OpenCode Review: The Free Terminal AI Coding Agent

A beginner searching for a free terminal AI coding agent in 2026 keeps running into the same three open-source names: OpenCode, Goose, and Aider. They all run in your terminal, they all work with multiple AI models, and none of them charge a subscription. So which one should you actually install first?

This OpenCode review answers that for one specific person: a vibe coder or beginner who wants a free terminal agent, hasn't picked one yet, and is choosing between OpenCode, Goose, and Aider. We'll cover what OpenCode does, how to install it, the honest catch behind the word "free," and exactly who should pick it over the alternatives.

One quick note to clear up confusion: OpenCode is not the same as OpenClaw, a different AI agent we've covered separately. Different tool, different team, similar-sounding name.

What is OpenCode?

OpenCode is a free, open-source AI coding agent that runs entirely in your terminal. You type a task in plain English, and it reads your project files, writes or edits code, runs commands, and works through the task step by step — the same kind of agentic loop you get from Claude Code, but with no subscription attached.

The thing that makes OpenCode stand out is its interface. It ships a polished TUI (terminal user interface) — a full keyboard-driven app that runs inside your terminal window, with a built-in editor, file change tracking, and session management. It looks and feels more like a real app than a bare command prompt. It's also available as a desktop app and an IDE extension if you'd rather not live in the terminal.

One naming note worth clearing up: there was an earlier OpenCode written in Go, but that project was archived in September 2025 and continued under the name Crush. The OpenCode that everyone uses today — the one at opencode.ai — is a newer, separate project built mainly in TypeScript. That's the tool this review covers.

With over 169,000 GitHub stars, OpenCode has a large, active community behind it — a good sign for a beginner, because it means bugs get fixed quickly and there are plenty of tutorials to lean on.

Free, but you bring your own key

Here's the part that matters most for a budget. OpenCode is free and open source — there's no account to create and no subscription to buy. But the AI model it talks to is not free.

OpenCode works on a "bring your own key" model. You plug in an API key from a provider like Anthropic (Claude), OpenAI (GPT), or Google (Gemini), and you pay that provider directly for what you use. The OpenCode software costs nothing; the tokens it burns through the model do.

There is one way to make it genuinely $0: point OpenCode at a local model running through Ollama. That runs the AI on your own machine with no API bill at all. The trade-off is that local models are less capable than Claude or GPT, and you need a reasonably powerful computer to run them well.

What OpenCode actually does

OpenCode is a full agent, not just an autocomplete. You describe what you want, and it plans the work, edits multiple files, and runs shell commands to get there — installing packages, running tests, checking git status.

Build mode vs Plan mode

OpenCode splits its work into two modes. Build mode is the default — the agent actively writes and edits your files. Plan mode disables file changes entirely and lets the agent analyze your code and propose an approach without touching anything.

Plan mode is genuinely useful for beginners. You can ask "how would you add user login to this app?" and read the plan before letting it loose on your files. It's a safety net against the agent making big changes you didn't expect.

Works with Claude, GPT, Gemini, and local models

OpenCode is model-agnostic. It supports 75+ LLM providers — Anthropic, OpenAI, Google, and local models via Ollama among them — so you're not locked into one company's model. If Claude is too expensive for a task, switch to a cheaper model in the config; if you want zero cost, route to a local model.

This flexibility is the core pitch. Where Claude Code only runs Anthropic's models, OpenCode lets you pick the right model for the job and the right price for your wallet.

OpenCode vs Goose vs Aider for beginners

These are the three free open-source terminal agents a beginner actually chooses between. Here's how OpenCode stacks up against each.

OpenCode vs Goose

Goose is Block's free, open-source terminal agent. Like OpenCode, it's model-agnostic, supports MCP servers, and can run on free local models. The two are closely matched on capability.

The difference is feel. OpenCode's TUI is more polished and app-like, with its Build/Plan split and built-in editor. Goose is a capable agent but its interface is plainer. If you care about the terminal experience feeling smooth and modern, OpenCode has the edge. If you're already in Block's ecosystem or following Goose tutorials, Goose is a fine pick.

OpenCode vs Aider

Aider is the veteran of this group — a terminal AI pair programmer that's been around for years and is built around git. Its signature move is auto-committing every change it makes, so your project history becomes a clean trail of AI edits you can roll back at any time.

Aider's strength is that git-native workflow and years of real-world polish. OpenCode's strength is the modern TUI and the Plan mode safety net. For a beginner who wants the smoothest interface, OpenCode wins. For a beginner who wants automatic version control baked in from the first command, Aider is hard to beat. We compare Aider to another free option in Cline vs Aider if you want a wider view.

How to install OpenCode

OpenCode offers a one-line install script on macOS and Linux:

curl -fsSL https://opencode.ai/install | bash

It's also available through common package managers. With npm:

npm install -g opencode-ai

Or with Homebrew on macOS:

brew install anomalyco/tap/opencode

After installing, set the API key for whichever provider you want to use as an environment variable. For Claude, that looks like:

export ANTHROPIC_API_KEY=your_key_here

Then run it inside a project folder:

opencode

That drops you into the TUI, where you type tasks in plain English. Always double-check the current install steps on the official docs — install methods for fast-moving open-source tools change often.

The honest catch for beginners

Two things to know before you commit.

First, "free" still costs money unless you go local. The software is free, but every task you run calls a paid AI provider. A few short tasks cost cents; a long agentic loop on a big project can add up faster than you'd expect. If you want a true $0 experience, you either run a local model through Ollama (less capable, needs a decent machine) or look at a tool with a hard free quota like Gemini CLI.

Second, a terminal agent is more intimidating than an app builder. OpenCode lives in the terminal. There's no website to click around in, no visual app preview. The TUI makes that less scary than a raw command line, but if you've never opened a terminal, a browser-based tool will feel friendlier to start with. OpenCode rewards a little terminal comfort.

Who should use OpenCode?

OpenCode is one of the best-looking free terminal agents available, and the bring-your-own-key model gives you real control over cost and model quality.

Install OpenCode if: you want a free, polished terminal agent, you're comfortable bringing your own API key, and you like the idea of switching models per task or running local for free. The Plan mode safety net makes it more beginner-forgiving than most terminal tools.

Pick Goose instead if: you want a similar free, model-agnostic agent and don't mind a plainer interface, or you're already following Goose's docs.

Pick Aider instead if: you want automatic git commits on every change and a tool with years of community polish over a slicker interface.

Skip terminal agents entirely if you've never used a terminal and want the gentlest possible start — a browser-based tool will be less intimidating for your first project.

For the bigger picture on where OpenCode fits among zero-cost options, see our best free AI coding tools for 2026 roundup. And if you're weighing the other free terminal agents side by side, our Claude Code vs Codex CLI vs Gemini CLI showdown maps out the whole category.