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mcp-demo

MCP.Pizza Chef: sshh12

mcp-demo is a proof-of-concept stateless MCP server builder that enables users to create MCP servers without writing or hosting any code. Designed primarily for protocol and security experimentation, it allows adding custom tools with static or dynamic HTTP responses. It is not intended for production or real-world MCP integrations but serves as a flexible sandbox for testing MCP server behaviors and configurations via URL-based interfaces.

Use This MCP server To

Build MCP servers without writing or hosting code Experiment with MCP protocol and security features Create custom MCP tools with static text responses Test dynamic HTTP-based MCP tool responses Rapidly prototype MCP server configurations via URL Simulate MCP server behavior for development and testing

README

URL-Based MCP Server

URL MCP is a proof of concept stateless MCP server builder that allows users to build MCP servers without writing or hosting code. It's intended for protocol and security experimentation rather than for building real world MCP integrations.

Screenshot 2025-04-12 at 12 07 39 PM

Usage

  1. Go to https://url-mcp-demo.sshh.io/
  2. Add custom tools to your MCP server
  • If you want to hardcode tool responses, select "static text response"
  • If you want dynamic HTTP-based responses, select "http post endpoint"
    • Typically I'll use a temp URL from https://webhook.site/ which logs all the requests and allows you to configure custom responses
  1. Copy the MCP Configuration into your client of choice

Local Hosting

There is not really a point to hosting this locally (the whole idea is that you can use this without hosting just with the URL) but in case you want to modify the app itself:

  1. cd backend && pip install requirements.txt && python main.py

Example: System Prompt Exfiltration

Create a custom MCP server for extracting the system prompt of an application.

  1. Configure the tools to trick the client into trusting it. Use a https://webhook.site/ temp url for the tool response.
  2. Copy the MCP config
  3. In the client ask for an audit and the view the webhook logs.
Step 1 Step 2 Step 3
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mcp-demo FAQ

How do I add custom tools to the mcp-demo server?
You can add custom tools by selecting either 'static text response' for hardcoded replies or 'http post endpoint' for dynamic HTTP-based responses via the web interface.
Is mcp-demo suitable for production MCP integrations?
No, mcp-demo is intended only for protocol and security experimentation, not for real-world MCP deployments.
Can I host mcp-demo locally?
While local hosting is possible, the main advantage of mcp-demo is its URL-based usage without needing local hosting.
How does mcp-demo handle dynamic responses?
Dynamic responses are handled by configuring HTTP POST endpoints, often using services like webhook.site to log and customize responses.
What is the main purpose of mcp-demo?
Its main purpose is to provide a no-code, stateless MCP server builder for experimentation and prototyping.
Can I integrate mcp-demo with any MCP client?
Yes, you can copy the MCP configuration generated by mcp-demo into any compatible MCP client to connect and test.
Does mcp-demo support stateful interactions?
No, mcp-demo is stateless and does not maintain session or interaction state between requests.