MCP for Delphi

Server · Client · Agent — a full-stack MCP toolkit for DMVCFramework

A production-ready Model Context Protocol (MCP) toolkit for Delphi. It is not just a server library — it gives Delphi the complete MCP triangle in one package.

📖 Full documentation & guide → www.danieleteti.it/mcp-server-delphi

This README is just a hook. Every detail — getting started, API reference, the client, the agent, the REST→MCP bridge, configuration and testing — lives in the official documentation.

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What is this?

Most "MCP for X" libraries only let you build a server the AI calls into. This one gives Delphi all three corners of the MCP world:

	Role	What it does
🟢	Server	Expose your Delphi tools, resources, and prompts to AI assistants (Claude, Gemini, ChatGPT, …) over HTTP or stdio — attribute-driven, zero boilerplate.
🔵	Client	Consume any spec-compliant MCP server from your own Delphi code with TMCPClient (Streamable HTTP) or TMCPStdioClient (spawns a server as a child process and talks over pipes).
🟣	Agent	Drive an MCP server from an LLM with TMCPOpenAIAgent — a complete agent loop (tool discovery → LLM round-trips → tool dispatch → token accounting) that works with any OpenAI-compatible model: OpenAI, OpenRouter, Anthropic-compat, Together, Groq, Ollama, vLLM, llama.cpp --api.
🌉	REST → MCP Bridge	Auto-expose an existing DMVCFramework REST API as MCP tools by scanning the engine's routes via RTTI. Make your current backend AI-ready without writing a single tool by hand.

In short: build AI-powered Delphi applications where Delphi is the server, the client, and the agent.

🚀 MCP with DMVCFramework? Sure — even for on-premises AI engines.

Expose your ERP and let a Delphi-side agent chain your tools. Ask: "Reorder customer C-1024's best-selling product from last March — but only if they're within their credit limit." The agent finds March's top product, reads the customer's balance, decides, and drafts the invoice — several tool calls, planned on the fly, all against your data. 💡

Features at a glance

• MCP Protocol 2025-03-26 compliant
• Server, client AND agent in one library — plus a REST→MCP bridge
• Attribute-driven tool/resource/prompt registration using RTTI — no manual wiring
• Dual transport, server and client side: Streamable HTTP and stdio
• Type-safe parameter binding with automatic JSON Schema generation
• Rich content types: Text, Image, Audio, Embedded Resources — with a fluent multi-content API
• URI resource templates (RFC 6570 Level 1)
• Session management with automatic cleanup
• DMVCFramework integration via the idiomatic PublishObject pattern
• Apache 2.0 — free for commercial and personal use

A 30-second taste

Expose a tool (server):

[MCPTool('reverse_string', 'Reverses a string')]
function ReverseString(
  [MCPParam('The string to reverse')] const Value: string
): TMCPToolResult;

Call a server (client):

LClient := TMCPClient.Create('http://localhost:8080/mcp');
LClient.Initialize;
WriteLn(LClient.CallTool('reverse_string',
  TJSONObject.Create.AddPair('Value', 'hello')));

Drive a server from an LLM (agent):

LAgent := TMCPOpenAIAgent.Create('http://localhost:8080/mcp', LApiKey, 'gpt-4o-mini');
LAgent.SystemPrompt := 'You are a helpful Delphi-powered assistant.';
LResult := LAgent.Run(LUserMessages);   // tool discovery + LLM loop + dispatch
WriteLn(LResult.Content);

👉 Full, runnable examples and the complete API are in the documentation.

Quick Start

Copy a ready-to-run Quick Start project and customize it — all share the same provider units in quickstart/shared/:

Project	Role	Transport	Use when
quickstart/quickstart/	Server	HTTP + stdio	You want a network server AI clients connect to via HTTP
quickstart/quickstart_stdio/	Server	stdio only	You want the AI client (e.g. Claude Desktop) to launch the server locally
quickstart/quickstart_stdio_agent/	Agent (host+client)	stdio	You want a Delphi-side AI agent that spawns and consumes a stdio MCP server, driven by an LLM

Open the .dproj in Delphi, add DMVCFramework and this repo's sources/ to the search path, build, run. Step-by-step instructions, IDE wiring, and how to connect Claude Desktop / Gemini CLI / Claude Code / Continue are all in the documentation.

Testing ✅

Extensively tested by four independent compliance suites: a Python HTTP suite (185 cases), a Python stdio suite (147 cases), a TMCPClient suite (21 Delphi cases, run over both HTTP and stdio), and a TMCPOpenAIAgent suite (8 Delphi cases driving the agent loop against an embedded fake LLM). See the documentation for how to build and run them.

Requirements

• Delphi 11+ (Alexandria) or later
• DMVCFramework 3.5.x

License

Apache License 2.0 — see LICENSE.

Links

• 📖 Official Documentation & Full Guide ← start here
• Model Context Protocol Specification
• DMVCFramework
• Issue Tracker

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Built with ❤️ by Daniele Teti