tg-rich-streaming

tg-rich-streaming

Stream AI-generated text into a Telegram private chat with native draft animation and a "thinking" indicator — the same UX as ChatGPT or Claude, directly inside the bot.

Core pattern

Four mandatory steps. Skip step 3 and the draft disappears after ~30 seconds.

Step 1 — open draft with Thinking block

Send the first sendRichMessageDraft immediately after the LLM call starts. draft_id is any non-zero integer you generate once per response; keep it for all updates. RichBlockThinking signals the model is working.

POST /sendRichMessageDraft
{
  "chat_id": <integer>,          // private chat only — no @username
  "draft_id": 42,
  "rich_message": {
    "markdown": "<tg-thinking>Thinking…</tg-thinking>"
  }
}

Rich HTML tags (like <tg-thinking>) are valid pass-through inside the markdown field — spec explicitly allows HTML tags in Rich Markdown.

RichBlockThinking is only valid in sendRichMessageDraft. It is never stored in a Message.

Step 2 — update draft as tokens arrive

Call sendRichMessageDraft again with the same draft_id each time you have enough new text. The client animates the transition.

Throttle: send at most once every 1–2 seconds. The draft is ephemeral (~30 s window) — keep sending updates or move to step 3 before the window closes.

Drop the Thinking block from the first update that contains real content.

# pseudocode — generic async LLM stream

draft_id = generate_nonzero_id()
accumulated = ""
last_sent = 0

send_draft(chat_id, draft_id, thinking_markdown())   # step 1

for chunk in llm.stream(prompt):
    accumulated += chunk.text
    now = time.monotonic()
    if now - last_sent >= 1.5:                        # throttle
        send_draft(chat_id, draft_id, accumulated)
        last_sent = now

finalize(chat_id, accumulated)                        # step 3 — mandatory

Step 3 — finalize with sendRichMessage (mandatory)

After the LLM stream ends, call sendRichMessage. This creates the permanent message. If you skip this, the draft vanishes.

POST /sendRichMessage
{
  "chat_id": <integer>,
  "rich_message": {
    "markdown": "<full generated text>"
  }
}

Step 4 — edits after finalization

Use editMessageText with the rich_message parameter to update the permanent message later (corrections, appended content, etc.).

POST /editMessageText
{
  "chat_id": <integer>,
  "message_id": <id from step 3 response>,
  "rich_message": {
    "markdown": "<revised text>"
  }
}

text and rich_message are mutually exclusive in editMessageText — use exactly one.

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Pitfalls

Trap	What happens	Fix
Skipped sendRichMessage after stream ends	Draft disappears after ~30 s, no permanent message	Always call sendRichMessage with full text as last step
chat_id is a String or @username	sendRichMessageDraft returns error	Only Integer chat_id supported for drafts; fall back to sendMessage + editMessageText in groups/channels
Sending a draft update every token	Flood / rate limit, poor animation	Batch tokens, send at most every 1–2 s
RichBlockThinking in sendRichMessage	Not stored in Message; spec prohibits it	Remove Thinking block before finalization
Partial Markdown mid-stream	Unclosed ``` or ** renders broken	Either send complete blocks only, or use raw text during streaming and apply Markdown only at finalization
30-second window expires mid-stream	Draft gone	If stream is slow, send a keep-alive draft update (even unchanged text) before the window closes

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Group / channel fallback

sendRichMessageDraft is private-chat only. For groups and channels:

1. Send initial sendMessage with "⌛ Generating…" placeholder.
2. Edit with editMessageText (rich_message) when done.

No real-time animation, but the final message is rich-formatted.

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Request reference

sendRichMessageDraft  POST /bot<TOKEN>/sendRichMessageDraft
  chat_id        Integer   required — private chat only
  draft_id       Integer   required — non-zero; same id = animated update
  rich_message   InputRichMessage   required

sendRichMessage       POST /bot<TOKEN>/sendRichMessage
  chat_id        Integer or String   required
  rich_message   InputRichMessage    required
  → returns Message (use .message_id for edits)

editMessageText       POST /bot<TOKEN>/editMessageText
  chat_id        Integer or String
  message_id     Integer
  rich_message   InputRichMessage    (mutually exclusive with "text")

InputRichMessage fields: exactly one of html or markdown, optional is_rtl, optional skip_entity_detection.

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Related

• ../tg-rich-messages/SKILL.md — full block & inline type reference
• ../../reference/rich-messages-spec.md — extracted Bot API 10.1 spec