How to Build an MCP Server with Gradio

Updated! (September 2025) This post has been updated with the latest Gradio MCP features including Resources, Prompts, enhanced authentication, and many more.

Gradio is a Python library used by more than 1 million developers each month to build interfaces for machine learning models. Beyond just creating UIs, Gradio also exposes API capabilities and — now! — Gradio apps can be launched Model Context Protocol (MCP) servers for LLMs. This means that your Gradio app, whether it's an image generator or a tax calculator or something else entirely, can be called as a tool by an LLM.

This guide will show you how to use Gradio to build an MCP server in just a few lines of Python.

Prerequisites

If not already installed, please install Gradio with the MCP extra:

pip install "gradio[mcp]"

This will install the necessary dependencies, including the mcp package. You'll also need an LLM application that supports tool calling using the MCP protocol, such as Claude Desktop, Cursor, or Cline (these are known as "MCP Clients").

An MCP server is a standardized way to expose tools so that they can be used by LLMs. An MCP server can provide LLMs with all kinds of additional capabilities, such as the ability to generate or edit images, synthesize audio, or perform specific calculations such as prime factorize numbers.

Gradio makes it easy to build these MCP servers, turning any Python function into a tool that LLMs can use.

Example: Counting Letters in a Word

LLMs are famously not great at counting the number of letters in a word (e.g., the number of "r"s in "strawberry"). But what if we equip them with a tool to help? Let's start by writing a simple Gradio app that counts the number of letters in a word or phrase:

Notice that we have set mcp_server=True in .launch(). This is all that's needed for your Gradio app to serve as an MCP server! Now, when you run this app, it will:

1. Start the regular Gradio web interface
2. Start the MCP server
3. Print the MCP server URL in the console