GPT-6 Luna changelog

GPT-6 Luna in ChatGPT updated on October 28 with more concise replies

OpenAI updated GPT-6 Luna in ChatGPT, which launched there on October 7. The updated model gives more concise responses and reduces overly agreeable language.

Decisions API generally available with GPT-6 Luna

The Decisions API, which returns typed answers from text and images with GPT-6 Luna, is now generally available after a beta that began October 6. Each request now supports up to 400 questions, up from 200 in the public beta.

Who is affected:

Developers using or evaluating the Decisions API.

What to do:

Review the changes since the public beta before moving beta integrations to production.

Decisions API priced at $0.10 per million input tokens with no output charges

The Decisions API is generally available with GPT-6 Luna. It costs $0.10 per million input tokens and $0.01 per million cached input tokens, with no output-token charges.

Who is affected:

Developers using GPT-6 Luna for classification, routing and scoring decisions can budget on input tokens only.

What to do:

Review the pricing guide for 30-minute and 12-hour cached write rates.

GPT-6 becomes the ChatGPT model on free and paid plans

OpenAI launched GPT-6 to everyone in ChatGPT on free and paid plans globally, replacing GPT-5.6 Sol and GPT-5.6 Luna in ChatGPT. Codex and ChatGPT Work keep the September versions.

Who is affected:

Everyone using ChatGPT.

What to do:

No action needed. re-check saved prompts and GPTs for changed behavior.

OpenAI fixes an image encoding bug that degraded GPT-6 Sol and Luna image understanding

OpenAI's API changelog says a bug in image encoding degraded image understanding in GPT-6 Sol and GPT-6 Luna, and the fix improves visual tasks in the API and Codex, including computer use.

Who is affected:

Apps and Codex sessions that sent image inputs or used computer use with GPT-6 Sol or GPT-6 Luna after their September 22 release.

What to do:

Rerun evaluations and retry workflows that used image inputs with GPT-6 Sol or GPT-6 Luna.

GPT-6 Sol and GPT-6 Luna available in GitHub Copilot

GPT-6 Sol is available on Copilot Pro+, Max, Business and Enterprise, and GPT-6 Luna also on Pro, under usage-based billing.

GPT-6 Sol and Luna roll out in Codex and ChatGPT Work

GPT-6 Sol and GPT-6 Luna rolled out to Codex and ChatGPT Work for Plus, Pro, Business, Enterprise and Edu at lower token prices than GPT-5.6. Free and Go get Luna in the desktop app. They are not available in ChatGPT Chat.

Who is affected:

Codex and ChatGPT Work users.

What to do:

Pick gpt-6-sol or gpt-6-luna. Enterprise admins must enable them.

GPT-6 Luna released at $0.10 input and $0.50 output

GPT-6 Luna launched on the Responses and Chat Completions APIs at $0.10 input, $0.01 cached input and $0.50 output per million tokens for prompts up to 272K tokens.

Who is affected:

Developers running high-volume workloads on GPT-5.6 Luna or smaller models.

What to do:

Test GPT-6 Luna for high-volume tasks.