MCP(Model Context Protocol) for Dart #

The Model Context Protocol (MCP) is a standardized protocol for communication between AI applications and external services. It enables:

• Tools: Allow AI to execute actions (API calls, computations, etc.)
• Resources: Provide context and data to AI (files, databases, APIs)
• Prompts: Pre-built prompt templates with arguments

Understanding MCP: Client, Server, and Host #

MCP follows a client-server architecture with three key components:

• MCP Host: The AI application that provides the user interface and manages connections to multiple MCP servers.

  • Example: Claude Desktop, IDEs like VS Code, custom AI applications
  • Manages server lifecycle, discovers capabilities, and orchestrates interactions

• MCP Client: The protocol implementation within the host that communicates with servers.

  • Handles protocol negotiation, capability discovery, and request/response flow
  • Typically built into or used by the MCP host

• MCP Server: Provides capabilities (tools, resources, prompts) that AI can use through the host.

  • Example: Servers for file system access, database queries, or API integrations
  • Runs as a separate process and communicates via standardized transports (stdio, StreamableHTTP)

Typical Flow: User ↔ MCP Host (with Client) ↔ MCP Protocol ↔ Your Server ↔ External Services/Data

Requirements #

• Dart SDK version ^3.0.0 or higher

Ensure you have the correct Dart SDK version installed. See https://dart.dev/get-dart for installation instructions.

What This SDK Provides #

This SDK lets you build both MCP servers and clients in Dart/Flutter.

• ✅ Build MCP Servers - Create servers that expose tools, resources, and prompts to AI hosts
• ✅ Build MCP Clients - Create AI applications that can connect to and use MCP servers
• ✅ Full MCP Protocol Support - Complete MCP specification 2025-11-25 implementation
• ✅ Multiple Transport Options - Stdio, StreamableHTTP, Stream, or custom transports
• ✅ All Capabilities - Tools, Resources, Prompts, Sampling, Roots, Completions, Elicitation, Tasks
• ✅ OAuth2 Support - Complete authentication with PKCE
• ✅ Type-Safe - Comprehensive type definitions with null safety
• ✅ Cross-Platform - Works on Linux, Windows, macOS, Web, and Flutter

The goal is to make this SDK as similar as possible to the official SDKs available in other languages, ensuring a consistent developer experience across platforms.

Model Context Protocol Version #

The current version of the protocol is 2025-11-25. This library is designed to be compatible with this version, and any future updates will be made to ensure continued compatibility.

It's also backward compatible with previous versions including 2025-06-18, 2025-03-26, 2024-11-05, and 2024-10-07.

Documentation #

Getting Started #

• 📖 Quick Start Guide - Get up and running in 5 minutes
• 🔧 Server Guide - Complete guide to building MCP servers
• 💻 Client Guide - Complete guide to building MCP clients

Core Concepts #

• 🛠️ Tools Documentation - Implementing executable tools
• 🔌 Transport Options - Built-in and custom transport implementations
• 📚 Examples - Real-world usage examples
• ⚡ Quick Reference - Fast lookup guide

Advanced Features #

• 🔐 OAuth Authentication - OAuth2 guides and examples
• 📝 For resources, prompts, and other features, see the Server and Client guides

Quick Start with CLI #

The fastest way to create an MCP server is using the mcp_dart_cli:

# Install the CLI
dart pub global activate mcp_dart_cli

# Create a new project
mcp_dart create my_server

# Navigate and run
cd my_server
mcp_dart serve

Your server is now running! Use mcp_dart inspect to test it:

mcp_dart inspect              # List all capabilities
mcp_dart inspect --tool add --json-args '{"a": 1, "b": 2}'   # Call a tool

CLI Commands #

📖 Full CLI Documentation

Connecting to AI Hosts #

Configure your server with AI hosts like Claude Desktop:

{
  "mcpServers": {
    "my_server": {
      "command": "mcp_dart",
      "args": ["serve"],
      "cwd": "/path/to/my_server"
    }
  }
}

Authentication #

This library supports OAuth2 authentication with PKCE for both clients and servers. For complete authentication guides and examples, see the OAuth Authentication documentation.

Platform Support #

Custom Transports: You can implement your own transport layer by extending the transport interfaces if you need specific communication patterns not covered by the built-in options.

More Examples #

For additional examples including authentication, HTTP clients, and advanced features:

• All Examples
• Authentication Examples

Community & Support #

• Issues & Bug Reports: GitHub Issues
• Package: pub.dev/packages/mcp_dart
• Protocol Spec: MCP Specification

Credits #

This library is inspired by the following projects:

• https://github.com/crbrotea/dart_mcp
• https://github.com/nmfisher/simple_dart_mcp_server