MCP Server Tester

> ⚠️ WORK IN PROGRESS: This project is under active development and has not been thoroughly tested yet. Features may be incomplete, contain bugs, or change significantly. Use at your own risk in non-production environments only.

A powerful, configuration-driven testing tool for Model Context Protocol (MCP) servers. This project provides a comprehensive solution for validating, benchmarking, and ensuring reliability of MCP servers that integrate with AI models like Claude.

Current Status

This tool is moving toward an alpha release and currently offers:
- ✅ Basic configuration framework
- ✅ MCP server connection and CLI support
- ✅ Test generation using Claude AI
- ✅ Natural language query generation for tests
- ✅ Comprehensive response validation with multiple rules
- ✅ Report generation in console, JSON, HTML, and Markdown formats
- 🚧 Broader automated test coverage of the tester
- 🚧 Production hardening and packaging improvements

If you're interested in contributing, please feel free to open issues and submit pull requests.

Introduction

The Model Context Protocol (MCP) enables AI models to access external tools and data sources through standardized interfaces. As MCP servers grow in complexity and importance, ensuring their correct functionality becomes critical. The MCP Server Tester addresses this need by:

- Automating tests for all tools exposed by an MCP server
- Leveraging Claude AI to generate intelligent, contextually-relevant test cases
- Validating responses against expected outcomes and schemas
- Providing detailed reports to identify issues and performance bottlenecks

This tool is designed for MCP server developers, AI integration teams, and quality assurance professionals who need to ensure their MCP implementations are robust, reliable, and correctly follow the protocol specifications.

Concept

The Model Context Protocol is a standard that allows AI models to call external tools. An MCP server exposes one or more tools through a simple HTTP interface. Each tool describes its name, parameters, and response schema so that a model can invoke it safely.

mcp-server-tester automates the process of checking that an MCP server and its tools work correctly:

1. Discovery – it queries the server for all available tools.
2. Test generation – it uses Claude AI to create realistic test cases for each tool.
3. Execution – it runs those tests against the server.
4. Validation – it verifies the responses using configurable rules.
5. Reporting – it summarizes the results in the console or in JSON, HTML, or Markdown formats.

The goal is to quickly spot mismatches between expected and actual behaviour so that you can fix issues before exposing the tools to production models.

Purpose

- Reliability – catch bugs or inconsistent behaviour in your MCP server.
- Regression testing – run the same set of tests whenever the server changes.
- Documentation – generated reports describe the queries and expected outcomes for each tool.
- Automation – integrate the tester into CI pipelines to ensure ongoing quality.

Repository

- GitHub: https://github.com/r-huijts/mcp-server-tester
- Issues: https://github.com/r-huijts/mcp-server-tester/issues
- License: MIT

Features

- 🔍 Automatically discovers available tools from any MCP server
- 🧪 Generates realistic test cases for each tool using Claude AI
- ⚡ Executes tests and validates responses
- 📊 Provides detailed test reports
- 🔑 Supports multiple connection methods through configuration
- Configuration-Based: Simple JSON configuration for defining MCP servers to test
- Multiple Server Support: Test multiple MCP servers at once
- Comprehensive Testing: Tests all tools exposed by each server
- Natural Language Context: Includes the user query that would trigger each tool, providing real-world context
- Detailed Reports: Generate reports in console, JSON, HTML, or Markdown formats
- Secure: Keeps API keys in environment variables, not in configuration files

Prerequisites

- Node.js 18 or higher
- An Anthropic API key for generating test cases

Installation

Since this project is still in development, installation is done by cloning the repository:

```bash