GPT-5.6 Sol sets new SOTA on cybersecurity and ARC-AGI-3 benchmarks

GPT-5.6 Sol achieved 7.8% on ARC-AGI-3 and set a new cybersecurity SOTA on 'The Last Ones' cyber range. Sam Altman said Sol is half the price and ~twice as token efficient as the previous model. OpenAI also introduced two additional tiers (Terra and Luna) and made Codex available inside ChatGPT with 150+ updates.