Advanced Topics

TypeScript

Type safety and TypeScript features in the Nuxt MCP module.

Type Safety

The Nuxt MCP module provides full TypeScript support with complete type inference and type safety.

Auto-Imports

All helper functions are automatically imported in your server files:

// No imports needed - auto-imported!
export default defineMcpTool({
  name: 'example',
  inputSchema: {
    message: z.string(),
  },
  handler: async ({ message }) => {
    // message is typed as string
  },
})

Available auto-imports:

  • defineMcpTool
  • defineMcpResource
  • defineMcpPrompt
  • defineMcpHandler

Type Inference

Tool Input Types

Input types are automatically inferred from your inputSchema:

export default defineMcpTool({
  name: 'example',
  inputSchema: {
    name: z.string(),
    age: z.number(),
    email: z.string().email().optional(),
  },
  handler: async ({ name, age, email }) => {
    // name: string
    // age: number
    // email: string | undefined
  },
})

Tool Output Types

Output types are inferred from outputSchema:

export default defineMcpTool({
  name: 'example',
  inputSchema: {
    value: z.number(),
  },
  outputSchema: {
    result: z.number(),
    doubled: z.number(),
  },
  handler: async ({ value }) => {
    const result = value * 2

    return {
      content: [{ type: 'text', text: String(result) }],
      structuredContent: {
        result,      // TypeScript knows this is number
        doubled: result * 2, // TypeScript knows this is number
      },
    }
  },
})

Prompt Argument Types

Prompt argument types are inferred from inputSchema:

export default defineMcpPrompt({
  name: 'example',
  inputSchema: {
    text: z.string(),
    maxLength: z.string().optional(),
  },
  handler: async ({ text, maxLength }) => {
    // text: string
    // maxLength: string | undefined
  },
})

Runtime Config Types

Access typed runtime configuration:

server/api/config.ts
export default defineEventHandler((event) => {
  const config = useRuntimeConfig(event).mcp

  // config is typed with:
  // - enabled: boolean
  // - route: string
  // - browserRedirect: string
  // - name: string
  // - version: string
  // - dir: string

  return config
})

Next Steps

  • Tools - Learn about creating tools
  • Resources - Learn about creating resources
  • Prompts - Learn about creating prompts