GPT-5.6 Preview
Limited preview of the GPT-5.6 series
OpenAI’s limited preview release of the GPT-5.6 language-model series, comprising Sol (flagship), Terra (lower-cost), and Luna (fast, cost-efficient), initially for selected trusted partners through the API and Codex.
Pricing
Current GPT-5.6 Sol API rates: $4 per 1M input tokens, $20 per 1M output tokens, and $0.40 per 1M cached input tokens. OpenAI docs state promotional pricing available at least through November 21, 2026. Prompts over 272K input tokens are priced at 2x input and 1.5x output.
OpenAI's original GPT-5.6 preview announcement describes Sol as the flagship preview, and current OpenAI API documentation gives token rates for the corresponding generally available GPT-5.6 Sol model. The documentation does not list a separate current SKU called “GPT-5.6 Preview”; this finding uses Sol's current public rate as the closest documented match. The model accepts text and image input and outputs text.
Model Intelligence
Recent stories
OpenAI launched ChatGPT Work, a Codex- and GPT-5.6-powered ChatGPT agent with a desktop app that can access local files and apps. OpenAI staff said Work and Codex use the same sandboxing with UI changes.
Posts say Sol, Terra, and Luna are set for a July 9 launch. One report says Sol was added to the Codex codebase as OpenAI’s strongest model for code, research, and documents.
OpenAI says GPT-5.6 Sol, Terra, and Luna will launch publicly Thursday as preview access expands. Testers describe Sol as strong for coding, agents, and computer use; Wafer reports Cerebras serving up to 750 tokens/sec.
Codex app code now references GPT-5.6 Sol, Terra, and Luna, while posts claim Sol Ultra reaches 91.9% on TerminalBench at lower cost. Treat release timing, limits, and benchmark claims as unofficial until OpenAI publishes details.
OpenAI introduced GeneBench-Pro to test whether agents can handle messy, judgment-heavy computational biology work instead of fixed bio QA. GPT-5.6 Sol Pro reached 31.5%, which shows progress on research workflows but also how far current systems remain from expert-level autonomy.
The Information reported that OpenAI is holding GPT-5.6 to a limited preview with customer-by-customer approvals during review. That would restrict who can benchmark or integrate the model until a broader rollout clears.