What did the agent change?

preen worktrees       # or: preen wt

Agents work in git worktrees. When one says it is finished, the question is always the same: what did it actually change? This mode answers it in two levels.

Level one: pick a worktree

You get one line per worktree, with the file count first:

   1 file   worktree-cutoff           .claude/worktrees/cutoff
   5 files  worktree-read-render      .claude/worktrees/read-render
   6 files  worktree-rewire           .claude/worktrees/rewire

The count leads because the list pane is narrow, and the path is the one column that can afford to run off the end.

The preview on the right shows, for the worktree under the cursor:

the worktree path
its branch
the base it is measured against, and which branch that base came from
every commit made on it since that base
the whole diff, in your chosen layout

The main checkout is not in the list. git always reports it first, so preen takes that first record as the repository root and drops it. This mode is about the other worktrees.

A repository with no worktrees besides the main checkout says so and exits.

Level two: browse its files

Pick a worktree with enter and the normal file picker opens on it: file list on the left, delta diff on the right, ctrl-s to flip layout, enter for the full file in a pager, ctrl-e to open it in $EDITOR.

esc goes back to the worktree list
ctrl-c quits altogether

That is the one place esc does not mean quit. Going back is what you want when you are working through three worktrees in a row.

A worktree that has changed nothing against its base says so instead of showing an empty list, and esc takes you back.

Measured against the merge-base

The count and the diff are both against the merge-base with the default branch, not against its tip.

That is the difference between what this worktree did and everything that has happened since it branched. Compare against the tip and every commit someone else landed on main in the meantime shows up as though the agent had touched it.

The default branch is read from origin/HEAD. If that is not set, preen falls back to main and then master, preferring a local branch of that name over the remote-tracking one.

Uncommitted and untracked files in the worktree are counted and browsable too, so work an agent has not committed yet is not invisible.

It is read-only

Like preen pr, this mode only reads. The complete list of git commands it runs is:

git worktree list
git merge-base
git symbolic-ref, git rev-parse
git log
git diff
git ls-files

No checkout, no fetch, no stash and no commit, in any worktree. Whatever an agent has half-done in there stays exactly as it left it.

Keys

key	action
`enter`	open the worktree (level one) or the file (level two)
`ctrl-s`	toggle side-by-side / inline
`ctrl-e`	open in `$EDITOR` — level two only
`ctrl-d` / `ctrl-u`	scroll the preview 8 lines
`pgdn` / `pgup`	scroll the preview half a page
`esc`	go back one level, or quit from level one
`ctrl-c`	quit

The full key table is in Browsing.