Codiff

Codiff is a beautiful, minimal, local diff viewer for reviewing Git changes and committing them.

Why Codiff

• Fast Local Reviews: Review and commit changes in any Git repository.
• LLM Walkthroughs: Run codiff -w to generate an optimized commit walkthrough.
• Inline Review Comments: Comment directly on Pull Requests or copy review comments as Markdown for follow-ups.

Download

Install with Homebrew:

brew install --cask nkzw-tech/tap/codiff

Download the latest Codiff app from GitHub Releases.

After installing the app, run Codiff > Install Terminal Helper to make the codiff command available in your shell.

Command Line

codiff

Run it from any Git repository, or pass a path:

codiff /path/to/repository

Review a specific commit:

codiff a1b2c3d

Review the current branch against a target branch:

codiff main

Start with an LLM-generated narrative walkthrough:

codiff -w
codiff -w a1b2c3d

Show all available options:

codiff --help

Launching Codiff in multiple repositories opens a separate native window for each repository.

Command Bar

Open the command bar with Cmd+Shift+P on macOS, or Ctrl+Shift+P on other platforms. Type to filter commands, use Up/Down to move through results, press Enter to run the selected command, and press Esc to close it.

The command bar includes actions for common review workflows:

• Focus File Filter
• Find in Diffs
• Show File Tree, Show History, and Show Walkthrough
• Copy Review Comments
• Copy Review Comments and Close
• Toggle Viewed for the currently selected file
• Toggle Diff Layout, with the target layout action shown as the hint
• Open the currently selected file in your editor
• Toggle Sidebar
• Reload Window

Configuration

Codiff reads configuration from ~/.codiff/codiff.jsonc. Open Codiff > Open Config File... to create the file with defaults and open it in your editor. The file supports JSONC comments and trailing commas, includes a JSON schema reference for editor completion, and is watched while Codiff is running so changes apply to open windows.

{
  "$schema": "https://raw.githubusercontent.com/nkzw-tech/codiff/main/src/config/codiff-config.schema.json",
  "settings": {
    "agentBackend": "codex",
    "claudeModel": "claude-sonnet-4-6",
    "codeFontFamily": "",
    "codeFontSize": 13,
    "copyCommentsOnClose": false,
    "diffStyle": "split",
    "editorCommand": "",
    "lastRepositoryPath": "",
    "openAIModel": "gpt-5.3-codex-spark",
    "showWhitespace": false,
    "theme": "system",
    "wordWrap": false,
  },
  "keymap": {
    "commandBar": "Mod+Shift+p",
    "diffSearch": "Mod+f",
    "fileFilter": "Mod+p",
    "nextSearchMatch": "Enter",
    "openFile": "Mod+k",
    "prevSearchMatch": "Shift+Enter",
    "closeSearch": "Escape",
    "submitComment": "Mod+Enter",
    "discardComment": "Escape",
    "toggleSidebar": "Mod+b",
  },
}

Set settings.editorCommand to customize file opening. Use {file} for the selected file and {repo} for the repository root, for example "subl \"{repo}\" \"{file}\"".

Choose View > Diff > Split or View > Diff > Unified, use Toggle Diff Layout in the command bar, or set settings.diffStyle to split for side-by-side diffs or unified for unified diffs. Choose View > Diff > Word Wrap, use Toggle Word Wrap in the command bar, or set settings.wordWrap to true to wrap long diff lines. Choose View > Diff > Font Size, use the code font size commands in the command bar, or use Cmd/Ctrl++, Cmd/Ctrl+-, and Cmd/Ctrl+0 to change only diff and code rendering font size. Set settings.codeFontFamily manually to an installed CSS font family name, for example "JetBrains Mono" or "SF Mono". Leave it empty to use Codiff's bundled mono stack. Use Mod for Cmd on macOS and Ctrl on other platforms. Shortcut strings can combine Mod, Ctrl, Alt, Shift, or Meta with a key, for example Mod+Shift+p or Alt+Enter.

Walkthroughs

Codiff uses a local agent CLI for walkthroughs and inline review assistance. It supports two backends, selected with the settings.agentBackend config value (or the --agent flag for a single launch) and the Agent application menu:

• codex (default) — the OpenAI Codex CLI, configured with settings.openAIModel.
• claude — the Claude Code CLI, configured with settings.claudeModel.

Install the backend you want and verify it is available before using codiff -w:

codex --version
claude --version

Codiff looks for the CLI on PATH and the usual install locations. It does not run your shell startup files to discover them. If a CLI is installed somewhere else, launch Codiff with an explicit path:

CODIFF_CODEX_PATH=/absolute/path/to/codex codiff -w
CODIFF_CLAUDE_PATH=/absolute/path/to/claude codiff --agent claude -w

Claude Code rides your existing claude login (subscription or ANTHROPIC_API_KEY); run claude once and complete /login if you have not already.

To drive Codiff from your agent, install its skills from the application menu (Install Codex Skill or Install Claude Code Skill). Codiff updates keep the installed skill current. Invoke it from the agent:

$codiff       /codiff        # author a narrative walkthrough and open Codiff

codiff asks Codiff for the current authoring guide (codiff --walkthrough-guide), writes a narrative walkthrough JSON to a temporary file, and opens Codiff on it with --walkthrough-file plus the current session id. Because the guidance lives in Codiff, the installed skill stays a thin shim while the walkthrough sees the original conversation context without a lossy summary handoff.

Development

vp install
vp build
vpr codiff

For live development:

vpr dev
ELECTRON_RENDERER_URL=http://127.0.0.1:5173 vpr electron

Useful checks:

vp check
vp test
vp build