mcp2ws

Did you just wake up from a 20 year coma? Did you build a bunch of buzzword compliant web services back in the early 2000s and want all your SOAP and WSDL to be relevant again? Now you can put the smooth sheen of AI on your pile of angle brackets by exposing your SOAP-based web service as a Model Context Protocol (MCP) server.

Prerequisites

• Have a web service described by a WSDL file.
• Have a compatible version of Python (tested with 3.13) or uv installed on your computer.

Running

With uv:

uv run main.py

With regular python:

python -m venv venv
source ./venv/bin/activate
pip install -r requirements.txt
python main.py

Usage

To start the MCP server, run the main.py script with the URL of the WSDL file you want to access.

uv run main.py <WSDL_URL>

For example, if you have a WSDL at http://www.dneonline.com/calculator.asmx?wsdl:

uv run main.py http://www.dneonline.com/calculator.asmx?wsdl

This tool has been tested with these random WSDL files I found on the internet:

• http://www.dneonline.com/calculator.asmx?wsdl
• http://webservices.oorsprong.org/websamples.countryinfo/CountryInfoService.wso?WSDL

Configure your agentic coding tool

Configure your MCP client (e.g., Gemini CLI, or an IDE extension) to run this script.

Example generic MCP config:

{
  "mcpServers": {
    "soap-service": {
      "command": "uv",
      "args": [
        "run",
        "--project",
        "/path/to/mcp2ws/pyproject.toml",
        "/path/to/mcp2ws/main.py",
        "http://webservices.oorsprong.org/websamples.countryinfo/CountryInfoService.wso?WSDL"
      ]
    }
  }
}

Example Session

In Gemini CLI, using the http://webservices.oorsprong.org/websamples.countryinfo/CountryInfoService.wso?WSDL service:

> What is the capital city of France? Use the soap tool.

✦ I will find the ISO code for France and then use it to get the capital city.

╭────────────────────────────────────────────────────────────────────────╮
│ ✓  CountryISOCode (soap-service MCP Server) {"sCountryName":"France"}  │
│                                                                        │
│ FR                                                                     │
╰────────────────────────────────────────────────────────────────────────╯
✦ I will now retrieve the capital city of France using its ISO code.
╭────────────────────────────────────────────────────────────────────────╮
│ ✓  CapitalCity (soap-service MCP Server) {"sCountryISOCode":"FR"}      │
│                                                                        │
│ Paris                                                                  │
╰────────────────────────────────────────────────────────────────────────╯
✦ The capital city of France is Paris.

TODO

• Better support for mapping XML schema to JSON schema for input. Currently only primitive types are supported.
• Implement support for more web service standards like WS-* and UDDI. This probably won't happen because this stops being a fun joke and starts being a job.