GPT-6 Sol (OpenAI)

OpenAI released GPT-6 Sol on September 22, 2026, positioning it as the middle-tier option in the GPT-6 lineup for demanding coding and agent workflows that need judgment but not the highest price. The model carries the API ID gpt-6-sol, sits between Astra for hard tasks and Luna for narrow high-volume work, and is presented as a sensible upgrade target from the older GPT-5.6 Sol. Standard API pricing is $2 per million input tokens and $10 per million output tokens, with cached input at $0.20 and cache writes at $2.50, and requests above 272,000 tokens shifting to long-context rates. OpenAI reports 68.8% on DeepSWE v1.1 at max effort, 33.2% on AutomationBench 1.0.6 at xhigh, and 60.5% on OSWorld 2.0 offline at xhigh, though the article notes these are vendor results without independent verification. The model accepts text and images, supports a 1,050,000-token context with 128,000-token output, and exposes web search, code interpreter, computer use, and other Responses API tools, but fine-tuning is unavailable and native audio or video input is not supported.

On September 22, 2026, OpenAI launched GPT-6 Sol and GPT-6 Luna, extending the GPT-6 lineup into faster, cheaper mid-tier and budget models roughly 90 minutes after Anthropic unveiled Claude Opus 5.5. API prices were cut 50% versus GPT-5.6 promotional rates, with OpenAI calling the new pricing permanent and claiming Sol makes about half as many factual mistakes as its predecessor. GPT-6 Sol is priced at $2 per million input tokens and $10 output, while Luna costs $0.10 input and $0.50 output, supporting a 1.05 million-token context and the full agent toolkit. Both are rolling out in ChatGPT Work and Codex for paid tiers, with Luna also in the desktop app for Free and Go users. OpenAI's internal benchmarks put Sol ahead of Opus 5 on tasks like AutomationBench at roughly one-eleventh the per-task cost, though independent verification is still pending.

Morph's September 2026 coding-model ranking explicitly lists GPT-6 Sol among the models OpenAI shipped on September 22, 2026, alongside the cheaper GPT-6 Luna and the earlier flagship GPT-6 Astra (September 3, 2026). It situates Sol within OpenAI's three-model GPT-6 lineup as the mid-tier option for agentic and coding For coding fit, the article does not assign GPT-6 Sol a top slot: Claude Opus 5.5 leads Terminal-Bench 4.0 at 66.4% for $4/$20 with a 1M context window, GPT-6 Astra is ranked first on the Arena.ai Frontend Code Arena at a 1793 score with 57.9% Terminal-Bench 4.0 at $10/$50, and Kimi K3 is the top open-weight pick at 2.