OpenCode is an open-source AI coding agent: an assistant that writes and edits code and runs commands for you, in a terminal, a desktop app or an editor.
In plain words
You give OpenCode a task in plain language and it works on your code with the model you pick. It can connect to more than 75 model providers, such as the makers of Claude, GPT and Gemini, and can also run local models. It has two main modes: Build, which may use every tool, and Plan, which by default refuses to edit any file except its own plan notes, so you can study code and make a plan without changing anything.
A quick example
Imagine you join a project and don't know its code yet. You switch to Plan mode and ask how login works. The agent reads the files and explains them without editing anything. Then you switch to Build mode and ask it to add a password reset page.
Where you'll meet it
- Writing and changing code from the terminal with any model you choose.
- Exploring and planning changes in unfamiliar code without touching it.
Related
Sources
- DocsIntro, OpenCode docs · read 17 Oct 2026
- DocsAgents, OpenCode docs · read 20 Oct 2026
- DocsProviders, OpenCode docs · read 17 Oct 2026
- DocsOpenCode, OpenCode · read 17 Oct 2026
Checked by WhatIsAI against the sources above · 23 Oct 2026. A full five-minute explainer with a diagram may follow. Spotted an error? Report it.