Reunite

Reunite

Union the desktop app's per-account conversation indexes, so whichever account is signed in sees the whole history.

What is actually lost

Nothing. Establish that before offering to fix anything, because the fix is much smaller than the symptom suggests.

Two stores hold a conversation, and only one of them knows about accounts:

So switching accounts hides conversations from the sidebar and deletes none of them. claude --resume in a terminal reads the transcript store directly and has been listing all of them the whole time — say so, because it is the answer for anyone who only needs to reach one old conversation.

Run it

python3 scripts/merge.py                  # report only — what would be copied, and how much disk
python3 scripts/merge.py --apply          # write
python3 scripts/merge.py --undo           # remove exactly what --apply wrote

Report first, always. The report names each account index, its conversation count, and the org subdirectory a copy would land in. Read it out before writing: --apply on three accounts moved 114MB here, and someone who has not seen the number has not agreed to it.

--into narrows what receives the union — all (default), current for just the signed-in account, or a specific accountUuid. Narrow it when one of the accounts is long dead and does not deserve a copy of everything.

"Signed in" means the desktop app, not the CLI. They hold separate logins and are routinely on different accounts, so ~/.claude.json answers a different question — it names the account claude authenticates as, not the one whose sidebar is on screen. The app records its own as lastKnownAccountUuid in config.json beside the index, and that is the index a rename actually lands in. Check it before concluding a rename did not work; it may have worked in the other account.

Titles drift after a union, and a second run is where that shows

A rename writes one index file. So once a conversation exists in three indexes, renaming it under one account leaves the other two holding the old name, and copying cannot fix it — the entry is already there, so a plain union skips it.

Each run therefore also reconciles titles: where copies of one conversation disagree, the most recently written file wins, and its title, titleSource and previousTitles are written into the others. Nothing else in those files moves; the rest is that account's own record of the conversation.

File mtime is the signal because it is the only timestamp a rename actually moves — lastActivityAt records the conversation, not the record of it. That is not infallible: an unrelated rewrite of a stale copy makes it the newest, and it then wins with the older name. So every reconciliation is listed by name in the report, the value it replaced is recorded, and --no-titles turns the whole pass off.

This is what makes a naming sweep worth running. Rename under one account, run this, and the names reach the others.

What the script refuses to do

• It never deletes. Every run only adds files, and records both what it added and every title it replaced in .session-merge-manifest.json beside the account directories. --undo removes exactly those paths and puts exactly those titles back — not files the app wrote, not titles this skill never touched. A manifest written before titles were reconciled is a bare list of paths and is still read as one, so an older merge stays undoable.
• It skips orphans. An index entry whose cliSessionId has no transcript under ~/.claude/projects/ would appear in the sidebar and open to nothing, which is worse than not appearing. The report counts them; --keep-orphans copies them anyway.
• It is idempotent. A second run with nothing new plans zero copies and zero reconciliations. Run it again after every stretch of work under one account, and after any renaming pass: new conversations only land in that account's index, and new names only land in that account's copy.

The restart

A merge does not show up until the desktop app restarts. The app reads this index at startup and does not rescan the directory while running — verified by writing an entry with a current timestamp and watching it stay invisible to a running app.

So the last line of any report is the restart, and it is worth naming what the restart costs: running conversations are interrupted. Check what is live first — list_sessions on the session-management MCP shows which ones are still running — and let the user pick the moment.

Reporting

Session index <root>
  account <uuid>  <N> conversations  lands in <orgUuid>  <- signed in
  ...

Plan: <N> entries to copy into <M> account index(es), +<size>
  skipped <N> whose transcript is gone
  <N> stale titles to reconcile
    <account>  → <winning title>

After --apply, say how many were copied and how many titles were reconciled, that --undo takes both back, and that the sidebar is unchanged until the app restarts. A merge reported as done while the sidebar still looks the same reads as a failure.

Platform

The paths above are macOS. CLAUDE_DESKTOP_SESSIONS_DIR overrides the index root; the script exits with that hint rather than guessing when the directory is not there.