OpenAI's cheaper GPT-6 tiers arrive, availability splits by plan

On September 22, 2026, GitHub said two more OpenAI models, GPT-6 Sol and GPT-6 Luna, are available in GitHub Copilot, joining GPT-6 Astra. GitHub describes Sol as a balanced model for interactive and agentic coding, and Luna as a lightweight, cost-efficient model for smaller, faster tasks and the lowest-cost option in the GPT-6 family.

Which plan gets which model differs. GitHub says Sol is available on Copilot Pro+, Max, Business and Enterprise. Luna is available on Pro, Pro+, Max, Business and Enterprise. You pick them in the model picker in editors such as VS Code, Visual Studio, JetBrains and Xcode, in the Copilot CLI, on github.com and in GitHub Mobile. GitHub says the rollout is gradual.

GitHub says these models are billed under usage-based billing. For Business and Enterprise, GitHub says new models are turned on automatically unless an administrator has turned off the global default or switched off the specific model.

The Codex CLI release rust-v0.156.1, published on September 23, says you can choose Sol or Luna in the model picker. We have not re-checked the pricing and regional figures that other outlets reported for these models, so this briefing leaves them out. See the sources below.