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Known Limitations

Claimed Hosts​

RevitDevTool documents Revit and AutoCAD-family as the two marketed host products. Civil 3D, Plant 3D, and other AutoCAD verticals load the same AcadDevTool add-in but are not promoted as separate product lines.

Observability​

Visualization Is Revit-Only​

The geometry visualization module (DirectContext3D) is a Revit-specific rendering API. AutoCAD-family hosts do not have an equivalent transient rendering path in RevitDevTool. Logging (Monitor, file, HTTP) works on all claimed hosts.

Log Output​

The HTTP log sink requires network configuration and a reachable endpoint. It is optional — Monitor and file sinks work without it.

AutoCAD-Family Host​

  • Command Browser is Revit-only — not yet available for AutoCAD-family hosts
  • Host API stubs are not bundled for every Autodesk version; generate .pyi files from the target .NET assemblies when needed
  • Geometry visualization is not available (Revit only)

Execution​

IronPython Has No Debugger​

IronPython scripts (*_ipy_script.py) and IronPython tests (test_*_ipy.py) run without breakpoint debugging. On Revit, both prefer the pyRevit engine when installed (default IronPython 2.7.12). Use logging, print output, or convert to CPython for debugpy breakpoint debugging.

Plant 3D Python Backend​

Plant 3D is the only current host with an embedded CPython runtime. PEP 723 packages install via a uv sidecar to %APPDATA%\RevitDevTool\uv-env\{major.minor} — not via Pixi. This is a runtime backend exception, not a separate RevitDevTool product.

AI Tool Integration​

  • .NET 10 required — local MCP clients spawn DevTools.Daemon.exe --stdio as the MCP server; without the runtime, AI tools are unavailable even when hosts are running
  • Host must load the add-in — the MCP server discovers pipes only from running hosts with RevitDevTool loaded; a crash during add-in startup leaves no MCP pipe (see crash_* logs in Troubleshooting)
  • Local MCP v2 clients only — any local tool that supports MCP v2 (from 28 July 2026): Cursor, Claude Desktop, VS Code Copilot, ChatGPT Desktop, …. Configure a stdio command. Cloud marketplace connectors are not included in this release.

Testing​

  • IronPython tests (test_*_ipy.py) use unittest semantics — no pytest fixtures or PEP 723 dependency install. On Revit they use the pyRevit engine when installed (default IronPython 2.7.12), else IronPython 3.4.2
  • CPython vs IPy split — one pytest invocation cannot mix two separate conftest.py trees; run CPython and IronPython test folders as separate pytest sessions against the same host
  • Sequential execution — host API calls run on the main thread via IHostContextExecutor; tests in a session do not run in parallel inside one host instance

Python Runtime​

Python execution depends on local machine state:

  • Pixi-owned (Revit and AutoCAD-family) — CPython 3.14 in %APPDATA%\RevitDevTool\pixi-env; requires writable AppData and reachable conda-forge/PyPI
  • Plant 3D only — host-owned + uv sidecar — PEP 723 packages install to %APPDATA%\RevitDevTool\uv-env\{major.minor} matched to the host interpreter; the host prefix itself is not modified
  • Fallback — if Pixi is blocked (or uv on Plant 3D), RevitDevTool falls back to pip or pyRevit's bundled CPython when pyRevit is installed
  • If no manager or fallback is available, the CPython execution pipeline is unavailable — contact IT to whitelist Pixi (or uv on Plant 3D) or pyRevit
  • CPython debugging requires debugpy and an available debug port in the active runtime