server-side TurnState in the harness, exposed via /api/state

new TurnState { Idle, Thinking, Compacting } on hive_ag3nt::events::Bus
with set_state + state_snapshot. the turn loops in hive-ag3nt and
hive-m1nd flip Thinking before drive_turn and Idle after; the
web_ui's /api/compact handler flips Compacting around compact_session.

per-agent /api/state grows turn_state + turn_state_since (unix
seconds). frontend prefers the server-reported state over the
client-derived one — setStateAbs takes the absolute since-time so
the 'last turn' chip reads the actual server-side duration instead
of the client's perceived gap between SSE events. SSE turn_start /
turn_end still drive state instantly between renders; /api/state
re-anchors on each turn_end refresh.

new compacting state gets its own purple badge with pulse
animation (mirrors thinking's amber). napping will slot in the
same way once the nap tool lands.

TODO.md

@@ -27,19 +27,10 @@ Pick anything from here when relevant. Cross-cutting design notes live in
 
 ## UI / UX
 
-- **State badge: compacting + napping states.** Idle/thinking already
-  ship (driven from SSE turn_start/turn_end). Add `compacting 📦` and
-  `napping 😴` once the `/compact` trigger and `nap` tool exist —
-  both need a harness signal (an explicit `LiveEvent::StateChange`
-  variant or piggyback on Note).
-- **Server-side state badge.** Today the badge is computed client-side
-  from `turn_start`/`turn_end` events. On page reload mid-turn the
-  history replay re-derives it, but with a `compacting` / `napping`
-  state coming and a non-trivial state machine it's better to track
-  authoritative state in the harness and expose it via
-  `GET /api/state` (`status: "thinking" | "idle" | "compacting" |
-  "napping"`). JS just renders. Drops the
-  derive-from-events-and-pray code path.
+- **State badge: napping state.** Idle / thinking / compacting
+  already ship from server-side `TurnState`. Add `napping 😴`
+  once the `nap` tool exists — it just adds a new `TurnState`
+  variant the harness flips into for the duration of the nap.
 - **Terminal: `/model` slash command.** Operator-typeable model
   override from the terminal. Depends on the model-override work
   above; once an override mechanism exists, wire a `/model <name>`

hive-ag3nt/assets/agent.css

@@ -228,6 +228,11 @@ pre.diff {
   text-shadow: 0 0 6px rgba(250, 179, 135, 0.65);
   animation: badge-pulse 1.8s ease-in-out infinite;
 }
+.state-badge.state-compacting {
+  color: var(--purple); border-color: var(--purple);
+  text-shadow: 0 0 6px rgba(203, 166, 247, 0.65);
+  animation: badge-pulse 1.8s ease-in-out infinite;
+}
 .state-badge.state-just-changed {
   animation: state-flash 600ms ease-out;
 }

hive-ag3nt/assets/app.js

@@ -295,6 +295,7 @@
     offline:    { glyph: '○',  text: 'offline' },
     idle:       { glyph: '💤', text: 'idle' },
     thinking:   { glyph: '🧠', text: 'thinking' },
+    compacting: { glyph: '📦', text: 'compacting' },
   };
   let stateName = 'loading';
   let stateSince = Date.now();
@@ -318,19 +319,22 @@
     if (cancelBtn) cancelBtn.hidden = stateName !== 'thinking';
   }
   function setState(next) {
-    if (next === stateName) return;
-    // Capture the just-ending state's duration when leaving 'thinking'
-    // so the operator can eyeball turn length without scrolling the
-    // terminal back.
+    setStateAbs(next, Math.floor(Date.now() / 1000));
+  }
+  /// Set state with an authoritative since-unix from the server. Lets
+  /// `last turn` track the actual server-side duration rather than
+  /// whatever the client perceived between SSE events.
+  function setStateAbs(next, sinceUnix) {
+    if (next === stateName && sinceUnix * 1000 === stateSince) return;
     if (stateName === 'thinking' && next !== 'thinking') {
       const elapsedMs = Date.now() - stateSince;
       renderLastTurn(elapsedMs);
     }
+    const flashing = next !== stateName;
     stateName = next;
-    stateSince = Date.now();
+    stateSince = sinceUnix * 1000;
     const badge = $('state-badge');
-    if (badge) {
-      // Re-add the flash class so the animation replays.
+    if (badge && flashing) {
       badge.classList.remove('state-just-changed');
       void badge.offsetWidth;
       badge.classList.add('state-just-changed');
@@ -411,11 +415,15 @@
       if (!headerSet) { setHeader(s.label, s.dashboard_port); headerSet = true; }
       renderTermInput(s.label, s.status === 'online');
       renderInbox(s.inbox || []);
-      // Drive the state badge from the harness status. Live SSE events
-      // override to 'thinking' / 'idle' as turns start/end; this only
-      // kicks in for the not-online (offline) case and the initial seed.
-      if (s.status !== 'online') setState('offline');
-      else if (stateName === 'loading' || stateName === 'offline') setState('idle');
+      // Authoritative state comes from the harness via /api/state.
+      // Login-not-yet → 'offline'; otherwise use the server-reported
+      // turn_state (idle / thinking / compacting). stateSince in
+      // unix-seconds is converted to a client-side Date.now() anchor.
+      if (s.status !== 'online') {
+        setState('offline');
+      } else if (s.turn_state) {
+        setStateAbs(s.turn_state, s.turn_state_since);
+      }
       // Skip the re-render if nothing structurally changed. The most
       // common case is `online` polling itself — without this guard, the
       // operator's <input value> gets clobbered every cycle.

hive-ag3nt/src/bin/hive-ag3nt.rs

@@ -4,7 +4,7 @@ use std::time::Duration;
 
 use anyhow::Result;
 use clap::{Parser, Subcommand};
-use hive_ag3nt::events::{Bus, LiveEvent};
+use hive_ag3nt::events::{Bus, LiveEvent, TurnState};
 use hive_ag3nt::login::{self, LoginState};
 use hive_ag3nt::{DEFAULT_SOCKET, DEFAULT_WEB_PORT, client, mcp, turn, web_ui};
 use hive_sh4re::{AgentRequest, AgentResponse};
@@ -126,6 +126,7 @@ async fn serve(
                     body: body.clone(),
                     unread,
                 });
+                bus.set_state(TurnState::Thinking);
                 let prompt = format_wake_prompt(&from, &body, unread);
                 let outcome = turn::drive_turn(
                     &prompt,
@@ -137,6 +138,7 @@ async fn serve(
                 )
                 .await;
                 turn::emit_turn_end(&bus, &outcome);
+                bus.set_state(TurnState::Idle);
             }
             Ok(AgentResponse::Empty) => {}
             Ok(AgentResponse::Ok | AgentResponse::Status { .. } | AgentResponse::Recent { .. }) => {

hive-ag3nt/src/bin/hive-m1nd.rs

@@ -8,7 +8,7 @@ use std::time::Duration;
 
 use anyhow::Result;
 use clap::{Parser, Subcommand};
-use hive_ag3nt::events::{Bus, LiveEvent};
+use hive_ag3nt::events::{Bus, LiveEvent, TurnState};
 use hive_ag3nt::login::{self, LoginState};
 use hive_ag3nt::{DEFAULT_SOCKET, DEFAULT_WEB_PORT, client, mcp, turn, web_ui};
 use hive_sh4re::{HelperEvent, ManagerRequest, ManagerResponse, SYSTEM_SENDER};
@@ -124,6 +124,7 @@ async fn serve(socket: &Path, interval: Duration, bus: Bus) -> Result<()> {
                     unread,
                 });
                 let prompt = format_wake_prompt(&from, &body, unread);
+                bus.set_state(TurnState::Thinking);
                 let outcome = turn::drive_turn(
                     &prompt,
                     &mcp_config,
@@ -134,6 +135,7 @@ async fn serve(socket: &Path, interval: Duration, bus: Bus) -> Result<()> {
                 )
                 .await;
                 turn::emit_turn_end(&bus, &outcome);
+                bus.set_state(TurnState::Idle);
             }
             Ok(ManagerResponse::Empty) => {}
             Ok(

hive-ag3nt/src/events.rs

@@ -24,6 +24,14 @@ const HISTORY_CAPACITY: usize = 2000;
 /// `HYPERHIVE_EVENTS_DB` env var (used in tests and one-shot tools).
 const DEFAULT_EVENTS_DB: &str = "/state/hyperhive-events.sqlite";
 
+fn now_unix() -> i64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .ok()
+        .and_then(|d| i64::try_from(d.as_secs()).ok())
+        .unwrap_or(0)
+}
+
 const SCHEMA: &str = "
 CREATE TABLE IF NOT EXISTS events (
     id           INTEGER PRIMARY KEY AUTOINCREMENT,
@@ -116,6 +124,22 @@ impl EventStore {
     }
 }
 
+/// Authoritative turn-loop state. The harness owns it; the web UI
+/// reads via `/api/state` and renders. Lives alongside the bus
+/// because everyone who has a `Bus` already has the right handle to
+/// poke the state on transitions.
+#[derive(Debug, Clone, Copy, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum TurnState {
+    /// Inbox is empty / waiting on `Recv`.
+    Idle,
+    /// `claude --print` is running for a turn.
+    Thinking,
+    /// Operator-triggered `/compact` is running on the persistent
+    /// session.
+    Compacting,
+}
+
 #[derive(Clone)]
 pub struct Bus {
     tx: Arc<broadcast::Sender<LiveEvent>>,
@@ -123,6 +147,8 @@ pub struct Bus {
     /// at construction — we keep going so the harness doesn't die on a
     /// missing `/state/` mount in dev / test scenarios.
     store: Option<Arc<EventStore>>,
+    /// Current turn-loop state + since-when (unix seconds).
+    state: Arc<Mutex<(TurnState, i64)>>,
 }
 
 impl Bus {
@@ -144,9 +170,26 @@ impl Bus {
         Self {
             tx: Arc::new(tx),
             store,
+            state: Arc::new(Mutex::new((TurnState::Idle, now_unix()))),
         }
     }
 
+    /// Update the harness's authoritative turn-loop state. Records
+    /// the transition time so `state_snapshot` can return a since-age.
+    pub fn set_state(&self, next: TurnState) {
+        let mut guard = self.state.lock().unwrap();
+        if guard.0 == next {
+            return;
+        }
+        *guard = (next, now_unix());
+    }
+
+    /// Current state + since-when (unix seconds). Snapshot copy, no lock held.
+    #[must_use]
+    pub fn state_snapshot(&self) -> (TurnState, i64) {
+        *self.state.lock().unwrap()
+    }
+
     pub fn emit(&self, event: LiveEvent) {
         if let Some(store) = &self.store
             && let Err(e) = store.append(&event)

hive-ag3nt/src/web_ui.rs

@@ -153,6 +153,11 @@ struct StateSnapshot {
     /// from the broker via the per-agent socket on each render.
     /// Empty on transport failure.
     inbox: Vec<hive_sh4re::InboxRow>,
+    /// Authoritative turn-loop state from the harness and the unix
+    /// timestamp the state was entered. The JS computes the age
+    /// client-side off this rather than tracking it from SSE events.
+    turn_state: crate::events::TurnState,
+    turn_state_since: i64,
 }
 
 #[derive(Serialize)]
@@ -187,12 +192,15 @@ async fn api_state(State(state): State<AppState>) -> axum::Json<StateSnapshot> {
         .and_then(|s| s.parse::<u16>().ok())
         .unwrap_or(7000);
     let inbox = recent_inbox(&state.socket, state.flavor).await;
+    let (turn_state, turn_state_since) = state.bus.state_snapshot();
     axum::Json(StateSnapshot {
         label: state.label.clone(),
         dashboard_port,
         status,
         session: session_view,
         inbox,
+        turn_state,
+        turn_state_since,
     })
 }
 
@@ -359,7 +367,10 @@ async fn post_compact(State(state): State<AppState>) -> Response {
                 return;
             }
         };
-        if let Err(e) = crate::turn::compact_session(&settings, &bus).await {
+        bus.set_state(crate::events::TurnState::Compacting);
+        let r = crate::turn::compact_session(&settings, &bus).await;
+        bus.set_state(crate::events::TurnState::Idle);
+        if let Err(e) = r {
             bus.emit(crate::events::LiveEvent::Note(format!(
                 "/compact failed: {e:#}"
             )));