opencode

opencode is an open-source AI coding agent that lives in your terminal. It's built by Anomaly, the team behind SST, and it's the project now hosted at opencode.ai (the old sst/opencode repo redirects here). Bring any model provider, Anthropic, OpenAI, Google, GitHub Copilot, or a local model, and it reads, writes, and edits files and runs shell commands from a clean TUI. MIT licensed.

The design choice that sets it apart is a two-agent flow: a plan agent that only reads and analyzes, and a build agent that actually makes changes, so you review the plan before anything touches your code. It pulls in LSP diagnostics as it works. Install is trivial, npm, Homebrew, or a one-line script, no Docker or GPU. You supply an API key for a hosted model, or point it at a local one and run for free.

This is a serious, actively maintained tool with near-daily releases, not a weekend project. If you're happy in the terminal and want a coding agent without a subscription, opencode competes head-on with Cursor, GitHub Copilot, and Claude Code, and you pay only for the model tokens you use. Solo devs and small teams who already have API access get the most out of it.

The catch is the model bill and the terminal-first workflow. opencode is free, but the models it drives are not, and heavy use adds up the same way a subscription would. And if you want a graphical editor experience, this isn't it. It's a TUI first, with a desktop app still in beta. For people who live in the terminal, that's the appeal, not the drawback.