OpenAI has released the GPT-5.6 model family, comprising three sizes: Luna (smallest), Terra, and Sol (largest). These models feature a one million token context window, 128,000 maximum output tokens, and a knowledge cutoff of February 16th, 2026. Key updates to the API include programmatic tool calling via JavaScript orchestration, native multi-agent support for parallel task execution, explicit prompt cache breakpoints, and an option to receive unresized images in requests.
* Three model tiers: Luna, Terra, and Sol
* Improved performance in long-running agentic professional workflows
* New API features including programmatic tool calling and multi-agent orchestration
* Three model tiers: Luna, Terra, and Sol
* Improved performance in long-running agentic professional workflows
* New API features including programmatic tool calling and multi-agent orchestration
Simon Willison tests OpenAI's newly released ChatGPT Images 2.0 model using a complex Where's Waldo style prompt involving a raccoon holding a ham radio. By comparing results against previous versions and competitors like Google's Nano Banana, the article evaluates the model's ability to handle high-detail illustrations and specific text elements.
Simon Willison’s annual review of the major trends, breakthroughs, and cultural moments in the large language model ecosystem in 2025, covering reasoning models, coding agents, CLI tools, Chinese open‑weight models, image editing, academic competition wins, and the rise of AI‑enabled browsers.
LLM 0.26 introduces tool support, allowing LLMs to access and utilize Python functions as tools. The article details how to install, configure, and use these tools with various LLMs like OpenAI, Anthropic, Gemini, and Ollama models, including examples with plugins and ad-hoc functions. It also discusses the implications for building 'agents' and future development plans.
OpenAI's documentation for their o1 and o3 'reasoning models' includes tips on how to best prompt them, such as using developer messages, delimiters, and specific instructions.
