OpenCode is an open-source AI coding agent that allows users to write code in their terminal, IDE, or desktop, with support for multiple models and providers, including Claude, GPT, and Gemini. It is designed with privacy in mind and does not store any code or context data. OpenCode has gained significant traction, with over 160,000 GitHub stars and 7.5 million monthly users. The project offers a range of features, including multi-session support and integration with GitHub Copilot and ChatGPT.