Four builders repeated the same batch-mode SSH option list and the same POSIX "~/.local/bin/herdr or PATH" fallback script, and the delete/stop helpers were near-identical copies. Build every remote command through ssh_command()/posix_herdr_script() and run Session mutations through one helper. Generated argv is byte-for-byte unchanged. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>