
Anomaly · Open-Source AI Coding Agent for the Terminal
An open-source AI coding agent built by the team behind SST. Runs in the terminal, desktop app, or as an IDE panel — and works with any of 75+ LLM providers. Uses a multi-agent architecture with Build and Plan modes for controlled or fully autonomous code editing.
Best for
Developers who want a terminal-based AI coding agent with no vendor lock-in, the ability to bring any LLM provider, and undo control over agent file changes
Not ideal for
Developers who want deep IDE integration with inline autocomplete and minimal configuration — Cursor or Windsurf provide a more polished out-of-the-box experience
Who it's for
Developers who want a model-agnostic, terminal-first AI coding agent without IDE or vendor lock-in
OpenCode's core bet is that developer tooling should not be locked to a single model provider or IDE vendor. The Build/Plan agent split is well-designed: Plan mode lets you reason about what to change before anything is written, which is genuinely useful on complex refactors where you want to validate the approach first. The file snapshot system means you can safely let the agent run a multi-file edit and undo the whole thing if the output misses the mark. The trade-off is real: OpenCode does not have the polished, zero-configuration feel of Cursor, and it does not provide ambient tab-complete suggestions like Copilot. If you value portability and model flexibility over out-of-the-box experience, OpenCode fits well. If you want the fastest path to AI-assisted coding with minimal setup, Cursor or Windsurf will serve you better.
Who should use it
Developers who work primarily in the terminal, want to choose their own LLM provider, or need an open-source coding agent they can audit, customize, and run fully air-gapped with local models.
Who should skip it
Developers who want deep IDE-native AI integration with inline autocomplete and a polished out-of-the-box experience — Cursor or Windsurf are better fits for that workflow.
OpenCode
Free
OpenCode Zen
Low cost (see opencode.ai)
Note: The core tool is always free. API costs are billed directly by your chosen LLM provider. OpenCode Zen is Anomaly's managed model subscription option for users who prefer not to manage provider keys.
Modalities
Text, Code, Image (attachment for visual context)
Available models
Multi-file refactoring from the terminal
Build mode edits across multiple files and runs shell commands in sequence — useful for refactors that span a module boundary or require coordinated changes a single-file prompt cannot handle.
Architecture planning before writing code
Plan mode is read-only and requires explicit approval before any file is written. Useful for reasoning through a design decision and reviewing a proposed approach before the agent makes changes.
Air-gapped or privacy-sensitive coding workflows
With Ollama, OpenCode runs entirely on local hardware with no data leaving your machine — practical for environments where sending code to cloud APIs is restricted or prohibited.
Reusing an existing Copilot or ChatGPT subscription
OpenCode supports GitHub Copilot and ChatGPT Plus/Pro as backing models via passthrough — useful if you already subscribe and want to avoid paying separately for another AI coding tool.
OpenCode vs. Cursor
Cursor is a full VS Code fork with deep editor-level integration: inline AI suggestions, multi-file Composer edits, and background cloud agents that return PRs. OpenCode is a terminal agent that works alongside any editor as a floating panel but does not replace it. Cursor provides a more polished, lower-friction experience; OpenCode gives model flexibility and no IDE lock-in.
OpenCode vs. GitHub Copilot
GitHub Copilot is primarily an inline autocomplete and chat tool tightly integrated with the GitHub ecosystem. OpenCode is a full agentic system that executes multi-step tasks, edits files, and runs shell commands. Copilot is always-present in the editor and easier to start with; OpenCode handles deeper agentic tasks but requires deliberate invocation.
OpenCode vs. Aider
Both are terminal-based and model-agnostic, but Aider is Python-based with a focus on git-diff workflows and stronger git-native operations. OpenCode has a richer TUI, desktop app, IDE panel extensions, a multi-agent system, and MCP support. Choose Aider for a minimal git-focused workflow; choose OpenCode for a richer feature set and broader integration surface.
Is OpenCode free to use?
Yes. The tool itself is free and open source under the MIT license. You pay only for the LLM API provider you connect — or use local models via Ollama at no API cost.
Can OpenCode replace Cursor?
They solve related but different problems. Cursor is a full AI-native IDE with inline suggestions, deep editor integration, and cloud background agents. OpenCode is a terminal-first coding agent that augments your existing editor as a floating panel. If you want a polished AI-first IDE, use Cursor. If you want a flexible, open-source agent that works with any editor and any LLM, OpenCode fits better.
Does OpenCode work with GitHub Copilot?
Yes. OpenCode supports GitHub Copilot as a backing model via subscription passthrough — you can reuse an existing Copilot subscription instead of paying for a separate API key.
What is the difference between Build mode and Plan mode?
Build mode gives the agent full access to edit files and run shell commands. Plan mode is read-only — the agent can analyze code and reason about what to change, but cannot write files or run commands without your explicit approval. Plan mode is useful for reviewing a proposed approach before committing to changes.
Can OpenCode run without an internet connection?
Yes, if you use a local model via Ollama or another local inference server. In that configuration, all inference runs on your own hardware with no network calls to external APIs.
Anysphere
VS Code developers who want multi-file AI editing, autonomous background agents, and model flexibility — not a plugin layered on top of an existing editor
FreemiumGitHub (Microsoft)
Developers on GitHub who want AI autocomplete and PR summaries embedded in their existing IDE
PaidExafunction
Developers wanting free, fast AI autocomplete in their existing IDE without switching tools
FreemiumCodeium
Developers who want an AI agent that can autonomously plan and execute larger coding tasks
FreemiumOpenCode is a terminal-first coding agent with no account lock-in and no required proprietary model. Connect it to any LLM via 75+ provider integrations — including GitHub Copilot or ChatGPT Plus as a passthrough subscription, or local models via Ollama for fully air-gapped workflows. It uses a multi-agent system: the Build agent has full file-edit and bash access; the Plan agent is read-only for architecture analysis; three specialized subagents (General, Explore, Scout) handle delegated subtasks. A file snapshot system lets you undo agent changes step by step. OpenCode installs as a floating panel inside VS Code, Cursor, and Windsurf via IDE extensions, but it does not replace those editors — it augments them. The main tradeoff versus tools like Cursor is that OpenCode requires more configuration and lacks deep editor-native features like inline autocomplete or tab-complete suggestions.
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