarking metric, to argue that its new model family outshines Anthropic’s models at every turn. On that index, Sol sets a new state-of-the-art score of 80, 2.8 points above Anthropic’s Fable 5, while using less than half the output tokens, taking less than half the time, and costing about one-third less. According to OpenAI, that advantage extends across the family: Terra performs just above Fable 5, while Luna outperforms Opus 4.8.

Speaking to CNBC, CEO Sam Altman said OpenAI’s newest models are orders of magnitude more efficient and cost-effective than previous versions, and he specifically noted that Sol is 54% more token efficient on AI coding tasks. OpenAI says GPT-5.6 is now available across ChatGPT, Codex, and the OpenAI API, and has published new per-million-token pricing across the family:

• Sol: $5 input / $30 output
• Terra: $2.50 input / $15 output
• Luna: $1 input / $6 output

GPT-5.6 also supports defensive activities, including threat modeling (identifying and prioritizing potential security threats), code review and patching, and blue teaming (simulating an attack on your own systems to find weaknesses before real hackers do). OpenAI describes the model as its “strongest cybersecurity model yet, achieving frontier performance with significantly fewer tokens.” The Trump administration previously sought to restrict its rollout, ostensibly due to fears of how the model could be misused.

Why it matters

OpenAI’s GPT-5.6 launch appears aimed squarely at Anthropic, using benchmark data to claim superior performance, speed, and cost-efficiency over its rival.