xk6-infobip-mcp

k6 extension for Model Context Protocol (MCP) integration

This k6 extension enables performance testing of MCP (Model Context Protocol) servers by providing a JavaScript API for creating MCP clients, calling tools, and managing connections. It is ideal for load testing MCP-based applications and validating MCP server performance under various conditions.

Originally developed to load test Infobip MCP Servers, this extension works with any MCP-compliant server implementation.

Example

import mcp from "k6/x/infobip_mcp";

export const options = {
  vus: 10,
  duration: '30s',
};

export default function () {
  // Create MCP client
  const client = mcp.NewClient({
    endpoint: "https://your-mcp-server.com/mcp",
    timeout: 30,
    isSSE: false,
    headers: {
      "Authorization": "Bearer your-token",
      "Content-Type": "application/json"
    }
  });

  // Call a tool on the MCP server
  const result = client.callTool("your_tool_name", {
    param1: "value1",
    param2: 42
  });

  console.log("Tool response:", result);

  // Clean up connection
  client.closeConnection();
}

Quick Start

1. Build a custom k6 binary with xk6-infobip-mcp
   Use xk6 to build k6 with this extension:

   go install go.k6.io/xk6/cmd/xk6@latest
   xk6 build --with github.com/infobip/xk6-infobip-mcp
   

2. Write your test script
   Use the example above or create your own test script script.js.

3. Run your test
   Use your custom k6 binary to run the script:

   ./k6 run script.js
   

API Reference

NewClient(config)

Creates a new MCP client instance.

Parameters:

• config.endpoint (string): MCP server endpoint URL
• config.timeout (number): Connection timeout in seconds used for connection and tool call
• config.isSSE (boolean): Use Server-Sent Events transport
• config.headers (object, optional): Custom HTTP headers

Returns: MCPClient instance

MCPClient.callTool(toolName, args)

Calls a tool on the MCP server.

Parameters:

• toolName (string): Name of the tool to call
• args (object): Arguments to pass to the tool

Returns: Tool response as a string

MCPClient.closeConnection()

Closes the MCP client connection.

Metrics

MCP-Specific Metrics

HTTP Metrics

Since MCP communication happens over HTTP, standard k6 HTTP metrics are also collected:

Metric Tags

All metrics include the following tags for detailed analysis:

• method: HTTP method used (GET, POST, etc.)
• url: The MCP server endpoint URL
• status: HTTP response status code

Contribute

If you wish to contribute to this project, please start by reading the Contributing Guidelines.