Committing with Jujutsu (jj)

Manages the commit workflow for repositories using the Jujutsu version control system.

Pre-check: Detect VCS

Before doing anything, check if the repo uses jj by running jj root in the workspace root.

• •If it succeeds, proceed with this skill.
• •If it fails (not a jj repo), fall back to regular git commands instead and do NOT follow the rest of this skill.

Key Concepts

• •In jj, the working copy is always part of a change (no staging area).
• •Changes are mutable until they become immutable (e.g., merged to main).
• •jj commit = jj describe + jj new (describe the current change and start a new one).
• •jj describe updates the description without creating a new change.
• •Bookmarks are jj's equivalent of Git branches.

Workflow

1. •

   Check the repository state. Run jj status to see what files are modified and the current change.

2. •

   Show the current log. Run jj log --limit 10 to understand where the working copy (@) is in the change graph.

3. •

   Review the diff. Run jj diff to see what changes are in the current working copy change.

4. •

   Determine the commit action based on the user's request:

   User wants to...	Command
   Finalize current change with a message and start a new one	jj commit -m "message"
   Set/update description without starting a new change	jj describe -m "message"
   Describe a specific revision	jj describe -r <rev> -m "message"
   Split current change into multiple changes	jj split (interactive) or jj split <files>
   Create a new empty change on top of current	jj new
   Create a new change with a message	jj new -m "message"
   Create a new change inserted after a specific revision	jj new -A <rev>
   Create a new change inserted before a specific revision	jj new -B <rev>

5. •

   Do not push any changes to remote

6. •

   Verify the result. Run jj log --limit 5 to confirm the commit graph looks correct.

Commit Message Guidelines

When generating commit messages:

• •Use conventional commit format if the project uses it (check existing log with jj log --limit 20).
• •First line: imperative mood, max 72 characters.
• •If the diff is large, include a blank line then a body explaining the "why".
• •If it's a bug fix, include the root causes, and the fix.
• •Do NOT include jj change IDs or revision IDs in the message.

Common Patterns

Amend a previous change

jj describe -r <rev> -m "updated message"

Rules

• •Always run jj status first to understand the current state.
• •Never force-push or delete remote bookmarks unless explicitly asked.
• •If the working copy is empty (no diff), inform the user — do not create empty commits unless asked.
• •Prefer jj describe over jj commit when the user just wants to set a message on the current change.
• •When the user says "commit", use jj commit -m "..." (which finalizes and starts a new change).
• •When the user says "describe", use jj describe -m "..." (which only sets the message).
• •Always show the result with jj log after committing.