One wanderbooks executable. The books are open while the viewer, an agent session or a terminal holds them: a host process takes leases on a socket, starts the server (the hidden mode `wanderbooks server`) with a pipe on its input, and closes it 10 s after the last lease ends. No background service. One host even in a race (run/host.lock). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj