The entry already warned that run-canary is silent twice over, but stopped there -- and fixing only the mutes still yields an unfaithful capture, because a PulseAudio null sink s monitor is wall-clocked and invents silence when the client is late. Adds the pointer to the ALSA file-tee page, with the two things a reader needs before starting: the slave must pace or the tee free-runs at about 250x real time, and a size guard is not optional. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd