The new Claude Code trust dialog appeared inside the tmux PTY despite -p mode and stdout being piped, blocking the agent indefinitely. With < /dev/null the dialog could never be answered. Replace < /dev/null with printf '\n' | so the Enter keypress confirms the default "Yes, I trust this folder" option. After that single newline stdin reaches EOF, which -p mode ignores. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>