GPT-6 Sol

• 🧠 OpenAI's GPT-6 coding and agentic workflow model, released September 2026
• 📏 1.05M-token context window with up to 128K output tokens
• 🔧 Reasoning effort configurable from none through low, medium, high, xhigh, max
• 👁️ Accepts text and image inputs, generates text
• 🎯 Function calling, structured outputs and Responses API built-in tools
• ⚡ OpenAI reports substantial gains over GPT-5.6 Sol on FrontierCode
• 🏢 Positioned as the intelligence-and-cost balance tier between Astra and Luna

OpenAI

OpenAI is an American artificial intelligence research organization headquartered in San Francisco, structured as both a for-profit public benefit corporation and a nonprofit foundation. The lab developed the GPT family of large language models, the DALL-E…

GPT-6 Sol is OpenAI's GPT-6-generation model built for complex coding and agentic workflows, launched alongside GPT-6 Luna on 22 September 2026. In OpenAI's own guidance, GPT-6 Astra is the flagship for the hardest reasoning and coding, Sol is the choice for balancing intelligence and cost, and Luna targets cost-sensitive, high-volume workloads.

Technically, Sol handles a 1,050,000-token context window with up to 128,000 output tokens, accepts text and image inputs, and exposes a reasoning-effort dial spanning none, low, medium (default), high, xhigh and max. Structured outputs, function calling and the Responses API built-in tools make it suited to multi-step automation and long-horizon repository work.

Compared with its direct predecessor, GPT-5.6 Sol — which carried the same 1.05M context window and the same reasoning-effort settings — OpenAI reports that GPT-6 Sol improves substantially on FrontierCode, an evaluation of whether coding agents produce changes ready to merge into real codebases. OpenAI also publishes self-reported figures of 56.4% on Agents' Last Exam at max effort, 68.8% on DeepSWE v1.1 at max effort, and 60.5% on OSWorld 2.0 offline at xhigh effort.

OpenAI states that the release focuses on capability improvements and cost efficiency for Sol and Luna, accompanied by higher usage limits.