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Krypton's Tools Free
Model Context Protocol
JSON-RPC 2.0 Compliant

WebMCP Verifier & Validator

Test, validate, and debug your Model Context Protocol (MCP) SSE endpoints, inspect exposed tools and JSON schemas, and monitor live JSON-RPC traffic.

Validate Website WebMCP Support

Enter any webpage URL to check its native WebMCP (navigator.modelContext), DOM form annotations, and tool discoverability.

Enter a URL above to inspect WebMCP readiness

Paste any URL to test whether the webpage supports the ModelContext API, declares DOM form annotations, and exposes tools to AI agents.

Protocol Guide

How to Test & Validate an MCP Server Endpoint

Test your Server-Sent Events (SSE) stream, JSON-RPC 2.0 protocol handshake, and tool schemas in 3 straightforward steps.

1

Enter Server SSE Endpoint

Input your live MCP server SSE URL (e.g. /sse) or click the built-in Sandbox demo to test instant local mocking.

2

Perform Handshake & Tool Discovery

Connect to trigger the initialize negotiation, send client confirmations, and discover exposed tools with their input schemas.

3

Execute Tools & Inspect Traffic

Select any discovered tool, fill out the dynamically generated parameter form, and monitor real-time bidirectional JSON-RPC 2.0 logs in the terminal.

Specifications

Model Context Protocol (MCP) Compliance Matrix

Model Context Protocol (MCP) is an open protocol standard that connects AI models (LLMs) with external tools, APIs, and data sources over standard JSON-RPC 2.0 messages.

Feature / StageMethod / SpecSupportedPurpose
Transport LayerSSE (Server-Sent Events)✓ YesUnidirectional streaming from server with HTTP POST backchannel
Protocol Handshakeinitialize✓ YesNegotiates protocol version (2024-11-05), server info, and capabilities
Client Confirmationnotifications/initialized✓ YesConfirms initialization is complete and client is ready
Tool Discoverytools/list✓ YesRetrieves tool names, descriptions, and JSON Schema definitions
Tool Executiontools/call✓ YesSends arguments to the server and captures structured result contents
FAQ

Frequently Asked Questions about WebMCP & Model Context Protocol

Common questions regarding MCP verification, CORS issues, and client integration.

The Model Context Protocol (MCP) is an open standard introduced by Anthropic that allows AI applications and large language models (LLMs) to discover and invoke tools, query external datasources, and access contextual information in a secure, standardized JSON-RPC 2.0 format.

Standard MCP servers typically communicate over standard I/O (stdio) locally on a machine. WebMCP and MCP SSE servers communicate over HTTP Server-Sent Events (SSE), allowing web browsers, AI agent extensions (e.g. Chrome 146+ navigator.modelContext), and remote cloud assistants to interface with tools directly across the web.

Browsers enforce Cross-Origin Resource Sharing (CORS) security. If your MCP server is hosted on a different domain or port than this validator, your server must include the proper Access-Control-Allow-Origin, Access-Control-Allow-Headers, and Access-Control-Allow-Methods headers in both the initial SSE response and subsequent POST request handlers.

No. The WebMCP verifier executes client-side within your browser. All endpoint connections, JSON-RPC handshakes, and tool invocations are dispatched directly between your browser and your target MCP endpoint.