XMCP – Control the Xojo IDE from your AI assistant

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I came across MCPKit by @GarryPettet a few weeks ago and wanted to try it. I got a bit carried away and ended up building something bigger than I originally intended.

XMCP is an MCP server that lets an AI assistant talk directly to the XOJO IDE. Navigate the project, read and write code, build, run, look up documentation. The AI does it, not you.

https://github.com/o3jvind/XMCP

It communicates via the IDE’s IPC socket using the IDE Communicator Protocol v2, and exposes 20 tools to the AI client over stdin/stdout JSON-RPC — the standard MCP protocol. Garry’s MCPKit handles all the MCP plumbing, which made this possible without starting completely from scratch.

In the spirit of the project itself, the code was written by AI — Claude Code mainly, with some OpenAI Codex. I was the architect.

It works. I’ve tested it quite a bit. But it’s experimental, and there are some limitations that come from what the IDE scripting API allows — you can’t navigate directly to individual methods, for example, only to classes and folders.

If anyone else is playing with MCP and XOJO I’d love to hear about it.

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v1.2.0 update

A few significant improvements since the initial post.

The AI now knows what it can’t do

The biggest addition is a usage-guide.md that ships with the project and is exposed as an MCP resource. Compatible clients like Claude Code fetch it automatically at session start — so the AI immediately knows about XMCP’s capabilities, the IDE scripting limitations (e.g. can’t navigate to individual methods or window event handlers), and what to do instead. Previously the AI would just hit a wall and get confused; now it gets actionable guidance.

You can also edit the file to add project-specific notes without rebuilding.

Compile errors flow directly to the AI

When the AI calls build_project or run_project, any compile errors come back directly in the response — error type, message, file, and line number. The AI sees exactly what’s wrong and can fix it immediately without you having to copy-paste anything or take screenshots.

get_system_log also works for reading System.DebugLog output from both debug runs and built apps, so the AI can instrument code and check output without leaving the session.

Better error messages

When tools like select_project_item or get_code hit a scripting limitation, the error now tells the AI exactly what alternative to use — direct file editing, revert_project, etc.

get_project_info now returns the project directory

Useful when the AI needs to fall back to editing .xojo_code or .xojo_window files directly on disk.

Protocol fixes

Several JSON-RPC correctness fixes — integer id preservation, correct JSON types for tool parameter defaults, shell injection prevention in get_system_log.

Full details in the CHANGELOG on GitHub.

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This sounds fantastic.

I’ve been using Claude Code with Opus 4.6, after a hiatus. Previously using with Sonnet, which was good if the task wasn’t too ambitious. What a difference with Opus. I’ve been converting Xojo apps that I spent months on, into web apps, in a matter of hours. In one case just a screenshot of the Xojo app form…plus a reference to a folder containing the files that the Xojo app used. This is taking a few hours to get it all done, but I am not straining my brain doing it. No reference to Xojo code, yet, its generating python and js from scratch.

But with your MCP for Xojo my methods can change. I think the presentation, with an native application, is generally much better than a web app. So I am looking forward to this. I’ve got a ton of code.

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Honestly Opus is blowing my mind right now as if regenerates code (in Python) that I so painstakingly wrote in Xojo. With very little intervention. It’s embrace or die. I mention this to you because clearly you understand, having made the effort to implement MCP.

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If you decide to try XMCP, there’s one small but important tip: add this to your prompt at the start of the session:

Run list_mcp_resources and read file://usage-guide.md before coding.

Make sure usage-guide.md sits next to the XMCP binary.
That ensures the AI loads the built-in usage guide first, so it understands the IDE limitations and the intended workflows. It makes a big difference in how smoothly things go.

Would love to hear how it works for your projects if you give it a spin.

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