let me switch Claude accounts mid-thread when they share history (works in cmux)

[sopenlaz0]

hey! been using T3 Code a lot lately and loving it, but there's one thing that keeps getting in my way.

i have a few Claude subscriptions and i switch between them when one hits its limit. i've got each one set up as its own Claude instance in T3 with a different CLAUDE_CONFIG_DIR. all those config dirs symlink their history to one shared folder, so every account sees the same sessions.

in cmux (and in the plain Claude CLI with claude --resume) this works great. an account runs out, i switch to another one and just keep going in the same conversation, full context and everything. in T3 i can't switch once a thread has started. it just says "Start a new thread to use this model."

what hurts

• hitting a limit mid-task kills the thread. i have to start over in a new thread and lose everything: the files it already read, the plan, the decisions we made.
• summarizing and pasting into a new thread is a pain. it burns tokens and time, and the summary always misses stuff.
• T3 is the only tool in my setup that blocks this. the CLI and cmux read the exact same session files and let me switch no problem.
• one task ends up split across a bunch of threads, one per account, so the history is all over the place.

my setup

~/.claude-account-a/projects      -> ~/.claude-shared/projects
~/.claude-account-a/sessions      -> ~/.claude-shared/sessions
~/.claude-account-a/history.jsonl -> ~/.claude-shared/history.jsonl
~/.claude-account-a/todos, tasks, transcripts -> same thing
(same for ~/.claude-account-b, ~/.claude-account-c)

each dir still has its own .claude.json and login, so auth stays separate but the history is shared.

"providerInstances": {
  "claudeA": { "driver": "claudeAgent", "config": { "homePath": "~/.claude-account-a" } },
  "claudeB": { "driver": "claudeAgent", "config": { "homePath": "~/.claude-account-b" } }
}

how to repro

1. set up two Claude instances whose config dirs both symlink projects/ to the same folder
2. start a thread on instance A and send a message
3. open the model picker and pick a model from instance B

i expected it to just continue on B, since the session file is literally in the same folder. instead it gets blocked with "Start a new thread to use this model."

why it happens (i think)

i looked around a bit, and makeClaudeContinuationGroupKey builds the key from path.resolve(homePath). the picker blocks the switch when the keys don't match. since it goes by the folder path and doesn't follow symlinks, my accounts all get different keys even though their sessions live in the same place. feels like the same kind of thing as #12616, just with symlinks.

some ideas (any of these would work for me)

1. build the key from where sessions actually live, like fs.realpath(<homePath>/projects), and fall back to the current behavior if that folder doesn't exist. no new settings, nothing changes for anyone else.
2. add a manual "shared history group" field per instance that overrides the key.
3. do what the Codex driver already does. Codex has shadowHomePath ("Keeps auth.json separate while sharing state from CODEX_HOME"). something like that for Claude would solve this without people having to set up symlinks by hand.

questions for @t3dotgg

• how do you handle multiple Claude accounts yourself? do you share history between them like this, or keep them separate and just start fresh threads?
• is this even a good idea? i've been doing it every day in cmux and haven't had problems, but i'm not sure about some stuff:
  • caching. i'm guessing prompt cache is per account, so the first message after switching is a full cache miss. is that the only cost or does it mess with anything else?
  • could resuming a session another account wrote break things like checkpoints, rewind, or /compact forks (kinda like [Bug]: Claude rewind fails after a /compact that preserved recent messages, and leaves the forked transcript on disk #13638)?
  • any risk if two accounts write to the shared sessions/ or history.jsonl at the same time?
• if this isn't something you want to support, that's totally fine, just good to know so i don't lean on it too much 🙏

thanks!

env: T3 Code (Alpha) 0.0.33 on macOS, Claude Code CLI 2.1.283

[juliusmarminge]

Closing as a duplicate of #7547 — same request: mid-thread Claude account switching / continuation when multiple instances share session state (Codex already has shadowHomePath for this).

#12616 (cited here) was a narrower key-normalization bug (empty vs ~/.claude) and is already fixed; the broader shadow-path / shared-history continuation design is tracked in #7547. The symlink/realpath and explicit continuation-group options you listed are useful detail for that discussion — please add them there if they are not already covered.