Add threading and quoted replies documentation

teams.md/src/components/include/essentials/sending-messages/csharp.incl.md

@@ -87,3 +87,24 @@ In .NET, reaction APIs are marked with `[Experimental("ExperimentalTeamsReaction
 </PropertyGroup>
 ```
 :::
+
+<!-- context-send-method-name -->
+
+`Send()`
+
+<!-- context-reply-method-name -->
+
+`Reply()`
+
+<!-- threading-reactive-example -->
+
+```csharp
+app.OnMessage(async context =>
+{
+    // Send in the same thread, no quote
+    await context.Send("Acknowledged");
+
+    // Send in the same thread with a visual quote of the inbound message
+    await context.Reply("Got it!");
+});
+```

teams.md/src/components/include/essentials/sending-messages/proactive-messaging/csharp.incl.md

@@ -50,4 +50,35 @@ public static async Task SendTargetedNotification(string conversationId, Account
             .WithRecipient(recipient, isTargeted: true)
     );
 }
+```
+
+<!-- app-reply-method-name -->
+
+`app.Reply()`
+
+<!-- to-thread-id-method-name -->
+
+`Conversation.ToThreadedConversationId()`
+
+<!-- app-send-method-name -->
+
+`app.Send()`
+
+<!-- threading-proactive-example -->
+
+```csharp
+// Send to a specific thread proactively
+await app.Reply(conversationId, messageId, "Thread update!");
+
+// Send to a flat conversation (1:1, group chat)
+await app.Reply(conversationId, "Hello!");
+```
+
+<!-- threading-helper-example -->
+
+```csharp
+using Microsoft.Teams.Api;
+
+var threadId = Conversation.ToThreadedConversationId(conversationId, messageId);
+await app.Send(threadId, "Sent via helper");
 ```

teams.md/src/components/include/essentials/sending-messages/proactive-messaging/python.incl.md

@@ -48,4 +48,35 @@ async def send_targeted_notification(conversation_id: str, recipient: Account):
         MessageActivityInput(text="This is a private notification just for you!")
             .with_recipient(recipient, is_targeted=True)
     )
+```
+
+<!-- app-reply-method-name -->
+
+`app.reply()`
+
+<!-- to-thread-id-method-name -->
+
+`to_threaded_conversation_id()`
+
+<!-- app-send-method-name -->
+
+`app.send()`
+
+<!-- threading-proactive-example -->
+
+```python
+# Send to a specific thread proactively
+await app.reply(conversation_id, message_id, "Thread update!")
+
+# Send to a flat conversation (1:1, group chat)
+await app.reply(conversation_id, "Hello!")
+```
+
+<!-- threading-helper-example -->
+
+```python
+from microsoft_teams.apps import to_threaded_conversation_id
+
+thread_id = to_threaded_conversation_id(conversation_id, message_id)
+await app.send(thread_id, "Sent via helper")
 ```

teams.md/src/components/include/essentials/sending-messages/proactive-messaging/typescript.incl.md

@@ -53,4 +53,35 @@ const sendTargetedNotification = async (conversationId: string, recipient: Accou
       .withRecipient(recipient, true)
   );
 };
+```
+
+<!-- app-reply-method-name -->
+
+`app.reply()`
+
+<!-- to-thread-id-method-name -->
+
+`toThreadedConversationId()`
+
+<!-- app-send-method-name -->
+
+`app.send()`
+
+<!-- threading-proactive-example -->
+
+```typescript
+// Send to a specific thread proactively
+await app.reply(conversationId, messageId, 'Thread update!');
+
+// Send to a flat conversation (1:1, group chat)
+await app.reply(conversationId, 'Hello!');
+```
+
+<!-- threading-helper-example -->
+
+```typescript
+import { toThreadedConversationId } from '@microsoft/teams.apps';
+
+const threadId = toThreadedConversationId(conversationId, messageId);
+await app.send(threadId, 'Sent via helper');
 ```

teams.md/src/components/include/essentials/sending-messages/python.incl.md

@@ -69,5 +69,29 @@ async def handle_message(ctx: ActivityContext[MessageActivity]):
 <!-- targeted-preview-note -->
 N/A
 
+<!-- reactions-preview-note -->
+N/A
+
+<!-- context-send-method-name -->
+
+`send()`
+
+<!-- context-reply-method-name -->
+
+`reply()`
+
+<!-- threading-reactive-example -->
+
+```python
+@app.on_message
+async def handle_message(ctx: ActivityContext[MessageActivity]):
+    # Send in the same thread, no quote
+    await ctx.send("Acknowledged")
+
+    # Send in the same thread with a visual quote of the inbound message
+    await ctx.reply("Got it!")
+```
+N/A
+
 <!-- reactions-preview-note -->
 N/A

teams.md/src/components/include/essentials/sending-messages/typescript.incl.md

@@ -64,4 +64,24 @@ app.on('message', async ({ send, activity }) => {
 N/A
 
 <!-- reactions-preview-note -->
-N/A
+N/A
+
+<!-- context-send-method-name -->
+
+`send()`
+
+<!-- context-reply-method-name -->
+
+`reply()`
+
+<!-- threading-reactive-example -->
+
+```typescript
+app.on('message', async ({ send, reply }) => {
+  // Send in the same thread, no quote
+  await send('Acknowledged');
+
+  // Send in the same thread with a visual quote of the inbound message
+  await reply('Got it!');
+});
+```

teams.md/src/pages/templates/essentials/sending-messages/README.mdx

@@ -64,3 +64,15 @@ Reactions allow your agent to add or remove emoji reactions on messages in a con
 ### Reactions in preview 
 
 <LanguageInclude section="reactions-preview-note" />
+
+## Threading
+
+In Teams channels, messages can be organized into threads. A thread is identified by appending `;messageid={messageId}` to the conversation ID. The SDK provides helpers to simplify working with threads.
+
+### Reactive Threading (Within a Handler)
+
+When your agent receives a message in a thread, the conversation context already carries the thread ID. Use <LanguageInclude section="context-send-method-name" /> to send a message in the same thread without quoting, or <LanguageInclude section="context-reply-method-name" /> to send with a visual quote of the inbound message.
+
+<LanguageInclude section="threading-reactive-example" />
+
+For proactive threading (sending to a thread outside of a handler), see [Proactive Messaging](./proactive-messaging#proactive-threading).

teams.md/src/pages/templates/essentials/sending-messages/proactive-messaging.mdx

@@ -32,3 +32,19 @@ Targeted messages, also known as ephemeral messages, are delivered to a specific
 When sending targeted messages proactively, you must explicitly specify the recipient account.
 
 <LanguageInclude section="targeted-proactive-example" />
+
+## Proactive Threading
+
+To send a message to a thread outside of a handler, use <LanguageInclude section="app-reply-method-name" /> with the conversation ID and thread root message ID. The SDK constructs the threaded conversation ID for you.
+
+<LanguageInclude section="threading-proactive-example" />
+
+You can also pass just a conversation ID to <LanguageInclude section="app-reply-method-name" /> for flat contexts (1:1, group chat, meetings).
+
+For reactive threading (within a handler), see [Threading](./#threading).
+
+### Thread ID Helper
+
+For advanced scenarios, the <LanguageInclude section="to-thread-id-method-name" /> helper constructs the threaded conversation ID directly. Use it with <LanguageInclude section="app-send-method-name" /> when you need full control. Note that <LanguageInclude section="to-thread-id-method-name" /> is only valid for conversations that support threading (channels and some 1:1 chats) — group chats and meetings do not support threading at this time.
+
+<LanguageInclude section="threading-helper-example" />