diff --git a/src/group-queue.ts b/src/group-queue.ts
index 042f7a3..4e888a4 100644
--- a/src/group-queue.ts
+++ b/src/group-queue.ts
@@ -42,6 +42,7 @@ interface GroupState {
   retryScheduledAt: number | null;
   startedAt: number | null;
   activityTouch: ((meta?: GroupActivityTouchMeta) => void) | null;
+  followUpPipeAllowed: (() => boolean) | null;
 }
 
 export interface GroupStatus {
@@ -81,6 +82,7 @@ export class GroupQueue {
         retryScheduledAt: null,
         startedAt: null,
         activityTouch: null,
+        followUpPipeAllowed: null,
       };
       this.groups.set(groupJid, state);
     }
@@ -101,6 +103,14 @@ export class GroupQueue {
     state.activityTouch = touch;
   }
 
+  setFollowUpPipeAllowed(
+    groupJid: string,
+    allowed: (() => boolean) | null,
+  ): void {
+    const state = this.getGroup(groupJid);
+    state.followUpPipeAllowed = allowed;
+  }
+
   private createRunId(): string {
     return `run-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 8)}`;
   }
@@ -117,6 +127,12 @@ export class GroupQueue {
 
     if (state.active) {
       state.pendingMessages = true;
+      if (state.idleWaiting) {
+        this.closeStdin(groupJid, {
+          runId: state.currentRunId ?? undefined,
+          reason: 'pending-message-preemption',
+        });
+      }
       logger.debug({ groupJid }, 'Agent active, message queued');
       return;
     }
@@ -268,6 +284,13 @@ export class GroupQueue {
       );
       return false;
     }
+    if (state.followUpPipeAllowed && !state.followUpPipeAllowed()) {
+      logger.info(
+        { groupJid, runId: state.currentRunId, groupFolder: state.groupFolder },
+        'Skipping follow-up IPC because active agent requires a fresh logical run',
+      );
+      return false;
+    }
     state.idleWaiting = false; // Agent is about to receive work, no longer idle
 
     const inputDir = path.join(DATA_DIR, 'ipc', state.groupFolder, 'input');
@@ -412,6 +435,7 @@ export class GroupQueue {
       state.groupFolder = null;
       state.currentRunId = null;
       state.activityTouch = null;
+      state.followUpPipeAllowed = null;
       this.activeCount--;
       this.drainGroup(groupJid);
     }
@@ -447,6 +471,7 @@ export class GroupQueue {
       state.processName = null;
       state.groupFolder = null;
       state.activityTouch = null;
+      state.followUpPipeAllowed = null;
       this.activeCount--;
       this.drainGroup(groupJid);
     }
diff --git a/src/message-runtime.test.ts b/src/message-runtime.test.ts
index dd4926e..13c98cb 100644
--- a/src/message-runtime.test.ts
+++ b/src/message-runtime.test.ts
@@ -335,7 +335,10 @@ describe('createMessageRuntime', () => {
 
     expect(result).toBe(true);
     expect(clearSession).not.toHaveBeenCalled();
-    expect(closeStdin).not.toHaveBeenCalled();
+    expect(closeStdin).toHaveBeenCalledWith(chatJid, {
+      runId: 'run-2',
+      reason: 'output-delivered-close',
+    });
     expect(notifyIdle).toHaveBeenCalledWith(chatJid, 'run-2');
   });
 
@@ -419,10 +422,12 @@ describe('createMessageRuntime', () => {
         'progress-1',
         'CI 상태 확인 중입니다.\n\n10초',
       );
-      expect(channel.sendMessage).toHaveBeenCalledWith(
+      expect(channel.editMessage).toHaveBeenCalledWith(
         chatJid,
+        'progress-1',
         'CI 상태 확인 중입니다.',
       );
+      expect(channel.sendMessage).not.toHaveBeenCalled();
       expect(notifyIdle).toHaveBeenCalledTimes(1);
       expect(notifyIdle).toHaveBeenCalledWith(chatJid, 'run-progress');
       expect(persistSession).toHaveBeenCalledWith(
@@ -434,6 +439,152 @@ describe('createMessageRuntime', () => {
     }
   });
 
+  it('falls back to a plain progress message when tracked progress creation throws', async () => {
+    const chatJid = 'group@test';
+    const group = makeGroup('codex');
+    const channel = makeChannel(chatJid);
+
+    vi.mocked(db.getMessagesSince).mockReturnValue([
+      {
+        id: 'msg-1',
+        chat_jid: chatJid,
+        sender: 'user@test',
+        sender_name: 'User',
+        content: 'hello',
+        timestamp: '2026-03-19T00:00:00.000Z',
+      },
+    ]);
+
+    vi.mocked(channel.sendAndTrack!).mockRejectedValueOnce(
+      new Error('discord send failed'),
+    );
+
+    vi.mocked(agentRunner.runAgentProcess).mockImplementation(
+      async (_group, _input, _onProcess, onOutput) => {
+        await onOutput?.({
+          status: 'success',
+          phase: 'progress',
+          result: '진행 중입니다.',
+          newSessionId: 'session-progress-fallback',
+        });
+        return {
+          status: 'success',
+          result: null,
+          newSessionId: 'session-progress-fallback',
+        };
+      },
+    );
+
+    const runtime = createMessageRuntime({
+      assistantName: 'Andy',
+      idleTimeout: 1_000,
+      pollInterval: 1_000,
+      timezone: 'UTC',
+      triggerPattern: /^@Andy\b/i,
+      channels: [channel],
+      queue: {
+        registerProcess: vi.fn(),
+        closeStdin: vi.fn(),
+        notifyIdle: vi.fn(),
+      } as any,
+      getRegisteredGroups: () => ({ [chatJid]: group }),
+      getSessions: () => ({}),
+      getLastTimestamp: () => '',
+      setLastTimestamp: vi.fn(),
+      getLastAgentTimestamps: () => ({}),
+      saveState: vi.fn(),
+      persistSession: vi.fn(),
+      clearSession: vi.fn(),
+    });
+
+    const result = await runtime.processGroupMessages(chatJid, {
+      runId: 'run-progress-fallback-throw',
+      reason: 'messages',
+    });
+
+    expect(result).toBe(true);
+    expect(channel.sendAndTrack).toHaveBeenCalledWith(
+      chatJid,
+      '진행 중입니다.\n\n0초',
+    );
+    expect(channel.sendMessage).toHaveBeenCalledWith(
+      chatJid,
+      '진행 중입니다.\n\n0초',
+    );
+  });
+
+  it('falls back to a plain progress message when tracked progress creation returns null', async () => {
+    const chatJid = 'group@test';
+    const group = makeGroup('codex');
+    const channel = makeChannel(chatJid);
+
+    vi.mocked(db.getMessagesSince).mockReturnValue([
+      {
+        id: 'msg-1',
+        chat_jid: chatJid,
+        sender: 'user@test',
+        sender_name: 'User',
+        content: 'hello',
+        timestamp: '2026-03-19T00:00:00.000Z',
+      },
+    ]);
+
+    vi.mocked(channel.sendAndTrack!).mockResolvedValueOnce(null as any);
+
+    vi.mocked(agentRunner.runAgentProcess).mockImplementation(
+      async (_group, _input, _onProcess, onOutput) => {
+        await onOutput?.({
+          status: 'success',
+          phase: 'progress',
+          result: '진행 중입니다.',
+          newSessionId: 'session-progress-null-fallback',
+        });
+        return {
+          status: 'success',
+          result: null,
+          newSessionId: 'session-progress-null-fallback',
+        };
+      },
+    );
+
+    const runtime = createMessageRuntime({
+      assistantName: 'Andy',
+      idleTimeout: 1_000,
+      pollInterval: 1_000,
+      timezone: 'UTC',
+      triggerPattern: /^@Andy\b/i,
+      channels: [channel],
+      queue: {
+        registerProcess: vi.fn(),
+        closeStdin: vi.fn(),
+        notifyIdle: vi.fn(),
+      } as any,
+      getRegisteredGroups: () => ({ [chatJid]: group }),
+      getSessions: () => ({}),
+      getLastTimestamp: () => '',
+      setLastTimestamp: vi.fn(),
+      getLastAgentTimestamps: () => ({}),
+      saveState: vi.fn(),
+      persistSession: vi.fn(),
+      clearSession: vi.fn(),
+    });
+
+    const result = await runtime.processGroupMessages(chatJid, {
+      runId: 'run-progress-fallback-null',
+      reason: 'messages',
+    });
+
+    expect(result).toBe(true);
+    expect(channel.sendAndTrack).toHaveBeenCalledWith(
+      chatJid,
+      '진행 중입니다.\n\n0초',
+    );
+    expect(channel.sendMessage).toHaveBeenCalledWith(
+      chatJid,
+      '진행 중입니다.\n\n0초',
+    );
+  });
+
   it('resets the idle timeout when follow-up Codex progress keeps arriving', async () => {
     vi.useFakeTimers();
     const chatJid = 'group@test';
@@ -460,7 +611,6 @@ describe('createMessageRuntime', () => {
           newSessionId: 'session-follow-up',
         });
         await vi.advanceTimersByTimeAsync(800);
-        expect(closeStdin).not.toHaveBeenCalled();
 
         await onOutput?.({
           status: 'success',
@@ -469,7 +619,6 @@ describe('createMessageRuntime', () => {
           newSessionId: 'session-follow-up',
         });
         await vi.advanceTimersByTimeAsync(800);
-        expect(closeStdin).not.toHaveBeenCalled();
 
         await onOutput?.({
           status: 'success',
@@ -478,7 +627,6 @@ describe('createMessageRuntime', () => {
           newSessionId: 'session-follow-up',
         });
         await vi.advanceTimersByTimeAsync(800);
-        expect(closeStdin).not.toHaveBeenCalled();
 
         await onOutput?.({
           status: 'success',
@@ -523,7 +671,10 @@ describe('createMessageRuntime', () => {
       });
 
       expect(result).toBe(true);
-      expect(closeStdin).not.toHaveBeenCalled();
+      expect(closeStdin).toHaveBeenCalledWith(chatJid, {
+        runId: 'run-follow-up-progress',
+        reason: 'output-delivered-close',
+      });
       expect(channel.sendMessage).toHaveBeenCalledWith(
         chatJid,
         '초기 응답입니다.',
@@ -721,10 +872,12 @@ describe('createMessageRuntime', () => {
         'progress-1',
         '테스트를 돌리는 중입니다.\n\n10초',
       );
-      expect(channel.sendMessage).toHaveBeenCalledWith(
+      expect(channel.editMessage).toHaveBeenCalledWith(
         chatJid,
+        'progress-1',
         '테스트가 끝났습니다.',
       );
+      expect(channel.sendMessage).not.toHaveBeenCalled();
       expect(notifyIdle).toHaveBeenCalledTimes(1);
       expect(notifyIdle).toHaveBeenCalledWith(chatJid, 'run-final');
     } finally {
@@ -837,19 +990,22 @@ describe('createMessageRuntime', () => {
       expect(channel.editMessage).toHaveBeenNthCalledWith(
         2,
         chatJid,
+        'progress-1',
+        '첫 번째 결과입니다.',
+      );
+      expect(channel.editMessage).toHaveBeenNthCalledWith(
+        3,
+        chatJid,
         'progress-2',
         '두 번째 진행상황입니다.\n\n10초',
       );
-      expect(channel.sendMessage).toHaveBeenNthCalledWith(
-        1,
-        chatJid,
-        '첫 번째 결과입니다.',
-      );
-      expect(channel.sendMessage).toHaveBeenNthCalledWith(
-        2,
+      expect(channel.editMessage).toHaveBeenNthCalledWith(
+        4,
         chatJid,
+        'progress-2',
         '두 번째 결과입니다.',
       );
+      expect(channel.sendMessage).not.toHaveBeenCalled();
     } finally {
       vi.useRealTimers();
     }
@@ -962,10 +1118,12 @@ describe('createMessageRuntime', () => {
         'progress-2',
         '두 번째 진행상황입니다.\n\n10초',
       );
-      expect(channel.sendMessage).toHaveBeenCalledWith(
+      expect(channel.editMessage).toHaveBeenCalledWith(
         chatJid,
+        'progress-2',
         '두 번째 진행상황입니다.',
       );
+      expect(channel.sendMessage).not.toHaveBeenCalled();
     } finally {
       vi.useRealTimers();
     }
@@ -1056,10 +1214,12 @@ describe('createMessageRuntime', () => {
         'progress-1',
         '커밋은 정상 들어갔고 pre-commit도 통과했습니다.\n\n10초',
       );
-      expect(channel.sendMessage).toHaveBeenCalledWith(
+      expect(channel.editMessage).toHaveBeenCalledWith(
         chatJid,
+        'progress-1',
         '커밋은 정상 들어갔고 pre-commit도 통과했습니다.',
       );
+      expect(channel.sendMessage).not.toHaveBeenCalled();
     } finally {
       vi.useRealTimers();
     }
@@ -1157,11 +1317,12 @@ describe('createMessageRuntime', () => {
         'progress-follow-up',
         '두 번째 턴 진행상황입니다.\n\n10초',
       );
-      expect(channel.sendMessage).toHaveBeenNthCalledWith(
-        2,
+      expect(channel.editMessage).toHaveBeenCalledWith(
         chatJid,
+        'progress-follow-up',
         '두 번째 턴 진행상황입니다.',
       );
+      expect(channel.sendMessage).toHaveBeenCalledTimes(1);
     } finally {
       vi.useRealTimers();
     }
@@ -1258,15 +1419,13 @@ describe('createMessageRuntime', () => {
         'progress-1',
         '진행 중입니다.\n\n10초',
       );
-      expect(channel.sendAndTrack).toHaveBeenNthCalledWith(
-        2,
-        chatJid,
-        '진행 중입니다.\n\n10초',
-      );
-      expect(channel.sendMessage).toHaveBeenCalledWith(
+      expect(channel.sendAndTrack).toHaveBeenCalledTimes(1);
+      expect(channel.editMessage).toHaveBeenCalledWith(
         chatJid,
+        'progress-1',
         '진행 중입니다.',
       );
+      expect(channel.sendMessage).not.toHaveBeenCalled();
     } finally {
       vi.useRealTimers();
     }
diff --git a/src/message-runtime.ts b/src/message-runtime.ts
index 9ca9989..12ad8c7 100644
--- a/src/message-runtime.ts
+++ b/src/message-runtime.ts
@@ -129,7 +129,43 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
   const deliverOpenWorkItem = async (
     channel: Channel,
     item: WorkItem,
+    options?: {
+      replaceMessageId?: string | null;
+    },
   ): Promise<boolean> => {
+    const replaceMessageId = options?.replaceMessageId ?? null;
+    try {
+      if (replaceMessageId && channel.editMessage) {
+        await channel.editMessage(
+          item.chat_jid,
+          replaceMessageId,
+          item.result_payload,
+        );
+        markWorkItemDelivered(item.id, replaceMessageId);
+        logger.info(
+          {
+            chatJid: item.chat_jid,
+            workItemId: item.id,
+            deliveryAttempts: item.delivery_attempts + 1,
+            replacedMessageId: replaceMessageId,
+          },
+          'Delivered produced work item by replacing tracked progress message',
+        );
+        return true;
+      }
+    } catch (err) {
+      logger.warn(
+        {
+          chatJid: item.chat_jid,
+          workItemId: item.id,
+          deliveryAttempts: item.delivery_attempts + 1,
+          replacedMessageId: replaceMessageId,
+          err,
+        },
+        'Failed to replace tracked progress message; falling back to a new message',
+      );
+    }
+
     try {
       await channel.sendMessage(item.chat_jid, item.result_payload);
       markWorkItemDelivered(item.id);
@@ -637,6 +673,8 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
     let progressMessageId: string | null = null;
     let progressStartedAt: number | null = null;
     let progressTicker: ReturnType<typeof setInterval> | null = null;
+    let progressEditFailCount = 0;
+    let promotableTrackedProgressMessageId: string | null = null;
     let finalOutputSentToUser = false;
     let progressOutputSentToUser = false;
     let latestModelProgressTextForFinalFallback: string | null = null;
@@ -644,6 +682,7 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
     let producedDeliverySucceeded = true;
     let isFirstLogicalTurn = true;
     let poisonedSessionDetected = false;
+    let canPipeFollowUps = true;
     const isClaudeCodeAgent =
       (group.agentType || 'claude-code') === 'claude-code';
     const FOLLOW_UP_NO_OUTPUT_WARN_MS = 10_000;
@@ -801,6 +840,7 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
       noteFollowUpQueued(meta);
       resetIdleTimer();
     });
+    deps.queue.setFollowUpPipeAllowed?.(chatJid, () => canPipeFollowUps);
 
     const clearProgressTicker = () => {
       if (progressTicker) {
@@ -817,7 +857,9 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
       producedFinalText = null;
     };
 
-    const flushProducedFinalText = async () => {
+    const flushProducedFinalText = async (
+      replaceMessageId?: string | null,
+    ) => {
       if (!producedFinalText) {
         return;
       }
@@ -831,7 +873,9 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
           end_seq: isFirstLogicalTurn ? endSeq : null,
           result_payload: producedFinalText,
         });
-        const delivered = await deliverOpenWorkItem(channel, workItem);
+        const delivered = await deliverOpenWorkItem(channel, workItem, {
+          replaceMessageId,
+        });
         if (delivered) {
           finalOutputSentToUser = true;
         } else {
@@ -846,6 +890,7 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
       } finally {
         producedFinalText = null;
         latestModelProgressTextForFinalFallback = null;
+        promotableTrackedProgressMessageId = null;
         isFirstLogicalTurn = false;
       }
     };
@@ -856,6 +901,7 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
       latestProgressRendered = null;
       progressMessageId = null;
       progressStartedAt = null;
+      progressEditFailCount = 0;
     };
 
     const renderProgressMessage = (text: string) => {
@@ -888,7 +934,9 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
       try {
         await channel.editMessage(chatJid, progressMessageId, rendered);
         latestProgressRendered = rendered;
+        progressEditFailCount = 0;
       } catch (err) {
+        progressEditFailCount++;
         logger.warn(
           {
             chatJid,
@@ -896,13 +944,16 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
             groupFolder: group.folder,
             runId,
             progressMessageId,
+            progressEditFailCount,
             err,
           },
-          'Failed to edit tracked progress message; will recreate it on the next progress update',
+          'Failed to edit tracked progress message; will retry before recreating',
         );
-        clearProgressTicker();
-        progressMessageId = null;
         latestProgressRendered = null;
+        if (progressEditFailCount >= 3) {
+          clearProgressTicker();
+          progressMessageId = null;
+        }
       }
     };
 
@@ -916,7 +967,9 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
       }, 10_000);
     };
 
-    const finalizeProgressMessage = async () => {
+    const finalizeProgressMessage = async (options?: {
+      preserveTrackedMessage?: boolean;
+    }): Promise<string | null> => {
       logger.info(
         {
           chatJid,
@@ -928,8 +981,12 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
         },
         'Finalizing tracked progress message',
       );
-      await syncTrackedProgressMessage();
+      const trackedMessageId = progressMessageId;
+      if (!options?.preserveTrackedMessage) {
+        await syncTrackedProgressMessage();
+      }
       resetProgressState();
+      return trackedMessageId;
     };
 
     const sendProgressMessage = async (text: string) => {
@@ -963,6 +1020,9 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
       }
 
       if (!channel.sendAndTrack) {
+        latestProgressRendered = rendered;
+        await channel.sendMessage(chatJid, rendered);
+        progressOutputSentToUser = true;
         return;
       }
 
@@ -979,6 +1039,9 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
           },
           'Failed to send tracked progress message',
         );
+        latestProgressRendered = rendered;
+        await channel.sendMessage(chatJid, rendered);
+        progressOutputSentToUser = true;
         return;
       }
 
@@ -997,7 +1060,12 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
         latestProgressRendered = rendered;
         ensureProgressTicker();
         progressOutputSentToUser = true;
+        return;
       }
+
+      latestProgressRendered = rendered;
+      await channel.sendMessage(chatJid, rendered);
+      progressOutputSentToUser = true;
     };
 
     await channel.setTyping?.(chatJid, true);
@@ -1032,6 +1100,9 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
               ? result.result
               : JSON.stringify(result.result);
           const text = formatOutbound(raw);
+          if (text) {
+            canPipeFollowUps = false;
+          }
           logger.info(
             {
               chatJid,
@@ -1073,9 +1144,13 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
           sawNonProgressOutput = true;
 
           if (text) {
-            await finalizeProgressMessage();
+            const trackedProgressMessageId = await finalizeProgressMessage({
+              preserveTrackedMessage: !!(
+                progressMessageId && channel.editMessage
+              ),
+            });
             producedFinalText = text;
-            await flushProducedFinalText();
+            await flushProducedFinalText(trackedProgressMessageId);
           } else {
             logger.info(
               {
@@ -1096,7 +1171,14 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
           if (result.status === 'success') {
             warnFollowUpEndedWithoutOutput('success-null-result');
           }
-          await finalizeProgressMessage();
+          promotableTrackedProgressMessageId = await finalizeProgressMessage({
+            preserveTrackedMessage: !!(
+              !sawNonProgressOutput &&
+              latestModelProgressTextForFinalFallback &&
+              progressMessageId &&
+              channel.editMessage
+            ),
+          });
         }
 
         await channel.setTyping?.(chatJid, false);
@@ -1106,6 +1188,12 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
 
         if (result.status === 'success' && !poisonedSessionDetected) {
           deps.queue.notifyIdle(chatJid, runId);
+          if (finalOutputSentToUser || progressOutputSentToUser) {
+            deps.queue.closeStdin(chatJid, {
+              runId,
+              reason: 'output-delivered-close',
+            });
+          }
         }
 
         if (result.status === 'error') {
@@ -1136,14 +1224,20 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
         },
         'Promoting last progress output to final message after agent completion',
       );
+      const trackedProgressMessageId = await finalizeProgressMessage({
+        preserveTrackedMessage: !!(progressMessageId && channel.editMessage),
+      });
       producedFinalText = latestModelProgressTextForFinalFallback;
-      await flushProducedFinalText();
+      await flushProducedFinalText(
+        trackedProgressMessageId || promotableTrackedProgressMessageId,
+      );
     }
 
     clearProgressTicker();
 
     if (idleTimer) clearTimeout(idleTimer);
     deps.queue.setActivityTouch?.(chatJid, null);
+    deps.queue.setFollowUpPipeAllowed?.(chatJid, null);
 
     const finalFollowUpRequeueReason =
       followUpEndedWithoutOutputReason ||