GPT-6.1 Sol

• 🆕 OpenAI's upgrade to GPT-6 Sol, released September 29, 2026
• 📏 1.05M-token context: 922K input, 128K output
• 👁️ Text and image inputs, text output
• 🔧 Reasoning effort selectable from low through max
• 🎯 Built for agentic coding, computer use, professional document work
• 🧠 On OpenAI's reported DeepSWE v1.1, +6.4 points over GPT-6 Sol
• 🔒 Supports US and EU data residency; no fast mode in EU
• 🌐 Function calling, hosted tools, and web search via Responses API

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-6.1 Sol is OpenAI's mid-tier reasoning model in the GPT-6 generation, sitting between the high-end GPT-6 Astra and the efficiency-oriented GPT-6 Luna. OpenAI positions it as delivering near-Astra capability at substantially lower cost for complex coding, computer use, and professional work. It carries a 1.05-million-token context window (922K input, 128K output), accepts text and image inputs, and exposes reasoning effort settings from low through max, with the minimal and none settings unsupported.

Its direct predecessor, GPT-6 Sol, shipped just a week earlier. OpenAI reports meaningful generational gains: on DeepSWE v1.1, a long-horizon software-engineering benchmark, GPT-6.1 Sol exceeds GPT-6 Sol's best score by 6.4 percentage points while running at lower reasoning effort and cost, and matches GPT-6 Astra at roughly a fifth of Astra's cost per task. OpenAI also reports that cached input pricing was halved relative to GPT-6 Sol, which matters for agents that reuse long prefixes.

The capability set aligns with the rest of the current generation: reasoning, vision, function calling, hosted tools and web search, with data residency options in the US and EU (fast mode is unavailable in the EU).

Access is through the Responses API for tool calling, with Chat Completions supported for non-tool use, plus Batch and Flex processing tiers. Earlier Sol-line models in the catalog include GPT-5.6 Sol and GPT-5.6 Sol Pro.