Jj

jj

Use jj for version control when a repository has a .jj/ directory or jj status succeeds.

jj status

Core Model

• There is no staging area; commands operate on the current change or selected revisions.
• The working copy is a mutable commit/change. Use jj describe to set its message.
• Change IDs are stable across rewrites; commit IDs change when contents or metadata change.
• Most history edits are safe because jj records operations in the operation log.

Inspect State

Start with these read-only commands:

jj status
jj log --limit 20
jj diff --git

Inspect a specific revision:

jj show <revset>
jj evolog -r <revset>

Useful revsets:

• @: current working-copy commit
• @-: parent of the working-copy commit
• ::@: ancestors of the working-copy commit
• @::: descendants of the working-copy commit
• trunk(): repository trunk/main baseline
• mine(): changes authored by the current user
• conflicted(): changes with conflicts
• mutable(): changes that can be rewritten

Quote revsets in shell commands when they contain special characters:

jj log -r 'trunk()..@'

Make Commits

Describe the current change before creating a new one:

jj describe -m "Explain why this change exists"
jj new

Create a new change from a specific parent:

jj new <revset>

Prefer small, atomic changes. If the working copy mixes concerns, split it before describing or submitting.

jj desc is the common shorthand for jj describe; use either form consistently with nearby docs or commands.

Refine History

Move selected changes from the working copy into its parent:

jj squash

Absorb modifications into matching mutable ancestors:

jj absorb

Split a mixed change:

jj split

Split whole files or filesets non-interactively by passing paths and a message:

jj split -r @ path/to/file1 path/to/file2 -m "Move focused changes into their own commit"
jj split -r @ 'glob:src/**/*.rs' -m "Update Rust sources"

Rebase

Use --onto/-o for destinations:

jj rebase -r <revset> -o <destination>

Common forms:

jj rebase -r @ -o trunk()
jj rebase -s <source> -o <destination>
jj rebase -b <branch> -o <destination>

Avoid deprecated --destination/-d examples unless an installed jj version requires them.

Git Interop

Fetch and push through jj in colocated Git repositories:

jj git fetch
jj git push

Create or update a Git bookmark before pushing when needed:

jj bookmark set <name> -r <revset>
jj git push --bookmark <name>

Do not use git add, git commit, or Git staging workflows in a jj repository unless the user explicitly asks for Git commands.

Operation Log

Inspect recent jj operations:

jj op log

Undo or redo the most recent operation:

jj undo
jj redo

Recover from a bad operation by restoring a previous operation only when the user explicitly approves:

jj op restore <operation-id>

Non-Interactive Safety

Prefer explicit messages and non-interactive flags:

jj describe -m "Message"
jj new --no-edit <revset>
jj --no-pager log --limit 20

Use jj diff --git for familiar unified diffs; jj's default diff format can be harder for agents to read.

Guardrails

• Only push, restore operations, abandon changes, or rewrite unrelated user changes when explicitly requested.
• Before mutating history, inspect jj status and jj log --limit 20 so you understand the current stack.