GPT-6 Sol and Luna: OpenAI Halves Prices, Coding Models Enter the Half-Price Era
On September 22 — the same day Anthropic shipped Opus 5.5 — OpenAI answered with GPT-6 Sol and GPT-6 Luna, halving prices versus their GPT-5.6 namesakes. The coding-model arms race is now fought on price.
On September 22 — the same day Anthropic shipped Opus 5.5 — OpenAI countered with GPT-6 Sol and GPT-6 Luna, halving prices against the GPT-5.6 models that carried the same names.
What each model is for
- GPT-6 Sol: $2 per million input tokens, $10 per million output — tuned for complex coding and agent workflows, the natural pick for vibe coders.
- GPT-6 Luna: $0.10 / $0.50 per million — an order of magnitude cheaper, built for high-volume, focused tasks like bulk completions and fast iteration.
- Rolling out to Plus and above, with Free/Go users able to try Luna.
Tooling followed immediately
Codex CLI 0.157.0/0.157.1 (September 25–26) added Sol/Luna support. In ChatGPT Work and Codex, Sol is already available as a coding model.
What it means for vibe coding
When the strongest coding models cost half as much, the marginal cost of "writing code with AI" gets crushed again. For indie developers, that means more luxurious agent usage: longer contexts, more parallel attempts, less token-anxiety.
Sources
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