❯ OpenAI launches GPT-6 Sol and Luna, halving both mistakes and API prices

two new modelsOpenAI released GPT-6 Sol and GPT-6 Luna on September 22, positioned to bring the advances behind GPT-6 Astra — the flagship launched September 3 — down to faster, cheaper tiers. The company says Sol makes about half as many mistakes as GPT-5.6 Sol, while Luna matches GPT-5.6 Sol’s performance at roughly 1% of the cost. Both are live in ChatGPT, Codex and the API.

how the prices fellPer OpenAI, where the GPT-5.6 family had been billed at promotional rates, Sol now costs $2 per million input tokens and $10 output, against $4 and $20 before; Luna costs $0.10 input and $0.50 output, against $0.20 and $1.20. This halving comes on top of the 80% cut to Luna at the end of July. On alignment, the company reports internal coding-deception rates of 1.3% for Sol and 2.8% for Luna, against 10.4% for the previous Sol. Artificial Analysis’s third-party read is more measured: Intelligence Index scores close to their predecessors, at half the cost, with fewer hallucinations at max effort.

pricing per taskAltman’s line was that on per-task pricing, “I don’t think there is anything competitive anywhere in the market.” That names OpenAI’s real play this round — not single benchmark scores but what it costs to finish a job. The release landed about 90 minutes after Anthropic’s Opus 5.5, with both companies throwing in a usage-limit reset. Engineering teams that choose models on cost per task benefit directly, and Luna’s 1% ratio will make a class of product features that could not afford a frontier model viable first.

▪ SIGNALFlagship capability pushed down and prices cut in half — OpenAI has changed the unit of competition from model scores to cost per task.