diff --git a/ui/src/pages/chat/chat-send.test.ts b/ui/src/pages/chat/chat-send.test.ts
index 42545b90a6e..0fe51f42757 100644
--- a/ui/src/pages/chat/chat-send.test.ts
+++ b/ui/src/pages/chat/chat-send.test.ts
@@ -2589,6 +2589,74 @@ describe("handleSendChat", () => {
     expect(host.lastError).toBe("Message will send when the Gateway reconnects.");
   });
 
+  it("restores a pre-ack send when browser storage rejects the reconnect queue", async () => {
+    const storage = createStorageMock();
+    vi.spyOn(storage, "setItem").mockImplementation(() => {
+      throw new DOMException("quota exceeded", "QuotaExceededError");
+    });
+    vi.stubGlobal("sessionStorage", storage);
+    const request = vi.fn((method: string) => {
+      if (method === "chat.send") {
+        throw new Error("gateway closed (1006): network lost");
+      }
+      throw new Error(`Unexpected request: ${method}`);
+    });
+    const replyTarget = {
+      messageId: "reply-before-ack",
+      text: "quoted body",
+      senderLabel: "User",
+    };
+    const host = makeHost({
+      client: { request } as unknown as ChatHost["client"],
+      chatMessage: "retry after reconnect",
+      chatReplyTarget: replyTarget,
+    });
+
+    await handleSendChat(host);
+
+    expect(host.chatMessage).toBe("retry after reconnect");
+    expect(host.chatQueue).toStrictEqual([]);
+    expect(host.chatReplyTarget).toEqual(replyTarget);
+    expect(host.lastError).toBe(
+      "Could not store this message for reconnect. Free browser storage or reconnect before sending.",
+    );
+  });
+
+  it("keeps a pre-ack send queued when newer composer input blocks restoration", async () => {
+    const storage = createStorageMock();
+    vi.spyOn(storage, "setItem").mockImplementation(() => {
+      throw new DOMException("quota exceeded", "QuotaExceededError");
+    });
+    vi.stubGlobal("sessionStorage", storage);
+    const sent = createDeferred<unknown>();
+    const request = vi.fn((method: string) => {
+      if (method === "chat.send") {
+        return sent.promise;
+      }
+      throw new Error(`Unexpected request: ${method}`);
+    });
+    const host = makeHost({
+      client: { request } as unknown as ChatHost["client"],
+      chatMessage: "original send",
+    });
+
+    const send = handleSendChat(host);
+    await Promise.resolve();
+    host.chatMessage = "new draft";
+    sent.reject(new Error("gateway closed (1006): network lost"));
+    await send;
+
+    expect(host.chatMessage).toBe("new draft");
+    expect(host.chatQueue).toEqual([
+      expect.objectContaining({
+        text: "original send",
+        sendError:
+          "Could not store this message for reconnect. Free browser storage or reconnect before sending.",
+        sendState: "failed",
+      }),
+    ]);
+  });
+
   it("queues normal sends made while disconnected", async () => {
     const host = makeHost({
       client: null,
@@ -2714,6 +2782,48 @@ describe("handleSendChat", () => {
     expect(host.chatStream).toBeNull();
   });
 
+  it("keeps an existing queued send visible when retry persistence fails", async () => {
+    const storage = createStorageMock();
+    vi.spyOn(storage, "setItem").mockImplementation(() => {
+      throw new DOMException("quota exceeded", "QuotaExceededError");
+    });
+    vi.stubGlobal("sessionStorage", storage);
+    const request = vi.fn((method: string) => {
+      if (method === "chat.send") {
+        throw new Error("gateway closed (1006): network lost");
+      }
+      throw new Error(`Unexpected request: ${method}`);
+    });
+    const host = makeHost({
+      client: { request } as unknown as ChatHost["client"],
+      connected: true,
+      chatQueue: [
+        {
+          id: "queued-retry-storage-failure",
+          text: "keep this queued message",
+          createdAt: 1,
+          sendRunId: "run-retry-storage-failure",
+          sendState: "waiting-reconnect",
+          sessionKey: "agent:main",
+        },
+      ],
+    });
+
+    await retryReconnectableQueuedChatSends(host);
+
+    expect(host.chatQueue).toEqual([
+      expect.objectContaining({
+        id: "queued-retry-storage-failure",
+        sendError:
+          "Could not store this message for reconnect. Free browser storage or reconnect before sending.",
+        sendState: "failed",
+      }),
+    ]);
+    expect(host.lastError).toBe(
+      "Could not store this message for reconnect. Free browser storage or reconnect before sending.",
+    );
+  });
+
   it("defers queued global send agent selection until defaults are known", async () => {
     const request = vi.fn((method: string) => {
       if (method === "chat.send") {
diff --git a/ui/src/pages/chat/chat-send.ts b/ui/src/pages/chat/chat-send.ts
index 7780581b6e8..80e4577c606 100644
--- a/ui/src/pages/chat/chat-send.ts
+++ b/ui/src/pages/chat/chat-send.ts
@@ -489,12 +489,31 @@ function restoreComposerAfterFailedSend(
   }
 }
 
+type PendingComposerSnapshot = {
+  previousAttachments?: ChatAttachment[];
+  previousDraft?: string;
+};
+
+function pendingComposerRestorePlan(host: ChatHost, snapshot: PendingComposerSnapshot) {
+  const willRestoreDraft = snapshot.previousDraft != null && !host.chatMessage.trim();
+  const willRestoreAttachments = Boolean(
+    snapshot.previousAttachments?.length &&
+    host.chatAttachments.length === 0 &&
+    (willRestoreDraft || !host.chatMessage.trim()),
+  );
+  return {
+    complete:
+      (!snapshot.previousDraft?.trim() || willRestoreDraft) &&
+      (!snapshot.previousAttachments?.length || willRestoreAttachments),
+    willRestoreAttachments,
+    willRestoreDraft,
+  };
+}
+
 function cancelPendingSendBeforeRequest(
   host: ChatHost,
   queued: ChatQueueItem,
-  opts: {
-    previousAttachments?: ChatAttachment[];
-    previousDraft?: string;
+  opts: PendingComposerSnapshot & {
     restoreComposer?: boolean;
   },
 ) {
@@ -504,14 +523,9 @@ function cancelPendingSendBeforeRequest(
     queued.sessionKey,
   );
   const restoreComposer = opts.restoreComposer !== false && removed != null;
-  const willRestoreDraft =
-    restoreComposer && opts.previousDraft != null && !host.chatMessage.trim();
-  const willRestoreAttachments = Boolean(
-    restoreComposer &&
-    opts.previousAttachments?.length &&
-    host.chatAttachments.length === 0 &&
-    (willRestoreDraft || !host.chatMessage.trim()),
-  );
+  const restorePlan = pendingComposerRestorePlan(host, opts);
+  const willRestoreDraft = restoreComposer && restorePlan.willRestoreDraft;
+  const willRestoreAttachments = restoreComposer && restorePlan.willRestoreAttachments;
   if (restoreComposer) {
     if (willRestoreDraft) {
       host.chatMessage = opts.previousDraft ?? "";
@@ -765,17 +779,33 @@ async function sendQueuedChatMessage(
       const stored = Boolean(
         waiting && persistQueuedMessagesForSession(host, sessionKey, waiting.id),
       );
-      if (!stored && waiting) {
-        updateQueuedMessageForSession(host, sessionKey, id, (item) => ({
-          ...item,
-          sendError: OFFLINE_QUEUE_STORAGE_ERROR,
-        }));
+      if (!stored) {
+        const hasComposerSnapshot =
+          opts?.previousDraft !== undefined || opts?.previousAttachments !== undefined;
+        // Remove the queue item only when its full payload can be restored
+        // without overwriting newer composer input.
+        if (hasComposerSnapshot && pendingComposerRestorePlan(host, opts ?? {}).complete) {
+          cancelPendingSendBeforeRequest(host, waiting ?? prepared, {
+            previousDraft: opts?.previousDraft,
+            previousAttachments: opts?.previousAttachments,
+          });
+        } else {
+          updateQueuedMessageForSession(host, sessionKey, id, (item) => ({
+            ...item,
+            sendError: OFFLINE_QUEUE_STORAGE_ERROR,
+            sendState: "failed",
+          }));
+        }
+        if (isVisibleSession()) {
+          setChatError(host, OFFLINE_QUEUE_STORAGE_ERROR);
+        }
+        recordChatSendTiming(host, prepared, "failed", prepared.sendSubmittedAtMs, {
+          error: OFFLINE_QUEUE_STORAGE_ERROR,
+        });
+        return "failed";
       }
       if (isVisibleSession()) {
-        setChatError(
-          host,
-          stored ? "Message will send when the Gateway reconnects." : OFFLINE_QUEUE_STORAGE_ERROR,
-        );
+        setChatError(host, "Message will send when the Gateway reconnects.");
       }
       recordChatSendTiming(host, prepared, "waiting-reconnect", prepared.sendSubmittedAtMs, {
         error,