diff --git a/src/pages/Chat/index.tsx b/src/pages/Chat/index.tsx
index 1325de5..61f1c78 100644
--- a/src/pages/Chat/index.tsx
+++ b/src/pages/Chat/index.tsx
@@ -82,6 +82,7 @@ export function Chat() {
   const streamingMessage = useChatStore((s) => s.streamingMessage);
   const streamingTools = useChatStore((s) => s.streamingTools);
   const pendingFinal = useChatStore((s) => s.pendingFinal);
+  const activeRunId = useChatStore((s) => s.activeRunId);
   const sendMessage = useChatStore((s) => s.sendMessage);
   const abortRun = useChatStore((s) => s.abortRun);
   const clearError = useChatStore((s) => s.clearError);
@@ -280,8 +281,12 @@ export function Chat() {
       );
     });
     const runStillExecutingTools = hasToolActivity && !hasFinalReply;
+    // runStillExecutingTools bridges the brief gap between tool rounds when
+    // Gateway temporarily clears sending.  However, after an explicit abort
+    // (which clears activeRunId), we must NOT keep the run "open" — so we
+    // gate it on activeRunId being present.
     const isLatestOpenRun = nextUserIndex === -1
-      && (sending || pendingFinal || hasAnyStreamContent || runStillExecutingTools);
+      && (sending || pendingFinal || hasAnyStreamContent || (runStillExecutingTools && !!activeRunId));
     const replyIndexOffset = findReplyMessageIndex(segmentMessages, isLatestOpenRun);
     const replyIndex = replyIndexOffset === -1 ? null : idx + 1 + replyIndexOffset;
 
diff --git a/src/stores/chat/helpers.ts b/src/stores/chat/helpers.ts
index c3068f6..737fa88 100644
--- a/src/stores/chat/helpers.ts
+++ b/src/stores/chat/helpers.ts
@@ -23,6 +23,12 @@ let _historyPollTimer: ReturnType<typeof setTimeout> | null = null;
 // before committing the error to give the recovery path a chance.
 let _errorRecoveryTimer: ReturnType<typeof setTimeout> | null = null;
 
+// Track the last run ID that was explicitly aborted by the user.
+// Prevents lingering Gateway events from the aborted run from re-arming
+// the sending state after abortRun clears it.
+let _lastAbortedRunId: string | null = null;
+const _blockedRunEvents = new Map<string, Record<string, unknown>[]>();
+
 function clearErrorRecoveryTimer(): void {
   if (_errorRecoveryTimer) {
     clearTimeout(_errorRecoveryTimer);
@@ -1020,6 +1026,27 @@ function getLastChatEventAt(): number {
   return _lastChatEventAt;
 }
 
+function setLastAbortedRunId(id: string | null): void {
+  _lastAbortedRunId = id;
+}
+
+function getLastAbortedRunId(): string | null {
+  return _lastAbortedRunId;
+}
+
+function queueBlockedRunEvent(runId: string, event: Record<string, unknown>): void {
+  const events = _blockedRunEvents.get(runId) ?? [];
+  events.push({ ...event });
+  if (events.length > 100) events.shift();
+  _blockedRunEvents.set(runId, events);
+}
+
+function takeBlockedRunEvents(runId: string): Record<string, unknown>[] {
+  const events = _blockedRunEvents.get(runId) ?? [];
+  _blockedRunEvents.delete(runId);
+  return events;
+}
+
 export {
   toMs,
   clearErrorRecoveryTimer,
@@ -1050,4 +1077,8 @@ export {
   setErrorRecoveryTimer,
   setLastChatEventAt,
   getLastChatEventAt,
+  setLastAbortedRunId,
+  getLastAbortedRunId,
+  queueBlockedRunEvent,
+  takeBlockedRunEvents,
 };
diff --git a/src/stores/chat/runtime-event-actions.ts b/src/stores/chat/runtime-event-actions.ts
index beec597..b22bb93 100644
--- a/src/stores/chat/runtime-event-actions.ts
+++ b/src/stores/chat/runtime-event-actions.ts
@@ -1,4 +1,4 @@
-import { clearHistoryPoll, setLastChatEventAt } from './helpers';
+import { clearHistoryPoll, getLastAbortedRunId, queueBlockedRunEvent, setLastAbortedRunId, setLastChatEventAt } from './helpers';
 import type { ChatGet, ChatSet, RuntimeActions } from './store-api';
 import { handleRuntimeEventState } from './runtime-event-handlers';
 
@@ -16,6 +16,28 @@ export function createRuntimeEventActions(set: ChatSet, get: ChatGet): Pick<Runt
       // Only process events for the active run (or if no active run set)
       if (activeRunId && runId && runId !== activeRunId) return;
 
+      // Reject lingering events from a run that the user explicitly aborted.
+      // The 'aborted' confirmation event is allowed through to finalize state.
+      // '*' is a wildcard meaning "abort was requested before we knew the runId".
+      const lastAbortedRunId = getLastAbortedRunId();
+      if (lastAbortedRunId && runId && (lastAbortedRunId === '*' || runId === lastAbortedRunId)) {
+        if (eventState === 'aborted' && lastAbortedRunId === '*') {
+          // Gateway confirmed which run was aborted. Narrow the wildcard so
+          // later unrelated runs can be adopted while this run stays blocked.
+          setLastAbortedRunId(runId);
+        }
+        // Let the 'aborted' event fall through to handleRuntimeEventState
+        // which properly clears all state.  Other wildcard-blocked events may
+        // belong to a newer send whose runId has not returned yet, so keep a
+        // bounded queue and replay only if that runId becomes the active run.
+        if (eventState !== 'aborted') {
+          if (lastAbortedRunId === '*' && !activeRunId && get().sending) {
+            queueBlockedRunEvent(runId, event);
+          }
+          return;
+        }
+      }
+
       setLastChatEventAt(Date.now());
 
       // Defensive: if state is missing but we have a message, try to infer state.
diff --git a/src/stores/chat/runtime-send-actions.ts b/src/stores/chat/runtime-send-actions.ts
index b268786..ddb2da6 100644
--- a/src/stores/chat/runtime-send-actions.ts
+++ b/src/stores/chat/runtime-send-actions.ts
@@ -3,9 +3,12 @@ import { useAgentsStore } from '@/stores/agents';
 import {
   clearErrorRecoveryTimer,
   clearHistoryPoll,
+  getLastAbortedRunId,
   getLastChatEventAt,
   setHistoryPollTimer,
   setLastChatEventAt,
+  setLastAbortedRunId,
+  takeBlockedRunEvents,
   upsertImageCacheEntry,
 } from './helpers';
 import type { ChatSession, RawMessage } from './types';
@@ -39,6 +42,8 @@ function ensureSessionEntry(sessions: ChatSession[], sessionKey: string): ChatSe
   return [...sessions, { key: sessionKey, displayName: sessionKey }];
 }
 
+let sendGeneration = 0;
+
 export function createRuntimeSendActions(set: ChatSet, get: ChatGet): Pick<RuntimeActions, 'sendMessage' | 'abortRun'> {
   return {
     sendMessage: async (
@@ -48,6 +53,7 @@ export function createRuntimeSendActions(set: ChatSet, get: ChatGet): Pick<Runti
     ) => {
       const trimmed = text.trim();
       if (!trimmed && (!attachments || attachments.length === 0)) return;
+      const currentSendGeneration = ++sendGeneration;
 
       const targetSessionKey = resolveMainSessionKeyForAgent(targetAgentId) ?? get().currentSessionKey;
       if (targetSessionKey !== get().currentSessionKey) {
@@ -220,13 +226,43 @@ export function createRuntimeSendActions(set: ChatSet, get: ChatGet): Pick<Runti
 
         console.log(`[sendMessage] RPC result: success=${result.success}, runId=${result.result?.runId || 'none'}`);
 
+        const returnedRunId = result.result?.runId;
+        if (returnedRunId && currentSendGeneration !== sendGeneration) {
+          // This send was stopped or superseded while the RPC was in flight.
+          // If the stop happened before activeRunId was known, narrow the
+          // wildcard abort marker to the concrete runId we just learned.
+          // Keep '*' while a newer send is still pending its runId so early
+          // events from that newer run cannot re-arm the UI before ownership
+          // is established.
+          const lastAbortedRunId = getLastAbortedRunId();
+          if (!get().sending && (!lastAbortedRunId || lastAbortedRunId === '*' || lastAbortedRunId === returnedRunId)) {
+            setLastAbortedRunId(returnedRunId);
+          }
+          return;
+        }
+
+        if (currentSendGeneration !== sendGeneration) return;
+
         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 (returnedRunId && get().sending) {
+          set({ activeRunId: returnedRunId });
+          // Now that we have a valid activeRunId for the new run, the
+          // activeRunId guard will filter stale events from the old run.
+          // Safe to clear the abort marker.
+          setLastAbortedRunId(null);
+          const blockedEvents = takeBlockedRunEvents(returnedRunId);
+          if (blockedEvents.length > 0) {
+            queueMicrotask(() => {
+              for (const blockedEvent of blockedEvents) {
+                get().handleChatEvent(blockedEvent);
+              }
+            });
+          }
         }
       } catch (err) {
+        if (currentSendGeneration !== sendGeneration) return;
         clearHistoryPoll();
         set({ error: String(err), sending: false });
       }
@@ -235,10 +271,16 @@ export function createRuntimeSendActions(set: ChatSet, get: ChatGet): Pick<Runti
     // ── Abort active run ──
 
     abortRun: async () => {
+      sendGeneration += 1;
       clearHistoryPoll();
       clearErrorRecoveryTimer();
-      const { currentSessionKey } = get();
-      set({ sending: false, streamingText: '', streamingMessage: null, pendingFinal: false, lastUserMessageAt: null, pendingToolImages: [] });
+      const { currentSessionKey, activeRunId } = get();
+      // Mark the run as aborted BEFORE clearing state, so the event handler
+      // rejects any lingering Gateway events from this run.  Use wildcard '*'
+      // when activeRunId is not yet known (user stopped before chat.send
+      // returned a runId) to block ALL run events from re-arming sending.
+      setLastAbortedRunId(activeRunId || '*');
+      set({ sending: false, activeRunId: null, streamingText: '', streamingMessage: null, pendingFinal: false, lastUserMessageAt: null, pendingToolImages: [] });
       set({ streamingTools: [] });
 
       try {
@@ -250,6 +292,9 @@ export function createRuntimeSendActions(set: ChatSet, get: ChatGet): Pick<Runti
       } catch (err) {
         set({ error: String(err) });
       }
+      // Reload history to pick up final transcript state from Gateway,
+      // which resolves hasFinalReply and clears hasActiveExecutionGraph.
+      void get().loadHistory(true);
     },
 
     // ── Handle incoming chat events from Gateway ──