macOS: Worktree thread closes immediately when using the Bitwarden SSH agent

[bjesuiter]

I am documenting this because the UI symptom looks like a thread crash, but the failure happens earlier during Git setup.

Environment:

• T3 Code 0.0.33 on macOS
• repository remote uses GitHub SSH
• Bitwarden SSH agent is configured in the interactive shell
• Bitwarden was installed from the Mac App Store

When I started a worktree thread, T3 Code closed it immediately. Retrying could then produce Thread '<id>' already exists and cannot be created twice.

The server trace contained the useful error:

GitVcsDriver.fetchRemote (...): git fetch origin failed

T3 Code fetches origin before it creates a worktree when the thread starts from the remote branch. The desktop process had an SSH_AUTH_SOCK, but it pointed to Apple's launchd agent at /var/run/.../Listeners, which had no identities. My terminal shell pointed to Bitwarden's agent socket and could fetch the same repository without trouble.

This is a slightly different case from #971. That fix fills in SSH_AUTH_SOCK when the variable is missing. Here the variable exists, but points to the wrong agent. The deleted-thread retry symptom is related to #4647.

How can I make T3 Code use the Bitwarden agent for this repository without changing the global SSH setup?

[bjesuiter]

A repo-local Git setting fixed it for me:

git config --local core.sshCommand \
  "ssh -o IdentityAgent=$HOME/Library/Containers/com.bitwarden.desktop/Data/.bitwarden-ssh-agent.sock"

This writes the resolved socket path to the clone's shared .git/config. Git uses it for the main checkout and every linked worktree, regardless of which SSH_AUTH_SOCK T3 Code inherited when the desktop app launched.

I verified the setting before trying T3 Code again:

git config --local --get core.sshCommand
git fetch --dry-run origin

After that, T3 Code could fetch origin, create the linked worktree, and open the thread normally.

To remove the override later:

git config --local --unset core.sshCommand

If Bitwarden was installed outside the Mac App Store, its socket path may differ. Bitwarden documents the platform-specific paths in its SSH agent setup guide: https://bitwarden.com/help/ssh-agent/