GPT-5.6 Leaked: 1.5M Context Window & AI UI Generation

Developers recently found an unreleased large model, "GPT-5.6," in OpenAI Codex backend logs. This new flagship, internally called "iris-alpha," shows impressive technical specifications. It is expected to be officially released in June. The most striking feature is its ultra-long context window of up to 1.5 million tokens. This is a nearly 43% increase compared to the current GPT-5.5 API. This means it can handle long contracts, large codebases, and complex multi-step tasks. Developers tested it with an auxiliary tool called OpenCode. The model responded smoothly with 900,000 tokens of input data. It even handled overload requests exceeding 1.05 million tokens. What's more, GPT-5.6 also brings a revolutionary change in frontend interface generation. Leaked screenshots show the model generated a minimalist note-taking application interface, called Lumen Notes, without detailed prompts. This advancement could significantly impact how complex digital tasks are managed and developed.