MCP Server Tester

What is MCP Server Tester?

MCP Server Tester is a configuration-driven testing tool for Model Context Protocol (MCP) servers. It automates the validation, benchmarking, and reliability testing of MCP servers that integrate with AI models like Claude. Designed for MCP server developers, AI integration teams, and QA professionals, it discovers server tools, generates test cases using Claude AI, executes tests, validates responses, and generates detailed reports.

How to use MCP Server Tester?

Install by cloning the repository, running npm install, npm run build, and optionally npm link. Create a .env file with your ANTHROPIC_API_KEY and a configuration file (mcp-servers.json) defining MCP servers (command, args, env). Run mcp-server-tester or specify a custom config file path. Use command-line options like --init, --list, or --servers to filter servers.

Key features of MCP Server Tester

• Automatically discovers all tools exposed by an MCP server
• Generates realistic test cases for each tool using Claude AI
• Validates responses with multiple rule types (contains, matches, equals, etc.)
• Generates reports in console, JSON, HTML, or Markdown formats
• Supports testing multiple MCP servers simultaneously
• Keeps API keys secure in environment variables, not config files

Use cases of MCP Server Tester

• Catch bugs or inconsistent behavior in an MCP server before production
• Run regression tests whenever server code changes
• Generate documented test reports describing queries and expected outcomes
• Integrate automated MCP testing into CI/CD pipelines

FAQ from MCP Server Tester

What is the current status of MCP Server Tester?

It is a work-in-progress, under active development, moving toward alpha release. Basic features are available, but broader test coverage and production hardening are still in progress. Use in non-production environments only.

What are the prerequisites to run MCP Server Tester?

Node.js 18 or higher and an Anthropic API key for generating test cases. A .env file or environment variable ANTHROPIC_API_KEY is required.

How does MCP Server Tester generate test cases?

It uses Claude AI to analyze tool names, descriptions, parameters, types, and constraints, then produces happy path, edge case, and error case tests per tool, including input parameters and expected outcome criteria.

What report formats are supported?

Console output (default), JSON structure, HTML with visualizations, and Markdown. The output format is set via the outputFormat configuration option.

Can I test multiple MCP servers at once?

Yes. Define multiple servers in the mcpServers section of the configuration file. Use the servers array or --servers CLI option to filter which ones to test.