Agent stack build plans · № 6

Hermes as your smart home’s brain

An evening to wire it into Home Assistant, then a few weeks of it quietly learning how your household actually lives.

CLI: hermes MIT · model-agnostic v0.19.0 · July 2026 219k GitHub stars

Hermes is Nous Research’s open-source agent — a terminal agent plus an always-on gateway daemon that speaks Telegram, Discord, Signal and about twenty other platforms. One of those platforms is Home Assistant: Hermes subscribes to state-change events over HA’s WebSocket and gets four REST tools to act with — ha_list_entities, ha_get_state, ha_list_services, ha_call_service. (If you’ve seen list_entities / read_state / call_services floating around in AI answers: those names are wrong. Part of why this page exists.)

What that combination buys you is the thing HA automations can’t do: judgment over fuzzy rules. “Lamps on around sunset, but not if we’re out.” “Nudge me if the garage sits open, but not every time.” You don’t write those as YAML triggers. The agent watches events, keeps a small distilled memory of the household’s patterns, and messages you on Telegram before it touches anything you’ve marked sensitive.

Honest effort: an evening to a working agent (the HA add-on claims “zero to working agent in less than five minutes”; the token path took us closer to an hour with tuning), then two to three weeks of it running before its memory is worth anything. Honest cost: Hermes is MIT and bring-your-own-model — but every watched event is a model turn, so an always-on gateway on a frontier model is a self-inflicted bill. Route the gateway to a cheap model; the HA toolset itself needs no paid subscription, just HASS_TOKEN.

The plan, in six parts

1What you getan evening-at-home timeline — sensor events on the left, agent decisions on the right 2Product specwho this is for, a day in the life, and what it deliberately won’t do 3ArchitectureWebSocket events in, four tools out, a 2,200-character memory in between 4Set it upadd-on or HASS_TOKEN, event watching, approvals — real commands and file paths 5The promptsstaged, paste-able — map the house, write the rules, build the pattern distiller 6The trapsadmin tokens, event floods that eat your model budget, and the wrong lamp

Is this for you?

Yes, if you already run Home Assistant and you’ve hit the ceiling of deterministic automations — the rules you actually want are conditional, social, and slightly vague. Yes, if you want proactive nudges on Telegram rather than another dashboard. Skip it if you don’t run HA yet (install that first; this plan starts where HA ends), or if “cloud model reads my motion sensors” is a hard no — event awareness means exactly that. This plan deliberately does not cover voice, HA add-on internals, or multi-person profiles — the last one is the capstone plan, Hermes as a family operating system, which builds on this page.