jj (Jujutsu) — Version Control for Agent Workflows

jj is a version control tool that coexists with Git. You use jj locally; the remote is still standard Git. GitHub and collaborators see ordinary git commits and branches.

This skill teaches you how to use jj correctly and idiomatically, especially in agent-assisted development workflows.

Core Mental Model

jj revolves around changes, not branches. Key differences from Git:

• No staging area. File modifications are automatically part of the current change. There is no git add.
• No stash. Just jj new to start fresh work; previous changes stay where they are.
• No detached HEAD. jj edit lets you jump to any change and keep working; descendants auto-rebase.
• Branches are called bookmarks and are only needed when pushing to a remote.

The working copy IS a change. Every file modification is instantly tracked in the current change.

Detecting a jj Repo