Swift MCP Server Generator

swift-mcp-server-generator skill for programming & development

Category: development Source: github

An AI skill that generates Swift based Model Context Protocol servers, producing type safe project scaffolding with tool definitions, async handlers, and transport configuration for building MCP integrations in Apple ecosystem environments.

What Is This?

Overview

This skill creates complete Swift MCP server projects from a description of the tools and resources you want to expose. It generates the Swift Package Manager project structure, async handler implementations using Swift concurrency, Codable types for tool input and output schemas, transport layer setup, and structured error handling. The generated code leverages Swift type safety and modern concurrency features for reliable MCP server implementations.

Who Should Use This

Built for Swift developers who want to expose their services to AI assistants through MCP. Ideal for iOS and macOS developers with existing Swift backends, teams building Apple platform tools, and developers who prefer Swift's type system for building protocol compliant services.

Why Use It?

Problems It Solves

Implementing MCP servers in Swift requires setting up async/await patterns, defining Codable types for JSON-RPC messages, handling transport protocols, and managing tool registration. The Swift MCP ecosystem is newer than TypeScript or Python, meaning fewer examples and libraries. This skill generates all the boilerplate so developers can focus on tool logic.

Core Highlights

Swift Package Manager generates complete SPM project with dependencies
Codable Schemas creates type safe input and output types for all tools
Async Concurrency uses Swift structured concurrency for handler implementations
Transport Options supports stdio and HTTP transport configurations
Error Handling implements Swift Result type patterns throughout the server

How to Use It?

Basic Usage

Describe your tools and receive a complete Swift MCP server project.

// Generated: Sources/MyServer/Tools/SearchTool.swift
import Foundation

struct SearchInput: Codable {
    let query: String
    let limit: Int?
    
    enum CodingKeys: String, CodingKey {
        case query, limit
    }
}

struct SearchOutput: Codable {
    let results: [SearchResult]
    let total: Int
}

struct SearchTool: MCPTool {
    static let name = "search_docs"
    static let description = "Search documentation by keyword"
    
    func handle(input: SearchInput) async throws -> SearchOutput {
        let results = try await DocumentIndex.search(input.query, limit: input.limit ?? 10)
        return SearchOutput(results: results, total: results.count)
    }
}

Real-World Examples

macOS Developer Tool Integration

A team building macOS developer utilities generated an MCP server that exposed their Xcode project analyzer, build log parser, and dependency checker as AI accessible tools. The server ran as a local process, communicating via stdio with the AI assistant.

// Generated: Sources/DevToolsServer/main.swift
import MCPServer

@main
struct DevToolsServer {
    static func main() async throws {
        let server = MCPServer(
            name: "dev-tools",
            version: "1.0.0"
        )
        server.registerTool(AnalyzeProjectTool())
        server.registerTool(ParseBuildLogTool())
        server.registerTool(CheckDependenciesTool())
        
        try await server.run(transport: .stdio)
    }
}

Advanced Tips

Use Swift protocols to define a common interface for all tool handlers, enabling easy testing with mock implementations. Leverage Swift Package Manager plugins for code generation of Codable types from JSON schemas. Profile memory usage for tools that process large datasets.

When to Use It?

Use Cases

macOS Tool Integration expose Xcode and development tools to AI assistants
iOS Backend Bridge connect Swift backend services via MCP
Apple Ecosystem Tools wrap CoreML, Vision, or NLP frameworks as AI tools
Developer Utilities share build and analysis tools through MCP
Cross Platform Services add MCP interfaces to existing Swift services

Important Notes

Requirements

Swift 5.9 or later for full structured concurrency support
Swift Package Manager for project and dependency management
An MCP compatible client for testing the generated server
Basic familiarity with Swift async/await and Codable protocols

Usage Recommendations

Do:

Use the generated Codable types as the single source of truth for your API
Write tests using Swift Testing framework for each tool handler
Handle errors with typed throws rather than generic error catching
Run swift build in CI to catch type errors before deployment

Don't:

Force unwrap optionals in handlers as crashes terminate the server process
Block the concurrency runtime with synchronous operations in async handlers
Skip input validation relying only on Codable decoding for correctness
Ignore platform availability when using Apple framework APIs in tool handlers

Limitations

Swift MCP libraries are early stage with a smaller ecosystem than other languages
Server side Swift deployment options are more limited than Node.js or Python
Generated code targets Linux and macOS but may need adjustments for other platforms
Complex tool schemas produce verbose Codable type definitions