VS Code Extension

The MDL extension for VS Code provides a rich editing experience for .mdl files, bringing IDE-level support for Mendix Definition Language. The extension communicates with the mxcli lsp language server to provide real-time diagnostics, code completion, hover documentation, and navigation.

Feature Summary

Feature	Description
Syntax highlighting	MDL keyword, string, comment, and identifier coloring
Parse diagnostics	Real-time error reporting as you type
Semantic diagnostics	Reference validation on save (entities, microflows, pages)
Code completion	Context-aware keyword and snippet suggestions
Hover	View MDL definitions by hovering over `Module.Name` references
Go-to-definition	Ctrl+click to open element source as a virtual document
Document outline	Navigate MDL statements via the Outline panel
Folding	Collapse statement blocks and widget trees
Context menu	Run File, Run Selection, and Check File commands
Project tree	Browse modules and documents in a Mendix-specific tree view

How It Works

The extension spawns mxcli lsp --stdio as a background process and communicates via the Language Server Protocol over standard I/O. This means all analysis, completion, and navigation is performed by the same engine that powers the mxcli command line.

┌──────────────┐     stdio      ┌──────────────────┐     ┌────────────┐
│  VS Code     │◀──────────────▶│  mxcli lsp       │────▶│  .mpr file │
│  Extension   │   LSP JSON-RPC │  --stdio          │     │            │
└──────────────┘                └──────────────────┘     └────────────┘

Requirements

VS Code 1.80 or later (or any VS Code fork such as Cursor)
mxcli binary on PATH or configured via the mdl.mxcliPath setting
A Mendix project (.mpr file) for semantic features

Settings

Setting	Default	Description
`mdl.mxcliPath`	`mxcli`	Path to the mxcli executable
`mdl.mprPath`	(auto-discovered)	Path to `.mpr` file; if empty, the extension searches the workspace

Getting Started

The fastest way to get started is mxcli init, which automatically installs the extension into your project. See Installation for details, or jump to specific features: