lumen
Beautiful git diff viewer, generate commits with AI, get summary of changes, all from the CLI
Lumen is a terminal-based git diff viewer and code review TUI written in Rust that doubles as a Claude Code plugin for AI-assisted code review workflows. It provides side-by-side diff visualization with syntax highlighting, AI-powered commit message generation, and the ability to review GitHub pull requests directly from the command line. The tool integrates seamlessly with coding agents like Claude Code and Codex by allowing developers to annotate changes inline and send feedback back to the agent via stdin/stdout, creating an interactive review loop where the agent can address comments automatically.
Key Features
Use Cases
- 01Reviewing large git diffs or GitHub pull requests in a fast, terminal-based interface
- 02Generating meaningful commit messages automatically based on staged changes with optional context
- 03Annotating code changes during AI agent sessions and feeding corrections back for automated fixes
- 04Understanding complex code changes by asking AI to explain specific commits or ranges
- 05Comparing branches side-by-side with file filtering and stacked commit navigation
- 06Integrating code review workflows into Claude Code, Codex, or other shell-enabled coding agents
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lumen — FAQ
What is lumen and how does it work with Claude Code?+
Lumen is a Rust-based terminal diff viewer and code review tool that acts as a Claude Code plugin through shell-escape commands. You trigger it with `!lumen diff` from Claude Code, annotate changes inline, and press 's' to send your review comments back to the agent as its next prompt via stdout.
How do I install lumen?+
Install lumen using Homebrew with `brew install jnsahaj/lumen/lumen` on macOS/Linux, or via Cargo with `cargo install lumen` if you have Rust installed. Git is required; fzf and mdcat are optional for enhanced list selection and formatted output.
Which AI coding agents and clients does lumen support?+
Lumen works with Claude Code, Codex, and any agent with shell access or shell-escape capabilities. It integrates through standard stdin/stdout, so no special plugins or extensions are needed beyond shell command execution.
Do I need an API key to use lumen's AI features?+
The diff viewer works without any API key. AI features like commit message generation and change explanations require configuring an AI provider (OpenAI, Claude, Gemini, Groq, DeepSeek, xAI, OpenRouter, Vercel) with an API key, except for Ollama which runs locally. Run `lumen configure` to set up your provider interactively.
Is lumen free to use?+
Yes, lumen itself is free and open-source. However, AI features may incur costs depending on your chosen provider; some providers like Groq offer free tiers, and Ollama runs entirely locally at no cost.
Can I review GitHub pull requests with lumen?+
Yes, use `lumen diff --pr 123` or paste a full PR URL to review GitHub pull requests in the terminal. You can mark files as viewed (syncs with GitHub) using the space key, and navigate commits in stacked mode.
How do I install lumen?+
Open the source repository on GitHub and follow its README. lumen is a plugin — MCP Agents Market links you directly to the official repo.
Is lumen free?+
lumen is an open-source project hosted on GitHub. Check the repository for its license and any usage requirements.