About URL-Based MCP Server
URL-Based MCP Server is a proof-of-concept builder for stateless MCP servers, aimed at protocol and security experimentation rather than production integrations. It lets users configure tools through a URL without writing or hosting server code.
Key features
- 01Configure custom MCP tools
- 02Return static text responses
- 03Use HTTP POST endpoints for dynamic responses
- 04Share configuration with an MCP client
Use cases
- 01Experiment with MCP protocol behavior
- 02Test client security using configured tools
MCP support
It builds stateless MCP servers from URL-based configurations and lets users copy the resulting configuration into an MCP client.
Configuration
Local server config is the same for every client. Copy it into your client’s MCP config file.
We haven’t collected a package or remote endpoint for this server. Follow the instructions in the project README.
Tools
Local servers expose tools only once running on your machine, and the maintainer has not provided a tool list.
Details
From the project READMEURL-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.
Usage
- Go to https://url-mcp-demo.sshh.io/
- 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
- Copy the
MCP Configurationinto 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:
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.
- Configure the tools to trick the client into trusting it. Use a https://webhook.site/ temp url for the tool response.
- Copy the MCP config
- In the client ask for an audit and the view the webhook logs.
| Step 1 | Step 2 | Step 3 |
|---|---|---|
Comments
New to MCP?
From what the protocol is to installing your first server, these answers cover most first questions.
An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.