[Fix] Telegram Fast replies show a blank draft before streaming

apps/docs/providers/communications/telegram.mdx

@@ -119,12 +119,12 @@ Roomote user. `/new` starts a fresh conversation instead of continuing the
 current one, opening a new topic when Telegram supports it; in a plain private
 chat the request joins that chat's conversation.
 
-While a private-chat Fast turn is running, Telegram shows its native
-**Thinking** status. Roomote refreshes the temporary draft for long turns and
-starts filling that draft with the response when generation takes long enough
-to stream. The completed response is always sent as a normal message so it
-remains in the conversation. Roomote keeps activity active across intermediate
-replies while more work remains, and a final reply clears it naturally.
+While a private-chat Fast turn is running, Telegram shows a non-empty
+**Roomote is working...** native draft, then replaces it with response text as
+generation continues. The completed response is always sent as a normal message
+so it remains in the conversation. Roomote keeps activity active across
+intermediate replies while more work remains, and a final reply clears it
+naturally.
 Telegram does not support native drafts in group chats, so groups use
 Telegram's standard typing status and receive completed replies instead.
 

packages/sdk/src/server/lib/fast-agent-telegram-activity.ts

@@ -16,17 +16,18 @@ import { createFastAgentTypingActivity } from './fast-agent-typing-activity';
 export const FAST_AGENT_TELEGRAM_DRAFT_REFRESH_MS = 25_000;
 export const FAST_AGENT_TELEGRAM_TYPING_REFRESH_MS = 4_000;
 export const FAST_AGENT_TELEGRAM_REASSERT_DELAY_MS = 500;
-// Telegram allows 40 draft updates per 30 seconds; stay just above its 750ms floor.
+// Pace draft updates independently of model token cadence.
 export const FAST_AGENT_TELEGRAM_STREAM_INTERVAL_MS = 800;
+const FAST_AGENT_TELEGRAM_THINKING_TEXT = 'Roomote is working...';
 
 function isTelegramPrivateChatId(channelId: string): boolean {
   const parsed = Number(channelId);
   return Number.isSafeInteger(parsed) && parsed > 0;
 }
 
 /**
- * Uses Telegram's native Thinking draft in private chats. Groups do not
- * support drafts, so they retain Telegram's ordinary typing action.
+ * Uses a non-empty Thinking draft in private chats, then replaces it with
+ * streamed response text. Groups retain Telegram's ordinary typing action.
  */
 export function createFastAgentTelegramActivity({
   provider,
@@ -56,7 +57,10 @@ export function createFastAgentTelegramActivity({
           await provider.sendMessageDraft({
             ...replyTarget,
             draftId: draftId!,
-            text: draftText.slice(0, TELEGRAM_MAX_MESSAGE_LENGTH),
+            text: (draftText || FAST_AGENT_TELEGRAM_THINKING_TEXT).slice(
+              0,
+              TELEGRAM_MAX_MESSAGE_LENGTH,
+            ),
           });
           lastDraftWriteAtMs = Date.now();
           return;