OpenCode is an open-source AI coding agent built for the terminal, developed by the team behind SST, the serverless framework, and now operating as Anomaly Innovations. First released in June 2025 at opencode.ai, the project grew quickly into one of the largest open-source developer tools of the cycle, reaching well over 150,000 GitHub stars and millions of monthly active developers by 2026.
OpenCode runs as a Go-based CLI that opens a terminal user interface for interacting with large language models. From that TUI, developers can read, write, and edit files, run shell commands, navigate large codebases, and orchestrate multi-step changes. A distinctive design choice is the dual-agent model: a build agent has full access to make changes and run commands, while a read-only plan agent must ask permission before executing anything, making it easier to use OpenCode in environments where blast radius matters.
Model choice is deliberately open. OpenCode supports connections to Anthropic Claude, OpenAI GPT models, Google Gemini, local Llama variants, and dozens of other backends through providers such as OpenRouter, Portkey, and direct API keys, with documentation listing more than 75 supported providers. This makes it a natural pairing with low-cost backends such as DeepSeek for users who want strong capability at a small monthly bill.
OpenCode itself is free and open source under a permissive license; users pay only for whatever model provider they choose. The project is best suited to developers who prefer terminal-first workflows, value transparent and auditable agents, and want to avoid being locked into a single AI vendor. It is less of a fit for teams that want a polished GUI IDE experience or a single bundled subscription.