OpenCode is the leading open-source AI coding agent in 2026, designed for terminal, IDE, and desktop use. It empowers developers to plan, write, debug, and refactor code via natural language, supporting 75+ LLM providers (Claude, GPT, Gemini, local models & more), with built-in tools for file editing, bash execution, LSP integration, and custom MCP extensions. Privacy-focused (no code storage), it boasts 70k+ GitHub stars, 650k+ monthly users, and excels in agentic, multi-session workflows.