OpenAI has unveiled its new GPT-5.6 model series, featuring three distinct capability tiers named Sol, Terra, and Luna, currently available through a limited preview for select trusted partners.

Key Points

• The GPT-5.6 series includes Sol (flagship), Terra (balanced), and Luna (fast and affordable) models.
• New reasoning features include "max" effort for deep thinking and "ultra" mode utilizing subagents for complex tasks.
• OpenAI is coordinating with the U.S. government to conduct a limited preview before a broader public release.
• Pricing is set per million tokens, ranging from $1 to $5 for input and $6 to $30 for output.
• The update introduces improved prompt caching with explicit breakpoints and a 30-minute minimum cache life.
• The models demonstrate performance advancements in coding, biology, and cybersecurity applications.

Why it Matters

This release marks a shift in OpenAI’s deployment strategy by prioritizing government coordination and a phased rollout to ensure safety and security. The new tiered naming system and specialized reasoning modes provide developers with more granular control over balancing computational costs and model performance.