jnsahaj/lumen

Beautiful git diff viewer, generate commits with AI, get summary of changes, all from the CLI

What it solves

Lumen is a fast terminal-based user interface (TUI) for viewing code diffs and conducting code reviews. It eliminates the need to leave the terminal to review git diff, commits, branches, or GitHub Pull Requests side-by-side, providing a high-performance experience even with very large diffs.

How it works

Written in Rust, Lumen provides an interactive side-by-side viewer with tree-sitter syntax highlighting. It integrates with Git and Jujutsu (jj) and supports various review workflows, including a "stacked" mode for reviewing commits one by one. Users can annotate selections, hunks, or entire files, and these annotations can be exported or sent back to coding agents.

Who it’s for

Developers who prefer terminal-centric workflows and want a fast, visual way to review code changes without switching to a GitHub web interface or a GUI tool.

Highlights

  • Side-by-side Diff Viewer: High-performance TUI with syntax highlighting.
  • GitHub PR Integration: Review and mark files as viewed directly from the terminal using lumen diff --pr.
  • AI-Powered Helpers: Optional integration with 10+ AI providers to generate commit messages, explain changes, and generate Git commands from natural language.
  • Coding Agent Surface: Acts as a review surface for AI coding agents (like Claude Code or Codex), allowing users to annotate diffs and send feedback directly back to the agent via stdout.
  • Stacked Commit Review: Navigate through a range of commits individually while preserving progress.
  • Flexible Configuration: Supports themes, project-specific settings, and multiple AI provider configurations.

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