From the archive
GPT-6.1 Sol lowers cached-input costs for agent workflows
OpenAI upgrades Sol for coding and professional work, with API access and a rollout in ChatGPT Work and Codex.
OpenAI introduced GPT-6.1 Sol on September 29, 2026. The release updated the Sol model for coding, computer use, and professional work, with API pricing below GPT-6 Astra.
API pricing and reused context
The announced prices were $2 per million input tokens, $10 per million output tokens, and $0.10 per million cached input tokens. The cached-input rate was half that of GPT-6 Sol. That made repeated context an important part of the cost of agents working across several requests.
Work and coding access
GPT-6.1 Sol reached Plus, Pro, Business, Enterprise, and Edu accounts in ChatGPT Work and Codex. The announcement specified that it was not yet available in Chat. API access used the model name gpt-6.1-sol.
OpenAI reported improvements in several work evaluations, while Astra remained its choice for the most demanding tasks.