MCP Protocol Validator

A testing suite and reference implementation for the Model Context Protocol (MCP).

Summary

The MCP Protocol Validator provides a comprehensive environment for testing and validating MCP server implementations. With reference implementations for both STDIO and HTTP transports, along with an extensive testing framework, it ensures developers can verify their servers comply with the MCP specification. The modular architecture supports various server configurations, transport methods, and provides detailed compliance reporting, making it an essential tool for MCP server development and validation.

Overview

This repository contains:

1. Minimal MCP Server: A reference implementation using STDIO transport
2. Minimal HTTP MCP Server: A reference implementation using HTTP transport
3. MCP Testing Framework: A comprehensive testing framework for verifying MCP server implementations

The current implementation is fully compliant with the latest MCP protocol specification (2025-03-26).

✅ All tests pass for the reference implementations!

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Reference Implementations

Minimal MCP Server (STDIO)

A simple reference implementation that uses STDIO for transport and supports:

• Basic protocol operations (initialization, shutdown)
• Synchronous tool calls
• Asynchronous tool calls (for 2025-03-26)
• Utility tools for file system operations

# Run the server
python ./minimal_mcp_server/minimal_mcp_server.py

Supported Tools

• echo: Echo input text
• add: Add two numbers
• sleep: Sleep for specified seconds (useful for testing async operations)
• list_directory: List files in a directory
• read_file: Read a file
• write_file: Write a file

Minimal HTTP MCP Server

A reference implementation using HTTP transport with:

• JSON-RPC 2.0 over HTTP implementation
• Support for both protocol versions (2024-11-05 and 2025-03-26)
• Synchronous and asynchronous tool calls
• Resources capability (for 2025-03-26)
• Batch request support
• CORS support for browser clients

# Run the server with default settings (localhost:8000)
python ./minimal_http_server/minimal_http_server.py

# Run with custom host and port
python ./minimal_http_server/minimal_http_server.py --host 0.0.0.0 --port 8080

# Run a basic HTTP test suite
python ./minimal_http_server/test_http_server.py

# Run compliance tests against the HTTP server
python -m mcp_testing.scripts.http_test --server-url http://localhost:8000 --protocol-version 2025-03-26

See the HTTP Server README for more details.

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MCP Testing Framework

A flexible framework for verifying MCP server compliance with protocol specifications.

Key Features

• Support for both 2024-11-05 and 2025-03-26 protocol versions
• Support for both STDIO and HTTP transport protocols
• Dynamic tool testing that adapts to server capabilities