GPT-6 Sol

API id gpt-6-sol, released 2026-09-22 together with GPT-6 Luna as cheaper GPT-6-generation tiers 'trained with similar methods as GPT-6 Astra'. It costs $2/$10 per Mtok, 50% below GPT-5.6 Sol's promotional $4/$20. It has a 1.05M context and 128K max output. It launched in ChatGPT Work/Codex and the API, and on 2026-10-07 became the default GPT-6 in ChatGPT for paid tiers. GPT-6.1 Sol superseded it in the API on 2026-09-29. On 2026-09-25 OpenAI fixed an image-encoding bug that had degraded GPT-6 Sol/Luna image understanding, so vision-dependent launch-week third-party scores may understate it. Most launch claims are cost-relative charts; only the four numeric figures below were printed.