chunk

chunk is a terminal diff reviewer for Git repositories. It shows a tree file list beside a syntax-highlighted unified diff, with live worktree refresh, file/hunk staging, guarded discard actions, mouse support, and optional AI actions through OpenCode, Claude Code, or Codex.

Requirements

• Rust 2024 toolchain
• Git
• OpenCode, Claude Code, or Codex for Ask AI actions
• A Nerd Font for file/status glyphs

Usage

Run inside a Git worktree:

cargo run -- diff       # live worktree review; also the default command
cargo run -- pr [base]  # branch review from merge-base(base, HEAD) to HEAD
cargo run -- diff --json

diff reviews staged, unstaged, mixed, and untracked changes against HEAD and live-refreshes as the worktree changes.

pr is read-only: no live refresh, staging, or discard. Without a base ref it tries origin/HEAD, then main, then master.

diff --json prints one worktree snapshot for external frontends instead of starting the terminal UI. The output includes title, source_label, and files; each file includes paths, status, stage, line counts, binary state, and hunks with stable old/new ranges and diff lines.

Controls

These are the default keys. Most single-character actions can be remapped in [keybinds]; special keys and Ctrl-* combos stay fixed.

Keys	Action
j / k	Move in the focused list or scroll the diff
Tab / Shift-Tab, Left, Right, Enter	Change focus between panes
f	Toggle the file list
/, n, N	Search the selected file; jump next/previous match or hunk
PageDown / Ctrl-d, PageUp / Ctrl-u	Page the diff
g / Home, G / End	Jump to top or bottom
?	Toggle in-app help
a, x, u	Ask AI, explain selection, or summarize unpublished changes
F2	Configure the AI harness, model, and effort; persist to config.toml
y, Y	Copy the focused path, branch, commit, or hunk; or the selected file diff
r	Toggle reviewed state for the selected file
Space	Stage/unstage the selected file or hunk in diff mode
d	Discard unstaged file/folder/hunk changes after confirmation in diff mode
e	Open the selected file in $EDITOR near its first changed line
Custom command keys	Run configured shell commands from the Git root
q / Ctrl-c	Quit

Mouse hover changes focus. Click files, folders, branches, commits, and hunks to select or expand them; use the wheel to move or scroll the pointed pane. Drag visible text to copy it.

Command output and Ask AI panes use the same scroll keys; close them with Esc or q. Ask AI answers can be copied with y.

Configuration

chunk reads ${XDG_CONFIG_HOME:-$HOME/.config}/chunk/config.toml when it exists.

theme = "github-dark"
harness = "codex"
opencode_model = "opencode/claude-fable-5"
opencode_variant = "xhigh"
claude_model = "fable"
claude_effort = "xhigh"
codex_model = "gpt-5.6-sol"
codex_effort = "high"

[keybinds]
quit = "Q"
discard = "D"

[[commands]]
key = "C"
label = "commit and push"
command = "git add . && com && git push"

Supported themes are gruvbox (default) and github-dark.

Supported AI harnesses are opencode (default), claude-code, and codex. Press F2 to configure and persist separate model/effort profiles for each:

• OpenCode uses provider/model names and calls effort a model variant. Presets include current Claude 5 and GPT-5.6 models; custom config values are also accepted because available models and variants are provider-specific.
• Claude Code presets use its rolling fable, best, opus, sonnet, and haiku aliases. Its effort names are low, medium, high, xhigh, and max.
• Codex presets are gpt-5.6-sol, gpt-5.6-terra, and gpt-5.6-luna. Its picker uses low, medium, high, xhigh, max, and, where supported, ultra.

Leaving a model or effort unset inherits that harness's own default.

Keybind values must be single characters; use a literal space for Space. Unknown actions, invalid keys, conflicting keys, and duplicate custom command keys are rejected at startup. Remapping a built-in frees its default key for a custom command.

Custom commands run from the Git root through the user shell. After they finish, chunk shows stdout, stderr, and exit status, then reloads the review source.

Development

cargo fmt --check
cargo test
cargo clippy --all-targets -- -D warnings