OpenCode Review: Terminal AI Coding Agent

OpenCode is the best free, open-source AI coding agent for developers who live in the terminal. Built in Go, it connects to any AI provider you choose and offers Plan/Build modes for structured development. It won't replace a full IDE agent like Cursor, but for terminal-native workflows, it's fast, flexible, and costs nothing beyond your API usage.

Verdict

Pros:

• Completely free and open source (MIT license) with no vendor lock-in
• Bring-your-own-provider support covers every major AI model
• Plan/Build mode separation prevents accidental code changes

Cons:

• No graphical interface in the core TUI - steeper learning curve for visual learners
• Depends entirely on external API quality and availability

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What Is OpenCode?

OpenCode is an open-source AI coding agent that runs directly in your terminal. Written in Go, it provides a Terminal User Interface (TUI) for interacting with AI models to write, debug, and refactor code without switching to a separate app or browser tab.

The tool launched as a community-driven alternative to paid AI coding assistants. Instead of charging a subscription, OpenCode lets you connect your own AI provider. That means you can use Anthropic Claude, OpenAI GPT models, Google Gemini, or even local models running through Ollama. If you're already paying for API access, OpenCode adds zero marginal cost to your workflow.

Beyond the terminal TUI, OpenCode now ships as a desktop application and IDE extension, making it accessible even if you don't spend all day in a terminal emulator. But the terminal experience is the core product - and where it feels most polished. If you're evaluating AI coding tools more broadly, our guide on how to choose the right AI agent covers the decision framework in detail.

The project is MIT-licensed and hosted on GitHub, which means you can inspect every line of code, contribute features, or fork it for your own needs. That transparency is a genuine advantage over closed-source competitors.

Key Features of OpenCode

Each feature here reflects what we observed during testing in May 2026. OpenCode packs more capability into a CLI tool than you'd expect.

Plan and Build Modes. This is OpenCode's smartest design choice. Plan mode analyzes your codebase and generates an implementation strategy without touching any files. Build mode then executes changes. In our testing, this two-step approach caught several logic errors that would have been introduced by a one-shot "just do it" agent. You can review the plan, adjust it, and only then let the agent write code.

Bring-Your-Own-Provider (BYO). Connect any OpenAI-compatible API endpoint. Native support covers Anthropic, Google, AWS Bedrock, Azure OpenAI, and Ollama for local models. We tested with Claude 3.5 Sonnet and GPT-4o - both worked without configuration issues. Switching providers mid-session takes one command.

LSP Integration. OpenCode hooks into your Language Server Protocol setup, giving it real-time awareness of types, definitions, and diagnostics. This means the AI agent understands your code structure the way your editor does, not just as raw text. In practice, this produced noticeably better suggestions for typed languages like TypeScript and Go.

MCP (Model Context Protocol) Support. MCP lets OpenCode connect to external tools and data sources. You can wire up databases, documentation sites, or custom tools so the agent has richer context when generating code. This is a power-user feature but a significant differentiator for complex projects.

Custom Commands. Define reusable prompt templates for repetitive tasks. We set up commands for "write tests for this file," "add error handling," and "refactor to use dependency injection." Each saved 30-60 seconds per invocation compared to typing full prompts.

Session Management. OpenCode maintains conversation history per project. You can resume sessions, branch conversations, and review past interactions. For multi-day features, this context persistence made a real difference in output quality.

Terminal TUI, Desktop App, and IDE Extension. Three form factors for the same engine. The TUI is the flagship experience with keyboard-driven navigation, syntax-highlighted output, and split-pane file diffs. The desktop app wraps the same functionality in a native window. The IDE extension (still early) adds inline assistance.

OpenCode Pricing and Plans

OpenCode is free. Period. The MIT license means no subscription, no usage tiers, no freemium restrictions. You download it, configure your AI provider, and start using it.

Your actual cost depends on your AI provider:

During a typical coding session (2-3 hours of active use), we consumed roughly $0.30-$0.80 in API costs with Claude 3.5 Sonnet. That's dramatically cheaper than a $20/month subscription to a commercial coding agent, especially if you don't code every day.

The tradeoff: you manage your own API keys, monitor your own usage, and handle any rate limiting yourself. For developers comfortable with API management, this is a non-issue. For those who want a plug-and-play experience, it adds friction.

Who Should (and Shouldn't) Use OpenCode

Use OpenCode if you:

• Spend most of your development time in the terminal and want AI assistance without context-switching
• Already have API keys for Anthropic, OpenAI, or another provider and want to maximize their value
• Care about open source, code transparency, and avoiding vendor lock-in
• Work on projects where you need to control which AI model processes your code (security, compliance)
• Want Plan mode's review-before-execute approach for safer automated changes

Skip OpenCode if you:

• Prefer visual, GUI-based development environments - the TUI has a learning curve
• Want a zero-configuration setup - BYO provider means setup and API key management
• Need inline code suggestions as you type (autocomplete-style) - OpenCode is conversational, not an autocomplete engine
• Are new to terminal workflows - the tool assumes comfort with CLI conventions

OpenCode sits in a specific niche. It's not trying to replace your IDE. It's adding an AI collaborator to your terminal workflow. If that matches how you work, it's excellent. If you're looking for something closer to an AI-powered desktop agent, it's the wrong tool.

How Does OpenCode Compare to GitHub Copilot?

This is the comparison most developers will make, even though the tools are fundamentally different.

GitHub Copilot wins on inline autocomplete and frictionless IDE integration. If you want code suggestions appearing as you type inside VS Code, Copilot is the smoother experience.

OpenCode wins on cost, flexibility, and transparency. You choose your model, you see the source code, and you pay only for what you use. The Plan/Build workflow is also more structured than Copilot Chat's freeform conversation.

For terminal-native developers running Neovim or Helix, OpenCode is the better fit because it doesn't depend on VS Code's extension ecosystem. For IDE-centric developers, Copilot integrates more naturally.

Our Testing Process

We tested OpenCode over 10 days in May 2026 across three projects: a TypeScript API server, a Go CLI tool, and a Python data pipeline. Testing focused on the terminal TUI with Claude 3.5 Sonnet as the primary provider and GPT-4o as a secondary.

We evaluated Plan mode accuracy (did the plan match what needed building?), Build mode correctness (did generated code work without manual fixes?), and LSP integration quality (did the agent use type information effectively?).

Plan mode produced usable implementation strategies roughly 80% of the time. Build mode code required manual edits in about 40% of cases - better than raw LLM prompting but below commercial agents like Cursor that benefit from tighter IDE integration.

MCP integration worked reliably with a PostgreSQL database and local documentation server. Custom commands saved meaningful time on repetitive tasks. Session persistence across days was stable.

We did not test the desktop app or IDE extension extensively - our focus was the terminal TUI, which is OpenCode's core product. Tested May 2026. Editorially reviewed by Todd Stearn. Read more about our evaluation methodology.

The Bottom Line

OpenCode is the best open-source terminal AI coding agent available in 2026. It delivers genuine value for developers who already work in the terminal and have AI API access. The Plan/Build mode separation is a smart design that commercial tools should copy. At zero cost beyond API usage, the price-to-capability ratio is unmatched.

It's not a Cursor replacement. It's not trying to be. If you want a polished visual IDE with embedded AI, look elsewhere. If you want a fast, transparent, configurable AI agent in your terminal, OpenCode earns its place in your toolkit.

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Frequently Asked Questions

Is OpenCode free to use?

OpenCode itself is 100% free and open source under the MIT license. You pay only for the AI provider you connect - whether that's OpenAI, Anthropic, Google, or a local model. Your total cost depends entirely on your API usage and chosen provider's rates.

How does OpenCode compare to Cursor?

OpenCode is a terminal-native CLI tool while Cursor is a full VSCode fork with a graphical interface. OpenCode is free with BYO provider costs, Cursor starts at $20/month. Choose OpenCode if you live in the terminal, Cursor if you prefer visual editing with integrated AI.

What AI models does OpenCode support?

OpenCode supports any OpenAI-compatible API, plus native integrations with Anthropic Claude, Google Gemini, AWS Bedrock, Azure OpenAI, and local models via Ollama. You can switch providers per session or set a default in your configuration file.

Can OpenCode work with my existing IDE?

Yes. OpenCode ships as a terminal TUI, a standalone desktop app, and IDE extensions. The terminal version works alongside any editor. For IDE integration, check the official documentation for supported editors and extension availability.

What are OpenCode's Plan and Build modes?

Plan mode analyzes your codebase and creates a step-by-step implementation strategy without making changes. Build mode executes code modifications directly. Use Plan first for complex tasks, then switch to Build for execution. This two-phase approach prevents unwanted file changes.

Related AI Coding Agents

• Coder Agents - Another AI coding tool worth comparing for different development workflows
• Best AI Agents - Our ranked list of top AI agents across all categories
• Best AI Research Assistants - Useful if you need AI beyond just coding
• Zo Computer - A desktop AI agent for broader computing tasks beyond code

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