AI FAQ assistant with guardrails

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

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

// The persona is the main guardrail: one business, what to answer, what to decline.
const PERSONA = [
  'You are the assistant of Northwind Bikes, a bicycle shop with a repair workshop.',
  'Answer only about our bikes, accessories, repairs, opening hours (Mon-Sat 9:00-19:00) and orders.',
  'If the question is about anything else, say in one sentence that you can only help with Northwind Bikes',
  'and suggest typing "agent" to talk to a person.',
  'Never make up prices, stock or policies: if you do not know, say so. Answer in at most three short sentences.',
].join(' ')

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

  bot.plug(slashCommandsPlugin, {
    greeting: '🚲 Hi! I am the Northwind Bikes assistant. Ask me about bikes, repairs or opening hours.',
  })

  // Fixed answers never reach the model: instant, free and always right.
  bot.when(['hours', 'opening hours'], (ctx) => ctx.reply('🕘 We are open Mon-Sat, 9:00-19:00.'))
  bot.when(['agent', 'human'], (ctx) => ctx.reply('👤 Call us at +1 555 0100 or write to help@northwind.example.'))

  // A deterministic guardrail: very long messages are not sent to the model.
  bot.when(
    (ctx) => ctx.body.length > 500,
    (ctx) => ctx.reply('✂️ That is a long message. Please ask one short question at a time.'),
  )

  // Everything else goes to the model. Plugged last, so its /reset also clears the AI history.
  bot.plug(aiPlugin({
    provider: 'anthropic',
    apiKey: process.env.ANTHROPIC_API_KEY,
    model: 'claude-haiku-5-5',     // a small model is enough for FAQs
    persona: PERSONA,
    maxTokens: 300,                // short answers: cheaper and faster
    context: { maxMessages: 10 },  // history sent with each question
  }))

  return bot
})

export default createBot

// `node bot.js` connects to WhatsApp; `npx botmesh dev bot.js` skips this block.
if (isMainModule(import.meta)) {
  const bot = await createBot(new BaileysProvider({ session: 'faq-bot' }))
  bot.on('ready', () => console.log('✅ Connected'))
  await bot.start()
}

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

user › /start
bot › 🚲 Hi! I am the Northwind Bikes assistant. Ask me about bikes, repairs or opening hours.
user › hours
bot › 🕘 We are open Mon-Sat, 9:00-19:00.
user › do you repair electric bikes?
bot › Yes, our workshop services electric bikes too: motor, battery and brakes. Bring it in Mon-Sat, 9:00-19:00.
user › write me a poem about the sea
bot › Sorry, I can only help with Northwind Bikes. Type "agent" to talk to a person.
user › agent
bot › 👤 Call us at +1 555 0100 or write to help@northwind.example.