Jj Workflow

Jujutsu (jj) Workflow

Jujutsu is a modern version control system that provides a simpler mental model than Git while remaining Git-compatible. This skill covers the core concepts and workflow commands.

CRITICAL: Avoid Interactive Mode

Always use -m to prevent jj from opening an editor:

# WRONG — opens editor, blocks AI
jj new
jj describe
jj squash

# CORRECT — non-interactive
jj new -m "message"
jj describe -m "message"
jj squash -m "message"

jj split is inherently interactive — no non-interactive mode exists. Use jj restore --from @- to remove a file from the current change instead.

Core Concepts

Changes vs Commits

• Change: A mutable revision identified by a change ID (e.g., kkmpptxz). Changes can be modified.
• Commit: An immutable snapshot identified by a commit ID (SHA). Once created, commits are permanent.
• The working copy (@) is always a change that can be modified freely.

Working Copy

• The working copy is denoted by @ and represents your current state.
• @- refers to the parent of the working copy.
• Unlike Git, there's no staging area—all changes are automatically tracked.

When to Use What

| Situation | Do This | | --- | --- | | Starting new work | jj new -m "what I'm trying" | | Forgot to start with jj new | jj describe -r @ -m "type: what I'm doing" (do this immediately) | | Change has no description | Run the Description Check Protocol (see below) | | jj git push rejected with "no description set" | jj describe -r -m "type: message" | | Work is done, move on | jj new -m "next task" | | Annotate what you did | jj describe -m "feat: auth" | | Broke something | jj op log → jj op restore | | Undo one file | jj restore --from @- | | Exclude file from current change | jj restore --from @- | | Stop tracking an ignored file | Add ignore rule first, then jj file untrack | | Stop tracking ignored directory contents | Add ignore rule first, then jj file untrack 'glob:dir/**' | | Combine messy commits | jj squash -m "combined message" | | Try something risky | jj new -m "experiment", then jj abandon @ if it fails |

Permission Requirements

CRITICAL: Jujutsu commands require GPG signing and SSH/GitHub authentication. Always request elevated permissions when running jj or gh commands:

required_permissions: ["all"]

Never run jj commands in the default sandbox—they will fail due to authentication requirements.

Essential Commands

Viewing State

jj status          # Show working copy status
jj log             # View commit history
jj diff            # Show uncommitted changes
jj show @          # Show current change details

Creating and Describing Changes

jj new                                # Create a new empty change on top of @
jj describe -r @ -m "feat: message"   # Set commit message for current change (always use -r to target explicitly)
jj new -m "feat: message"             # Create new change with message

Syncing with Remote

jj tug                         # Fetch updates and rebase current change onto latest remote
jj git fetch                   # Fetch from remote without rebasing
jj git push                    # Push current changes to remote (requires description on the change)
jj git push --bookmark   # Push AND set up remote tracking (like git push -u origin )

jj git push will reject changes without descriptions ("no description set"). Always run the Description Check Protocol before pushing. jj git push --bookmark is the unified push+track command — it creates the bookmark on the remote and sets up tracking in one step.

Modifying History

jj squash                        # Squash current change into parent
jj squash --into @-              # Explicitly squash into parent
jj restore --from @-       # Remove a file from current change (non-interactive alternative to split)
jj file untrack            # Stop tracking a path that is already ignored
jj edit               # Edit an existing change

Untracking Ignored Files

Use jj file untrack when a file should stay on disk locally but stop being tracked by jj. This is an ignore-driven workflow: add the path to .gitignore first, then untrack it.

jj file untrack only works for paths that are already ignored, usually via .gitignore or .git/info/exclude in colocated workspaces.

# 1. Add an ignore rule first
echo "local-config.json" >> .gitignore

# 2. Stop tracking the ignored file
jj file untrack local-config.json

# Untrack ignored directory contents with a fileset glob
jj file untrack 'glob:.agents/**'

Use jj restore --from @- when you only want to remove a path from the current change. Use jj file untrack when you want jj to stop tracking an ignored path going forward.

Working with Bookmarks

jj bookmark create  -r @  # Create a bookmark at @
jj bookmark set  -r @     # Move bookmark to @
jj bookmark list                 # List all bookmarks

Working with Workspaces

Workspaces are jj's equivalent of git worktrees — multiple working directories backed by the same repository. Each workspace has its own @ (working copy), enabling true parallel development without branch locking.

jj workspace add           # Create new workspace at path (e.g., ../myproject-fix)
jj workspace list                # List all workspaces with their @ revisions
jj workspace forget        # Stop tracking a workspace (run from another workspace)
jj workspace root                # Print the root path of current workspace
jj workspace update-stale        # Fix a stale working copy after concurrent changes

Key differences from git worktrees:

• No branch locking — multiple workspaces can check out the same revision simultaneously
• Each workspace gets its own @ change automatically on creation
• Changes made in one workspace don't affect another's @

Commit Message Format

Use Conventional Commits format:

• feat: — New feature
• fix: — Bug fix
• refactor: — Code change that neither fixes a bug nor adds a feature
• perf: — Performance improvement
• docs: — Documentation changes
• chore: — Maintenance tasks
• test: — Adding or updating tests

Examples:

jj describe -r @ -m "feat: add user authentication"
jj describe -r @ -m "fix: resolve null pointer in parser"
jj describe -r @ -m "refactor: extract validation logic"

Description Check Protocol

Always run this protocol before pushing or creating a PR. jj git push rejects changes without descriptions. This is a hard requirement, not a quality preference.

Step 1: Check if a description exists

# Check the first line (used as PR title)
jj log -r  -T description --no-graph | head -1

# If first line is blank, check for an existing body
jj log -r  -T description --no-graph | tail -n +2

Gate logic:

• First line is non-empty: The change has a meaningful description — stop here. Do not overwrite.
• First line is blank AND no body: Proceed to Step 2 to generate a full description.
• First line is blank BUT body exists: Generate a title only, then prepend it to the existing body using jj describe --stdin (see Step 5). Never use -m in this case — it would replace the body.

Step 2: Pick the right change

Default to @ (working copy), but verify with jj status first:

• If @ has modified files, use @.
• If @ has no modified files (fresh "next task" placeholder), check @- before using it:

# Check if @- has actual work
jj diff -r @-

# Check @- bookmarks for trunk markers
jj log -r @- -T 'bookmarks' --no-graph

Safety gate — stop and ask the user if ANY of these are true:

• @- has an empty diff (nothing to describe)
• @- carries a trunk bookmark (main, master, or any bookmark with @origin suffix like main@origin)
• @- has no bookmark AND no diff (ambiguous — could be a bare trunk ancestor)

Only proceed with @- when it has a non-empty diff AND no trunk/remote bookmarks. If @- carries main because work was rebased onto it during conflict resolution, it will have a non-empty diff — but still ask the user to confirm before mutating a revision that holds a trunk bookmark.

Step 3: Analyze the diff

jj diff -r 

Focus on the high-level nature of changes: file paths, new vs modified files, and the overall purpose. If the diff is empty, warn that there are no changes to describe — do not generate a description.

Step 4: Determine the conventional commit type

Map the diff content to a type:

| Type | Signals in the diff | |---|---| | feat: | New files, new functions/exports, new API routes, new components, new public methods | | fix: | Bug fixes, error handling additions, null/type guards, boundary condition checks | | refactor: | Code moves/renames, extractions, restructuring with no new behavior | | perf: | Caching, async/parallel, lazy loading, memoization, reduced allocations | | docs: | Only documentation files changed (README, markdown, comments, JSDoc) | | chore: | Dependencies, config files, CI/CD, build tooling, formatting, lint rules | | test: | Only test files changed (*_test.*, *.spec.*, __tests__/, test fixtures) |

Priority when multiple types apply: if only docs changed → docs:; if only tests changed → test:; otherwise use the first matching type from: feat > fix > perf > refactor > chore.

Step 5: Generate and apply the description

Case A: No existing description (most common)

jj describe -r  -m "type: concise imperative description"

Case B: Blank first line but existing body (from Step 1 gate)

Use --stdin to prepend the title while preserving the body:

printf 'type: concise title\n\n' | cat -  -T description --no-graph | tail -n +2) | jj describe -r  --stdin

Never use -m for this case — it would replace the entire description and lose the body.

Rules for the description:

• Use present tense imperative mood ("add" not "adds" or "added")
• Keep it under 72 characters
• No trailing period
• Capitalize after the colon only for proper nouns

Edge Cases

• Empty diff: Warn the user — there's nothing to describe. Do not generate a placeholder.
• Existing description (non-empty first line): Never overwrite. The check in Step 1 gates on the first line being empty.
• Blank first line with body: Use Case B in Step 5 (--stdin) to prepend a title while preserving the existing body. Never use -m.
• Large diff: Focus on the most significant files and changes. Don't try to enumerate every line.
• @- with trunk bookmark: If @- carries main, master, or a remote-tracking bookmark (e.g., main@origin), stop and ask the user which change to target. See Step 2 safety gate.

Common Pattern: Ensuring a Change Has a Description

# 1. Check current description
jj log -r @ -T description --no-graph

# 2. If empty, check which change has the work
jj status

# 3. Analyze the diff (use @- if @ is a placeholder)
jj diff -r @

# 4. Determine type from the diff, then set the description
jj describe -r @ -m "type: concise description"

Common Patterns

Starting New Work

jj tug                              # Sync with remote
jj new -m "feat: new feature"       # Start new change
# ... make changes ...
# Before pushing: run the Description Check Protocol if @- has no description
jj describe -r @- -m "feat: new feature"  # Ensure description is set
jj new                              # Finalize and start next

Amending Current Change

Simply make changes—they're automatically included in @. Use jj describe -r @ -m "type: message" to update the message if needed. If the change has no description yet, run the Description Check Protocol.

Rebasing onto Latest

jj tug    # Fetches and rebases in one command

Viewing What Will Be Pushed

# Run the Description Check Protocol first — jj git push requires descriptions
jj log -r 'remote_bookmarks()..@'    # Changes not yet on remote

Recovery

The operation log records every operation. Nothing is lost.

jj op log              # See all operations
jj undo                # Undo last operation
jj op restore      # Jump to any past state

Working with Multiple Workspaces

# Create a new workspace for parallel work
jj workspace add ../myproject-hotfix
cd ../myproject-hotfix
jj new -m "fix: critical hotfix"     # New @ in the new workspace
# ... make changes, push, etc. ...

# Back in original workspace — unaffected
cd ../myproject
jj log                               # Other workspace's changes appear in shared history

# Clean up when done
jj workspace forget hotfix           # Run from any other workspace
rm -rf ../myproject-hotfix           # Remove the directory

Use cases:

• Run long test suites in one workspace while coding in another
• Work on a hotfix without disturbing your in-progress feature
• Compare file states across different revisions simultaneously

Key Differences from Git

1. No staging area: All changes are tracked automatically
2. Mutable working copy: The current change can always be modified
3. Change IDs: Stable identifiers that persist through rebases
4. Anonymous branches: You can work without named branches
5. Automatic conflict handling: Conflicts are recorded and can be resolved later
6. Workspaces: Multiple working copies without branch locking (vs git worktrees which require a unique branch per worktree)

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: HotThoughts
• Source: HotThoughts/jj-skills
• License: MIT

Install and usage instructions live in the source repository linked above.