Heron AI for AutoCAD

Dear Modelers - please do not install this yet.

This repository is public so the work is open, but it is not finished. The plug-in inside AutoCAD still has to pass its live checks (NEEDS-CHECKING). I will announce it when it is ready to install.

Programmers and AI engineers: your thoughts are welcome. Read the code and share suggestions or corrections through an Issue.

Let a chat work in your AutoCAD - only when you connect it, and only as far as your padlocks allow.

The modeller focuses on the drawing. Heron does the AutoCAD work behind it.

Heron AI for AutoCAD is the AutoCAD member of the Heron AI family. Same name, same ribbon, same padlocks, same "Heron AI is changing your drawing" banner: a modeller who knows Heron in Revit knows it here.

What it is

You describe the work in plain language; Claude does it in the AutoCAD you already have open:

"Check the connection and tell me what's open."
"Draw a 5000 x 3000 rectangle at the origin on layer A-WALL, in red."
"Check this drawing against our layer standard."
"Make me a camera schedule from the CAM blocks."
"Put sheet E-101 on A1 with our title block, ground floor at 1:100."
"This IFC came in on IfcWall, IfcDuct... make it a shop drawing."
"My UCS is rotated 23 degrees - draw it square to that."
"Draw a 200 flange, 8 holes on a 160 PCD."
"Give me the flat pattern for that 200 to 100 reducer."
"Dimension these grid lines, with the overall above."
"Extrude this outline 200 up and cut the bolt holes out."
"Show me what you drew."

Geometry appears live, every change is one undo step, and nothing reaches AutoCAD until you press Heron on the ribbon.

Related MCP server: vn-autocad-claude

What you see in AutoCAD

Ribbon tab Heron, panel AI Bridge:

While Heron works, a small card at the top of AutoCAD says "Heron AI is reading your drawing" (blue) or "Heron AI is changing your drawing" (amber), then finished (green) or stopped (red). The command line keeps a line such as Heron: Draw Line. Done in 0.4 s.

Everything starts off. Turning a padlock on asks first; turning it off never asks. The same switches are commands: HERON, HERONSTATUS, HERONCHANGES, HERONPUBLISH, HERONADMIN, HERONASKTOKEEP. Full detail: docs/06-heron-plugin.md.

Parts

Documentation is in docs/; stopped experiments in archive/. Drawings stay on the PC that made them; none are in this repository.

What it can do

The live list is always .venv\Scripts\autocad-mcp.exe --list-tools. Every tool has a level, and the level decides which padlock it needs:

Every tool with its options: docs/03-tools-reference.md. Sheets, the UCS and turning an import into a shop drawing: docs/09-sheets-and-coordinates.md. Named shapes, dimension runs, annotation and 3D: docs/10-geometry-annotation-3d.md.

What keeps your drawing safe

• Invisible until connected. AutoCAD starts disconnected every time. The pipe answers only your Windows user, and each connect makes a new session password.

• Padlocks, off by default, read fresh on every call. A broken settings file means all off.

• One undo step per call. Optional Keep or Discard after each change.

• Wrong-drawing guard. If you switch drawings mid-job, a change is refused until Heron looks again.

• No double drawing. If AutoCAD goes busy half-way through a change, Heron does not retry; it says "outcome unknown, read the drawing back first".

• Every call audited to %LOCALAPPDATA%\Heron\autocad\audit\.

More: SECURITY.md.

Install (for testing only, see the banner above)

Needs Windows, full AutoCAD 2021 to 2027 (not LT), Python 3.10+, and the .NET SDK to build.

python -m venv .venv

.venv\Scripts\python.exe -m pip install -e ".[dev]"

.venv\Scripts\python.exe tools/build_plugin.py

Close AutoCAD, then:

.venv\Scripts\python.exe tools/install_plugin.py

Start AutoCAD, press Heron, and connect Claude Code (this folder's .mcp.json does it when Claude Code opens here). Full steps: docs/SETUP.md.

Where to read next

Licence

MIT. See LICENSE. AutoCAD is a trademark of Autodesk, Inc. This project is not affiliated with Autodesk.