You'll noticeTier: how much it should matter to you
2Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
WorktreesArea: what it touches
ImprovementsKind: in v2.1.300,
ImprovementsSection of the release
What
A worktree is a second working copy of a git repository in its own folder. With --worktree, Claude Code can create one from a pull request (PR) or merge request (MR) number. It now handles this more strictly:
It fetches the full reference name, refs/pull/N/head or refs/merge-requests/N/head, instead of a short name
It checks that the fetched result came from that reference on the expected remote
It refuses if both kinds of reference exist and point at different commits
It refuses if it cannot check the other kind of reference
It uses the exact commit it fetched, not whatever git last recorded as fetched
When it refuses, the error starts with Cannot use PR/MR #N: followed by the reason. This is on by default in the code unless it is switched off remotely. When it is off, Claude Code uses the old short names.
Why
A branch or tag that happens to have a name like a PR reference can no longer be mistaken for the PR itself, so the worktree is based on the code you asked for.
Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.
This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.300: on
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed sinceAnthropic's documentation has since written up --worktree, on Desktop application.| Session isolation | [`--worktree`](/docs/en/cli-reference) flag | [Run a session in its own worktree](#run-a-session-in-its-own-worktree) |desktopsee the edit
How sure we are
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up --worktree, on Desktop application.
Anthropic's release notes agreeFixed plugin WorktreeCreate and WorktreeRemove hooks not running when Claude Code starts with --worktree (not yet with --tmux)
The name it cites is new in this buildNew in this build: tengu_melodic_octopus
