pnpm add @nuxtjs/mcp-toolkit zod

npm install @nuxtjs/mcp-toolkit zod

yarn add @nuxtjs/mcp-toolkit zod

bun add @nuxtjs/mcp-toolkit zod

npx nuxt add mcp

export default defineNuxtConfig({
  modules: ['@nuxtjs/mcp-toolkit'],
  mcp: {
    name: 'My MCP Server',
    description: 'Read and update todos for the current user.',
  },
  nitro: {
    experimental: { asyncContext: true }, // required for useEvent / useMcpServer / useMcpLogger
  },
})

server/mcp/
├── tools/                 # Actions the AI can perform
│   └── admin/             # Subdirectory → group: 'admin'
├── resources/             # Data the AI can read
├── prompts/               # Reusable message templates
└── handlers/              # Optional: named handlers mounted at /mcp/<name>
    └── admin/
        ├── index.ts       # defineMcpHandler({ middleware: requireAdmin })
        ├── tools/         # auto-attached to /mcp/admin
        └── resources/
 
app/mcp/                   # Optional: MCP Apps (interactive Vue widgets)
└── palette.vue            # → app `palette`, callable from ChatGPT / Cursor

import { z } from 'zod'
 
export default defineMcpTool({
  description: 'Echo a message back to the user',
  inputSchema: {
    message: z.string().describe('Text to echo'),
  },
  handler: async ({ message }) => {
    return `Echo: ${message}` // string is auto-wrapped into a text content item
  },
})

import { z } from 'zod'
export default defineMcpTool({
  description: 'Get a user by ID',
  inputSchema: { id: z.string().describe('User ID') },
  handler: async ({ id }) => {
    const user = await getUser(id)
    if (!user) throw createError({ statusCode: 404, message: 'User not found' })
    return user // plain object — auto-stringified
  },
})

import { z } from 'zod'
export default defineMcpTool({
  description: 'Calculate Body Mass Index',
  inputSchema: {
    height: z.number().describe('Height in meters'),
    weight: z.number().describe('Weight in kilograms'),
  },
  outputSchema: {
    bmi: z.number(),
    category: z.string(),
  },
  handler: async ({ height, weight }) => {
    const bmi = weight / (height * height)
    const category = bmi < 18.5 ? 'underweight' : bmi < 25 ? 'normal' : bmi < 30 ? 'overweight' : 'obese'
    return { structuredContent: { bmi, category } }
  },
})

export default defineMcpTool({
  description: 'Delete a user account',
  annotations: {
    readOnlyHint: false,
    destructiveHint: true,
    idempotentHint: true,
    openWorldHint: false,
  },
  inputSchema: { id: z.string() },
  inputExamples: [{ id: 'usr_42' }, { id: 'admin' }],
  handler: async ({ id }) => {
    await deleteUser(id)
    return `Deleted ${id}.`
  },
})

export default defineMcpTool({
  group: 'admin',
  tags: ['destructive', 'user-management'],
  description: 'Delete a user account',
  // ...
})

export default defineMcpTool({
  cache: '5m',  // also accepts `Number` of ms or full Nitro cache options
  description: 'Fetch weather (cached)',
  inputSchema: { city: z.string() },
  handler: async ({ city }) => $fetch(`/api/weather?city=${city}`),
})

export default defineMcpTool({
  enabled: event => Boolean(event.context.user),
  description: 'List the current user’s todos',
  handler: async () => listTodos(useEvent().context.user.id),
})

export default defineMcpResource({
  description: 'Project README file',
  file: 'README.md', // URI, MIME type, and handler auto-generated
})

export default defineMcpResource({
  description: 'Application config',
  uri: 'config:///app',
  metadata: { mimeType: 'application/json' },
  handler: async (uri) => ({
    contents: [{
      uri: uri.toString(),
      mimeType: 'application/json',
      text: JSON.stringify({ env: process.env.NODE_ENV }, null, 2),
    }],
  }),
})

import { ResourceTemplate } from '@modelcontextprotocol/sdk/server/mcp.js'
 
export default defineMcpResource({
  description: 'Fetch a user by ID',
  uri: new ResourceTemplate('user:///{id}', { list: undefined }),
  handler: async (uri, { id }) => {
    const user = await getUser(String(id))
    return {
      contents: [{
        uri: uri.toString(),
        mimeType: 'application/json',
        text: JSON.stringify(user, null, 2),
      }],
    }
  },
})

export default defineMcpResource({
  description: 'Project README',
  file: 'README.md',
  metadata: {
    mimeType: 'text/markdown',
    annotations: {
      audience: ['user', 'assistant'],
      priority: 0.8,
      lastModified: new Date().toISOString(),
    },
  },
})

export default defineMcpPrompt({
  description: 'Code-review assistant',
  handler: async () => 'You are a senior reviewer. Be concise and actionable.',
})

import { z } from 'zod'
 
export default defineMcpPrompt({
  description: 'Generate a focused code review',
  inputSchema: {
    language: z.string().describe('Programming language'),
    focus: z.enum(['performance', 'security', 'maintainability']).describe('Review focus'),
  },
  handler: async ({ language, focus }) =>
    `Review my ${language} code. Focus on ${focus}.`,
})

import { z } from 'zod'
export default defineMcpPrompt({
  description: 'Open an issue for a project',
  inputSchema: {
    project: completable(z.string(), async (value) => {
      const projects = await listProjects()
      return projects.filter(p => p.startsWith(value)).slice(0, 5)
    }).describe('Project name'),
  },
  handler: async ({ project }) => `Open an issue for ${project}.`,
})

export default defineMcpPrompt({
  description: 'Structured debugging session',
  inputSchema: { issue: z.string(), env: z.enum(['dev', 'staging', 'prod']) },
  handler: async ({ issue, env }) => ({
    messages: [
      { role: 'user', content: { type: 'text', text: `Debug in ${env}:\n${issue}` } },
      { role: 'assistant', content: { type: 'text', text: 'Let me analyze step by step:' } },
    ],
  }),
})

server/mcp/
├── tools/                       # → /mcp (default handler)
└── handlers/
    ├── admin/
    │   ├── index.ts             # defineMcpHandler({ middleware: requireAdmin })
    │   ├── tools/               # → /mcp/admin (auto)
    │   └── prompts/
    └── public/
        ├── index.ts
        └── tools/               # → /mcp/public (auto)

export default defineMcpHandler({
  description: 'Admin tools — destructive operations gated by Bearer auth.',
  middleware: async (event) => {
    const apiKey = getHeader(event, 'authorization')?.replace('Bearer ', '')
    const user = apiKey ? await verifyAdmin(apiKey) : null
    if (user) event.context.user = user
    // No throw — let `enabled` guards on individual tools hide them when there's no user
  },
  // tools / resources / prompts omitted → folder convention auto-attaches them
})

import { defineMcpHandler, getMcpTools } from '@nuxtjs/mcp-toolkit/server'
export default defineMcpHandler({
  // Every tool tagged 'searchable', regardless of folder
  tools: event => getMcpTools({ event, tags: ['searchable'] }),
})

// Override the default `/mcp` handler with custom middleware
export default defineMcpHandler({
  middleware: async (event) => {
    // Soft auth: set context on success, never throw 401 from middleware
    // (throwing 401 triggers OAuth discovery in MCP clients)
    const apiKey = getHeader(event, 'authorization')?.replace('Bearer ', '')
    if (apiKey) {
      const user = await verifyApiKey(apiKey).catch(() => null)
      if (user) event.context.user = user
    }
  },
})

import { extractToolNames } from '@nuxtjs/mcp-toolkit/server'
export default defineMcpHandler({
  middleware: async (event, next) => {
    const start = Date.now()
    const response = await next()
    const tools = await extractToolNames(event)
    console.log(`[mcp] ${tools.join(',') || 'rpc'} took ${Date.now() - start}ms`)
    return response
  },
})

defineMcpHandler middleware → mcp:config:resolved → createMcpServer → mcp:server:created → transport

export default defineNitroPlugin((nitroApp) => {
  nitroApp.hooks.hook('mcp:config:resolved', ({ config, event }) => {
    if (!event.context.user) {
      config.tools = config.tools.filter(t => !t.tags?.includes('admin'))
    }
  })
})

export default defineNitroPlugin((nitroApp) => {
  nitroApp.hooks.hook('mcp:server:created', ({ server, event }) => {
    server.registerTool(
      'whoami',
      { description: 'Return the current user id' },
      async () => ({
        content: [{ type: 'text', text: String(event.context.userId ?? 'anonymous') }],
      }),
    )
  })
})

export default defineNuxtConfig({
  mcp: {
    sessions: true, // or { maxDuration: 30 * 60_000, maxSessions: 1000 }
  },
})

import { z } from 'zod'
 
export default defineMcpTool({
  description: 'Remember a fact for this session',
  inputSchema: { key: z.string(), value: z.string() },
  handler: async ({ key, value }) => {
    const session = useMcpSession<{ facts: Record<string, string> }>()
    const facts = (await session.get('facts')) ?? {}
    facts[key] = value
    await session.set('facts', facts)
    return `Remembered ${key}.`
  },
})

import { z } from 'zod'
export default defineMcpTool({
  description: 'Create a release after asking for the channel',
  inputSchema: { name: z.string() },
  handler: async ({ name }) => {
    const elicit = useMcpElicitation()
    if (!elicit.supports('form')) {
      return `Pass --channel via your client; "${name}" needs a release channel.`
    }
    const result = await elicit.form({
      message: `Pick a channel for "${name}"`,
      schema: {
        channel: z.enum(['stable', 'beta']).describe('Release channel'),
        notify: z.boolean().default(true),
      },
    })
    if (result.action !== 'accept') return `Cancelled (${result.action}).`
    return `Released ${name} on ${result.content.channel}.`
  },
})

import { z } from 'zod'
export default defineMcpTool({
  description: 'Charge a payment method',
  inputSchema: { userId: z.string(), amount: z.number().int().positive() },
  annotations: { destructiveHint: true, idempotentHint: false },
  handler: async ({ userId, amount }) => {
    const log = useMcpLogger('billing')
    log.set({ billing: { amount } })
    await log.notify.info({ msg: 'starting charge', amount })
    try {
      const receipt = await chargeCard(userId, amount)
      log.event('charge_completed', { receiptId: receipt.id })
      return `Charged ${amount}. Receipt: ${receipt.id}`
    }
    catch (err) {
      log.evlog.error('charge failed', err as Error)
      throw err
    }
  },
})

pnpm add evlog

npm install evlog

export default defineNuxtConfig({
  modules: ['evlog/nuxt', '@nuxtjs/mcp-toolkit'],
  evlog: { env: { service: 'my-app' } },
})

import { createAxiomDrain } from 'evlog/adapters/axiom'
 
export default defineNitroPlugin((nitroApp) => {
  nitroApp.hooks.hook('evlog:drain', createAxiomDrain())
})

<script setup lang="ts">
import { z } from 'zod'
 
defineMcpApp({
  description: 'Pick a colour and preview a palette.',
  inputSchema: { base: z.string().describe('Hex colour, e.g. #2563eb') },
  handler: async ({ base }) => ({
    structuredContent: await $fetch('/api/palette', { query: { base } }),
  }),
})
 
const { data, sendPrompt } = useMcpApp<{ swatches: { name: string, hex: string }[] }>()
</script>
 
<template>
  <div class="grid grid-cols-3 gap-2">
    <button
      v-for="s in data?.swatches"
      :key="s.hex"
      class="rounded-md p-3 text-white"
      :style="{ background: s.hex }"
      @click="sendPrompt(`Use ${s.name}`)"
    >
      {{ s.name }}
    </button>
  </div>
</template>

defineMcpApp({
  csp: {
    resourceDomains: ['https://images.example.com'], // <img>, <style>, fonts
    connectDomains: ['https://api.example.com'], // fetch / XHR / WebSocket
  },
  // ...
})

export default defineNuxtConfig({
  mcp: {
    name: 'Todos MCP',
    description: 'Read and update todos for the current user.', // shown in client UIs
    instructions: 'Always call list-todos before create-todo. Group results by status.', // injected into the LLM system prompt
    icons: [
      { src: 'https://example.com/icon.png', mimeType: 'image/png', sizes: ['64x64'] },
    ],
  },
})

import { listMcpDefinitions } from '@nuxtjs/mcp-toolkit/server'
 
export default defineEventHandler(async (event) => {
  const { tools, resources, prompts } = await listMcpDefinitions({ event })
  return {
    name: 'My MCP Server',
    tools: tools.map(t => ({ name: t.name, description: t.description })),
    resources: resources.map(r => ({ name: r.name, uri: r.uri })),
    prompts: prompts.map(p => ({ name: p.name, description: p.description })),
  }
})

export default defineMcpHandler({
  experimental_codeMode: {
    progressive: true,
    memoryLimit: 128,        // MB
    cpuTimeLimitMs: 5000,
    maxToolCalls: 20,
  },
})

npm install secure-exec

curl -X POST http://localhost:3000/mcp \
  -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

mcp: {
  security: {
    allowedOrigins: ['https://my-app.vercel.app'],
    // allowedOrigins: '*' // explicit opt-out — use with care
  },
}

pnpm add -D evalite vitest @ai-sdk/mcp ai

{
  "scripts": {
    "eval": "evalite",
    "eval:ui": "evalite watch"
  }
}

import { experimental_createMCPClient as createMCPClient } from '@ai-sdk/mcp'
import { generateText } from 'ai'
import { evalite } from 'evalite'
import { toolCallAccuracy } from 'evalite/scorers'
 
evalite('MCP Tool Selection', {
  data: async () => [
    {
      input: 'Calculate BMI for 70kg 1.75m',
      expected: [{ toolName: 'bmi-calculator', input: { weight: 70, height: 1.75 } }],
    },
  ],
  task: async (input) => {
    const mcp = await createMCPClient({
      transport: { type: 'http', url: 'http://localhost:3000/mcp' },
    })
    try {
      const result = await generateText({
        model: 'openai/gpt-4o',
        prompt: input,
        tools: await mcp.tools(),
      })
      return result.toolCalls ?? []
    }
    finally {
      await mcp.close()
    }
  },
  scorers: [
    ({ output, expected }) => toolCallAccuracy({ actualCalls: output, expectedCalls: expected }),
  ],
})

pnpm dev          # in one terminal
pnpm eval         # in another, or `pnpm eval:ui` for the watcher UI

export default defineNuxtConfig({
  modules: ['@nuxtjs/mcp-toolkit'],
  mcp: {
    name: 'My Server',
    description: 'What this server does',
    instructions: 'How the LLM should use it',
    route: '/mcp',
    sessions: true,
    defaultHandlerStrategy: 'orphans', // or 'all'
    security: { allowedOrigins: ['https://my-app.vercel.app'] },
    logging: true, // requires evlog/nuxt
  },
  nitro: { experimental: { asyncContext: true } },
})