Local diff reviewer for jj. Review your agent's work in the browser while it runs: visualize the stack of bookmarks you're on top of, click into any bookmark or change to see its diff, and leave line comments that export as agent-ready markdown.

Diffs are rendered with @pierre/diffs, the changed-file tree with @pierre/trees.

bun install
bun index.ts [path-to-repo]   # defaults to cwd; opens the browser

Options: -p/--port N (default: random — the URL is printed on startup), --no-open, --wait (block until review finishes; see below), --no-wait (disable auto-detection).

Agents can block on a human review:

jiffy --wait   # or: bun index.ts <repo> --wait
# approve in the browser        → exit 0
# request changes in the browser → comments on stdout, exit 1

Wait mode also turns on automatically when stdout is piped and CLAUDECODE=1 is set (i.e. when an agent like Claude Code launches jiffy); --no-wait overrides.

• Stack panel — segments of trunk()..@ grouped by bookmark, each with a push-status dot (synced / moved-needs-push / never pushed), a GitHub PR link when one exists, and the changes it contains. Click a segment or a single change to review its diff.
• Live updates — the server polls the jj op log and pushes SSE events; the UI refetches as your agent commits. Reads use --ignore-working-copy so background polling never races the agent for the working-copy lock.
• Line comments — click a line number, write feedback, then copy feedback to get markdown grouped by file with path:line references and the commented source line. Comments persist in .jj/jiffy/comments.json.

index.ts            CLI entry: arg parsing, server boot, browser open
config.toml         revset aliases shipped with jiffy (--config-file on every jj call)
lib/
  exec.ts           argv-array subprocess runner (no shell, no quoting bugs)
  jj.ts             Jj class: zod-validated jj CLI interface, JSON log template
  stack.ts          pure stack segmentation + push status (unit-testable)
  github.ts         gh CLI context (PRs by head bookmark); degrades to null
  comments.ts       CommentStore + agent-markdown export
  server.ts         Bun.serve routes + SSE RepoWatcher
  schema.ts         zod schemas shared by server and client
src/                React frontend (Bun HTML imports — no separate bundler)
test/               bun test suite incl. scripted jj fixture repos
scripts/
  demo-repo.ts      build a throwaway stacked repo for development
  screenshot.ts     drive headless Chrome against a running server

Everything crossing a boundary (jj output, gh output, HTTP payloads) is parsed with zod; the client imports the same schemas the server uses.

bun test                       # unit + integration (creates temp jj repos)
bun run typecheck
bun scripts/demo-repo.ts       # prints a demo repo path to point jiffy at