FML MCP Server

This is a local MCP server that lets you work with FML federations directly from an AI assistant like Claude Desktop. Once it's running, you can load models, run logic, and interact with your FML files through natural language.

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Step 1 — Build the project

Open PowerShell or CMD in the project root and run:

.\gradlew.bat build

That's it. Everything you need will be generated under build\.

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Step 2 — Connect it to Claude Desktop

Open your Claude Desktop config file (usually at %APPDATA%\Claude\claude_desktop_config.json) and add the server entry:

{
  "mcpServers": {
    "fml-mcp-server": {
      "command": "java",
      "args": [
        "-jar",
        "C:\\...\\openflexo-fml-mcp-server\\fml-mcp-server\\build\\libs\\fml-mcp-server-2.99-SNAPSHOT.jar",
        "--transport",
        "stdio",
        "--rc",
        "C:\\...\\openflexo-fml-mcp-server\\fml-mcp-server\\src\\test\\resources"
      ],
      "env": {}
    }
  },
}

Replace the path with wherever you cloned this repo. you can find the config file by going to the settings in Claude Desktop and clicking "Open config file" at the bottom.

Step 3 — Start a conversation

Once Claude Desktop picks up the server, you'll see it listed in the tools panel.

You can now talk to your FML models. For example:

• "Load the StudentFederation and show me the students"
• "Run the Calculator with inputs X and Y"
• "What does the MaintenanceFederation track?"

Available example models

All ready to use, sitting in src\test\resources\FML:

Model	What it does
HelloFML.fml	Basic hello world, good first test
Calculator.fml	Simple arithmetic operations
StudentFederation.fml	Works with the student CSV data
MaintenanceFederation.fml	Maintenance log example
ManufacturingFederation.fml	Manufacturing process model
WorkflowDemo.fml	Workflow steps demo

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Available tools

These are the tools the server exposes to your AI assistant. Claude will pick the right one automatically based on what you ask.

Tool	What it does
ping	Checks that the server is alive and responding
list_fml_models	Lists all FML models available in the resource center
load_fml_file	Loads an FML file so you can work with it
validate_fml_file	Validates an FML file and reports any errors
write_fml_file	Writes or saves an FML file
write_file	Writes a generic file to disk
describe_concept	Describes a concept inside a loaded model
list_resource_centers	Lists all registered resource centers
add_resource_center	Adds a new resource center by path
bind_resource	Binds a resource to a model
reload_model	Reloads a model if it has changed on disk
create_instance	Creates a new instance of a concept
initialize_instance	Runs initialization logic on an instance
destroy_instance	Destroys an existing instance
list_instances	Lists all existing instances of a concept
get_instance_state	Returns the current state of an instance
query_instances	Queries instances using conditions or filters
get_property	Gets a property value from an instance
set_property	Sets a property value on an instance
call_behaviour	Calls a behaviour (method) on an instance
batch_call_behaviour	Calls multiple behaviours in one go
execute_workflow	Executes a full workflow defined in a model

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Something not working?

• Make sure the build finished without errors before starting Claude Desktop
• Double check the jar path in the config — it needs to be the full absolute path
• Restart Claude Desktop after editing the config file