Claireon MCP
An Unreal Editor plugin that runs an MCP server so Claude Code can read and edit blueprints, assets and levels.
- 147 ★ on the repository
- Last commit
- MIT
Broad access
Why this level
- `python_execute` runs arbitrary Python in the editor and can change or delete project assets.
- The agent gets broad access to project content.
Install
- Works in
Manual install
git clone <repo-url> Plugins/ClaireonThe README command: replace `<repo-url>` with https://github.com/believer-oss/Claireon.git. Then regenerate project files, build and enable the plugin under Edit, Plugins, Claireon.
Access and checks
How we reviewBroad accessThe tool can change data, run commands or handle secrets.
- `python_execute` runs arbitrary Python in the editor and can change or delete project assets.
- The agent gets broad access to project content.
This is third-party code. Review the repository files before installing.
What it does
Claireon embeds into the Unreal Engine 5 editor and starts an MCP server over Streamable HTTP. Two tools are visible: `tool_search` finds the right command among hundreds of editor actions (hybrid SQLite FTS5 and a bundled embedding model) and `python_execute` runs Python in the editor with an audit log. Through them the agent works with blueprints, animation, State Tree, Behavior Tree, UMG widgets, Niagara, PCG, data tables, audio, levels and Unreal Insights, starts PIE and takes screenshots.
Who it is for. Unreal Engine 5 game developers who hand routine editor work to an agent: blueprint edits, data import, asset checks.
Good fit when
- Properties of many blueprints or components need a bulk fix.
- A data table is imported from CSV or JSON and the result is compared.
- Assets are validated and redirectors fixed before a build.
- The agent must start PIE, check behaviour and take a screenshot.
Not a fit when
- The project uses Unity, Godot or another engine.
- The editor runs on a non-Windows system: only Win64 is verified.
- The agent must not be trusted to run arbitrary Python in the project.
Example request
Find all blueprints with a light component, list their properties and adjust the radius from the data table.MCP
- Transport
- http
- Authentication
- not required
Limitations
The status is beta: verified on Unreal 5.5 and newer, Win64 only, with the Python plugin enabled. The plugin is built from source inside the project and no prebuilt package exists. The `python_execute` tool runs arbitrary code in the editor, so work on a copy of the project or under version control. The server port is derived from the project path and written to `Saved/Claireon/MCPServer.json`. The last commit dates from September 2026.
How to disable. Disable the plugin under Edit, Plugins, Claireon and restart the editor. Remove the server entry from the project's `.mcp.json`.
FAQ
Why only two tools?
A list of hundreds of commands bloats context. The agent therefore finds a command through `tool_search` and runs it through `python_execute`.
How do I find the server port?
It is stable for each project path and written to `Saved/Claireon/MCPServer.json` after launch. Put an address like `http://127.0.0.1:<port>/mcp` into `.mcp.json`.
What does the optional proxy give?
Claude Code stays connected while the editor restarts after builds or crashes. It is enabled with `-EnableMCPProxy` and off by default.
Can the server start without the toolbar button?
Yes, launch the editor with `-StartMCPServer` and the server starts at once.
Which Unreal versions work?
Verified on Unreal Engine 5.5 and newer on Windows (Win64). Other platforms may work but are untested, and the editor's Python plugin must be enabled.
Discussion
No questions or reviews yet.
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Comparison with similar tools
Cards that share the main search query, and how they differ.
| Tool | Official | Authentication | Repository stars | Main difference |
|---|---|---|---|---|
| Claireon (this card) | no | not required | 147 | |
| Unreal MCP | no | not required | 2,115 | a Python server with a separate tool per action; Claireon exposes two tools and searches commands locally |
| UnrealClaude | no | not required | 1,031 | embeds a Claude chat in the editor; Claireon connects an external client through MCP |
README in short
Capabilities are listed by editor area, followed by requirements (Unreal 5.x, Windows, Python plugin) and two ways to start the server. A separate section describes the proxy for frequent editor restarts.