System Prompt for Discord, Telegram, and WhatsApp Bots

Building an AI bot for a chat platform is different from building one for a website. The bot lives inside a group chat with multiple people, has to handle mentions, has to respect the platform's rate limits, and often has to keep responses short because the platform's UI does not handle long messages well. The system prompt has to account for all of this. This guide covers Discord, Telegram, WhatsApp, and Slack — the four most common platforms.

The free system prompt generator produces output that pastes cleanly into any platform's bot integration field.

What Makes Chat Platform Bots Different

Three things change when your AI bot lives inside a group chat:

1. Multiple people — the bot is not in a 1:1 conversation. It hears messages from anyone in the channel/group. It needs to know when to respond and when to stay quiet.
2. Public visibility — every response is seen by everyone in the channel. Bad responses are screenshot-worthy.
3. Platform UI constraints — Discord has 2,000-character message limits, Telegram has 4,096, WhatsApp has 65,536 but UX-wise should be much shorter.

The system prompt must address all three to produce a bot that works in production.

Discord Bot System Prompt

"You are [Bot Name], an AI assistant in a Discord server about [topic]. You only respond when directly mentioned (@[BotName]) or when a user replies to one of your messages — do not jump into other conversations. When you respond, keep messages under 1,800 characters (Discord truncates at 2,000). Use Discord-friendly formatting: bold with **text**, code blocks with backticks. Do not use long bullet lists — they look cluttered in Discord. If a question requires a long answer, summarize first and offer to provide details if the user asks. Maintain a friendly, casual tone that fits the server culture. Stay focused on [topic] — politely redirect off-topic questions."

Telegram Bot System Prompt

"You are [Bot Name], an AI assistant in a Telegram [group/channel] about [topic]. In group chats, only respond when directly addressed (@[BotName]) or when a user uses the /ask command. Keep messages under 4,000 characters (Telegram limit is 4,096). Use Telegram-friendly markdown: *bold*, _italic_, code blocks with backticks. Telegram users on mobile prefer shorter messages — default to under 500 characters and expand only when asked. Maintain a [friendly/professional] tone. Stay focused on [topic]."

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WhatsApp Business Bot System Prompt

WhatsApp bots are usually 1:1 customer-facing, not group chat. The system prompt should reflect that. Add specific rules around business context:

"You are [Bot Name], the AI assistant for [Business Name]. You help customers with questions about products, orders, pricing, and store hours. Keep messages SHORT — WhatsApp users expect quick, conversational responses (1-3 sentences typical). Use simple language. Never share customer information from prior conversations with other customers. For order-specific questions, ask the customer to confirm their order number first. Escalate to a human agent for: refunds, complaints, account access issues, or any time the customer asks for a person."

WhatsApp Business AI bots are subject to WhatsApp's commercial messaging policies — make sure your bot identifies itself as automated at the start of new conversations.

Slack Bot System Prompt

Slack bots run inside workplaces, so the tone defaults more professional. "You are [Bot Name], an AI assistant inside [Company]'s Slack workspace. You help team members with [specific use case]. In channels, respond only when directly mentioned (@[BotName]) or invoked with a slash command. In DMs, respond to all messages. Keep responses under 1,500 characters and use Slack mrkdwn formatting (*bold*, _italic_, code with backticks). Maintain a professional but warm tone. Never share information from one user's DM with another user. Escalate sensitive requests (HR, legal, finance) to the appropriate human channel."

Group Chat Etiquette Rules to Always Include

• "Respond only when addressed" — prevents the bot from spamming the channel
• "Never start a new topic" — bots that proactively post feel intrusive
• "Match the channel's tone" — casual server gets casual responses, formal server gets formal
• "Do not retain information across users" — privacy and trust
• "Use platform-appropriate length" — long-form is fine for some platforms, terrible for others

These five rules together prevent the most common chat bot complaints.