MCP Test Client

What is MCP Test Client?

A testing utility for Model Context Protocol (MCP) servers. It helps developers test MCP server implementations by providing a simple interface for making tool calls and validating responses.

How to use MCP Test Client?

Install it with bun install mcp-test-client, then import MCPTestClient, configure it with your server command and arguments, call init(), and use methods like listTools() or assertToolCall(). The package includes a mock calculator server for learning and testing.

Key features of MCP Test Client

• Easy-to-use testing interface for MCP servers
• Built-in support for tool listing and calls
• Type-safe implementation using TypeScript
• Assertion utilities for validating responses
• Mock calculator server included for examples

Use cases of MCP Test Client

• Test that your MCP server lists expected tools
• Validate tool call results with custom assertions
• Learn MCP tool operations using the provided calculator mock
• Automate server testing in a CI pipeline
• Debug server behavior without a production client

FAQ from MCP Test Client

What are the prerequisites?

Bun runtime v1.0.0 or higher is required.

How do I install MCP Test Client?

Run bun install mcp-test-client in your project.

How do I run the included tests?

After installing dependencies with bun install, execute bun test in the repository root.

What does the package include out of the box?

The MCPTestClient class with methods for listing tools, calling tools, and asserting results, plus a mock calculator server in ./tests/mocks/calculator.ts.

Is MCP Test Client open source?

Yes, it is released under the MIT license.