diff --git a/pkg/agent/loop.go b/pkg/agent/loop.go
index f731d4e5a..755197be8 100644
--- a/pkg/agent/loop.go
+++ b/pkg/agent/loop.go
@@ -1166,9 +1166,11 @@ func (al *AgentLoop) runLLMIteration(
 						outCtx, outCancel := context.WithTimeout(context.Background(), 5*time.Second)
 						defer outCancel()
 						_ = al.bus.PublishOutbound(outCtx, bus.OutboundMessage{
-							Channel: opts.Channel,
-							ChatID:  opts.ChatID,
-							Content: result.ForUser,
+							Channel:          opts.Channel,
+							ChatID:           opts.ChatID,
+							Content:          result.ForUser,
+							ThreadID:         opts.ThreadID,
+							ReplyToMessageID: opts.ReplyToMessageID,
 						})
 					}
 
diff --git a/pkg/channels/manager.go b/pkg/channels/manager.go
index 50dd24d8f..0ae0f40ba 100644
--- a/pkg/channels/manager.go
+++ b/pkg/channels/manager.go
@@ -84,9 +84,9 @@ type Manager struct {
 	mux           *http.ServeMux
 	httpServer    *http.Server
 	mu            sync.RWMutex
-	placeholders  sync.Map // "channel:chatID" → placeholderID (string)
-	typingStops   sync.Map // "channel:chatID" → func()
-	reactionUndos sync.Map // "channel:chatID" → reactionEntry
+	placeholders  sync.Map // "channel:chatID:threadID" → placeholderEntry
+	typingStops   sync.Map // "channel:chatID:threadID" → typingEntry
+	reactionUndos sync.Map // "channel:chatID:threadID" → reactionEntry
 }
 
 type asyncTask struct {
diff --git a/pkg/channels/manager_test.go b/pkg/channels/manager_test.go
index 201b6b00a..79d5f45b4 100644
--- a/pkg/channels/manager_test.go
+++ b/pkg/channels/manager_test.go
@@ -570,6 +570,44 @@ func TestPreSend_TypingAndPlaceholder(t *testing.T) {
 	}
 }
 
+func TestPreSend_ThreadIsolation(t *testing.T) {
+	m := newTestManager()
+
+	ch := &mockMessageEditor{
+		mockChannel: mockChannel{
+			sendFn: func(_ context.Context, _ bus.OutboundMessage) error {
+				return nil
+			},
+		},
+		editFn: func(_ context.Context, _, _, _ string) error {
+			return nil
+		},
+	}
+
+	// Register placeholder for thread "100"
+	m.RecordPlaceholder("test", "123", "100", "ph-100")
+
+	// Sending to the same chat but different thread should NOT find the placeholder
+	msg := bus.OutboundMessage{Channel: "test", ChatID: "123", Content: "hello", ThreadID: "200"}
+	edited := m.preSend(context.Background(), "test", msg, ch)
+	if edited {
+		t.Fatal("expected preSend to return false for a different threadID")
+	}
+
+	// Sending to the correct thread should find it
+	msg.ThreadID = "100"
+	edited = m.preSend(context.Background(), "test", msg, ch)
+	if !edited {
+		t.Fatal("expected preSend to return true for matching threadID")
+	}
+
+	// Second call to same thread should not find it (already consumed)
+	edited = m.preSend(context.Background(), "test", msg, ch)
+	if edited {
+		t.Fatal("expected preSend to return false after placeholder was consumed")
+	}
+}
+
 func TestRecordPlaceholder_ConcurrentSafe(t *testing.T) {
 	m := newTestManager()
 
diff --git a/pkg/channels/telegram/telegram.go b/pkg/channels/telegram/telegram.go
index ba2edfbfe..c7456e002 100644
--- a/pkg/channels/telegram/telegram.go
+++ b/pkg/channels/telegram/telegram.go
@@ -213,15 +213,9 @@ func (c *TelegramChannel) Send(ctx context.Context, msg bus.OutboundMessage) err
 func (c *TelegramChannel) sendHTMLChunk(ctx context.Context, chatID int64, htmlContent, mdFallback, threadID, replyToMsgID string) error {
 	tgMsg := tu.Message(tu.ID(chatID), htmlContent)
 	tgMsg.ParseMode = telego.ModeHTML
-	if threadID != "" {
-		if tid, err2 := strconv.Atoi(threadID); err2 == nil {
-			tgMsg.MessageThreadID = tid
-		}
-	}
-	if replyToMsgID != "" {
-		if mid, err2 := strconv.Atoi(replyToMsgID); err2 == nil {
-			tgMsg.ReplyParameters = &telego.ReplyParameters{MessageID: mid}
-		}
+	tgMsg.MessageThreadID = parseOptionalInt(threadID)
+	if mid := parseOptionalInt(replyToMsgID); mid != 0 {
+		tgMsg.ReplyParameters = &telego.ReplyParameters{MessageID: mid}
 	}
 
 	if _, err := c.bot.SendMessage(ctx, tgMsg); err != nil {
@@ -248,14 +242,9 @@ func (c *TelegramChannel) StartTyping(ctx context.Context, chatID string, thread
 		return func() {}, err
 	}
 
-	tid := 0
-	if threadID != "" {
-		tid, _ = strconv.Atoi(threadID)
-	}
-
 	sendTyping := func(sctx context.Context) {
 		params := tu.ChatAction(tu.ID(cid), telego.ChatActionTyping)
-		params.MessageThreadID = tid
+		params.MessageThreadID = parseOptionalInt(threadID)
 		_ = c.bot.SendChatAction(sctx, params)
 	}
 
@@ -318,15 +307,9 @@ func (c *TelegramChannel) SendPlaceholder(ctx context.Context, chatID string, th
 	}
 
 	params := tu.Message(tu.ID(cid), text)
-	if threadID != "" {
-		if tid, err2 := strconv.Atoi(threadID); err2 == nil {
-			params.MessageThreadID = tid
-		}
-	}
-	if replyToMsgID != "" {
-		if mid, err2 := strconv.Atoi(replyToMsgID); err2 == nil {
-			params.ReplyParameters = &telego.ReplyParameters{MessageID: mid}
-		}
+	params.MessageThreadID = parseOptionalInt(threadID)
+	if mid := parseOptionalInt(replyToMsgID); mid != 0 {
+		params.ReplyParameters = &telego.ReplyParameters{MessageID: mid}
 	}
 
 	pMsg, err := c.bot.SendMessage(ctx, params)
@@ -628,6 +611,15 @@ func parseChatID(chatIDStr string) (int64, error) {
 	return id, err
 }
 
+// parseOptionalInt converts a string to int, returning 0 if the string is empty or invalid.
+func parseOptionalInt(s string) int {
+	if s == "" {
+		return 0
+	}
+	n, _ := strconv.Atoi(s)
+	return n
+}
+
 func markdownToTelegramHTML(text string) string {
 	if text == "" {
 		return ""
diff --git a/pkg/channels/telegram/telegram_test.go b/pkg/channels/telegram/telegram_test.go
index 3a2f1aa66..e27c640d6 100644
--- a/pkg/channels/telegram/telegram_test.go
+++ b/pkg/channels/telegram/telegram_test.go
@@ -271,3 +271,21 @@ func TestSend_InvalidChatID(t *testing.T) {
 	assert.True(t, errors.Is(err, channels.ErrSendFailed), "error should wrap ErrSendFailed")
 	assert.Empty(t, caller.calls)
 }
+
+func TestParseOptionalInt(t *testing.T) {
+	tests := []struct {
+		input string
+		want  int
+	}{
+		{"", 0},
+		{"0", 0},
+		{"42", 42},
+		{"-1", -1},
+		{"abc", 0},
+		{"123456", 123456},
+	}
+	for _, tt := range tests {
+		got := parseOptionalInt(tt.input)
+		assert.Equal(t, tt.want, got, "parseOptionalInt(%q)", tt.input)
+	}
+}