OpenCode

Learning Objectives

• Understand what OpenCode is and how it differs from coding agents tied to one model vendor
• Know what is free, what Anomaly charges for, and where your API keys live in each setup
• Decide when OpenCode is a better fit than Claude Code, Codex or Cursor, and when it is not

What Is OpenCode?

OpenCode is an open-source AI coding agent built by Anomaly. Like Claude Code or OpenAI's Codex, it reads a codebase, plans changes, edits files and runs commands, asking for permission along the way. Unlike them, it is not tied to one model maker. It connects to models from more than 75 providers through the Models.dev catalog, including local models, and lets you sign in with an existing GitHub Copilot or ChatGPT Plus or Pro subscription.

The code is released under the MIT license, a permissive open-source license that allows commercial use. The project started in April 2025 and has grown into one of the most popular developer tools on GitHub, with more than 200,000 stars. Anomaly says more than 16 million developers use it each month, a figure it has not broken down.

OpenCode runs in three places: a full-screen terminal interface, a desktop app, and an IDE extension, with an installable web app added in October 2026.

OpenCode 2

OpenCode 2, which became the main release line in October 2026, rebuilt the app around a single background service that the terminal, desktop and web apps all share, so a session started in one can be picked up in another. The New Stack described it as a major overhaul. According to coverage of the release, it added background subagents that keep working while you do something else, a Code Mode that lets the agent chain several tool calls in one script, and a rebuilt API with a software development kit for embedding OpenCode in other tools. The upgrade breaks plugins written for version 1, so check your plugins before moving over.

Pricing

The agent itself costs nothing. What you pay for is the model behind it. You can bring your own key from any supported provider, use a subscription you already have, or buy access through Anomaly. The Console is pay as you go, and Anomaly says it sells at cost, adding only payment-processing fees. It also lists several models as free for a limited time.

The October 2026 Console Breach

In October 2026 OpenCode said attackers broke into an older part of the Console and reached the API keys stored by 1.4 percent of Console users, in what the company called a large-scale distillation attack. Developers reported surprise charges on their OpenAI, Anthropic and Google accounts, some above a thousand dollars. Anthropic and Google blocked the exposed keys, OpenAI refunded its affected customers, and OpenCode began issuing refunds. The open-source app was not affected, because keys you set locally never pass through Anomaly's servers.

The episode also showed a problem defenders now share. Co-founder Dax Raad said the AI models his team used to analyze the attack started refusing once the malicious code tripped their safety filters, until OpenAI granted access to its Daybreak Blue program for vetted security teams.

Strengths

• Model choice: more than 75 providers and local models, so you can switch models per task without switching tools
• Open source: the MIT license lets you read, modify and self-host the agent, and keep its code if Anomaly changes direction
• Uses subscriptions you already pay for: sign in with GitHub Copilot or ChatGPT instead of buying API credits
• Runs everywhere you work: terminal, desktop app, IDE extension and web app share one session service in version 2
• Low entry price: the Go plan gives access to a curated set of models for 10 dollars a month

Limitations and Considerations

• Results depend on the model you pick: OpenCode is a harness, not a model. A cheap model in OpenCode will not match Claude Code running Anthropic's best model
• Security is partly on you: the October 2026 Console breach exposed stored keys. Local keys were safe, but any hosted place you store credentials becomes a target
• Fast-moving and sometimes breaking: releases ship almost daily, and the move to version 2 broke version 1 plugins
• Usage claims are the company's own: the 16 million monthly developers figure is not independently measured
• Enterprise terms are not public: larger teams need to talk to sales for administration and support

Best Use Cases

• Teams that want one agent across many models, such as routing routine work to a cheap model and hard problems to a frontier one
• Developers who already pay for GitHub Copilot or ChatGPT and want an agent without a second subscription
• Privacy-sensitive work with local models, where nothing leaves the machine
• Building on top of an agent, using the version 2 API and software development kit

Getting Started

1. Install OpenCode from opencode.ai, or download the desktop app
2. Run it inside a project folder and connect a model, either by signing in to an existing subscription or by adding an API key
3. Start with a small, well-defined task and review each change before accepting it
4. Set spending limits on any provider account the agent can use before running long tasks

Key Takeaways

• OpenCode is a free, MIT-licensed coding agent from Anomaly that works with more than 75 model providers, including local models
• It runs in the terminal, as a desktop app, in an IDE and on the web; OpenCode 2 ties them to one shared background service
• Anomaly charges only for model access: OpenCode Go at 10 dollars a month, Go Plus at 40 dollars, and a pay-as-you-go Console
• In October 2026 attackers reached API keys stored by 1.4 percent of Console users; the open-source app and locally stored keys were not affected
• The agent is only as good as the model you choose, so it competes on flexibility and price rather than on raw capability