diff --git a/src/__tests__/unit/services/canvas-turn-persistence.test.ts b/src/__tests__/unit/services/canvas-turn-persistence.test.ts
index 2e9b2222b5..2df612c709 100644
--- a/src/__tests__/unit/services/canvas-turn-persistence.test.ts
+++ b/src/__tests__/unit/services/canvas-turn-persistence.test.ts
@@ -292,6 +292,54 @@ describe("appendTurnMessages", () => {
     expect(notify).not.toHaveBeenCalled();
   });
 
+  test("lands a turn's rows after its own user message, not after a later one", async () => {
+    withLockedRows([
+      { id: "turn-1-u", role: "user", content: "Q1" },
+      { id: "turn-2-u", role: "user", content: "Q2 (sent while turn 1 ran)" },
+    ]);
+
+    await appendTurnMessages({
+      conversationId: "conv-1",
+      rows,
+      idPrefix: "turn-1-a",
+      reason: "user-turn",
+      turnId: "turn-1",
+    });
+
+    const written = update.mock.calls[0][0].data.messages as { id: string }[];
+    expect(written.map((m) => m.id)).toEqual(["turn-1-u", "turn-1-a0", "turn-2-u"]);
+  });
+
+  test("appends when the turn is already last, or when no turn is given", async () => {
+    withLockedRows([
+      { id: "turn-0-u", role: "user", content: "Q0" },
+      { id: "turn-1-u", role: "user", content: "Q1" },
+    ]);
+    await appendTurnMessages({
+      conversationId: "conv-1",
+      rows,
+      idPrefix: "turn-1-a",
+      reason: "user-turn",
+      turnId: "turn-1",
+    });
+    const anchored = update.mock.calls[0][0].data.messages as { id: string }[];
+    expect(anchored.map((m) => m.id)).toEqual(["turn-0-u", "turn-1-u", "turn-1-a0"]);
+
+    update.mockClear();
+    withLockedRows([
+      { id: "turn-1-u", role: "user", content: "Q1" },
+      { id: "turn-2-u", role: "user", content: "Q2" },
+    ]);
+    await appendTurnMessages({
+      conversationId: "conv-1",
+      rows,
+      idPrefix: "turn-1-a",
+      reason: "user-turn",
+    });
+    const appended = update.mock.calls[0][0].data.messages as { id: string }[];
+    expect(appended.map((m) => m.id)).toEqual(["turn-1-u", "turn-2-u", "turn-1-a0"]);
+  });
+
   test("no-ops when the conversation row was deleted mid-turn", async () => {
     withNoRow();
 
diff --git a/src/app/api/ask/quick/route.ts b/src/app/api/ask/quick/route.ts
index 0d5e04c806..b09deec906 100644
--- a/src/app/api/ask/quick/route.ts
+++ b/src/app/api/ask/quick/route.ts
@@ -812,6 +812,7 @@ export async function POST(request: NextRequest) {
               rows,
               idPrefix: assistantPrefix,
               reason: "user-turn",
+              turnId: turnIdStr ?? undefined,
             });
           } catch (err) {
             console.error("❌ [quick-ask] Turn persist failed:", err);
@@ -831,6 +832,7 @@ export async function POST(request: NextRequest) {
               rows: [errorRow],
               idPrefix: assistantPrefix,
               reason: "user-turn",
+              turnId: turnIdStr ?? undefined,
             }).catch(() => {});
           }
         });
diff --git a/src/app/api/ask/sync/route.ts b/src/app/api/ask/sync/route.ts
index 64c2f43198..756fabc5f2 100644
--- a/src/app/api/ask/sync/route.ts
+++ b/src/app/api/ask/sync/route.ts
@@ -455,6 +455,7 @@ export async function POST(request: NextRequest) {
           rows,
           idPrefix: assistantPrefix,
           reason: "user-turn",
+          turnId,
         });
 
         // Snapshot the rendered prefix for the Agent Logs detail view, and
diff --git a/src/lib/mcp/orgMcpTools.ts b/src/lib/mcp/orgMcpTools.ts
index 18cc1b2619..dede654169 100644
--- a/src/lib/mcp/orgMcpTools.ts
+++ b/src/lib/mcp/orgMcpTools.ts
@@ -418,6 +418,7 @@ export function registerOrgTools(
               rows,
               idPrefix: assistantPrefix,
               reason: "user-turn",
+              turnId,
             });
 
             // Snapshot the rendered prefix for the Agent Logs detail view,
diff --git a/src/services/canvas-turn-persistence.ts b/src/services/canvas-turn-persistence.ts
index 37b3267e10..9cd0289663 100644
--- a/src/services/canvas-turn-persistence.ts
+++ b/src/services/canvas-turn-persistence.ts
@@ -398,6 +398,27 @@ export async function fetchStoredConversationMessages(args: {
   return Array.isArray(row.messages) ? (row.messages as unknown as StoredMessage[]) : [];
 }
 
+/**
+ * Where a turn's rows go: after the last stored row of that turn when it
+ * has one (its user message, or an earlier partial write), else at the
+ * end. Appending blindly puts a slow reply after a message that was sent
+ * while it ran.
+ */
+export function placeTurnRows<T extends { id?: unknown }>(
+  existing: T[],
+  rows: T[],
+  turnId?: string,
+): T[] {
+  if (!turnId) return [...existing, ...rows];
+  const prefix = `${turnId}-`;
+  let last = -1;
+  existing.forEach((m, i) => {
+    if (typeof m.id === "string" && m.id.startsWith(prefix)) last = i;
+  });
+  if (last < 0 || last === existing.length - 1) return [...existing, ...rows];
+  return [...existing.slice(0, last + 1), ...rows, ...existing.slice(last + 1)];
+}
+
 /**
  * Append rows into a canvas conversation under the same row-level lock
  * the fan-out worker and the autosave PUT use, so all writers serialize
@@ -414,8 +435,15 @@ export async function appendTurnMessages(args: {
   rows: StoredMessage[];
   idPrefix: string;
   reason: CanvasConversationUpdateReason;
+  /**
+   * The turn these rows finish. Its user row (`${turnId}-u`) is already
+   * stored, so the rows land right after that turn's last row rather
+   * than at the end — a reply that finishes after a later message was
+   * sent (another tab, a shared room) still reads user → reply → user.
+   */
+  turnId?: string;
 }): Promise<boolean> {
-  const { conversationId, rows, idPrefix, reason } = args;
+  const { conversationId, rows, idPrefix, reason, turnId } = args;
   if (rows.length === 0) return false;
 
   let didAppend = false;
@@ -437,7 +465,7 @@ export async function appendTurnMessages(args: {
     await tx.sharedConversation.update({
       where: { id: conversationId },
       data: {
-        messages: [...existing, ...rows] as unknown as never,
+        messages: placeTurnRows(existing, rows, turnId) as unknown as never,
         lastMessageAt: new Date(),
       },
     });