Securing an Always-On AI Agent at Home: A Journey Through Dead Ends
TL;DR
I run an always-on AI agent with shell access on a spare mini PC at home, and the hard part wasn't building it, it was making sure a compromise couldn't spread. Firewalling the agent in place failed: its whole job is making outbound calls, so egress filtering either breaks it or rots into an allowlist you babysit. What worked was moving the box onto its own router, off my home LAN entirely, so a full compromise can reach the internet but not my laptops or NAS. Remote access is an ngrok tunnel to key-only SSH; the rest is defense-in-depth on the box, plus an honest list of what none of this protects against.
How I went about securing Hermes Agent, an always-on CLI-based AI assistant from Nous Research, running on a spare mini PC at home. This is not a "here's the perfect setup" post. It's the honest record of three approaches that failed and the one that triumphed.