Converting Existing LlamaIndex Workflows & Tools to MCP

Convert your LlamaIndex tools and workflows into MCP servers for broader ecosystem compatibility.

Converting Workflows

Use workflow_as_mcp to convert any LlamaIndex Workflow into an FastMCP server:

from workflows import Context, Workflow, step
from workflows.events import StartEvent, StopEvent
from llama_index.tools.mcp.utils import workflow_as_mcp


class QueryEvent(StartEvent):
    query: str


class SimpleWorkflow(Workflow):
    @step
    def process_query(self, ctx: Context, ev: QueryEvent) -> StopEvent:
        result = f"Processed: {ev.query}"
        return StopEvent(result=result)


# Convert to MCP server
workflow = SimpleWorkflow()
mcp = workflow_as_mcp(workflow, start_event_model=QueryEvent)

If you were using FastMCP directly, it would look something like this:

from fastmcp import FastMCP

# Workflow definition
...

mcp = FastMCP("Demo 🚀")
workflow = SimpleWorkflow()


@mcp.tool
async def run_my_workflow(input_args: QueryEvent) -> str:
    """Add two numbers"""
    if isintance(input_args, dict):
        input_args = QueryEvent.model_validate(input_args)
    result = await workflow.run(start_event=input_args)
    return str(result)


if __name__ == "__main__":
    mcp.run()

Converting Individual Tools

We can also use FastMCP to directly convert existing functions and tools input MCP endpoints:

from fastmcp import FastMCP
from llama_index.tools.notion import NotionToolSpec

# Get tools from ToolSpec
tool_spec = NotionToolSpec(integration_token="your_token")
tools = tool_spec.to_tool_list()

# Create MCP server
mcp_server = FastMCP("Tool Server")

# Register tools
for tool in tools:
    mcp_server.tool(
        name=tool.metadata.name, description=tool.metadata.description
    )(tool.real_fn)

Running MCP Server

You can launch your server from the CLI (which is also great for debugging!):

# Install MCP CLI
pip install "mcp[cli]"

# Run server
mcp run your-server.py