Revit

Revit is the primary RevitDevTool v3.0 host — full four pillars.

Pillar	Entry points
Execution	Execution Overview, Modern Python Scripting, C# Scripts, F# Scripts, .NET Assembly
Testing	pytest, NUnit, TUnit, MSTest
AI Tool Integration	MCP .NET, MCP Python
Observability	Log Level, Geometry Visualization

Supported Versions

The current build matrix supports Autodesk/Revit configurations from 2022 through 2027:

Revit version	Target framework
2022-2024	net48
2025-2026	net8.0-windows
2027	net10.0-windows

What You Can Do In Revit

• run Python scripts that call the Revit API;
• install Python dependencies from script metadata;
• debug Python in VSCode;
• run compiled Revit add-ins;
• run C# .csx, F# .fsx, and IronPython scripts;
• inspect logs and Python stack traces;
• visualize temporary Revit geometry;
• expose selected tools through MCP;
• run pytest-style checks that need Revit context;
• run NUnit, TUnit, or MSTest inside a live Revit session;
• search and run commands through Command Browser;
• watch memory usage when diagnosing heavy scripts.

Good Use Cases

Use case	Recommended page
Quick Python automation	Modern Python Scripting
Revit API add-in development	.NET Assembly
Fast C# or F# experiment	C# Scripts, F# Scripts
Visual geometry debugging	Geometry Visualization
AI-assisted tool access	MCP .NET, MCP Python
Tests that need Revit API context (pytest)	pytest
Tests that need Revit API context (NUnit/TUnit/MSTest)	NUnit, TUnit, MSTest

Python Runtime

CPython runs through Python.NET with a Pixi-owned interpreter (Python 3.14 in %APPDATA%\RevitDevTool\pixi-env). Revit does not embed CPython — there is no uv sidecar on this host.

IronPython execution (*_ipy_script.py) and IronPython testing (test_*_ipy.py) both prefer the pyRevit engine when pyRevit is installed. pyRevit's current default engine is still IronPython 2.7.12, which matches most pyRevit tool development. Without pyRevit, RevitDevTool falls back to IronPython 3.4.2. See Modern Python Scripting, Python Ecosystems, and IronPython — pyRevit Folder Compatibility.

Revit API Context

Revit API calls must run in a valid Revit API context. Scripts launched through RevitDevTool are designed for that. Modeless UI or background work still needs to marshal Revit API calls back through the provided Revit execution path.

Geometry Visualization

Visualization is currently a Revit DirectContext3D feature. Geometry traced or printed by scripts can be shown temporarily in the active view without creating model elements.

Supported geometry categories include:

• XYZ/points
• curves and polylines
• bounding boxes/outlines
• meshes
• faces
• solids
• planes

See Geometry Visualization.

MCP Integration

Local MCP (MCP .NET or MCP Python) discovers running Revit instances (DevToolsMcp_Revit_{Year}_{PID}) and exposes host capabilities through search_dynamic and invoke_dynamic.

Revit-Specific Caveats

• Revit API behavior cannot be fully validated by pure unit tests.
• Some workflows need a live Revit session.
• Geometry visualization is tied to active Revit view/rendering state.
• net48 compatibility still matters for Revit 2022-2024.
• Python/IronPython behavior depends on installed runtimes and enterprise machine restrictions.