diff --git a/src/stores/chat/runtime-send-actions.ts b/src/stores/chat/runtime-send-actions.ts
index b268786..51a13a4 100644
--- a/src/stores/chat/runtime-send-actions.ts
+++ b/src/stores/chat/runtime-send-actions.ts
@@ -223,8 +223,19 @@ export function createRuntimeSendActions(set: ChatSet, get: ChatGet): Pick<Runti
         if (!result.success) {
           clearHistoryPoll();
           set({ error: result.error || 'Failed to send message', sending: false });
-        } else if (result.result?.runId) {
-          set({ activeRunId: result.result.runId });
+        } else {
+          if (result.result?.runId) {
+            set({ activeRunId: result.result.runId });
+          }
+          // The chat.send RPC blocks until the entire agent conversation
+          // finishes.  If sending is still true (streaming events haven't
+          // finalized it yet), finalize now — this is the authoritative
+          // signal that the run is complete.
+          if (get().sending) {
+            clearHistoryPoll();
+            set({ sending: false, activeRunId: null, pendingFinal: false, lastUserMessageAt: null });
+            get().loadHistory(true);
+          }
         }
       } catch (err) {
         clearHistoryPoll();
diff --git a/src/stores/gateway.ts b/src/stores/gateway.ts
index 38c2f4a..ee14a61 100644
--- a/src/stores/gateway.ts
+++ b/src/stores/gateway.ts
@@ -19,20 +19,6 @@ let lastLoadSessionsAt = 0;
 let lastLoadHistoryAt = 0;
 let cronRepairTriggeredThisSession = false;
 
-// Grace timer for agent phase completion.  The Gateway sends phase "end"
-// after each tool-execution round, not just at the end of the entire run.
-// We delay `sending=false` to give the next sub-run's "started" event
-// time to arrive.  If a new streaming event or started phase cancels the
-// timer, sending stays true seamlessly.
-let _phaseCompletionTimer: ReturnType<typeof setTimeout> | null = null;
-const PHASE_COMPLETION_GRACE_MS = 5_000;
-function clearPhaseCompletionTimer(): void {
-  if (_phaseCompletionTimer) {
-    clearTimeout(_phaseCompletionTimer);
-    _phaseCompletionTimer = null;
-  }
-}
-
 interface GatewayHealth {
   ok: boolean;
   error?: string;
@@ -144,7 +130,6 @@ function handleGatewayNotification(notification: { method?: string; params?: Rec
   if (hasChatData) {
     // Any streaming data cancels the phase-completion grace timer — the
     // run is still producing output (or a new sub-run has started).
-    clearPhaseCompletionTimer();
     const normalizedEvent: Record<string, unknown> = {
       ...data,
       runId: p.runId ?? data.runId,
@@ -166,7 +151,6 @@ function handleGatewayNotification(notification: { method?: string; params?: Rec
   const runId = p.runId ?? data.runId;
   const sessionKey = p.sessionKey ?? data.sessionKey;
   if (phase === 'started' && runId != null && sessionKey != null) {
-    clearPhaseCompletionTimer();
     import('./chat')
       .then(({ useChatStore }) => {
         const state = useChatStore.getState();
@@ -206,29 +190,11 @@ function handleGatewayNotification(notification: { method?: string; params?: Rec
         if (matchesCurrentSession || matchesActiveRun) {
           maybeLoadHistory(state);
         }
-        if ((matchesCurrentSession || matchesActiveRun) && state.sending) {
-          // The Gateway sends phase "end" after each tool-execution round,
-          // not only when the entire conversation finishes.  Delay the
-          // sending=false so a subsequent sub-run's "started" event or
-          // streaming delta can cancel it and keep the UI in the active state.
-          clearPhaseCompletionTimer();
-          _phaseCompletionTimer = setTimeout(() => {
-            _phaseCompletionTimer = null;
-            const current = useChatStore.getState();
-            // Only finalize if still in the same run and no new streaming data arrived.
-            if (current.sending && !current.streamingMessage) {
-              useChatStore.setState({
-                sending: false,
-                activeRunId: null,
-                pendingFinal: false,
-                lastUserMessageAt: null,
-                error: null,
-              });
-              // Reload history to get the final state.
-              maybeLoadHistory(current);
-            }
-          }, PHASE_COMPLETION_GRACE_MS);
-        }
+        // Note: we do NOT set sending=false here.  The Gateway sends
+        // phase "end" after each tool-execution round (sub-run), not only
+        // when the entire conversation finishes.  Run completion is
+        // determined by the chat.send RPC returning (runtime-send-actions)
+        // or a streaming "final" event with output (runtime-event-handlers).
       })
       .catch(() => {});
   }