OpenAI adds Sol and Luna under Astra

OpenAI published Introducing GPT-6 Sol and Luna on 22 September 2026. The post adds two GPT-6 family models below GPT-6 Astra: Sol for complex coding and agentic work, and Luna for efficient high-volume tasks.

OpenAI says API prices for Sol and Luna are 50% lower than GPT-5.6 promotional pricing. Docs list Sol at $2 input / $10 output per million tokens and Luna at $0.10 / $0.50. API model ids are gpt-6-sol and gpt-6-luna.

OpenAI GPT-6 Sol and Luna announcement social card Caption: OpenAI social card for GPT-6 Sol and Luna · Source: OpenAI, Introducing GPT-6 Sol and Luna, 22 September 2026 · link

Work, Codex, and API get both ids today

ChatGPT Work and Codex users on Plus, Pro, Business, Enterprise, and Edu plans get Sol and Luna starting 22 September. Free and Go users can use Luna in the desktop app only. OpenAI says the models are not yet available in Chat.

API customers can call gpt-6-sol and gpt-6-luna now. Official model pages document context window (1,050,000), max output (128,000 tokens), reasoning effort options through max, and Responses API tool support.

OpenAI also posted the same launch note on the Developer Community announcements board.

Two mid-tier ids at half GPT-5.6 promo prices

  1. Two mid-tier GPT-6 ids at 50% below GPT-5.6 promotional list prices. Sol: $2 / $10 per MTok (cached input $0.20). Luna: $0.10 / $0.50 (cached input $0.01). OpenAI frames both as a 50% cut versus GPT-5.6 Sol/Luna promotional rates.
  2. Product placement under Astra. The blog keeps GPT-6 Astra as the top model for hardest work. Sol and Luna are positioned as cheaper, faster carriers of Astra-trained methods for professional work, factuality, coding, computer use, and alignment.
  3. Higher usage headroom in ChatGPT Work / Codex for paid tiers, with a gradual same-day roll-out. Free/Go access is Luna on desktop only.
  4. Lab-reported eval deltas on AutomationBench, Agents' Last Exam, FrontierCode, DeepSWE, OSWorld, and an internal factuality evaluation. Treat these as OpenAI's own comparisons unless you re-run them.

No Chat date and lab-only competitor rows

The blog's competitor rows (Claude Opus 5, Claude Fable 5 / 5.1) come from OpenAI's research environment or public reports. Effort settings, tool harnesses, and fallback accounting differ by row. OpenAI notes some Fable cost figures omit Opus fallback spend.

Sol and Luna are not in Chat yet. Desktop-only Luna for Free/Go stays a surface limit until Chat availability ships.

Regional processing premiums, Batch/Flex/Fast multipliers, and prompts over 272K tokens change the invoice. Read the Sol and Luna pricing footnotes before forecasting.

No shipment date is given for Chat availability beyond "gradually throughout the day" for Work/Codex visibility.

Retarget gpt-6-sol and gpt-6-luna traffic

  • API teams on GPT-5.6 Sol/Luna: Retarget traffic to gpt-6-sol / gpt-6-luna and re-measure cost per task at the same reasoning.effort. Confirm cache-write billing at 1.25× input.
  • Codex / ChatGPT Work admins: Check model pickers after the staggered roll-out. If Sol/Luna are missing, retry later the same day as OpenAI advises.
  • Free/Go users: Expect Luna on desktop only. Do not plan Chat workflows on these ids yet.
  • Keep Astra for jobs that already need maximum depth; the blog still points hard work there.