Chat Smith has integrated GPT-5.6 Sol, OpenAI's flagship model from the GPT-5.6 family, now available directly inside Chat Smith. Pro plan subscribers can start using it today — no upgrade, no additional fees required.
Released by OpenAI on July 9, 2026, GPT-5.6 Sol is the most powerful of the three GPT-5.6 variants — Sol, Terra, and Luna — and is designed as OpenAI's workhorse for complex, high-stakes work. It sets a new bar across coding, reasoning, scientific research, cybersecurity, and enterprise workflows.
What makes Sol stand out
Best-in-class coding performance. GPT-5.6 Sol scores 88.8 on Terminal-Bench 2.1 (91.9 in Ultra mode), placing it at the top of the coding benchmark leaderboard. OpenAI describes it as their best coding model yet — and it achieves those results using 54% fewer tokens than comparable models, which means faster responses and lower latency for code-heavy tasks.
A 1.05M-token context window. Sol can hold and reason across extremely long documents, codebases, or multi-turn conversations — with up to 128K tokens of output per response. This makes it well-suited for deep research sessions, document analysis, and extended agentic tasks that require sustained context.
Built for agentic workflows. Sol's Ultra setting coordinates multiple agents across parallel workstreams, accelerating complex multi-step tasks that would otherwise require significant manual coordination. On Agents' Last Exam — a benchmark spanning 55 professional workflows — Sol outperforms every prior model in the GPT-5 lineage.
Stronger across science and research. OpenAI reports that Sol represents a 16.2-point improvement over GPT-5.5 on aggregate recursive self-improvement evaluations. Researchers inside OpenAI use it daily for diagnosing training failures, running experiments, and interpreting results — a signal of just how capable the model is in technical, high-precision environments.
Included in Chat Smith Pro — no extra cost
Accessing frontier models directly through their native platforms often comes with its own subscription costs and usage limits. With this integration, Chat Smith Pro plan subscribers can switch to GPT-5.6 Sol the same way they would any other supported model — from the model selector in any conversation. No new plan, no separate API key, no additional charge.
This continues Chat Smith's approach of bringing the best available models to one place — so users can compare, switch, and find what works best for their task without managing multiple subscriptions.
GPT-5.6 Sol is available now for all Chat Smith Pro users at chatsmith.io/model/gpt-5-6-sol.
