MDMCP Server for Unity

MDMCP (Markdown MCP) Server is an HTTP-based automation bridge for the Unity Editor. It lets you inspect, modify, and test your project via JSON requests, and is fully extensible via IEditorAction plugins.

What's included

Item	Description
Core server	Background HTTP listener with reflection-based action discovery
Baseline actions	Context, discovery, scene/prefab inspection, property setters, UI, wait/playmode, and more
New utilities	ping, addComponent, removeComponent, setMultipleProperties
Settings window	Auto-start toggle, port, log level; Start/Stop and Open Docs
Samples	Hello Action; Extensions Template (asmdef + sample action)
Docs	Full guide at Packages/com.clokk.mdmcp-unity/Documentation/MDMCPServer.md

Install (UPM - Git URL)

Add this line to your project's Packages/manifest.json:

"com.clokk.mdmcp-unity": "https://github.com/clokk/mdmcp-unity.git#v0.2.4"

Or use the Package Manager "Add package from Git URL…" with:

https://github.com/clokk/mdmcp-unity.git#v0.2.4

GUI path:

• Window → Package Manager → + (Add) → Add package from Git URL…
• Paste: https://github.com/clokk/mdmcp-unity.git (or a pinned tag as above)

Usage

• Start the server: Markdown > Start MCP Server
• Stop the server: Markdown > Stop MCP Server
• Default URL: http://localhost:43210/

OpenUPM (scoped registry)

Option A: CLI

openupm add com.clokk.mdmcp-unity

Option B: Scoped registry (manifest.json)

1. Add registry:

{
  "scopedRegistries": [
    {
      "name": "OpenUPM",
      "url": "https://package.openupm.com",
      "scopes": [ "com.clokk" ]
    }
  ]
}

2. In Package Manager, switch to My Registries and install by name: com.clokk.mdmcp-unity

Quickstart (curl)

curl -X POST http://localhost:43210 -d '{"action":"getContext"}'

Why MDMCP?

Automate in-editor flows with simple HTTP calls. For example:

# Enter play mode, wait, click a UI button, and inspect context
curl -X POST http://localhost:43210 -H "Content-Type: application/json" -d '{"action":"setPlayMode","payload":true}'
curl -X POST http://localhost:43210 -H "Content-Type: application/json" -d '{"action":"wait","payload":2}'
curl -X POST http://localhost:43210 -H "Content-Type: application/json" -d '{"action":"executeUIEvent","payload":{"targetPath":"/Canvas/MainMenu/PlayButton","eventType":"click"}}'
curl -X POST http://localhost:43210 -H "Content-Type: application/json" -d '{"action":"getContext"}'

Clients

Python (requests):

import requests, json
url = "http://localhost:43210"
resp = requests.post(url, json={"action":"getContext"})
print(json.dumps(resp.json(), indent=2))

Node (axios):

const axios = require("axios");
async function main() {
  const { data } = await axios.post("http://localhost:43210", { action: "listActions" });
  console.log(data);
}
main();

Prompting in Cursor

• Give the agent concrete context and speak in natural language about what you want to automate with MCP actions.
• Always attach the package guide: Packages/com.clokk.mdmcp-unity/Documentation/MDMCPServer.md (or MDMCPServer.md if copied locally).
• Prompt naturally, e.g.: “Enter play mode, wait 2s, click /Canvas/MainMenu/PlayButton, then return getContext.”
• Ensure the Unity Editor is open, compiled (no pending compilation), and the Editor window is active before running MCP commands.

Extend

Create a class that implements MCP.IEditorAction anywhere in an Editor assembly. The server discovers actions via reflection:

using MCP;
using UnityEditor;

namespace MyCompany.MDMCP.Actions
{
    public class HelloAction : IEditorAction
    {
        public string ActionName => "hello";
        public object Execute(EditorActionPayload payload)
        {
            return ActionResponse.Ok(new { message = "Hello from MDMCP!" });
        }
    }
}

Project-specific extensions:

• Create an Editor asmdef (e.g., YourCompany.MDMCP.Extensions.Editor) and reference Clokk.MDMCP.Editor
• Put your IEditorAction classes and any payload DTOs there (e.g., namespace MCP.Payloads)
• Validate discovery via listActions

Agent context tip:

• Pass the package guide to your agent: Packages/com.clokk.mdmcp-unity/Documentation/MDMCPServer.md

License

MIT © clokk