GPT-5.6 Luna Pro

• 🆕 Part of OpenAI's GPT-5.6 family: Sol, Terra, and Luna [9]
• 🔧 Same model as GPT-5.6 Luna, served with reasoning mode "pro"
• 🧠 Pro mode targets higher-quality answers on complex tasks
• 📏 Roughly one-million-token context window
• 👁️ Supports reasoning, vision, function-calling, and web search
• ⚡ Luna is the family's lighter, faster tier [9]
• 🏢 Released July 9, 2026, available via OpenAI's API [4]
• 🔒 Previewed to trusted partners under a layered safety rollout [9]

OpenAI

OpenAI is an American artificial intelligence research organization headquartered in San Francisco, structured as both a for-profit public benefit corporation and a nonprofit foundation. The lab developed the GPT family of large language models, the DALL-E…

GPT-5.6 Luna Pro is not a standalone model but a serving configuration of GPT-5.6 Luna, invoked with its reasoning mode set to "pro" for higher-quality responses on complex tasks. It belongs to OpenAI's GPT-5.6 generation, released July 9, 2026, a family that also includes the balanced GPT-5.6 Terra and the higher-capability GPT-5.6 Sol, each with its own pro variant.[9]

Within that lineup, Luna is positioned as the lighter, faster tier, while Sol sits at the more capable end.[9] Luna Pro carries the family's roughly one-million-token context window and its multimodal, tool-using feature set, including vision, function-calling, and web search, so the "pro" setting adds answer quality on demanding tasks rather than changing the underlying model.

Compared with earlier OpenAI releases such as GPT-5.5 and GPT-5.5 Pro, the GPT-5.6 models are the newer generation in the same provider's text lineup, listed in OpenAI's current API model catalog.[4] During its initial rollout, GPT-5.6 was previewed to trusted partners under a layered safety approach before broader availability, according to OpenAI's preview documentation.[9] For exact tier names, model identifiers, and availability, consult OpenAI's official API documentation.[4]