Artificial intelligence · September 2026

GPT-6 Sol and Luna

GPT-6 capability at half the price of GPT-5.6.

OpenAI released GPT-6 Sol and Luna at half the API price of GPT-5.6, with Sol at $2 and $10 per million tokens. OpenAI reported about half as many mistakes as GPT-5.6 Sol.

See it in the living tree Wikipedia Source

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

GPT-6 Astra 2026

Related measurements

The dashed line marks when it first worked.

Best AI score on GPQA Diamond Latest: 95.8 % correct (2026) Source: Epoch AI, Capabilities & benchmarking (benchmark_data.zip, gpqa_diamond.csv); Anthropic: Claude 3 public launch (March 4, 2024)

Training compute of notable AI models Source: Epoch AI, Notable AI Models (CC BY 4.0)