Streaming AI replies on Telegram

Level: Intermediate · Tags: AI, Streaming, Telegram, Performance Features shown: streaming autoreply (stream) · strategies per channel: drafts, edits, chunks · “typing…” while generating · Telegram provider · cost and latency settings · testing streams with MockProvider

Prerequisites

Node.js 22.12 or newer.
A Telegram bot token from @BotFather in TELEGRAM_TOKEN.
An Anthropic API key in ANTHROPIC_API_KEY (or another model provider, see below).

npm install @botmesh/core @botmesh/ai @anthropic-ai/sdk @botmesh/telegram

The bot

// bot.js
import { Bot, defineBot, isMainModule, slashCommandsPlugin } from '@botmesh/core'
import { TelegramProvider } from '@botmesh/telegram'
import { aiPlugin } from '@botmesh/ai'

const createBot = defineBot((provider) => {
  const bot = new Bot({ provider })

  bot.plug(slashCommandsPlugin, {
    greeting: '🍳 Hi! I am the Pantry cooking assistant. Ask me for a recipe or a cooking tip.',
  })

  bot.plug(aiPlugin({
    provider: 'anthropic',
    apiKey: process.env.ANTHROPIC_API_KEY,
    model: 'claude-haiku-5-5',      // small model: first words arrive sooner, each token costs less
    persona: 'You are the cooking assistant of the Pantry recipe app. Only talk about cooking. Use short paragraphs.',
    maxTokens: 800,                 // caps the length (and the bill) of each answer
    timeoutMs: 20_000,              // with streaming: the longest silence allowed between two chunks
    context: { maxMessages: 6 },    // less history per call: a shorter, cheaper prompt
    stream: { cursor: ' ▌', canStop: true },
  }))

  return bot
})

export default createBot

// `node --env-file=.env bot.js` connects to Telegram; `npx botmesh dev bot.js` skips this block.
if (isMainModule(import.meta)) {
  const bot = await createBot(new TelegramProvider({ token: process.env.TELEGRAM_TOKEN ?? '' }))
  bot.on('ready', () => console.log('✅ Connected. Write to your bot in Telegram.'))
  await bot.start()
}

How it works

One option. stream makes the autoresponder send the answer with ctx.stream() while the model generates it. The same code picks the best strategy for each channel:

Channel	What the user sees
Telegram private chat	A native draft that grows in place (`sendMessageDraft`), then the final message
Telegram group, Discord	One message edited as the text arrives
WhatsApp, Messenger, Instagram, the simulator	Sentence-sized messages with “typing…” in between

cursor is shown at the end of the text while it is being written and never in the final message. canStop adds Telegram’s stop button to the draft: pressing it aborts the model request, so you stop paying for it.
Typing. humanizeTyping (on by default) shows “typing…” until the first words arrive.
Tools turn streaming off. A turn that may call tools needs the whole answer first, so with tools configured the reply is sent in one message.

Cost and latency tips

Setting	Effect
`model`	The biggest lever. A small model (`claude-haiku-5-5`, `gpt-5-mini`, `gemini-3.8-flash`) answers sooner and costs a fraction of a large one.
`maxTokens`	Caps each answer. It includes the thinking tokens of reasoning models: too low and the answer comes out empty.
`timeoutMs`	Without streaming, the total time for a call; with streaming, the longest pause between chunks, so a long answer is never cut while it keeps flowing.
`context.maxMessages`	Every turn resends the history window: fewer messages, shorter prompt.
`effort` (Anthropic)	`'low'` thinks less: faster and cheaper on simple questions.
`stream`	Does not lower the cost, but the first words show in about a second instead of after the whole answer.

Answer the obvious without the model (commands, bot.when() triggers, flows), and see Cost and latency for the rest.

Try it

npx botmesh dev bot.js --env-file .env   # .env has the line ANTHROPIC_API_KEY=sk-ant-...

The simulator has no drafts or edits, so it shows the “chunk” strategy that WhatsApp uses: the answer arrives as sentence-sized messages. This run is scripted by the test that runs this page (packages/ai/tests/docs-examples-ai.test.ts), which also runs the bot on a mock Telegram-like provider and checks that the answer arrives as a growing draft there.

user › how do I make a quick tomato soup?
bot › Sauté a chopped onion and two garlic cloves in olive oil for five minutes. Add a 400 g can of crushed tomatoes, a cup of stock, salt and a pinch of sugar, and simmer for 15 minutes.
bot › Blend until smooth, then finish with fresh basil and a splash of cream. Serve it hot with toasted bread.

Other model providers

Switch to OpenAI, Gemini or a local Ollama model

Every provider streams. Keep the other options as they are.OpenAI (npm install openai, key in OPENAI_API_KEY):

aiPlugin({ provider: 'openai', apiKey: process.env.OPENAI_API_KEY, model: 'gpt-5-mini', stream: true })

Gemini (npm install @google/genai, key in GEMINI_API_KEY):

aiPlugin({ provider: 'gemini', apiKey: process.env.GEMINI_API_KEY, model: 'gemini-3.8-flash', stream: true })

Ollama on your machine (no package, no key; run ollama pull llama3.1 first): the first token arrives with no network round trip, and there is no output cap unless you set maxTokens.

aiPlugin({ provider: 'ollama', model: 'llama3.1', stream: true })

Run it on Telegram or WhatsApp

Put the token and the key in a .env file next to bot.js (TELEGRAM_TOKEN=... and ANTHROPIC_API_KEY=...), run node --env-file=.env bot.js and write to your bot in Telegram. For WhatsApp, install @botmesh/baileys and start the factory with new BaileysProvider({ session: 'pantry-bot' }) instead: the same code sends the answer in chunks with “typing…”.

Next steps

Streaming replies: ctx.stream() for your own handlers and every option
AI FAQ assistant: the persona and guardrails of a business assistant
Examples overview

Overview

Beginner

Intermediate

AI

Advanced

Streaming AI replies on Telegram

Prerequisites

The bot

How it works

Cost and latency tips

Try it

Other model providers

Run it on Telegram or WhatsApp

Next steps

​Prerequisites

​The bot

​How it works

​Cost and latency tips

​Try it

​Other model providers

​Run it on Telegram or WhatsApp

​Next steps

Prerequisites

The bot

How it works

Cost and latency tips

Try it

Other model providers

Run it on Telegram or WhatsApp

Next steps