Refunc MCP Server

What is Refunc MCP Server?

The Refunc MCP Server integrates Refunc serverless functions as tools in the Model Context Protocol (MCP), allowing you to expose functions as MCP endpoints via Server-Sent Events (SSE). It is designed for developers who want to create MCP-compatible tools from existing Refunc functions deployed on Kubernetes.

How to use Refunc MCP Server?

Deploy the Refunc components on Kubernetes using kubectl apply, then proxy the services locally. Install the refunc-cli and initialize a function with rfctl init. Edit the generated lambda.yaml to add an MCP event specification with a token and tool definitions. Finally, update the configuration with rfctl update-config and access the MCP SSE endpoint at the provided URL path.

Key features of Refunc MCP Server

• Deployable on Kubernetes with a single manifest file.
• Uses refunc-cli to create and manage functions.
• MCP event spec supports multiple tools per function.
• SSE endpoint follows a predictable URL format.
• Tools can be described inline with JSON Schema parameters.

Use cases of Refunc MCP Server

• Expose a serverless function as an MCP-compatible tool.
• Build a demo echo tool for testing MCP integrations.
• Create multiple MCP tools from a single function using the _call_method parameter.

FAQ from Refunc MCP Server

How do I deploy the Refunc MCP Server?

Apply the Kubernetes manifest from the repository and port-forward the two services (aws-api and mcp-server) to local ports 8000 and 8001 respectively.

What is the format of the MCP SSE endpoint?

The URL path format is /namespace/<token-secret-name>/<token>/<func-name>/sse. For the demo, it is http://127.0.0.1:8001/refunc-system/mcp-demo/test/mcp-demo/sse.

What are the requirements for creating a function?

You need Python 3, the refunc-cli package installed via pip, and a Kubernetes cluster with the Refunc components deployed.

Is data persistent in the demo deployment?

No, the data from the demo deployment is not persistent.

How do I add multiple tools to a single function?

Define multiple entries under the tools array in the MCP event specification. Each tool requires a name, description, and JSON Schema for parameters. The function receives a _call_method parameter to identify which tool was invoked.