Delphi MCP Server

A Model Context Protocol (MCP) server implementation in Delphi, designed to integrate with Claude Code and other MCP-compatible clients for AI-powered Delphi development workflows.

Table of Contents

• Features
• Requirements
• Installation
• Using as a Library
• Integration with Claude Code
• Testing with MCP Inspector
• Available Example Tools
• Available Example Resources
• Configuration
• License
• Contributing
• About GDK Software
• Support

Features

• Full MCP Protocol Support: Implements the Model Context Protocol specification for seamless AI integration
• Tool System: Extensible tool system with RTTI-based discovery and execution
• Resource Management: Modular resource system supporting various content types
• JSON-RPC 2.0: Standards-compliant JSON-RPC implementation
• Security: Built-in security features including CORS configuration
• High Performance: Native implementation using Indy HTTP Server
• Optional Parameters: Support for optional tool parameters using custom attributes
• Cross-Platform: Supports Windows (Win32/Win64) and Linux (x64)

Requirements

• Delphi 12 Athens or later
• Windows (Win32/Win64) or Linux (x64)
• No external dependencies (all required libraries included)

Installation

For Standalone Usage

1. Clone the repository:

git clone https://github.com/GDKsoftware/delphi-mcp-server.git
cd delphi-mcp-server

2. Build the project:

Windows Build

build.bat

Or specify configuration and platform:

build.bat Debug Win32
build.bat Release Win64

Linux Build

Prerequisites:

• Delphi Enterprise with Linux platform support
• PAServer running on Linux target machine
• Linux SDK configured in RAD Studio

From the batch file:

build.bat Release Linux64

Or from RAD Studio IDE:

1. Open MCPServer.dproj
2. Select Linux64 platform
3. Build

Using as a Library

The Delphi MCP Server is designed to be used both as a standalone application and as a library for your own MCP server implementations. This section covers how to integrate it into your existing Delphi projects.

Project Setup for Library Usage

Option 1: Git Submodule (Recommended)

# Add MCPServer as a submodule to your project
git submodule add https://github.com/GDKsoftware/delphi-mcp-server.git lib/mcpserver
git submodule update --init --recursive

Option 2: Direct Source Inclusion

Copy the src folder from MCPServer into your project and add the units to your uses clauses.

Delphi Project Configuration

1. Search Paths: Add the MCPServer source directories to your project search path:

   • lib\mcpserver\src\Core
   • lib\mcpserver\src\Managers
   • lib\mcpserver\src\Protocol
   • lib\mcpserver\src\Server
   • lib\mcpserver\src\Tools
   • lib\mcpserver\src\Resources

2. Required Units: Include these core units in your project:

   MCPServer.Types,
   MCPServer.Settings,
   MCPServer.Registration,
   MCPServer.ManagerRegistry,
   MCPServer.IdHTTPServer

Library Integration

Once you have the project setup complete, the simplest way to add MCP capabilities to your application:

program YourMCPServer;

{$APPTYPE CONSOLE}

uses
  System.SysUtils,
  MCPServer.Types in 'lib\mcpserver\src\Protocol\MCPServer.Types.pas',
  MCPServer.IdHTTPServer in 'lib\mcpserver\src\Server\MCPServer.IdHTTPServer.pas',
  MCPServer.Settings in 'lib\mcpserver\src\Core\MCPServer.Settings.pas',
  MCPServer.ManagerRegistry in 'lib\mcpserver\src\Core\MCPServer.ManagerRegistry.pas',
  MCPServer.CoreManager in 'lib\mcpserver\src\Managers\MCPServer.CoreManager.pas',
  MCPServer.ToolsManager in 'lib\mcpserver\src\Managers\MCPServer.ToolsManager.pas',
  MCPServer.ResourcesManager in 'lib\mcpserver\src\Managers\MCPServer.ResourcesManager.pas';

var
  Server: TMCPIdHTTPServer;
  Settings: TMCPSettings;
  ManagerRegistry: IMCPManagerRegistry;
  
begin
  Settings := TMCPSettings.Create;
  try
    ManagerRegistry := TMCPManagerRegistry.Create;
    ManagerRegistry.RegisterManager(TMCPCoreManager.Create(Settings));
    ManagerRegistry.RegisterManager(TMCPToolsManager.Create);
    ManagerRegistry.RegisterManager(TMCPResourcesManager.Create);
    
    Server := TMCPIdHTTPServer.Create(nil);
    try
      Server.Settings := Settings;
      Server.ManagerRegistry := ManagerRegistry;
      Server.Start;
      
      Writeln('MCP Server running on port ', Settings.Port);
      Readln; // Keep running
      
      Server.Stop;
    finally
      Server.Free;
    end;
  finally
    Settings.Free;
  end;
end.

Creating Custom Tools

unit YourProject.Tool.Custom;

interface

uses
  MCPServer.Tool.Base,
  MCPServer.Types,
  MCPServer.Registration;

type
  TCustomToolParams = class
  private
    FInput: string;
    FCount: Integer;
  public
    [SchemaDescription('Text input to process')]
    property Input: string read FInput write FInput;
    
    [Optional]
    [SchemaDescription('Number of times to repeat (default: 1)')]
    property Count: Integer read FCount write FCount;
  end;

  TCustomTool = class(TMCPToolBase<TCustomToolParams>)
  protected
    function ExecuteWithParams(const AParams: TCustomToolParams): string; override;
  public
    constructor Create; override;
  end;

implementation

constructor TCustomTool.Create;
begin
  inherited;
  FName := 'custom_tool';
  FDescription := 'A custom tool that processes input';
end;

function TCustomTool.ExecuteWithParams(const AParams: TCustomToolParams): string;
var
  I: Integer;
  Output: string;
begin
  Output := '';
  for I := 1 to AParams.Count do
    Output := Output + AParams.Input + #13#10;
  Result := 'Processed: ' + Output;
end;

initialization
  TMCPRegistry.RegisterTool('custom_tool',
    function: IMCPTool
    begin
      Result := TCustomTool.Create;
    end
  );

end.

Creating Custom Resources

unit YourProject.Resource.Custom;

interface

uses
  MCPServer.Resource.Base,
  MCPServer.Registration;

type
  TCustomData = class
  private
    FMessage: string;
    FTimestamp: TDateTime;
  public
    property Message: string read FMessage write FMessage;
    property Timestamp: TDateTime read FTimestamp write FTimestamp;
  end;

  TCustomResource = class(TMCPResourceBase<TCustomData>)
  protected
    function GetResourceData: TCustomData; override;
  public
    constructor Create; override;
  end;

implementation

constructor TCustomResource.Create;
begin
  inherited;
  FURI := 'custom://data';
  FName := 'Custom Data';
  FDescription := 'Custom resource data';
  FMimeType := 'application/json';
end;

function TCustomResource.GetResourceData: TCustomData;
begin
  Result := TCustomData.Create;
  Result.Message := 'Hello from custom resource';
  Result.Timestamp := Now;
end;

initialization
  TMCPRegistry.RegisterResource('custom://data',
    function: IMCPResource
    begin
      Result := TCustomResource.Create;
    end
  );

end.

Integration with Claude Code

Configure using the Streamable HTTP transport:

# Basic configuration
claude mcp add --transport http delphi-mcp-server http://localhost:3000/mcp

# With authentication (if configured)
claude mcp add --transport http delphi-mcp-server http://localhost:3000/mcp --header "Authorization: Bearer your-token"

Make sure the server is running before connecting Claude Code.

Testing with MCP Inspector

The easiest way to test and debug your MCP server is using the official MCP Inspector:

1. Start the server:

   # Build and run the server
   build.bat
   Win32\Debug\MCPServer.exe

2. Run MCP Inspector:

   # Install and run the MCP Inspector
   npx @modelcontextprotocol/inspector

3. Connect to your server:

   • Transport: HTTP
   • URL: http://localhost:3000/mcp
   • Click Connect

4. Test functionality:

   • Browse available tools and resources
   • Execute tools like echo, get_time, calculate
   • View resources like project://info, server://status
   • Monitor request/response JSON-RPC messages

The Inspector provides a web interface to interact with your MCP server, making it perfect for development and debugging.

Available Example tools

• echo: Echo a message back to the user
• get_time: Get the current server time
• list_files: List files in a directory
• calculate: Perform basic arithmetic calculations

Available Example resources

The server provides four essential resources accessible via URIs:

• project://info - Project information (JSON metadata with collections)
• project://readme - This README file (markdown content)
• logs://recent - Recent log entries from all categories (with thread safety)
• server://status - Current server status and health information

Configuration

The server supports configuration through settings.ini files. A default settings.ini.example is provided in the repository.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

We welcome contributions! Here's how to help:

Reporting Issues

• Use GitHub Issues for bugs and feature requests
• Include Delphi version, platform, and reproduction steps

Pull Requests

1. Fork the repository
2. Create a feature branch: git checkout -b feature/my-feature
3. Follow existing code style (inline vars, named constants)
4. Test your changes
5. Submit a pull request

Development Setup

• Requires Delphi 12+
• Open MCPServer.dproj or build with build.bat
• Test with npx @modelcontextprotocol/inspector or Claude Code or similar

About GDK Software

GDK Software is a software company specializing in Delphi development, upgrades, and migrations. We provide Delphi development, upgrades, maintenance, and modernization of application services. GDK Software also offers consulting and training related to Delphi and low-code development with Codolex. We have a global presence with offices in the Netherlands, UK, USA, and Brazil.

Support

• Create an issue on GitHub
• Visit our website at www.gdksoftware.com
• Contact us for commercial support