diff --git a/packages/core/chat/mutations.ts b/packages/core/chat/mutations.ts
index f8d05ed87..d30b717f8 100644
--- a/packages/core/chat/mutations.ts
+++ b/packages/core/chat/mutations.ts
@@ -1,7 +1,7 @@
 import { useMutation, useQueryClient } from "@tanstack/react-query";
 import { api } from "../api";
 import { useWorkspaceId } from "../hooks";
-import { chatKeys, sortChatSessions } from "./queries";
+import { chatKeys, sortChatSessions, QUICK_ACTIONS_PENDING_TIMEOUT_MS } from "./queries";
 import { createLogger } from "../logger";
 import type {
   ChatSession,
@@ -398,7 +398,11 @@ export function useRegenerateChatQuickActions() {
       // matches on message_id).
       qc.setQueryData<ChatQuickActionsPendingState | null>(
         chatKeys.quickActionsPending(sessionId),
-        { message_id: messageId, task_id: "" },
+        {
+          message_id: messageId,
+          task_id: "",
+          expires_at: Date.now() + QUICK_ACTIONS_PENDING_TIMEOUT_MS,
+        },
       );
       return { previous, sessionId };
     },
diff --git a/packages/core/chat/queries.ts b/packages/core/chat/queries.ts
index 19ec5d392..19177af58 100644
--- a/packages/core/chat/queries.ts
+++ b/packages/core/chat/queries.ts
@@ -1,7 +1,20 @@
 import { infiniteQueryOptions, queryOptions } from "@tanstack/react-query";
 import { api } from "../api";
 import type { TaskMessagePayload } from "../types/events";
-import type { ChatQuickActionsPendingState, ChatSession } from "../types/chat";
+import type {
+  ChatQuickActionsFailureState,
+  ChatQuickActionsPendingState,
+  ChatSession,
+} from "../types/chat";
+
+/**
+ * How long a quick-actions pending marker may stay unresolved before a client
+ * gives up and clears it (MUL-5149). Used to stamp the marker's absolute
+ * `expires_at` deadline at creation, and by `useQuickActionsPendingTimeout` to
+ * clear it — a shared deadline survives chat-surface switches instead of
+ * re-arming a fresh window on each remount.
+ */
+export const QUICK_ACTIONS_PENDING_TIMEOUT_MS = 30_000;
 
 // NOTE on workspace scoping:
 // `wsId` is used only as part of queryKey for cache isolation per workspace.
@@ -25,6 +38,10 @@ export const chatKeys = {
   quickActionsPendingAll: () => ["chat", "quick-actions-pending"] as const,
   quickActionsPending: (sessionId: string) =>
     [...chatKeys.quickActionsPendingAll(), sessionId] as const,
+  /** Client-only signal: this session's last refresh regeneration failed. */
+  quickActionsFailureAll: () => ["chat", "quick-actions-failure"] as const,
+  quickActionsFailure: (sessionId: string) =>
+    [...chatKeys.quickActionsFailureAll(), sessionId] as const,
   draftRestoresAll: () => ["chat", "draft-restores"] as const,
   /** Durable deferred-cancellation draft restores for a session (#5219). */
   draftRestores: (sessionId: string) => [...chatKeys.draftRestoresAll(), sessionId] as const,
@@ -246,3 +263,17 @@ export function chatQuickActionsPendingOptions(sessionId: string) {
     staleTime: Infinity,
   });
 }
+
+/**
+ * Client-only cache entry mirroring {@link chatQuickActionsPendingOptions}:
+ * the realtime layer writes it off a failed chat:quick_actions, a view reads
+ * it once to toast "couldn't refresh," then clears it. Never fetched.
+ */
+export function chatQuickActionsFailureOptions(sessionId: string) {
+  return queryOptions({
+    queryKey: chatKeys.quickActionsFailure(sessionId),
+    queryFn: async (): Promise<ChatQuickActionsFailureState | null> => null,
+    enabled: false,
+    staleTime: Infinity,
+  });
+}
diff --git a/packages/core/chat/use-quick-actions-pending-timeout.ts b/packages/core/chat/use-quick-actions-pending-timeout.ts
index fe0734790..06ba94b21 100644
--- a/packages/core/chat/use-quick-actions-pending-timeout.ts
+++ b/packages/core/chat/use-quick-actions-pending-timeout.ts
@@ -1,26 +1,23 @@
 import { useEffect } from "react";
 import { useQueryClient } from "@tanstack/react-query";
-import { chatKeys } from "./queries";
+import { chatKeys, QUICK_ACTIONS_PENDING_TIMEOUT_MS } from "./queries";
 import type { ChatQuickActionsPendingState } from "../types/chat";
 
-/**
- * How long a quick-actions pending marker may stay unresolved before we give up
- * and clear it. Normally a chat:quick_actions supplement resolves the marker
- * well within this window; the timeout only covers the paths where that event
- * never arrives (daemon died, or its supplement HTTP ultimately failed).
- */
-export const QUICK_ACTIONS_PENDING_TIMEOUT_MS = 30_000;
-
 /**
  * Clears a session's `quickActionsPending` marker from the query cache when no
- * chat:quick_actions supplement resolves it in time (MUL-5149). Unlike a
- * component-local timer, this drops the REAL cache state, so the pill spinner /
- * skeleton stops AND a later refresh — even after closing and reopening chat —
- * starts clean instead of re-reading a stuck marker.
+ * chat:quick_actions supplement resolves it before the marker's own deadline
+ * (MUL-5149). Unlike a component-local timer, this drops the REAL cache state,
+ * so the pill spinner / skeleton stops AND a later refresh — even after closing
+ * and reopening chat — starts clean instead of re-reading a stuck marker.
+ *
+ * The deadline is `marker.expires_at` (absolute), NOT a fresh window per mount:
+ * switching between the floating chat and the chat tab unmounts one host and
+ * mounts the other, and a per-mount timer would restart the full wait each time,
+ * letting a lost event strand the marker indefinitely. Reading the stored
+ * deadline means a remount waits only the remaining time. The final clear is
+ * message-scoped so it never wipes a newer turn's marker.
  *
  * Mount once per surface that reads the marker (chat page / floating window).
- * The effect re-arms whenever the pending message changes, and the final clear
- * is message-scoped so it never wipes a newer turn's marker.
  */
 export function useQuickActionsPendingTimeout(
   sessionId: string | null,
@@ -28,15 +25,22 @@ export function useQuickActionsPendingTimeout(
 ): void {
   const qc = useQueryClient();
   const messageId = pending?.message_id ?? null;
+  const expiresAt = pending?.expires_at ?? null;
   useEffect(() => {
     if (!sessionId || !messageId) return;
-    const timer = setTimeout(() => {
+    const clear = () =>
       qc.setQueryData<ChatQuickActionsPendingState | null>(
         chatKeys.quickActionsPending(sessionId),
         (current) =>
           current && current.message_id === messageId ? null : current,
       );
-    }, QUICK_ACTIONS_PENDING_TIMEOUT_MS);
+    // Remaining time to this marker's absolute deadline; an old marker without
+    // one falls back to a full window. Already-past deadlines clear next tick.
+    const remaining =
+      expiresAt != null
+        ? expiresAt - Date.now()
+        : QUICK_ACTIONS_PENDING_TIMEOUT_MS;
+    const timer = setTimeout(clear, Math.max(0, remaining));
     return () => clearTimeout(timer);
-  }, [qc, sessionId, messageId]);
+  }, [qc, sessionId, messageId, expiresAt]);
 }
diff --git a/packages/core/realtime/use-realtime-sync.ts b/packages/core/realtime/use-realtime-sync.ts
index a6a3ffdfa..6474776e1 100644
--- a/packages/core/realtime/use-realtime-sync.ts
+++ b/packages/core/realtime/use-realtime-sync.ts
@@ -48,7 +48,12 @@ import {
   type SystemNotificationPayload,
 } from "../platform/system-notification";
 import type { Workspace } from "../types/workspace";
-import { chatKeys, mergeTaskMessagesBySeq, sortChatSessions } from "../chat/queries";
+import {
+  chatKeys,
+  mergeTaskMessagesBySeq,
+  sortChatSessions,
+  QUICK_ACTIONS_PENDING_TIMEOUT_MS,
+} from "../chat/queries";
 import { useChatStore } from "../chat";
 import { resolvePostAuthDestination, useHasOnboarded } from "../paths";
 import type {
@@ -88,6 +93,7 @@ import type {
   ChatDonePayload,
   ChatQuickActionsPayload,
   ChatQuickActionsPendingState,
+  ChatQuickActionsFailureState,
   ChatCancelFinalizedPayload,
   ChatMessage,
   ChatPendingTask,
@@ -177,7 +183,11 @@ export function applyChatDoneToCache(
   qc.setQueryData<ChatQuickActionsPendingState | null>(
     chatKeys.quickActionsPending(sessionId),
     payload.quick_actions_pending === true && messageId
-      ? { message_id: messageId, task_id: taskId }
+      ? {
+          message_id: messageId,
+          task_id: taskId,
+          expires_at: Date.now() + QUICK_ACTIONS_PENDING_TIMEOUT_MS,
+        }
       : null,
   );
   // Authoritative refetch reconciles redaction / migrations / clients
@@ -191,6 +201,12 @@ export function applyChatDoneToCache(
  * message's quick_actions in both message caches and resolve the pending
  * placeholder. An empty/missing list is terminal ("no suggestions this
  * turn") — the placeholder still resolves.
+ *
+ * `payload.failed` marks a resolution whose regeneration failed: the carried
+ * actions are the turn's UNCHANGED prior pills, so the patch is a no-op, but a
+ * failure signal is raised for a view to toast — otherwise an explicit refresh
+ * that failed would look identical to one that succeeded with the same
+ * suggestions (MUL-5149 review).
  */
 export async function applyChatQuickActionsToCache(
   qc: QueryClient,
@@ -239,6 +255,15 @@ export async function applyChatQuickActionsToCache(
     (current) =>
       current && current.message_id !== payload.message_id ? current : null,
   );
+  // Raise a one-shot failure signal on an explicit refresh whose regeneration
+  // failed. A view consumes it to toast and clears it; the `at` nonce keeps a
+  // repeat failure on the same turn from being deduped away.
+  if (payload.failed === true) {
+    qc.setQueryData<ChatQuickActionsFailureState | null>(
+      chatKeys.quickActionsFailure(sessionId),
+      { message_id: payload.message_id, at: Date.now() },
+    );
+  }
 }
 
 function patchLatestChatMessagePage(
diff --git a/packages/core/types/chat.ts b/packages/core/types/chat.ts
index 4f8ba577c..5d66e9245 100644
--- a/packages/core/types/chat.ts
+++ b/packages/core/types/chat.ts
@@ -35,6 +35,27 @@ export interface ChatQuickAction {
 export interface ChatQuickActionsPendingState {
   message_id: string;
   task_id: string;
+  /**
+   * Absolute epoch-ms deadline after which a client gives up waiting for the
+   * chat:quick_actions supplement and clears this marker. Stored on the marker
+   * (not as a component timer) so switching chat surfaces — which unmounts and
+   * remounts the timeout hook — resumes the SAME deadline instead of re-arming
+   * a fresh window each time (MUL-5149 review).
+   */
+  expires_at: number;
+}
+
+/**
+ * Client-only signal (never persisted, never fetched) that an explicit refresh's
+ * background regeneration FAILED — the daemon suggestion pass never completed, so
+ * the turn's pills are unchanged. Set by the realtime layer off a failed
+ * chat:quick_actions and consumed once by a view to toast "couldn't refresh"
+ * before clearing itself. `at` is a per-event nonce so a second failure re-fires
+ * even when the message_id repeats (MUL-5149 review).
+ */
+export interface ChatQuickActionsFailureState {
+  message_id: string;
+  at: number;
 }
 
 /** Preview of a session's most recent message, for the IM-style list. */
diff --git a/packages/core/types/events.ts b/packages/core/types/events.ts
index 801f40b8c..bde2cf7cb 100644
--- a/packages/core/types/events.ts
+++ b/packages/core/types/events.ts
@@ -397,6 +397,14 @@ export interface ChatQuickActionsPayload {
   task_id: string;
   message_id: string;
   quick_actions?: import("./chat").ChatQuickAction[];
+  /**
+   * The regeneration behind an explicit refresh failed: the actions carried
+   * here are the turn's UNCHANGED prior pills, sent only to resolve the pending
+   * spinner. Clients surface a "couldn't refresh" notice rather than treating
+   * them as freshly generated. Absent/false on the normal success path and on
+   * older servers.
+   */
+  failed?: boolean;
 }
 
 /**
diff --git a/packages/core/types/index.ts b/packages/core/types/index.ts
index 4a97aa8c3..d69a98224 100644
--- a/packages/core/types/index.ts
+++ b/packages/core/types/index.ts
@@ -100,6 +100,7 @@ export type {
   ChatMessage,
   ChatQuickAction,
   ChatQuickActionsPendingState,
+  ChatQuickActionsFailureState,
   ChatMessagesPage,
   ChatPendingTask,
   PendingChatTaskItem,
diff --git a/packages/views/chat/chat-page.tsx b/packages/views/chat/chat-page.tsx
index 5f9392dc6..18b4e719d 100644
--- a/packages/views/chat/chat-page.tsx
+++ b/packages/views/chat/chat-page.tsx
@@ -16,6 +16,7 @@ import { useChatStore } from "@multica/core/chat";
 import { chatQuickActionsPendingOptions } from "@multica/core/chat/queries";
 import { useRegenerateChatQuickActions } from "@multica/core/chat/mutations";
 import { useQuickActionsPendingTimeout } from "@multica/core/chat/use-quick-actions-pending-timeout";
+import { useQuickActionsFailureToast } from "./components/use-quick-actions-failure-toast";
 import { useQuery } from "@tanstack/react-query";
 import type { Agent, ChatSession } from "@multica/core/types";
 import { PageHeader } from "../layout/page-header";
@@ -64,6 +65,8 @@ export function ChatPage() {
   // Drop a stuck pending marker (dead daemon / failed supplement) so the pill
   // spinner stops and a later refresh starts clean (MUL-5149).
   useQuickActionsPendingTimeout(c.activeSessionId ?? null, quickActionsPending);
+  // Toast when an accepted refresh later fails in the daemon (async half).
+  useQuickActionsFailureToast(c.activeSessionId ?? null);
   const regenerateQuickActions = useRegenerateChatQuickActions();
   const urlSession = searchParams.get("session") || null;
   const urlAgent = searchParams.get("agent") || null;
diff --git a/packages/views/chat/components/chat-window.tsx b/packages/views/chat/components/chat-window.tsx
index fdb843287..bad1d7323 100644
--- a/packages/views/chat/components/chat-window.tsx
+++ b/packages/views/chat/components/chat-window.tsx
@@ -51,6 +51,7 @@ import {
 import { useChatStore } from "@multica/core/chat";
 import { chatQuickActionsPendingOptions } from "@multica/core/chat/queries";
 import { useQuickActionsPendingTimeout } from "@multica/core/chat/use-quick-actions-pending-timeout";
+import { useQuickActionsFailureToast } from "./use-quick-actions-failure-toast";
 import { removeChatMessageFromCaches } from "@multica/core/realtime";
 import { useChatDraftRestore } from "./use-chat-draft-restore";
 import { useChatInputFocus } from "./use-chat-input-focus";
@@ -116,6 +117,8 @@ export function ChatWindow() {
   // Drop a stuck pending marker (dead daemon / failed supplement) so the pill
   // spinner stops and a later refresh starts clean (MUL-5149).
   useQuickActionsPendingTimeout(activeSessionId ?? null, quickActionsPending);
+  // Toast when an accepted refresh later fails in the daemon (async half).
+  useQuickActionsFailureToast(activeSessionId ?? null);
   const regenerateQuickActions = useRegenerateChatQuickActions();
   const selectedAgentId = useChatStore((s) => s.selectedAgentId);
   const selectedProjectId = useChatStore((s) => s.selectedProjectId);
diff --git a/packages/views/chat/components/use-quick-actions-failure-toast.ts b/packages/views/chat/components/use-quick-actions-failure-toast.ts
new file mode 100644
index 000000000..250c52e0b
--- /dev/null
+++ b/packages/views/chat/components/use-quick-actions-failure-toast.ts
@@ -0,0 +1,45 @@
+import { useEffect } from "react";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
+import {
+  chatKeys,
+  chatQuickActionsFailureOptions,
+} from "@multica/core/chat/queries";
+import type { ChatQuickActionsFailureState } from "@multica/core/types";
+import { toast } from "sonner";
+import { useT } from "../../i18n";
+
+/**
+ * Surfaces a toast when a session's explicit quick-actions refresh fails
+ * asynchronously — the HTTP call was accepted but the daemon's regeneration
+ * never produced suggestions, so the turn's pills are unchanged (MUL-5149). The
+ * failure arrives over chat:quick_actions with failed=true, which
+ * applyChatQuickActionsToCache turns into a one-shot client-only signal; this
+ * hook consumes it and clears it. The synchronous HTTP-failure path (409 busy,
+ * network) already toasts from QuickActions.handleRegenerate, so this covers
+ * only the async half — without it, a failed refresh would look identical to a
+ * successful one whose suggestions happened not to change.
+ *
+ * A stable toast id keyed on the failure nonce collapses duplicates when both
+ * chat surfaces (floating window + chat tab) are mounted and each runs this
+ * hook against the same signal. Mount once per surface that reads the marker.
+ */
+export function useQuickActionsFailureToast(sessionId: string | null): void {
+  const qc = useQueryClient();
+  const { t } = useT("chat");
+  const { data: failure = null } = useQuery(
+    chatQuickActionsFailureOptions(sessionId ?? ""),
+  );
+
+  useEffect(() => {
+    if (!sessionId || !failure) return;
+    toast.error(t(($) => $.message_list.quick_actions_regenerate_failed), {
+      id: `qa-refresh-fail:${sessionId}:${failure.at}`,
+    });
+    // Clear only this exact signal so a newer failure raised in the same tick
+    // is not swallowed.
+    qc.setQueryData<ChatQuickActionsFailureState | null>(
+      chatKeys.quickActionsFailure(sessionId),
+      (current) => (current && current.at === failure.at ? null : current),
+    );
+  }, [qc, t, sessionId, failure]);
+}
diff --git a/server/internal/daemon/chat_suggest.go b/server/internal/daemon/chat_suggest.go
index e8291f25a..a5fe66190 100644
--- a/server/internal/daemon/chat_suggest.go
+++ b/server/internal/daemon/chat_suggest.go
@@ -65,7 +65,7 @@ func (d *Daemon) chatSuggestJob(task Task, backend agent.Backend, opts agent.Exe
 			d.chatSuggestCancels.CompareAndDelete(task.ChatSessionID, handle)
 		}()
 
-		raw, usage := d.runChatSuggestPass(ctx, backend, opts, providerSessionID, taskLog)
+		raw, usage, _ := d.runChatSuggestPass(ctx, backend, opts, providerSessionID, taskLog)
 		if ctx.Err() != nil {
 			// A newer turn on this session cancelled us: its user message
 			// supersedes these suggestions. Skip the supplement — the client
@@ -118,17 +118,11 @@ func (d *Daemon) runChatQuickActionsRegenerate(ctx context.Context, task Task, b
 		"target_task", shortID(task.RegenerateQuickActionsFor),
 		"resume", opts.ResumeSessionID != "",
 	)
-	raw, usage := d.runChatSuggestPass(ctx, backend, opts, opts.ResumeSessionID, taskLog)
-
-	reportCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
-	defer cancel()
-	supplementErr := d.client.SupplementTaskQuickActions(reportCtx, task.RegenerateQuickActionsFor, raw)
-	if supplementErr != nil {
-		taskLog.Warn("chat quick-actions regenerate supplement failed", "error", supplementErr)
-	}
+	raw, usage, ok := d.runChatSuggestPass(ctx, backend, opts, opts.ResumeSessionID, taskLog)
 
 	// Report the pass's own token spend on this regenerate task (its own row —
 	// no merge with a main turn, there isn't one). Same shape as chatSuggestJob.
+	// Reported on every outcome — a failed pass still burned tokens.
 	var usageEntries []TaskUsageEntry
 	for model, u := range usage {
 		if u.InputTokens == 0 && u.OutputTokens == 0 && u.CacheReadTokens == 0 && u.CacheWriteTokens == 0 {
@@ -143,12 +137,32 @@ func (d *Daemon) runChatQuickActionsRegenerate(ctx context.Context, task Task, b
 			CacheWriteTokens: u.CacheWriteTokens,
 		})
 	}
-	if supplementErr != nil {
+
+	if !ok {
+		// The provider pass itself FAILED (didn't start / didn't complete /
+		// timed out) — distinct from a completed pass that produced no
+		// suggestions. Do NOT supplement: an empty raw would silently rebroadcast
+		// the old pills as if the refresh succeeded. Report failure so FailTask →
+		// resolveFailedRegenerateQuickActions broadcasts a FAILED
+		// chat:quick_actions and the user gets feedback (MUL-5149 review §3).
+		return TaskResult{
+			Status:        "blocked",
+			FailureReason: "quick_actions_generation_failed",
+			Usage:         usageEntries,
+		}, nil
+	}
+
+	// Generation succeeded (raw may be an empty list — a genuine "no new
+	// suggestions" that keeps the existing pills). Supplement the target turn.
+	reportCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	if err := d.client.SupplementTaskQuickActions(reportCtx, task.RegenerateQuickActionsFor, raw); err != nil {
 		// The supplement never landed, so no chat:quick_actions resolved the
 		// client's refresh spinner. Report failure (never retried, writes no
 		// visible turn — see FailTask's regenerate gates) so the server converges
 		// the marker via resolveFailedRegenerateQuickActions instead of leaving
 		// the client to its own timeout (MUL-5149).
+		taskLog.Warn("chat quick-actions regenerate supplement failed", "error", err)
 		return TaskResult{
 			Status:        "blocked",
 			FailureReason: "quick_actions_supplement_failed",
@@ -160,9 +174,11 @@ func (d *Daemon) runChatQuickActionsRegenerate(ctx context.Context, task Task, b
 
 // runChatSuggestPass runs one extra provider turn on the just-finished chat
 // session and returns its raw text output (the JSON array, hopefully — the
-// server parses leniently and treats garbage as "no suggestions"). Best-effort
-// by design: every failure path returns "" and the turn proceeds without
-// suggestions.
+// server parses leniently and treats garbage as "no suggestions"). ok is false
+// only when the pass itself FAILED (didn't start, didn't complete, or timed
+// out), distinct from a pass that completed and simply produced no suggestions
+// (ok=true, possibly empty raw). The automatic pass is best-effort and ignores
+// ok; the explicit-refresh caller uses it to surface failure feedback (MUL-5149).
 //
 // The pass deliberately reuses the main turn's backend and exec options so it
 // lands on the same provider, model, and workdir; only the resume pointer,
@@ -173,7 +189,7 @@ func (d *Daemon) runChatQuickActionsRegenerate(ctx context.Context, task Task, b
 // new session file) keep the suggestion exchange in the session history the
 // next user turn resumes. The prompt's leading line instructs the model to
 // never surface it.
-func (d *Daemon) runChatSuggestPass(ctx context.Context, backend agent.Backend, opts agent.ExecOptions, sessionID string, taskLog *slog.Logger) (raw string, usage map[string]agent.TokenUsage) {
+func (d *Daemon) runChatSuggestPass(ctx context.Context, backend agent.Backend, opts agent.ExecOptions, sessionID string, taskLog *slog.Logger) (raw string, usage map[string]agent.TokenUsage, ok bool) {
 	suggestCtx, cancel := context.WithTimeout(ctx, chatSuggestTimeout)
 	defer cancel()
 
@@ -186,7 +202,7 @@ func (d *Daemon) runChatSuggestPass(ctx context.Context, backend agent.Backend,
 	session, err := backend.Execute(suggestCtx, chatSuggestPrompt, opts)
 	if err != nil {
 		taskLog.Warn("chat suggest pass failed to start", "error", err)
-		return "", nil
+		return "", nil, false
 	}
 
 	// Drain and discard the message stream: backends block on an undrained
@@ -206,15 +222,15 @@ func (d *Daemon) runChatSuggestPass(ctx context.Context, backend agent.Backend,
 				"status", result.Status,
 				"error", result.Error,
 			)
-			return "", result.Usage
+			return "", result.Usage, false
 		}
 		taskLog.Debug("chat suggest pass finished",
 			"duration", time.Since(start).Round(time.Second).String(),
 			"output_bytes", len(result.Output),
 		)
-		return strings.TrimSpace(result.Output), result.Usage
+		return strings.TrimSpace(result.Output), result.Usage, true
 	case <-suggestCtx.Done():
 		taskLog.Warn("chat suggest pass timed out or was cancelled", "timeout", chatSuggestTimeout.String())
-		return "", nil
+		return "", nil, false
 	}
 }
diff --git a/server/internal/daemon/chat_suggest_test.go b/server/internal/daemon/chat_suggest_test.go
index 0f4d4d520..1161aa999 100644
--- a/server/internal/daemon/chat_suggest_test.go
+++ b/server/internal/daemon/chat_suggest_test.go
@@ -19,7 +19,10 @@ func TestRunChatSuggestPassReturnsTrimmedOutputAndResumesSession(t *testing.T) {
 	}
 	d := &Daemon{logger: slog.Default()}
 
-	raw, usage := d.runChatSuggestPass(context.Background(), backend, agent.ExecOptions{Model: "m1"}, "sess-1", slog.Default())
+	raw, usage, ok := d.runChatSuggestPass(context.Background(), backend, agent.ExecOptions{Model: "m1"}, "sess-1", slog.Default())
+	if !ok {
+		t.Fatal("a completed pass must report ok=true")
+	}
 	if raw != `[{"label":"Next","prompt":"Do the next thing"}]` {
 		t.Fatalf("raw = %q", raw)
 	}
@@ -43,14 +46,14 @@ func TestRunChatSuggestPassSoftFailsOnErrorAndNonCompletion(t *testing.T) {
 	d := &Daemon{logger: slog.Default()}
 
 	failedStart := &fakeBackend{errors: []error{context.DeadlineExceeded}, results: []agent.Result{{}}}
-	if raw, _ := d.runChatSuggestPass(context.Background(), failedStart, agent.ExecOptions{}, "sess-1", slog.Default()); raw != "" {
-		t.Fatalf("start failure must degrade to no suggestions, got %q", raw)
+	if raw, _, ok := d.runChatSuggestPass(context.Background(), failedStart, agent.ExecOptions{}, "sess-1", slog.Default()); raw != "" || ok {
+		t.Fatalf("start failure must report ok=false and no suggestions, got raw=%q ok=%v", raw, ok)
 	}
 
 	notCompleted := &fakeBackend{results: []agent.Result{{Status: "timeout", Error: "slow", Usage: map[string]agent.TokenUsage{"m": {InputTokens: 1}}}}}
-	raw, usage := d.runChatSuggestPass(context.Background(), notCompleted, agent.ExecOptions{}, "sess-1", slog.Default())
-	if raw != "" {
-		t.Fatalf("non-completed result must degrade to no suggestions, got %q", raw)
+	raw, usage, ok := d.runChatSuggestPass(context.Background(), notCompleted, agent.ExecOptions{}, "sess-1", slog.Default())
+	if raw != "" || ok {
+		t.Fatalf("non-completed result must report ok=false and no suggestions, got raw=%q ok=%v", raw, ok)
 	}
 	if usage["m"].InputTokens != 1 {
 		t.Fatalf("tokens burned by a failed pass must still be reported, got %+v", usage)
diff --git a/server/internal/handler/chat.go b/server/internal/handler/chat.go
index c3ee67406..df028c48f 100644
--- a/server/internal/handler/chat.go
+++ b/server/internal/handler/chat.go
@@ -973,6 +973,11 @@ func (h *Handler) RegenerateChatQuickActions(w http.ResponseWriter, r *http.Requ
 			// view is stale (a newer reply arrived). 409 → the client rolls back
 			// its optimistic marker and re-offers refresh on the new turn.
 			writeError(w, http.StatusConflict, "a newer reply arrived — refresh it instead")
+		case errors.Is(err, service.ErrChatQuickActionsBusy):
+			// A turn or another refresh is already running for this session; the
+			// result would be stale or a duplicate. 409 → the client rolls back
+			// and can refresh once the session settles.
+			writeError(w, http.StatusConflict, "still working — try refreshing in a moment")
 		case errors.Is(err, service.ErrChatQuickActionsNoTurn):
 			writeError(w, http.StatusConflict, "no assistant reply to refresh yet")
 		case errors.Is(err, service.ErrChatQuickActionsNotResumable):
diff --git a/server/internal/handler/chat_input_ownership_test.go b/server/internal/handler/chat_input_ownership_test.go
index 1498468d6..d52a2223b 100644
--- a/server/internal/handler/chat_input_ownership_test.go
+++ b/server/internal/handler/chat_input_ownership_test.go
@@ -565,7 +565,7 @@ func TestCompleteTask_ChatQuickActionsSupplement(t *testing.T) {
 	}
 
 	raw := "```json\n" + `[{"label":"From pass","prompt":"suggested prompt","primary":true}]` + "\n```"
-	if err := testHandler.TaskService.SupplementChatQuickActions(ctx, *task, raw); err != nil {
+	if err := testHandler.TaskService.SupplementChatQuickActions(ctx, *task, raw, false); err != nil {
 		t.Fatalf("supplement quick actions: %v", err)
 	}
 	rows = assistantRows(t, ctx, sessionID)
@@ -579,7 +579,7 @@ func TestCompleteTask_ChatQuickActionsSupplement(t *testing.T) {
 
 	// An empty supplement must not clobber existing actions (it only resolves
 	// the pending placeholder client-side).
-	if err := testHandler.TaskService.SupplementChatQuickActions(ctx, *task, ""); err != nil {
+	if err := testHandler.TaskService.SupplementChatQuickActions(ctx, *task, "", false); err != nil {
 		t.Fatalf("empty supplement: %v", err)
 	}
 	rows = assistantRows(t, ctx, sessionID)
@@ -655,13 +655,21 @@ func TestRegenerateChatQuickActions_StaleTargetRejected(t *testing.T) {
 	m1 := rows[0].ID
 
 	// Refreshing the current latest turn is accepted and targets exactly it.
-	target, _, err := testHandler.TaskService.RegenerateChatQuickActions(ctx, session, parseUUID(testUserID), m1)
+	target, regenTask, err := testHandler.TaskService.RegenerateChatQuickActions(ctx, session, parseUUID(testUserID), m1)
 	if err != nil {
 		t.Fatalf("regenerate latest turn: %v", err)
 	}
 	if target != m1 {
 		t.Fatalf("regenerate target = %v, want the latest turn %v", target, m1)
 	}
+	// That refresh enqueues a regen pass that occupies the session until the
+	// daemon finishes it. Settle it so the session is idle again — this test
+	// isolates the STALE check; the busy-rejection path has its own tests.
+	if _, err := testPool.Exec(ctx,
+		`UPDATE agent_task_queue SET status='completed', completed_at=now() WHERE id=$1`,
+		uuidToString(regenTask.ID)); err != nil {
+		t.Fatalf("settle regen task: %v", err)
+	}
 
 	// Turn 2 lands, so m1 is no longer the latest.
 	t2 := sendDirectChat(t, ctx, agentID, sessionID, "second question")
@@ -687,3 +695,79 @@ func TestRegenerateChatQuickActions_StaleTargetRejected(t *testing.T) {
 		t.Fatalf("regenerate new latest turn: %v", err)
 	}
 }
+
+// TestRegenerateChatQuickActions_ActiveTurnRejected pins finding §1 of the
+// MUL-5149 review: a newer reply that is queued/running but whose assistant row
+// has not landed yet leaves the OLD turn as the latest-persisted one, so the
+// stale check still passes on it. Regenerating then would resume the session
+// after the newer turn advanced its provider state, attaching suggestions built
+// from the newer context to the older turn. The in-flight task must refuse it.
+func TestRegenerateChatQuickActions_ActiveTurnRejected(t *testing.T) {
+	if testHandler == nil {
+		t.Skip("database not available")
+	}
+	ctx := context.Background()
+	agentID, sessionID, _, _ := setupDirectChatSession(t, ctx, "regen busy chat")
+
+	// Turn 1 completes with a resumable session → m1 is the latest assistant turn.
+	t1 := sendDirectChat(t, ctx, agentID, sessionID, "first")
+	markTaskRunning(t, ctx, t1)
+	if _, err := testHandler.TaskService.CompleteTask(ctx, parseUUID(t1), completeResult(t, "first reply"), "sess-1", "/tmp/wd", false, ""); err != nil {
+		t.Fatalf("complete turn 1: %v", err)
+	}
+	session, err := testHandler.Queries.GetChatSession(ctx, parseUUID(sessionID))
+	if err != nil {
+		t.Fatalf("reload session: %v", err)
+	}
+	rows := assistantRows(t, ctx, sessionID)
+	if len(rows) != 1 {
+		t.Fatalf("expected one assistant turn, got %d", len(rows))
+	}
+	m1 := rows[0].ID
+
+	// Turn 2 is in flight (running, no assistant row yet) so m1 is STILL the
+	// latest-persisted turn — the stale check passes — but the session is busy.
+	t2 := sendDirectChat(t, ctx, agentID, sessionID, "second")
+	markTaskRunning(t, ctx, t2)
+
+	if _, _, err := testHandler.TaskService.RegenerateChatQuickActions(ctx, session, parseUUID(testUserID), m1); !errors.Is(err, service.ErrChatQuickActionsBusy) {
+		t.Fatalf("busy-session regenerate error = %v, want ErrChatQuickActionsBusy", err)
+	}
+}
+
+// TestRegenerateChatQuickActions_ConcurrentRefreshRejected pins finding §2 of
+// the MUL-5149 review: a second refresh of the same turn while the first pass is
+// still in flight is refused rather than enqueuing a duplicate, quota-spending
+// pass. A per-client disabled button cannot stop a second client, so the guard
+// lives under the session lock next to the enqueue.
+func TestRegenerateChatQuickActions_ConcurrentRefreshRejected(t *testing.T) {
+	if testHandler == nil {
+		t.Skip("database not available")
+	}
+	ctx := context.Background()
+	agentID, sessionID, _, _ := setupDirectChatSession(t, ctx, "regen dedup chat")
+
+	t1 := sendDirectChat(t, ctx, agentID, sessionID, "q")
+	markTaskRunning(t, ctx, t1)
+	if _, err := testHandler.TaskService.CompleteTask(ctx, parseUUID(t1), completeResult(t, "a"), "sess-1", "/tmp/wd", false, ""); err != nil {
+		t.Fatalf("complete turn 1: %v", err)
+	}
+	session, err := testHandler.Queries.GetChatSession(ctx, parseUUID(sessionID))
+	if err != nil {
+		t.Fatalf("reload session: %v", err)
+	}
+	rows := assistantRows(t, ctx, sessionID)
+	if len(rows) != 1 {
+		t.Fatalf("expected one assistant turn, got %d", len(rows))
+	}
+	m1 := rows[0].ID
+
+	// First refresh is accepted and enqueues a regen pass that now occupies the session.
+	if _, _, err := testHandler.TaskService.RegenerateChatQuickActions(ctx, session, parseUUID(testUserID), m1); err != nil {
+		t.Fatalf("first refresh: %v", err)
+	}
+	// Second refresh of the same turn while the first pass is still queued is refused.
+	if _, _, err := testHandler.TaskService.RegenerateChatQuickActions(ctx, session, parseUUID(testUserID), m1); !errors.Is(err, service.ErrChatQuickActionsBusy) {
+		t.Fatalf("concurrent refresh error = %v, want ErrChatQuickActionsBusy", err)
+	}
+}
diff --git a/server/internal/handler/daemon.go b/server/internal/handler/daemon.go
index b5a9915f9..cd0f07ca0 100644
--- a/server/internal/handler/daemon.go
+++ b/server/internal/handler/daemon.go
@@ -2959,7 +2959,7 @@ func (h *Handler) SupplementTaskQuickActions(w http.ResponseWriter, r *http.Requ
 		writeError(w, http.StatusBadRequest, "invalid request body")
 		return
 	}
-	if err := h.TaskService.SupplementChatQuickActions(r.Context(), task, req.Raw); err != nil {
+	if err := h.TaskService.SupplementChatQuickActions(r.Context(), task, req.Raw, false); err != nil {
 		slog.Warn("supplement task quick actions failed", "task_id", taskID, "error", err)
 		writeError(w, http.StatusInternalServerError, err.Error())
 		return
diff --git a/server/internal/service/chat_quick_actions.go b/server/internal/service/chat_quick_actions.go
index 98a8711d6..f31e4c57d 100644
--- a/server/internal/service/chat_quick_actions.go
+++ b/server/internal/service/chat_quick_actions.go
@@ -208,7 +208,11 @@ func chatQuickActionsPending(result []byte, msg *db.ChatMessage) bool {
 // turn that never wrote an assistant row (no_response, channel empty-drop)
 // returns silently — no client is waiting in that case, because the pending
 // flag is only ever raised for a written ordinary message.
-func (s *TaskService) SupplementChatQuickActions(ctx context.Context, task db.AgentTaskQueue, raw string) error {
+//
+// failed marks the broadcast as a failure resolution (an explicit refresh whose
+// regeneration failed): the pills stay unchanged but the client shows a
+// "couldn't refresh" notice instead of treating them as freshly generated.
+func (s *TaskService) SupplementChatQuickActions(ctx context.Context, task db.AgentTaskQueue, raw string, failed bool) error {
 	if !task.ChatSessionID.Valid {
 		return nil
 	}
@@ -248,6 +252,7 @@ func (s *TaskService) SupplementChatQuickActions(ctx context.Context, task db.Ag
 		TaskID:        util.UUIDToString(task.ID),
 		MessageID:     util.UUIDToString(msg.ID),
 		QuickActions:  []protocol.ChatQuickAction{},
+		Failed:        failed,
 	}
 	_ = json.Unmarshal(msg.QuickActions, &payload.QuickActions)
 	s.Bus.Publish(events.Event{
diff --git a/server/internal/service/task.go b/server/internal/service/task.go
index c758f88a1..735cfd25b 100644
--- a/server/internal/service/task.go
+++ b/server/internal/service/task.go
@@ -1444,6 +1444,12 @@ var ErrChatQuickActionsNotResumable = errors.New("chat quick actions: session no
 // chat:quick_actions event will not match (MUL-5149).
 var ErrChatQuickActionsStale = errors.New("chat quick actions: refresh target is stale")
 
+// ErrChatQuickActionsBusy signals the session already has work in flight — a
+// running turn about to change the latest reply, or another regenerate pass —
+// so a new refresh is refused to avoid a stale-target supplement or a duplicate
+// quota-spending pass (MUL-5149).
+var ErrChatQuickActionsBusy = errors.New("chat quick actions: session busy")
+
 // EnqueueChatTask creates a task-owned input batch for a chat session. Channel
 // media makes the task deferred until binding completes or its durable fallback
 // deadline expires; other chat tasks are queued immediately. Unlike issue
@@ -1680,6 +1686,24 @@ func (s *TaskService) RegenerateChatQuickActions(ctx context.Context, chatSessio
 		if target.ID != expectedMessageID {
 			return ErrChatQuickActionsStale
 		}
+		// Refuse while the session already has work in flight (MUL-5149 review
+		// §1/§2). Two races this closes, both under the same session lock as the
+		// enqueue so neither can slip a sibling insert past it:
+		//   1. A normal turn is queued/running but its assistant row hasn't
+		//      landed, so the latest-persisted check above still passes on the
+		//      OLD turn. That turn will change the reply and advance the session
+		//      pointer before this regen claims, leaving the suggestions built
+		//      from the newer context but attached to the older turn.
+		//   2. A second concurrent refresh of the same turn would just enqueue a
+		//      duplicate pass and double-spend quota — the button being disabled
+		//      on one client can't stop another.
+		busy, berr := qtx.HasActiveChatTaskForSession(ctx, chatSession.ID)
+		if berr != nil {
+			return fmt.Errorf("check active chat task: %w", berr)
+		}
+		if busy {
+			return ErrChatQuickActionsBusy
+		}
 		created, cerr := qtx.CreateChatTask(ctx, db.CreateChatTaskParams{
 			AgentID:           chatSession.AgentID,
 			RuntimeID:         carrier.RuntimeID,
@@ -3562,13 +3586,14 @@ func (s *TaskService) FailTask(ctx context.Context, taskID pgtype.UUID, errMsg,
 	return &task, nil
 }
 
-// resolveFailedRegenerateQuickActions clears a refresh's client-side pending
-// spinner after the regeneration task itself failed before it could supplement
-// (MUL-5149). It loads the target turn the refresh was aimed at and re-broadcasts
-// that turn's current (unchanged) quick actions via chat:quick_actions, which
-// resolves the pending marker on every client — leaving the old suggestions in
-// place rather than stranding the user on a spinner. Best-effort: a lookup miss
-// just leaves the client's own skeleton-timeout fallback to clear it.
+// resolveFailedRegenerateQuickActions resolves a refresh whose regeneration
+// task failed before it could deliver suggestions (MUL-5149). It loads the
+// target turn the refresh was aimed at and broadcasts a FAILED
+// chat:quick_actions carrying that turn's current (unchanged) pills — which
+// resolves the pending marker on every client AND flags the failure so the UI
+// shows a "couldn't refresh" notice instead of stopping the spinner on
+// unchanged content as if it had succeeded. Best-effort: a lookup miss just
+// leaves the client's own timeout fallback to clear the marker.
 func (s *TaskService) resolveFailedRegenerateQuickActions(ctx context.Context, task db.AgentTaskQueue) {
 	if !task.RegenerateQuickActionsFor.Valid {
 		return
@@ -3581,8 +3606,8 @@ func (s *TaskService) resolveFailedRegenerateQuickActions(ctx context.Context, t
 	}
 	// Empty raw parses to no actions, so SupplementChatQuickActions re-broadcasts
 	// the target's existing pills (GetChatMessageByTaskAssistant) and resolves the
-	// marker without overwriting anything.
-	if err := s.SupplementChatQuickActions(ctx, target, ""); err != nil {
+	// marker without overwriting anything; failed=true marks it a failure.
+	if err := s.SupplementChatQuickActions(ctx, target, "", true); err != nil {
 		slog.Warn("regenerate failure: resolve pending marker failed",
 			"task_id", util.UUIDToString(task.ID), "error", err)
 	}
diff --git a/server/pkg/db/generated/chat.sql.go b/server/pkg/db/generated/chat.sql.go
index e6d4ab4e4..37df27cc7 100644
--- a/server/pkg/db/generated/chat.sql.go
+++ b/server/pkg/db/generated/chat.sql.go
@@ -869,6 +869,29 @@ func (q *Queries) GetPendingChatTask(ctx context.Context, chatSessionID pgtype.U
 	return i, err
 }
 
+const hasActiveChatTaskForSession = `-- name: HasActiveChatTaskForSession :one
+SELECT EXISTS (
+  SELECT 1 FROM agent_task_queue
+  WHERE chat_session_id = $1
+    AND status IN ('queued', 'dispatched', 'running', 'waiting_local_directory')
+) AS has_active
+`
+
+// True while ANY task — a normal user turn OR a background quick-actions
+// regenerate — is in flight for the session (contrast GetPendingChatTask, which
+// hides regenerate passes from the UI). A quick-actions refresh is refused when
+// this is true: a running turn is about to change the latest reply, so the
+// target we'd resume is already stale even before its assistant row lands; and a
+// second concurrent regenerate would double-spend quota on the same turn. Read
+// inside the same session lock as the enqueue so it cannot race a sibling insert
+// (MUL-5149 review §1/§2).
+func (q *Queries) HasActiveChatTaskForSession(ctx context.Context, chatSessionID pgtype.UUID) (bool, error) {
+	row := q.db.QueryRow(ctx, hasActiveChatTaskForSession, chatSessionID)
+	var has_active bool
+	err := row.Scan(&has_active)
+	return has_active, err
+}
+
 const hasPendingChatTasksByCreator = `-- name: HasPendingChatTasksByCreator :one
 SELECT EXISTS (
   SELECT 1
diff --git a/server/pkg/db/queries/chat.sql b/server/pkg/db/queries/chat.sql
index a2164dda7..36a0defbc 100644
--- a/server/pkg/db/queries/chat.sql
+++ b/server/pkg/db/queries/chat.sql
@@ -456,6 +456,21 @@ WHERE session_id NOT IN (SELECT session_id FROM retired_sessions)
 ORDER BY completed_at DESC
 LIMIT 1;
 
+-- name: HasActiveChatTaskForSession :one
+-- True while ANY task — a normal user turn OR a background quick-actions
+-- regenerate — is in flight for the session (contrast GetPendingChatTask, which
+-- hides regenerate passes from the UI). A quick-actions refresh is refused when
+-- this is true: a running turn is about to change the latest reply, so the
+-- target we'd resume is already stale even before its assistant row lands; and a
+-- second concurrent regenerate would double-spend quota on the same turn. Read
+-- inside the same session lock as the enqueue so it cannot race a sibling insert
+-- (MUL-5149 review §1/§2).
+SELECT EXISTS (
+  SELECT 1 FROM agent_task_queue
+  WHERE chat_session_id = $1
+    AND status IN ('queued', 'dispatched', 'running', 'waiting_local_directory')
+) AS has_active;
+
 -- name: GetPendingChatTask :one
 -- Returns the most recent in-flight task for a chat session, if any.
 -- Used by the frontend to recover pending state after refresh / reopen.
diff --git a/server/pkg/protocol/messages.go b/server/pkg/protocol/messages.go
index 953089d88..820bd2086 100644
--- a/server/pkg/protocol/messages.go
+++ b/server/pkg/protocol/messages.go
@@ -141,6 +141,13 @@ type ChatQuickActionsPayload struct {
 	TaskID        string            `json:"task_id"`
 	MessageID     string            `json:"message_id"`
 	QuickActions  []ChatQuickAction `json:"quick_actions"`
+	// Failed marks a supplement that resolves the client's refresh spinner
+	// because the regeneration FAILED (the provider pass or its delivery), not
+	// because it produced new suggestions. QuickActions then carries the turn's
+	// unchanged pills; the client shows a "couldn't refresh" notice instead of
+	// treating unchanged content as a silent success (MUL-5149). Omitted (false)
+	// on the normal success path and for the automatic best-effort pass.
+	Failed bool `json:"failed,omitempty"`
 }
 
 // TaskMessagePayload represents a single agent execution message (tool call, text, etc.)