Chat model · OpenAI ·
GPT-5.6 Sol is a chat model by OpenAI. In Endless it costs 324 credits per 1M input tokens and 1620 per 1M output tokens, on every plan.
GPT-5.6 Sol is the flagship of OpenAI's GPT-5.6 family, built for complex coding and agent work, with a max reasoning effort for hard problems.
GPT-5.6 Sol leads the GPT-5.6 family that OpenAI previewed in June 2026 and released widely in July. It launched as OpenAI's strongest model for coding, science and cybersecurity workflows, and it introduced a max reasoning effort that gives the model the most time to think through hard problems. It reads text and images, holds 1.05M tokens of context and writes up to 128K tokens per response.
Teams use it for long coding work: planning a change across many files, chasing down a failing test, or reviewing a pull request with the full repository in context. It also suits analysis that has to keep many documents in view at once, such as comparing technical specifications or a set of research papers.
Within GPT-5.6, Terra is the balanced everyday tier and Luna the fastest and lowest-cost one. The newer GPT-6 generation followed in September 2026, with GPT-6.1 Sol as its balanced tier and GPT-6 Astra as its most capable model. You can switch between these OpenAI models in the same workspace.
Start a chat in your workspace and choose GPT-5.6 Sol in the model picker.
Attach files, mention a project with @, or ask it to search the web and social media.
Generate images and video, write documents and save what matters to a project.
by OpenAI
Near-flagship agentic coding and professional work at lower cost
162 / 810 credits per 1M tokens
by OpenAI
Hard research and coding problems that need the deepest reasoning
1215 / 5062.5 credits per 1M tokens
by OpenAI
Fast, low-cost answers for focused, high-volume tasks
8.1 / 40.5 credits per 1M tokens
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