C1 by Thesys is an API that transforms large language model outputs into live, interactive user interfaces. It allows developers to create adaptive UIs in real time without hardcoding each response. The system supports multiple LLMs and integrates easily with existing design frameworks.

This article tracks the development of LLM extensions, highlighting significant milestones from ChatGPT Plugins to Claude Code. It discusses how user customization has evolved, focusing on tools like Custom Instructions and Agent Skills that enhance agent capabilities. The author reflects on the future of LLMs and the integration of general-purpose tools.

nanochat is a full-stack implementation of a ChatGPT-like language model that can be trained on an 8XH100 GPU node for about $800. It features a simple UI for interaction and is designed to be highly configurable and hackable by users, allowing them to train and customize their own models. While it currently outperforms GPT-2, it still has limitations compared to more advanced models like GPT-5.