cpp-mcp/IMPLEMENTATION_SUMMARY.md

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MCP Framework Implementation Summary

Overview

This implementation provides a complete C++ framework for the Model Context Protocol (MCP), designed for easy extension to agent workflows. The framework follows a modular architecture with clear separation of concerns, making it straightforward to customize and extend.

Directory Structure

/cpp-mcp/
├── include/                - Header files directory
│   ├── mcp_client.h        - Client interface definition
│   ├── mcp_message.h       - Core protocol definition
│   ├── mcp_resource.h      - Resource definition
│   ├── mcp_server.h        - Server interface definition
│   └── mcp_tool.h          - Tool system definition
├── src/                    - Source code directory
│   ├── mcp_client.cpp      - Client implementation
│   ├── mcp_message.cpp     - Protocol message implementation
│   ├── mcp_resource.cpp    - Resource system implementation
│   ├── mcp_server.cpp      - Server implementation
│   ├── mcp_tool.cpp        - Tool system implementation
│   └── CMakeLists.txt      - Source code build configuration
├── examples/               - Example code
│   ├── client_example.cpp  - Client example
│   └── server_example.cpp  - Server example
├── CMakeLists.txt          - Main build configuration
├── LICENSE                 - License file
└── README.md               - Project documentation

Key Components

1. Core Protocol (mcp_message.h/cpp)

Defines the fundamental message structures of the MCP protocol:

  • request and response structures
  • Error handling with error_code and mcp_exception
  • Resource interface (resource base class)

2. Server (mcp_server.h/cpp)

Provides an HTTP server that exposes MCP resources and tools:

  • Register resources at specific paths
  • Register tools with handlers
  • Process incoming HTTP requests
  • Route requests to appropriate resources

3. Client (mcp_client.h/cpp)

Implements a client for connecting to MCP servers:

  • Connect to servers
  • Discover available resources and tools
  • Make requests to resources
  • Call tools with parameters

4. Resource System (mcp_resource.h)

Defines various resource types:

  • file_resource: Access to the file system
  • directory_resource: Directory operations
  • api_resource: Custom API endpoints
  • image_resource: Image handling

5. Tool System (mcp_tool.h/cpp)

Provides tool-related functionality:

  • tool_registry: Central registry for tools
  • tool_builder: Fluent API for tool creation

Usage Examples

1. Creating a Server

// Create and configure the server
mcp::server server("localhost", 8080);
server.set_name("Example Server");

// Register a tool
mcp::tool time_tool = mcp::tool_builder("get_time")
    .with_description("Get the current time")
    .build();

server.register_tool(time_tool, get_time_handler);

// Register a resource
auto file_resource = std::make_shared<mcp::file_resource>("./files");
server.register_resource("/files", file_resource);

// Start the server
server.start(true);

2. Connecting with a Client

// Create a client
mcp::client client("localhost", 8080);

// Call a tool
mcp::json result = client.call_tool("get_time");

// Make a request to a resource
mcp::response res = client.get("/files/example.txt");

3. Creating and Using Workflows

// Create a workflow
mcp::workflow workflow("data_processing", "Process data");

// Add steps
workflow.add_tool_call("get_data", {{"source", "database"}});
workflow.add_tool_call("process_data", {{"filter", "recent"}});

// Execute the workflow
mcp::json result = workflow.execute();

4. Implementing Custom Agents

// Create a custom agent
class custom_agent : public mcp::agent {
public:
    explicit custom_agent(const std::string& name) : mcp::agent(name) {}
    
    void initialize(const mcp::json& config) override {
        // Initialize from config
    }
    
    mcp::json process(const mcp::json& input) override {
        // Process the input
        mcp::json output = call_tool("some_tool", input);
        return output;
    }
};

Agent Workflow Extension

The framework is specifically designed to support agent workflows with:

  1. Tool Registry: Centralized tool management
  2. Resource APIs: RESTful interfaces for workflow and agent management

Extending the Framework

Adding New Tools

// Define a new tool
mcp::tool my_tool = mcp::tool_builder("my_tool")
    .with_description("My custom tool")
    .with_string_param("input", "Input string")
    .build();

// Implement the tool handler
mcp::json my_tool_handler(const mcp::json& params) {
    std::string input = params["input"];
    // Process the input
    return {{"output", "Processed: " + input}};
}

// Register with the server
server.register_tool(my_tool, my_tool_handler);

Creating New Resource Types

class custom_resource : public mcp::resource {
public:
    resource_type type() const override {
        return resource_type::custom;
    }
    
    json metadata() const override {
        return {{"name", "Custom Resource"}};
    }
    
    response handle_request(const request& req) override {
        // Handle the request
        response res;
        res.set_json_body({{"status", "success"}});
        return res;
    }
};

Implementing New Agent Types

class my_agent : public mcp::agent {
public:
    explicit my_agent(const std::string& name) : mcp::agent(name) {}
    
    void initialize(const mcp::json& config) override {
        // Initialize from config
    }
    
    mcp::json process(const mcp::json& input) override {
        // Custom processing logic
        return result;
    }
};

Conclusion

This MCP Protocol framework provides a robust foundation for building agent-based systems. It offers:

  • Standardized Communication: Common protocol for all components
  • Extensible Design: Easy to add new tools, resources, and agents