AgentMCP

A lightweight Swift MCP (Model Context Protocol) client for macOS. Connect to any MCP server via stdio or HTTP — no external SDK required.

Features

• Stdio & HTTP transport support
• JSON-RPC 2.0 protocol implementation
• Tool discovery — auto-discover tools from connected servers
• Tool execution — call tools with typed arguments
• Resource reading — read resources from MCP servers
• Multi-server — manage connections to multiple servers simultaneously
• Zero dependencies — pure Swift, no external packages
• macOS 14+ / Swift 6.4

Installation

Add to your Package.swift:

dependencies: [
    .package(url: "https://github.com/AgentiLoop/AgentMCP.git", from: "1.6.10"),
]

Then add MCPClient to your target:

.target(name: "YourApp", dependencies: [
    .product(name: "MCPClient", package: "AgentMCP"),
]),

Usage

import MCPClient

// Create client and connect to an MCP server via stdio
let client = MCPClient()
let serverId = try await client.connect(
    name: "my-server",
    command: "/path/to/mcp-server",
    arguments: []
)

// Discover available tools
let tools = try await client.listTools(serverId: serverId)

// Call a tool
let result = try await client.callTool(
    serverId: serverId,
    name: "my_tool",
    arguments: ["key": .string("value")]
)

Architecture

File	Purpose
MCPClient.swift	Main client API — connect, list tools, call tools
MCPConnection.swift	Base connection protocol
StdioConnection.swift	Stdio transport (launches process)
HTTPConnection.swift	HTTP/SSE transport
ServerManager.swift	Multi-server connection manager
JSONValue.swift	Type-safe JSON encoding/decoding
MCPClientError.swift	Error types

Part of AgentiLoop Agent!

AgentMCP is one of the open-source building blocks of AgentiLoop Agent!, the native AI agent for macOS 14.6+ on Apple Silicon and Intel. Agent! codes in Xcode, drives any Mac app, runs shell as you or as root, and works with 23 LLM providers plus on-device Apple Intelligence.

🌐 agentiloop.ai · ⬇️ Download Agent! · 🍺 brew install --cask agentiloop-agent · 💻 CLIs: Rust / Go

More Agent! packages: AgentAccess · AgentAudit · AgentColorSyntax · AgentD1F · AgentEventBridges · AgentLLM · AgentSwift · AgentTerminalNeo · AgentTools · AgentScripts

License

MIT