Remote SSH connection fails when remote login shell is csh/tcsh

What happened?

Codex Desktop Remote Connections can discover an SSH host from ~/.ssh/config, but enabling the connection fails during remote app-server bootstrap when the remote account's login shell is /bin/csh.

Normal SSH to the host succeeds, passwordless auth works, and the remote has both /bin/bash and /bin/sh installed. The remote codex app-server --help command also works when run manually. The failure appears to happen because the Desktop remote bootstrap is executed through the remote login shell and uses Bourne/bash-style syntax or -l flags that csh does not accept.

Sanitized log excerpt

[remote-connections/discovery] discovery_completed collectedAliasCount=1 ... resolvedConnectionCount=1
[WindowContext] [ssh-websocket-v0] selected app-server transport websocketUrl=ws://127.0.0.1:<local-port>/rpc
[AppServerTransportSshWebsocket] ssh_websocket_v0.ensure_remote_app_server_and_tunnel localPort=<local-port> remotePort=<remote-port> sshAlias=<redacted> sshHost=<redacted> sshPort=<redacted>
[AppServerConnection] app_server_connection.transport_connect_failed
errorMessage="Unmatched '''.
fi: Command not found.
Unknown option: `-l'
Usage: csh [ -bcdefilmnqstvVxX ] [ argument ... ]."

Environment

• Codex Desktop on Windows
• Codex app version observed in local install/logs: 26.422.2437.0
• Remote app-server version reported by logs: 0.124.0-alpha.2
• Remote host: Unix/Linux via SSH
• Remote login shell: /bin/csh
• /bin/bash and /bin/sh are available on the remote
• SSH auth works normally outside Codex Desktop
• Host alias, hostname, user, and ports intentionally redacted

Expected behavior

Codex Desktop Remote Connections should either:

1. bootstrap through a POSIX shell explicitly, e.g. /bin/sh -lc ..., regardless of the account login shell;
2. support csh/tcsh login shells with compatible syntax; or
3. expose a per-connection "remote bootstrap shell" setting, e.g. /bin/bash, so users can keep their login shell as csh for existing remote workflows.

Why changing the login shell is not always viable

Some enterprise environments require csh/tcsh login shells for existing tool setup. In this environment the shell is managed by central account tooling and cannot be changed locally. Users may need to keep csh as the login shell while allowing Codex to use sh/bash only for its bootstrap.