uMCP

What is uMCP?

uMCP is a minimalistic and efficient MCP protocol server implementation for connecting AI agents to Unity applications. It communicates directly with MCP clients using the Streamable HTTP protocol without additional language runtimes, making it lightweight and Unity‑native.

How to use uMCP?

Install the CoreFramework package in Unity (2022.3 LTS or newer) via OpenUPM or Git URL. The MCP server starts automatically when the Unity project runs. Then configure your MCP client (e.g., VSCode Agent Mode, Cursor, CLINE) to point to http://localhost:7225/sse or http://localhost:7225/mcp.

Key features of uMCP

• Safety: prevents AI from executing arbitrary code; only pre‑authorized operations are allowed.
• Extensible: add custom commands using McpServerToolType and McpServerTool attributes.
• Direct Streamable HTTP communication without Python, Node.js, or other runtimes.
• Minimal dependencies – runs entirely inside Unity.

Use cases of uMCP

• Connect an AI assistant to a live Unity scene for real‑time manipulation.
• Enable AI agents to query and modify Unity objects during development and testing.
• Build interactive AI‑powered tools within Unity with minimal overhead.

FAQ from uMCP

What makes uMCP different from other MCP implementations?

uMCP communicates directly with the MCP client via Streamable HTTP, eliminating the need for Python, Node.js, or other language runtimes for a more efficient and lightweight setup.

What are the runtime requirements?

Unity Editor version 2022.3 LTS or newer. The MCP client must support Streamable HTTP (e.g., VSCode Agent Mode, Cursor, CLINE).

How do I extend uMCP with custom commands?

Create a class with the [McpServerToolType] attribute and add static methods marked with [McpServerTool] and [Description]. Return an IToolResult such as TextResult. See the provided example in the README.

Which transport protocol does uMCP use?

It uses Streamable HTTP, accessible at endpoints /sse and /mcp on the default port 7225.

Is uMCP limited to Unity Editor?

Yes, it is designed as a Unity Package and runs inside the Unity Editor. It does not support standalone builds.