slice

Review pull requests in your terminal, one behavioral slice at a time.

slice groups a diff by what each change does — the migration, model, controller, view, and spec that make one feature work — instead of by directory. Add --ai and Claude Code reads your repo to explain the change, walk you through it, and flag problems on the lines where they occur.

Why slice

• Review work before it's pushed. slice -w shows your uncommitted changes and updates live as you or an agent edit, so you can review as the work happens, not after a PR exists.
• The analysis sits next to the code. Slices, a walkthrough, key decisions, and findings appear beside the diff they describe. You never have to switch between a chat window and the code.
• Keyboard first. Every action is a key or two away: move between slices, jump between findings, mark files read, switch to split view.
• Finish the review where you started it. Comment on lines, then approve, comment, or request changes, all posted to GitHub without opening a browser.

Install

npm install -g @gavinomelia/slice

pnpm add -g @gavinomelia/slice

Requires Node 22+, macOS or Linux (Windows via WSL), and the GitHub CLI, authenticated. --ai also needs Claude Code. No API key is needed: the analysis runs through your existing Claude Code session.

Usage

slice              # the PR for the current branch, or the branch diff
slice 1679         # PR #1679
slice my-branch    # that branch's PR, or the branch diff if it has none
slice --branch     # the local branch against its base, ignoring any PR
slice -w           # uncommitted work, updated live as files change
slice --ai         # add the AI review: slices, walkthrough, findings
slice -p "..."     # the AI review, with an extra instruction for this run
slice -m opus      # analyze with this model, via --ai or the a key

By default, slice opens the diff without running a model. Press a in the viewer to analyze it without reopening, or pass --ai to start right away. Once a review has been analyzed, running slice again reopens that analysis. --refresh runs it again.

Keys

Press ? in slice to see every key. The essentials:

Key	Action
1 2 3 tab	focus slices / diff / findings
j k ↑ ↓	move; space b page
h l ← →	scroll the diff sideways; 0 back to the start
[ ]	previous / next slice
n p	next / previous finding
v	toggle unified / split diff
z	zoom the diff to full screen
x	mark the file, or the whole slice, as read
c	comment on the cursor line (H L pick the side in split view)
s A R	submit as comment / approve / request changes
y Y	copy findings here, or all of them, as a fix prompt
a	run the AI analysis in the background
r	reload the diff (-w also reloads on its own)
drag	select text within one pane and copy it; shift-drag for the terminal's own selection
?	show all keys
q	quit

c, s, A, and R open $EDITOR. Drafts are kept until you submit them, and saving an empty file cancels. y copies a prompt you can hand to any coding agent.

How the AI review works

Claude Code reads your repo with read-only tools (Read, Grep, Glob), so it can follow callers and check your conventions (.github/instructions/*.md, docs/CONVENTIONS.md) rather than judging the diff in isolation. Each finding is checked against the patch. Findings that point outside the diff are dropped or demoted.

A PR is someone else's input, so the analysis gets no write, execute, or network tools. A repo's config can't change that. Only your own config can.

Configuration

slice --init-config        # .slice.jsonc in the repo: how code is reviewed
slice --init-config user   # ~/.config/slice/config.jsonc: how slice looks
slice --print-config       # the resolved config and where it came from

// .slice.jsonc — committed with the repo
{
  "review": {
    "slicing": "Treat anything under db/migrate as its own slice.",
    "instructions": "Ignore anything under vendor/.",
    "severities": { "nit": null }
  }
}

// ~/.config/slice/config.jsonc — yours only
{
  "review": { "model": "opus", "effort": "medium" },
  "theme": { "preset": "dark", "syntax": "tokyo-night" },
  "layout": { "diffView": "split" }
}

Config is JSONC rather than JavaScript, so checking out a branch can never run code. allowedTools, promptFile, provider, model, and effort are only read from your own config. slice warns if a repo tries to set them.

Reading markdown

Changed .md, .markdown, .mmd, and .mermaid files in a review open rendered, with a mark in the gutter beside each block that changed. Press m to switch to the file's diff, which is where line comments go.

Mermaid flowcharts, sequence, state, class, ER, and XY diagrams are drawn as text. Other types, and anything too large to draw quickly, stay as source.

slice README.md renders a markdown or mermaid file in the terminal, with tables, syntax highlighted code, and your theme. It needs no git, gh, or model. Piped, it prints the rendered text instead, so slice README.md | less works too.

Cache

Patches, analyses, drafts, and read marks live in $XDG_CACHE_HOME/slice/ (default ~/.cache/slice/), never in the repo. slice --clear-cache removes them. slice --open <file>.review.json reopens a cached review without git or a model.

Development

npm install
npm test          # node:test
npm run format    # prettier

bin/slice.mjs resolves the target and runs the analysis, src/pipeline/ is the only code that talks to gh, git, or the model, src/viewer/ is the terminal UI (Ink), and src/config/ holds the defaults, themes, and config loader. Set SLICE_DEBUG=1 to see stack traces.

License

MIT

Credits

Diff parsing and syntax highlighting come from @pierre/diffs by Pierre Computer Company, used under the Apache License 2.0.

Markdown parsing comes from markdown-exit, and Mermaid drawing from beautiful-mermaid, both used under the MIT License.