AI answers from your own FAQ (RAG)

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

<!-- faq.md -->
# Lumen Lamps FAQ

## Shipping
We ship nationwide. Orders arrive in 2-3 business days; express shipping arrives the next business day.

## Returns
You can return any lamp within 30 days of delivery, unused and in its box. Refunds take 5 business days.

## Payments
We accept credit and debit cards, PayPal and bank transfer.

## Warranty
Every lamp has a 2-year warranty against manufacturing defects.

// bot.js
import { readFile } from 'node:fs/promises'
import { Bot, defineBot, isMainModule } from '@botmesh/core'
import { BaileysProvider } from '@botmesh/baileys'
import { aiPlugin } from '@botmesh/ai'

const STOP_WORDS = new Set(['the', 'and', 'you', 'your', 'for', 'with', 'how', 'what', 'does', 'can', 'are', 'our', 'after'])
const words = (text) =>
  new Set((text.toLowerCase().match(/[a-z0-9]{3,}/g) ?? []).filter((w) => !STOP_WORDS.has(w)))

/**
 * A small retriever over a Markdown file: one passage per `## ` section, ranked by the
 * words it shares with the question. The plugin only needs `retrieve(query)`, so a
 * vector database or a search API fits in the same place.
 */
function markdownRetriever(file) {
  let sections
  const load = async () => {
    sections ??= (await readFile(file, 'utf8'))
      .split(/^## /m)
      .slice(1)
      .map((part) => {
        const [title, ...body] = part.trim().split('\n')
        const text = body.join('\n').trim()
        return { title, text, words: words(`${title} ${text}`) }
      })
    return sections
  }
  return {
    warmup: async () => { await load() }, // aiPlugin calls it at startup
    async retrieve(query, { topK = 2 } = {}) {
      const asked = words(query)
      return (await load())
        .map((s) => ({ ...s, score: [...asked].filter((w) => s.words.has(w)).length }))
        .filter((s) => s.score > 0)
        .sort((a, b) => b.score - a.score)
        .slice(0, topK)
        .map((s) => ({ text: s.text, citation: `faq.md › ${s.title}`, score: s.score }))
    },
  }
}

const PERSONA = [
  'You are the support assistant of Lumen Lamps, an online lamp store.',
  'Answer only with the information of the context. If it does not have the answer,',
  'say you do not know and suggest writing to help@lumen.example. Answer in one or two sentences.',
].join(' ')

const RAG = {
  retriever: markdownRetriever(new URL('./faq.md', import.meta.url)),
  topK: 2,              // fewer passages, shorter prompt
  appendSources: true,  // adds "Sources: [1] faq.md › Shipping" to the answer
}

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

  bot.plug(aiPlugin({
    provider: 'anthropic',
    apiKey: process.env.ANTHROPIC_API_KEY,
    model: 'claude-haiku-5-5',
    persona: PERSONA,
    maxTokens: 300,
    rag: RAG,
  }))

  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-rag-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 › how long does shipping take?
bot › Orders arrive in 2-3 business days, or the next business day with express shipping [1].

      Sources: [1] faq.md › Shipping
user › do you sell desk fans?
bot › Sorry, I do not know that. Please write to help@lumen.example.
user › can I return a lamp after two weeks?
bot › Yes: you can return a lamp within 30 days of delivery, unused and in its box [1].

      Sources: [1] faq.md › Returns