I’ve run Home Assistant for six years, and this year I finally built the thing I always wanted on top of it: Postern, a self-hosted gateway that lets any AI agent I allow reach my home — and my mail, calendar, contacts, finances, and health — through one surface. I built it, it’s open source (Apache-2.0), and it has been running my own life for two months.
The HA side, concretely: Postern connects over the WebSocket API with a long-lived access token and keeps entities and states in a local Postgres cache. When an agent asks about the house, the read comes from that cache — your HA instance doesn’t get hammered. When an agent acts, Postern dispatches a real service call, then re-syncs the affected entities so the agent sees the result. Admin and system services are denylisted from both the catalog and dispatch, and every action an agent takes lands in an audit log.
The reason it exists is the other sectors. The same gateway carries mail, calendar, contacts, bank accounts, and health data, each behind a per-agent, default-deny grant. So the agent that turns off my lights can also see that my calendar says I’m leaving — Postern itself correlates nothing and has no LLM inside; your agent does the reasoning, the gateway keeps each sector cached, normalized, and permissioned.
Any MCP-speaking agent connects with a key and a grant — claude.ai and ChatGPT reach mine from the cloud (Tailscale Funnel + an OAuth bridge), Claude Code and a local agent reach it on the box.
It’s young (v0.1.2, public since Aug 1) and V0 is single-user. HA is the action-rich sector; most others are read-heavy for now, and actions never exceed what each source allows.
Docker quickstart is three commands —
setup guide at Postern — Your agent knows the world. Put it to work on yours.,
docs at https://docs.getpostern.com
Or skip the manual setup entirely: the repo root carries setup-with-your-agent.md — point your coding agent at it, say “set this up for me”, and it runs every step a program can run, stopping only where you have to sign in yourself.
I’d genuinely value feedback from this crowd, especially on the quickstart — you are exactly the people it was built for.