I checked — @livekit/plugins-ai-coustics is installed (dist + the 78MB
plugins_ai_coustics_uniffi.dll native binary), but there are no separate model
files, and livekit-agents download-files only downloaded files for the openai
plugin — nothing for ai-coustics. With NC on, the caller’s audio never reaches
the agent. Does the ai-coustics VF model need a separate download step, and how
do we trigger it (the DLL is present but download-files skips the plugin)?
So, the call is never answered? That sounds more like WhatsApp Connector: acceptWhatsAppCall never connects — caller keeps ringing (outbound works fine) - #7 by darryncampbell rather than something specific to having noise cancellation enabled.
Can you share a couple of Insights sessions that show this behaviour please: Agent insights in LiveKit Cloud | LiveKit Documentation. I think that would be clearer.
There shouldn’t be need for spearate model files, these should be directly in the plugin itself as .dll file. On the audio not reaching the agent, even if the noise cancellation failed the auth it would rather bypass than drop the whole audio, so it looks like the issue is elsewhere 
Specifically for Krisp, the original issue raised in this thread should be resolved in the latest release of the plugin:
https://www.npmjs.com/package/@livekit/noise-cancellation-node