> Index of every page on this site: [llms.txt](https://kubb.dev/llms.txt)

# MCP

The MCP plugin turns each operation into a typed MCP tool that AI assistants can call. Each tool uses Zod schemas from `@kubb/plugin-zod` for its input and output.

Each tool handler calls the function a client plugin generates for that operation. The plugin writes `server.ts`, `start.ts`, and `.mcp.json` at the root of its `output.path`. `start.ts` calls the `startServer()` that `server.ts` exports, and `.mcp.json` runs `start.ts` to start a stdio server.

## Installation

::code-group{sync="package-manager"}

```shell [bun]
bun add -d @kubb/plugin-mcp
```

```shell [pnpm]
pnpm add -D @kubb/plugin-mcp
```

```shell [npm]
npm install --save-dev @kubb/plugin-mcp
```

```shell [yarn]
yarn add -D @kubb/plugin-mcp
```

::

Or run `kubb add plugin-mcp` to install the version the [Kubb registry](/registry) pins and add `pluginMcp()` to `kubb.config.ts`.

## Setup

- Add `@kubb/plugin-zod`, `@kubb/plugin-ts` (optional with `pluginZod({ inferred: 'codec' })`), and a client plugin: `@kubb/plugin-fetch`, `@kubb/plugin-axios`, or `@kubb/plugin-client`. Leave `sdk` unset on the client plugin.
- Install `@modelcontextprotocol/server` v2 and `zod` 4.2 or a later v4 release in the app that runs the server. Add `axios` too when you use `@kubb/plugin-axios`.
- Install a TypeScript runner such as `tsx`. The generated `.mcp.json` runs `npx tsx`, which downloads `tsx` from npm when it is missing.
- Copy the server entry from the generated `.mcp.json` into the `.mcp.json` your MCP client reads, such as the one at the project root for Claude Code.

## Options worth knowing

- `client` picks `fetch` or `axios` when both client plugins are registered. A single client is detected automatically.
- `output.path` must be a folder name, such as the default `mcp`, because single-file output has no place for `server.ts`, `start.ts`, and `.mcp.json`.

The `args` path in `.mcp.json` points at `start.ts` relative to the Kubb `root`, because MCP clients start the command from their own working directory. Use an absolute path for a client that starts in another folder, or point it at your own entry file to run setup code before `startServer()`.

See [Options](https://kubb.dev/extensions/kubb-labs/plugin-mcp/options) for every option and its default.

## Example

The config below generates an MCP server whose tools call the Petstore API through `@kubb/plugin-fetch`.

```typescript [kubb.config.ts]
import { defineConfig } from 'kubb/config'
import { pluginTs } from '@kubb/plugin-ts'
import { pluginZod } from '@kubb/plugin-zod'
import { pluginFetch } from '@kubb/plugin-fetch'
import { pluginMcp } from '@kubb/plugin-mcp'

export default defineConfig({
  input: './petStore.yaml',
  output: { path: './src/gen' },
  plugins: [
    pluginTs(),
    pluginZod(),
    pluginFetch({ baseURL: 'https://petstore.swagger.io/v2' }),
    pluginMcp({ output: { path: 'mcp', mode: 'directory' } }),
  ],
})
```

## Sitemap

See the full [sitemap](https://kubb.dev/sitemap.md) for all pages.