diff --git a/examples/targeted-messages/src/main.py b/examples/targeted-messages/src/main.py
index f2e3de26..c4274cfd 100644
--- a/examples/targeted-messages/src/main.py
+++ b/examples/targeted-messages/src/main.py
@@ -4,9 +4,9 @@
 """
 
 import asyncio
+from datetime import datetime, timezone
 
-from microsoft_teams.api import Account, MessageActivity, MessageActivityInput
-from microsoft_teams.api.activities.typing import TypingActivityInput
+from microsoft_teams.api import MessageActivity, MessageActivityInput
 from microsoft_teams.apps import ActivityContext, App
 
 """
@@ -23,112 +23,93 @@
 @app.on_message
 async def handle_message(ctx: ActivityContext[MessageActivity]):
     """Handle message activities."""
-    await ctx.reply(TypingActivityInput())
+    activity = ctx.activity
+    text = (activity.text or "").lower()
 
-    text = (ctx.activity.text or "").lower()
+    print(f"[MESSAGE] Received: {text}")
 
-    # ============================================
-    # Test targeted SEND (create)
-    # ============================================
-    if "test send" in text:
-        members = await ctx.api.conversations.members(ctx.activity.conversation.id).get_all()
+    if "test update" in text:
+        # UPDATE: Send a targeted message, then update it after 3 seconds
+        conversation_id = activity.conversation.id
 
-        for member in members:
-            print(f"Member: {member.name} - {member.id}")
+        targeted_message = MessageActivityInput(
+            text="📝 This message will be **updated** in 3 seconds..."
+        ).with_recipient(activity.from_, is_targeted=True)
 
-            targeted_message = MessageActivityInput(
-                text="🔒 [SEND] This is a targeted message - only YOU can see this!"
-            ).with_recipient(Account(id=member.id, name=member.name), is_targeted=True)
+        result = await ctx.send(targeted_message)
 
-            result = await ctx.send(targeted_message)
-        print("[SEND] Sent targeted message")
-        return
-
-    # ============================================
-    # Test targeted REPLY
-    # ============================================
-    if "test reply" in text:
-        targeted_reply = MessageActivityInput(text="🔒 [REPLY] Targeted reply - only YOU can see this!").with_recipient(
-            ctx.activity.from_, is_targeted=True
-        )
+        if result.id:
+            message_id = result.id
 
-        result = await ctx.reply(targeted_reply)
-        print(f"Targeted REPLY result: {result}")
-        return
+            async def update_after_delay():
+                await asyncio.sleep(3)
+                try:
+                    timestamp = datetime.now(timezone.utc).strftime("%H:%M:%S")
+                    updated_message = MessageActivityInput(
+                        text=f"✏️ **Updated!** This message was modified at {timestamp}"
+                    )
+                    updated_message.id = message_id
 
-    # ============================================
-    # Test targeted UPDATE
-    # ============================================
-    if "test update" in text:
-        # First send a targeted message
-        targeted_message = MessageActivityInput(text="🔒 [UPDATE] Original targeted message...").with_recipient(
-            ctx.activity.from_, is_targeted=True
-        )
+                    await ctx.api.conversations.activities(conversation_id).update_targeted(message_id, updated_message)
+                    print("[UPDATE] Updated targeted message")
+                except Exception as err:
+                    print(f"[UPDATE] Error: {err}")
+
+            asyncio.create_task(update_after_delay())
+
+        print("[UPDATE] Scheduled update in 3 seconds")
+
+    elif "test delete" in text:
+        # DELETE: Send a targeted message, then delete it after 3 seconds
+        conversation_id = activity.conversation.id
 
-        result = await ctx.send(targeted_message)
-        print(f"Initial targeted message ID: {result.id}")
-
-        # Wait then update
-        async def update_after_delay():
-            await asyncio.sleep(3)
-            try:
-                # For targeted updates, do not include recipient in the payload.
-                updated_message = MessageActivityInput(
-                    text="🔒 [UPDATE] ✅ UPDATED targeted message! (only you see this)"
-                )
-                updated_message.id = result.id
-
-                await ctx.api.conversations.activities(ctx.activity.conversation.id).update_targeted(
-                    result.id, updated_message
-                )
-                print("Targeted UPDATE completed")
-            except Exception as err:
-                print(f"Targeted UPDATE error: {err}")
-
-        asyncio.create_task(update_after_delay())
-        return
-
-    # ============================================
-    # Test targeted DELETE
-    # ============================================
-    if "test delete" in text:
-        # First send a targeted message
         targeted_message = MessageActivityInput(
-            text="🔒 [DELETE] This targeted message will be DELETED in 5 seconds..."
-        ).with_recipient(ctx.activity.from_, is_targeted=True)
+            text="🗑️ This message will be **deleted** in 3 seconds..."
+        ).with_recipient(activity.from_, is_targeted=True)
 
         result = await ctx.send(targeted_message)
-        print(f"Targeted message to delete, ID: {result.id}")
-
-        # Wait then delete using the targeted API
-        async def delete_after_delay():
-            await asyncio.sleep(5)
-            try:
-                await ctx.api.conversations.activities(ctx.activity.conversation.id).delete_targeted(result.id)
-                print("Targeted DELETE completed")
-            except Exception as err:
-                print(f"Targeted DELETE error: {err}")
-
-        asyncio.create_task(delete_after_delay())
-        return
-
-    # ============================================
-    # Help / Default
-    # ============================================
-    if "help" in text:
-        await ctx.reply(
-            "**Targeted Messages Test Bot**\n\n"
+
+        if result.id:
+            message_id = result.id
+
+            async def delete_after_delay():
+                await asyncio.sleep(3)
+                try:
+                    await ctx.api.conversations.activities(conversation_id).delete_targeted(message_id)
+                    print("[DELETE] Deleted targeted message")
+                except Exception as err:
+                    print(f"[DELETE] Error: {err}")
+
+            asyncio.create_task(delete_after_delay())
+
+        print("[DELETE] Scheduled delete in 3 seconds")
+
+    elif "test public" in text:
+        # PUBLIC: Send a public message visible to everyone in the chat.
+        await ctx.send(MessageActivityInput(text="📋 Here is the public result — everyone can see this!"))
+        print("[PUBLIC] Sent public message")
+
+    elif "test send" in text:
+        # SEND: Send a targeted message visible only to the sender.
+        targeted_message = MessageActivityInput(
+            text="👋 This is a **targeted message** — only YOU can see this!"
+        ).with_recipient(activity.from_, is_targeted=True)
+        await ctx.send(targeted_message)
+        print("[SEND] Sent targeted message")
+
+    elif "help" in text:
+        await ctx.send(
+            "**🎯 Targeted Messages Demo**\n\n"
             "**Commands:**\n"
-            "- `test send` - Send a targeted message\n"
-            "- `test reply` - Reply with a targeted message\n"
-            "- `test update` - Send then update a targeted message\n"
-            "- `test delete` - Send then delete a targeted message\n\n"
-            "💡 *Test in a group chat to verify others don't see targeted messages!*"
+            "- `test send` - Send a targeted message (only visible to you)\n"
+            "- `test update` - Send a targeted message, then update it after 3 seconds\n"
+            "- `test delete` - Send a targeted message, then delete it after 3 seconds\n"
+            "- `test public` - Send a public reply (visible to all)\n\n"
+            "_Targeted messages are only visible to you, even in group chats!_"
         )
-        return
 
-    # Default
-    await ctx.reply('Say "help" for available commands.')
+    else:
+        await ctx.send(f"You said: '{activity.text}'\n\nType `help` to see available commands.")
 
 
 if __name__ == "__main__":
diff --git a/packages/api/src/microsoft_teams/api/activities/message/message.py b/packages/api/src/microsoft_teams/api/activities/message/message.py
index e94e0f9a..9493bf39 100644
--- a/packages/api/src/microsoft_teams/api/activities/message/message.py
+++ b/packages/api/src/microsoft_teams/api/activities/message/message.py
@@ -35,6 +35,7 @@
     Entity,
     Image,
     MessageEntity,
+    TargetedMessageInfoEntity,
 )
 from ..utils import StripMentionsTextOptions, strip_mentions_text
 
@@ -481,6 +482,36 @@ def add_quote(self, message_id: str, text: str | None = None) -> Self:
             self.add_text(f" {text}")
         return self
 
+    @experimental("ExperimentalTeamsTargeted")
+    def add_targeted_message_info(self, message_id: str) -> Self:
+        """Add a targetedMessageInfo entity for prompt preview.
+
+        If an entity with type ``"targetedMessageInfo"`` already exists,
+        it is not added again (one prompt preview per message).
+
+        When adding the entity, any ``quotedReply`` entities and matching
+        ``<quoted messageId="..."/>`` placeholder text are removed to avoid
+        collision with prompt preview.
+
+        Args:
+            message_id: The message ID of the targeted message.
+
+        Returns:
+            Self for method chaining
+        """
+        has_entity = any(isinstance(e, TargetedMessageInfoEntity) for e in (self.entities or []))
+
+        # Always strip quotedReply artifacts to avoid collision with prompt preview,
+        # if the developer already attached a targetedMessageInfo entity.
+        if self.entities is not None:
+            self.entities = [e for e in self.entities if getattr(e, "type", None) != "quotedReply"]
+        if self.text is not None:
+            self.text = self.text.replace(f'<quoted messageId="{message_id}"/>', "").strip()
+
+        if not has_entity:
+            self.add_entity(TargetedMessageInfoEntity(message_id=message_id))
+        return self
+
     def with_recipient(self, value: Account, is_targeted: Optional[bool] = None) -> Self:
         """
         Set the recipient.
diff --git a/packages/api/src/microsoft_teams/api/models/entity/__init__.py b/packages/api/src/microsoft_teams/api/models/entity/__init__.py
index 473c46b7..47bcdf37 100644
--- a/packages/api/src/microsoft_teams/api/models/entity/__init__.py
+++ b/packages/api/src/microsoft_teams/api/models/entity/__init__.py
@@ -21,6 +21,7 @@
 from .quoted_reply_entity import QuotedReplyData, QuotedReplyEntity
 from .sensitive_usage_entity import SensitiveUsage, SensitiveUsageEntity, SensitiveUsagePattern
 from .stream_info_entity import StreamInfoEntity
+from .targeted_message_info_entity import TargetedMessageInfoEntity
 
 __all__ = [
     "AIMessageEntity",
@@ -41,5 +42,6 @@
     "SensitiveUsage",
     "SensitiveUsagePattern",
     "StreamInfoEntity",
+    "TargetedMessageInfoEntity",
     "Entity",
 ]
diff --git a/packages/api/src/microsoft_teams/api/models/entity/entity.py b/packages/api/src/microsoft_teams/api/models/entity/entity.py
index b89ce533..0488c4aa 100644
--- a/packages/api/src/microsoft_teams/api/models/entity/entity.py
+++ b/packages/api/src/microsoft_teams/api/models/entity/entity.py
@@ -14,6 +14,7 @@
 from .quoted_reply_entity import QuotedReplyEntity
 from .sensitive_usage_entity import SensitiveUsageEntity
 from .stream_info_entity import StreamInfoEntity
+from .targeted_message_info_entity import TargetedMessageInfoEntity
 
 Entity = Union[
     ClientInfoEntity,
@@ -25,4 +26,5 @@
     SensitiveUsageEntity,
     ProductInfoEntity,
     QuotedReplyEntity,
+    TargetedMessageInfoEntity,
 ]
diff --git a/packages/api/src/microsoft_teams/api/models/entity/targeted_message_info_entity.py b/packages/api/src/microsoft_teams/api/models/entity/targeted_message_info_entity.py
new file mode 100644
index 00000000..aa97e57e
--- /dev/null
+++ b/packages/api/src/microsoft_teams/api/models/entity/targeted_message_info_entity.py
@@ -0,0 +1,26 @@
+"""
+Copyright (c) Microsoft Corporation. All rights reserved.
+Licensed under the MIT License.
+"""
+
+from typing import Literal
+
+from microsoft_teams.common.experimental import experimental
+
+from ..custom_base_model import CustomBaseModel
+
+
+@experimental("ExperimentalTeamsTargeted")
+class TargetedMessageInfoEntity(CustomBaseModel):
+    """Entity containing targeted message information for prompt preview.
+
+    .. warning:: Preview
+        This class is in preview and may change in the future.
+        Diagnostic: ExperimentalTeamsTargeted
+    """
+
+    type: Literal["targetedMessageInfo"] = "targetedMessageInfo"
+    "Type identifier for targeted message info"
+
+    message_id: str
+    "The ID of the targeted message this activity is replying to"
diff --git a/packages/api/tests/unit/test_targeted_message_info_entity.py b/packages/api/tests/unit/test_targeted_message_info_entity.py
new file mode 100644
index 00000000..82c35da2
--- /dev/null
+++ b/packages/api/tests/unit/test_targeted_message_info_entity.py
@@ -0,0 +1,109 @@
+"""
+Copyright (c) Microsoft Corporation. All rights reserved.
+Licensed under the MIT License.
+"""
+# pyright: basic
+
+import pytest
+from microsoft_teams.api import MessageActivityInput
+from microsoft_teams.api.models.entity.targeted_message_info_entity import TargetedMessageInfoEntity
+
+
+@pytest.mark.unit
+class TestTargetedMessageInfoEntity:
+    """Unit tests for TargetedMessageInfoEntity."""
+
+    def test_default_type(self) -> None:
+        entity = TargetedMessageInfoEntity(message_id="1772129782775")
+        assert entity.type == "targetedMessageInfo"
+
+    def test_message_id(self) -> None:
+        entity = TargetedMessageInfoEntity(message_id="1772129782775")
+        assert entity.message_id == "1772129782775"
+
+    def test_serialization_camel_case(self) -> None:
+        entity = TargetedMessageInfoEntity(message_id="1772129782775")
+        data = entity.model_dump(by_alias=True, exclude_none=True)
+        assert data == {
+            "type": "targetedMessageInfo",
+            "messageId": "1772129782775",
+        }
+
+    def test_deserialization_camel_case(self) -> None:
+        entity = TargetedMessageInfoEntity.model_validate(
+            {
+                "type": "targetedMessageInfo",
+                "messageId": "1772129782775",
+            }
+        )
+        assert entity.type == "targetedMessageInfo"
+        assert entity.message_id == "1772129782775"
+
+
+@pytest.mark.unit
+class TestAddTargetedMessageInfo:
+    """Tests for MessageActivityInput.add_targeted_message_info including QR collision guard."""
+
+    def test_adds_entity(self) -> None:
+        activity = MessageActivityInput(text="test")
+        activity.add_targeted_message_info("12345")
+
+        targeted = [e for e in (activity.entities or []) if isinstance(e, TargetedMessageInfoEntity)]
+        assert len(targeted) == 1
+        assert targeted[0].message_id == "12345"
+
+    def test_does_not_duplicate_when_entity_exists(self) -> None:
+        activity = MessageActivityInput(text="test")
+        activity.add_entity(TargetedMessageInfoEntity(message_id="9999"))
+        activity.add_targeted_message_info("12345")
+
+        targeted = [e for e in (activity.entities or []) if isinstance(e, TargetedMessageInfoEntity)]
+        assert len(targeted) == 1
+        assert targeted[0].message_id == "9999"
+
+    def test_strips_qr_even_when_entity_already_exists(self) -> None:
+        """When developer pre-attaches targetedMessageInfo and reply() adds quotedReply,
+        add_targeted_message_info should still strip the quotedReply artifacts."""
+        from unittest.mock import MagicMock
+
+        qr_entity = MagicMock()
+        qr_entity.type = "quotedReply"
+
+        activity = MessageActivityInput(text='<quoted messageId="12345"/> Here is my reply')
+        activity.add_entity(TargetedMessageInfoEntity(message_id="9999"))
+        activity.entities.append(qr_entity)  # type: ignore[arg-type]
+
+        activity.add_targeted_message_info("12345")
+
+        # Should not duplicate the entity
+        targeted = [e for e in (activity.entities or []) if isinstance(e, TargetedMessageInfoEntity)]
+        assert len(targeted) == 1
+        assert targeted[0].message_id == "9999"
+        # Should still strip quotedReply
+        assert not any(getattr(e, "type", None) == "quotedReply" for e in (activity.entities or []))
+        assert activity.text == "Here is my reply"
+
+    def test_strips_quoted_reply_entities(self) -> None:
+        activity = MessageActivityInput(text="test", entities=[])
+        # Simulate a quotedReply entity (generic entity with type="quotedReply")
+
+        # Use a mock-like approach: create a simple object with type="quotedReply"
+        from unittest.mock import MagicMock
+
+        qr_entity = MagicMock()
+        qr_entity.type = "quotedReply"
+        activity.entities = [qr_entity]  # type: ignore[list-item]
+
+        activity.add_targeted_message_info("12345")
+
+        assert not any(getattr(e, "type", None) == "quotedReply" for e in (activity.entities or []))
+        targeted = [e for e in (activity.entities or []) if isinstance(e, TargetedMessageInfoEntity)]
+        assert len(targeted) == 1
+
+    def test_strips_quoted_placeholder_from_text(self) -> None:
+        activity = MessageActivityInput(text='<quoted messageId="12345"/> Here is my reply')
+        activity.add_targeted_message_info("12345")
+
+        assert activity.text == "Here is my reply"
+        targeted = [e for e in (activity.entities or []) if isinstance(e, TargetedMessageInfoEntity)]
+        assert len(targeted) == 1
diff --git a/packages/apps/src/microsoft_teams/apps/activity_sender.py b/packages/apps/src/microsoft_teams/apps/activity_sender.py
index 78d02ae8..1ab97c96 100644
--- a/packages/apps/src/microsoft_teams/apps/activity_sender.py
+++ b/packages/apps/src/microsoft_teams/apps/activity_sender.py
@@ -47,6 +47,15 @@ async def send(self, activity: ActivityParams, ref: ConversationReference) -> Se
         Returns:
             The sent activity with id and other server-populated fields
         """
+        is_targeted = (
+            isinstance(activity, MessageActivityInput)
+            and activity.recipient is not None
+            and activity.recipient.is_targeted is True
+        )
+
+        if is_targeted and ref.conversation.conversation_type == "personal":
+            raise ValueError("Targeted messages are not supported in 1:1 (personal) chats.")
+
         # Create API client for this conversation's service URL
         api = ApiClient(service_url=ref.service_url, options=self._client)
 
@@ -54,11 +63,6 @@ async def send(self, activity: ActivityParams, ref: ConversationReference) -> Se
         activity.from_ = ref.bot
         activity.conversation = ref.conversation
 
-        is_targeted = (
-            isinstance(activity, MessageActivityInput)
-            and activity.recipient is not None
-            and activity.recipient.is_targeted is True
-        )
         is_update = hasattr(activity, "id") and activity.id
         activities = api.conversations.activities(ref.conversation.id)
 
diff --git a/packages/apps/src/microsoft_teams/apps/routing/activity_context.py b/packages/apps/src/microsoft_teams/apps/routing/activity_context.py
index ba9d3155..4fceaf68 100644
--- a/packages/apps/src/microsoft_teams/apps/routing/activity_context.py
+++ b/packages/apps/src/microsoft_teams/apps/routing/activity_context.py
@@ -6,6 +6,7 @@
 import base64
 import json
 import logging
+import warnings
 from dataclasses import dataclass
 from typing import TYPE_CHECKING, Any, Awaitable, Callable, Generic, Optional, TypeVar
 
@@ -35,7 +36,7 @@
 from microsoft_teams.api.models.oauth import OAuthCard
 from microsoft_teams.cards import AdaptiveCard
 from microsoft_teams.common import Storage
-from microsoft_teams.common.experimental import experimental
+from microsoft_teams.common.experimental import ExperimentalWarning, experimental
 from microsoft_teams.common.http.client_token import Token
 
 from ..activity_sender import ActivitySender
@@ -182,6 +183,8 @@ async def send(
         else:
             activity = message
 
+        self._add_targeted_message_info_entity(activity)
+
         ref = conversation_ref or self.conversation_ref
         res = await self._activity_sender.send(activity, ref)
         return res
@@ -229,6 +232,31 @@ def set_next(self, handler: Callable[[], Awaitable[None]]) -> None:
         """Set the next handler in the middleware chain."""
         self._next_handler = handler
 
+    def _is_incoming_targeted(self) -> bool:
+        """Check if the incoming activity is a targeted message."""
+        activity = self.activity
+        return (
+            hasattr(activity, "recipient")
+            and hasattr(activity.recipient, "is_targeted")
+            and activity.recipient.is_targeted is True
+        )
+
+    def _add_targeted_message_info_entity(self, activity_params: ActivityParams) -> None:
+        """Auto-populate targetedMessageInfo entity when replying to a targeted message.
+
+        In the reactive flow, the SDK reads the incoming targeted message ID
+        and attaches the entity automatically so the developer doesn't need to.
+        Skips if the developer already attached a targetedMessageInfo entity.
+        """
+        if not self._is_incoming_targeted():
+            return
+        if not isinstance(activity_params, MessageActivityInput):
+            return
+
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", ExperimentalWarning)
+            activity_params.add_targeted_message_info(self.activity.id)
+
     async def sign_in(self, options: Optional[SignInOptions] = None) -> Optional[str]:
         """
         Initiate a sign-in flow for the user.
diff --git a/packages/apps/tests/test_activity_context.py b/packages/apps/tests/test_activity_context.py
index ba476682..263878a9 100644
--- a/packages/apps/tests/test_activity_context.py
+++ b/packages/apps/tests/test_activity_context.py
@@ -9,7 +9,8 @@
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
-from microsoft_teams.api import Account, MessageActivityInput, SentActivity
+from microsoft_teams.api import Account, MessageActivityInput, SentActivity, TargetedMessageInfoEntity
+from microsoft_teams.api.activities.typing import TypingActivityInput
 from microsoft_teams.api.auth.cloud_environment import PUBLIC
 from microsoft_teams.api.models.entity import QuotedReplyEntity
 from microsoft_teams.apps.routing.activity_context import ActivityContext
@@ -530,3 +531,96 @@ async def test_sign_out_logs_error_and_does_not_raise_on_failure(self) -> None:
             mock_log_error.assert_called_once()
             logged_message = mock_log_error.call_args[0][0]
             assert "Failed to sign out user" in logged_message
+
+
+class TestActivityContextPromptPreview:
+    """Tests for reactive auto-population of targetedMessageInfo entity."""
+
+    def _make_targeted_activity(self, activity_id: str = "1772129782775") -> MagicMock:
+        mock_activity = MagicMock()
+        mock_activity.type = "message"
+        mock_activity.id = activity_id
+        mock_activity.text = "Hello from slash command"
+        mock_activity.from_ = Account(id="user-123", name="Test User")
+        mock_activity.recipient = Account(id="bot-456", name="Bot", is_targeted=True)
+        return mock_activity
+
+    def _make_non_targeted_activity(self) -> MagicMock:
+        mock_activity = MagicMock()
+        mock_activity.type = "message"
+        mock_activity.id = "normal-msg-id"
+        mock_activity.text = "Normal message"
+        mock_activity.from_ = Account(id="user-123", name="Test User")
+        mock_activity.recipient = Account(id="bot-456", name="Bot")
+        return mock_activity
+
+    @pytest.mark.asyncio
+    async def test_send_auto_adds_targeted_message_info_entity(self) -> None:
+        """When replying to a targeted message, the SDK auto-adds targetedMessageInfo."""
+        activity = self._make_targeted_activity("1772129782775")
+        ctx, mock_sender = _create_activity_context(activity=activity)
+
+        await ctx.send("Here is your agenda")
+
+        sent_activity = mock_sender.send.call_args[0][0]
+        assert sent_activity.entities is not None
+        assert len(sent_activity.entities) == 1
+        entity = sent_activity.entities[0]
+        assert isinstance(entity, TargetedMessageInfoEntity)
+        assert entity.message_id == "1772129782775"
+        assert entity.type == "targetedMessageInfo"
+
+    @pytest.mark.asyncio
+    async def test_send_does_not_add_entity_for_non_targeted(self) -> None:
+        """When replying to a normal message, no targetedMessageInfo is added."""
+        activity = self._make_non_targeted_activity()
+        ctx, mock_sender = _create_activity_context(activity=activity)
+
+        await ctx.send("Normal reply")
+
+        sent_activity = mock_sender.send.call_args[0][0]
+        assert sent_activity.entities is None
+
+    @pytest.mark.asyncio
+    async def test_send_does_not_duplicate_entity_if_already_present(self) -> None:
+        """If the developer already added targetedMessageInfo, the SDK does not duplicate it."""
+        activity = self._make_targeted_activity("1772129782775")
+        ctx, mock_sender = _create_activity_context(activity=activity)
+
+        msg = MessageActivityInput(text="Reply").add_entity(TargetedMessageInfoEntity(message_id="custom-id"))
+        await ctx.send(msg)
+
+        sent_activity = mock_sender.send.call_args[0][0]
+        assert sent_activity.entities is not None
+        assert len(sent_activity.entities) == 1
+        assert sent_activity.entities[0].message_id == "custom-id"
+
+    @pytest.mark.asyncio
+    async def test_reply_auto_adds_targeted_message_info_entity(self) -> None:
+        """reply() also auto-adds targetedMessageInfo for targeted messages.
+        The blockquote is added by reply(), then stripped by add_targeted_message_info
+        in send() to avoid collision with prompt preview."""
+        activity = self._make_targeted_activity("1772129782775")
+        ctx, mock_sender = _create_activity_context(activity=activity)
+
+        await ctx.reply("Reply with prompt preview")
+
+        sent_activity = mock_sender.send.call_args[0][0]
+        assert sent_activity.entities is not None
+        targeted_entities = [e for e in sent_activity.entities if isinstance(e, TargetedMessageInfoEntity)]
+        assert len(targeted_entities) == 1
+        assert targeted_entities[0].message_id == "1772129782775"
+
+        # quotedReply entities should be stripped by add_targeted_message_info
+        assert not any(getattr(e, "type", None) == "quotedReply" for e in sent_activity.entities)
+
+    @pytest.mark.asyncio
+    async def test_send_does_not_add_entity_for_non_message_activity(self) -> None:
+        """Non-message activities (e.g. typing) should not get targetedMessageInfo attached."""
+        activity = self._make_targeted_activity("1772129782775")
+        ctx, mock_sender = _create_activity_context(activity=activity)
+
+        await ctx.send(TypingActivityInput())
+
+        sent_activity = mock_sender.send.call_args[0][0]
+        assert sent_activity.entities is None
diff --git a/packages/apps/tests/test_activity_sender.py b/packages/apps/tests/test_activity_sender.py
index 384edbb9..59965934 100644
--- a/packages/apps/tests/test_activity_sender.py
+++ b/packages/apps/tests/test_activity_sender.py
@@ -36,6 +36,16 @@ def conversation_ref(self):
             service_url="https://test.service.url",
         )
 
+    @pytest.fixture
+    def group_conversation_ref(self):
+        """Create a group chat conversation reference for testing."""
+        return ConversationReference(
+            bot=Account(id="bot-123", name="Test Bot", role="bot"),
+            conversation=ConversationAccount(id="conv-789", conversation_type="groupChat"),
+            channel_id="msteams",
+            service_url="https://test.service.url",
+        )
+
     def _create_sent_activity(self, activity, activity_id="msg-123"):
         """Helper to create a proper SentActivity mock."""
         return SentActivity(id=activity_id, activity_params=activity)
@@ -94,7 +104,7 @@ async def test_send_sets_from_and_conversation(self, sender, conversation_ref):
             assert activity.conversation == conversation_ref.conversation
 
     @pytest.mark.asyncio
-    async def test_send_targeted_message_calls_create_targeted(self, sender, conversation_ref):
+    async def test_send_targeted_message_calls_create_targeted(self, sender, group_conversation_ref):
         """Test that targeted messages use the create_targeted method."""
         recipient = Account(id="user-123", name="Test User", role="user")
         activity = MessageActivityInput(text="Hello").with_recipient(recipient, is_targeted=True)
@@ -107,7 +117,7 @@ async def test_send_targeted_message_calls_create_targeted(self, sender, convers
             mock_api.conversations.activities.return_value = mock_activities
             mock_api_client.return_value = mock_api
 
-            await sender.send(activity, conversation_ref)
+            await sender.send(activity, group_conversation_ref)
 
             mock_activities.create_targeted.assert_called_once_with(activity)
             mock_activities.create.assert_not_called()
@@ -131,7 +141,7 @@ async def test_send_non_targeted_message_does_not_call_create_targeted(self, sen
             mock_activities.create_targeted.assert_not_called()
 
     @pytest.mark.asyncio
-    async def test_update_targeted_message_calls_update_targeted(self, sender, conversation_ref):
+    async def test_update_targeted_message_calls_update_targeted(self, sender, group_conversation_ref):
         """Test that targeted message updates use the update_targeted method."""
         activity = MessageActivityInput(text="Updated targeted message")
         activity.recipient = Account(id="user-123", name="Test User", role="user", is_targeted=True)
@@ -147,7 +157,7 @@ async def test_update_targeted_message_calls_update_targeted(self, sender, conve
             mock_api.conversations.activities.return_value = mock_activities
             mock_api_client.return_value = mock_api
 
-            await sender.send(activity, conversation_ref)
+            await sender.send(activity, group_conversation_ref)
 
             mock_activities.update_targeted.assert_called_once_with("existing-msg-id", activity)
             mock_activities.update.assert_not_called()
@@ -170,3 +180,32 @@ async def test_update_non_targeted_message_calls_update(self, sender, conversati
 
             mock_activities.update.assert_called_once_with("existing-msg-id", activity)
             mock_activities.update_targeted.assert_not_called()
+
+    @pytest.mark.asyncio
+    async def test_send_targeted_in_personal_chat_raises(self, sender, conversation_ref):
+        """Test that sending a targeted message in a personal (1:1) chat raises ValueError."""
+        activity = MessageActivityInput(text="Hello").with_recipient(
+            Account(id="user-1", name="User"), is_targeted=True
+        )
+
+        with pytest.raises(ValueError, match="Targeted messages are not supported in 1:1"):
+            await sender.send(activity, conversation_ref)
+
+    @pytest.mark.asyncio
+    async def test_send_targeted_in_group_chat_succeeds(self, sender, group_conversation_ref):
+        """Test that sending a targeted message in a group chat proceeds normally."""
+        activity = MessageActivityInput(text="Hello").with_recipient(
+            Account(id="user-1", name="User"), is_targeted=True
+        )
+
+        mock_activities = MagicMock()
+        mock_activities.create_targeted = AsyncMock(return_value=self._create_sent_activity(activity))
+
+        with patch("microsoft_teams.apps.activity_sender.ApiClient") as mock_api_client:
+            mock_api = MagicMock()
+            mock_api.conversations.activities.return_value = mock_activities
+            mock_api_client.return_value = mock_api
+
+            await sender.send(activity, group_conversation_ref)
+
+            mock_activities.create_targeted.assert_called_once()