v146 · MCP Tool Tester

MCP Tool Tester

Select a tool from a simulated MCP server's tool registry, fill in parameters, and invoke it. The JSON-RPC trace panel shows the exact tools/call request the model sends and the result response the server returns — the core of the Model Context Protocol message flow.

Chrome 146 — WebMCP API. WebMCP exposes an MCP server endpoint directly from a web page. This demo simulates the MCP JSON-RPC message exchange without a live server. Real usage requires navigator.mcpServer availability in Chrome 146+ with the WebMCP flag.

Tool registry4 tools

Select a tool

Pick a tool from the registry to configure and invoke it.

JSON-RPC trace

// Invoke a tool to see the JSON-RPC exchange here…