hermes-session-reset-policy

Re-arm Hermes Agent's session_reset policy (idle / daily / both) as a plugin.

Why

Upstream Hermes v2026.9.11 (commit 1d5d059410, "stop time-triggered conversation rotation") removed the background reset timers and made the session_reset config block inert: only explicit suspension (/stop, /new) replaces a routed conversation. If you want time-based conversation rotation back — fresh context after an hour of inactivity, or once per day at 04:00 — this plugin restores it without patching the core.

How it works

The plugin registers a pre_gateway_dispatch hook. On every inbound gateway message, before auth and dispatch, it:

1. Resolves the session key for the message: the hook payload's session_key when the gateway provides one publicly, else the gateway's own _session_key_for_source helper — so multiplexed profiles and platform key layouts match exactly. (No bare build_session_key fallback on purpose: under multiplexed profiles that key is not profile-namespaced and could resolve another profile's route for the same chat.)
2. Reads the profile's config.yaml session_reset block (the profile is resolved from the message's source.profile through Hermes' own get_profile_dir, anchored at the Hermes root so both gateway layouts read the right file: one multiplexed gateway at the root, or a standalone gateway per profile running with HERMES_HOME set to its own profiles/<name> dir — see issue #4).
3. Compares the routing entry's user-activity clock — the plugin's own srp_last_user_inbound session metadata, advanced only by messages that reach this hook (slash commands and internal/cron traffic never do) — against the idle threshold and/or the daily boundary. Entries that predate the plugin fall back to updated_at/created_at once, then the metadata clock takes over.
4. Past the boundary, and with no turn in flight (the entry's durable active_turn_token marker), resets the conversation through the gateway's own /new reset funnel (gateway._handle_reset_command, fed a text-free event) — the exact code path a typed /new takes, so everything a conversation boundary owes happens: run-generation bump and cached-agent cleanup/eviction (the compressor's previous summary cannot carry over), the conversation-scope clear (per-conversation /model and reasoning overrides), interruption of in-flight async delegations, SessionStore.reset_session(), the session:end/session:reset gateway hooks, and the on_session_finalize/on_session_reset plugin hooks. Then normal dispatch proceeds, so the message lands in the fresh session.

The event handed to the funnel is stripped of its text on purpose: the funnel treats event.get_command_args() as /new <title> — and on a plain message that returns the whole utterance, which would title the fresh session with whatever the user happened to send.

Because the trigger is the first inbound message past the boundary — never a timer — there are no background writes, no timer threads, and background/cron activity can neither keep a session alive nor reset it.

Config

The existing session_reset block in your (or your profile's) config.yaml drives everything; the plugin adds no keys:

session_reset:
  mode: both          # idle | daily | both | none
  idle_minutes: 60
  at_hour: 4          # local hour for the daily boundary

mode: none or an absent block disables the plugin entirely (no reset, no log noise).

Install

hermes plugins install https://github.com/fastfinge/hermes-session-reset-policy.git

or clone into ~/.hermes/plugins/ and enable:

plugins:
  enabled:
    - hermes-session-reset-policy

Restart the gateway afterwards.

Behaviour notes

• The reset is an explicit-style reset (like /new): the fresh session sets is_fresh_reset, so topic/channel-bound skills re-inject on the first turn — but it does not carry was_auto_reset bookkeeping, so the agent receives no "context was reset due to inactivity" sidecar note or channel-continuity hint. Add your own guidance if you need the agent to know.
• A turn in flight is never reset; the clock is left untouched and the reset re-arms on the next message.
• Boundary hooks keep firing downstream (session:end/session:reset, on_session_finalize/on_session_reset) — the reset goes through the /new funnel, not around it.
• When the funnel is unreachable (older gateways, renamed internals) the plugin degrades to a bare SessionStore.reset_session() plus the lifecycle hook pair and the delegation interrupt: a consistent rotation without the gateway-side cache/scope teardown. A funnel that fails after rotating is never rotated a second time by the fallback.
• Requires Hermes >= v2026.9.11 (needs the pre_gateway_dispatch hook payload with session_store). The full funnel path uses the gateway's private _handle_reset_command — deliberately reused until a public reset funnel exists (see issue #2); the fallback keeps old gateways working if it moves.

License

MIT — see LICENSE.