Heron-AutoCAD
Chat-driven AutoCAD assistant that works in the drawing only when connected, behind user-controlled permission gates.
What it does and how it connects
Heron AI for AutoCAD is the AutoCAD member of the Heron AI family. A chat works in the AutoCAD already open, through a C# plug-in that adds a Heron ribbon tab and a Python MCP server exposing autocad_* tools over COM. The plug-in is gated by padlocks the modeller controls: Heron, whether a chat can reach AutoCAD at all; Changes, read-only or draw, modify and delete; Publish, save, export and plot; Admin, commands, AutoLISP and system variables; and Ask to Keep, confirm each change or keep it at once.
Everything starts off, turning a padlock on asks first, and a banner in AutoCAD states whether Heron is reading or changing the drawing. Geometry appears live and every change is one undo step, with nothing reaching AutoCAD until the modeller presses Heron on the ribbon. Example requests in the README include drawing a 5000 by 3000 rectangle on layer A-WALL, checking a drawing against a layer standard, and making a camera schedule from CAM blocks.
The README states the work is not finished and asks modellers not to install it yet: the plug-in inside AutoCAD still has to pass its live checks, and the author will announce it when it is ready to install. Programmers and AI engineers are invited to read the code and share suggestions through issues.
Alternatives
Compare side by side- AutoCAD MCP Pro
An AutoCAD MCP server with live COM and headless ezdxf engines, rather than a chat gated by ribbon padlocks.
- Agent-CAD
An AI-native CAD agent that turns natural language and technical documents into structured 2D drawings and validated DXF files, rather than driving the AutoCAD application itself.
- TextoCAD
A browser-native text-to-CAD engine that turns a plain English description into an editable parametric model, rather than operating inside AutoCAD.
Recurring errors it addresses
Error Index entries this tool is built to reduce or work around.
- A local MCP server driving AutoCAD over COM, tried on a real 42-sheet drawing set. Write tools require an expected_document and return DOCUMENT_CHANGED without writing if the user switched tabs. Writes run once, never retried, and a timeout mid-call returns UNKNOWN_COMMIT. The author says they studied three community AutoCAD MCP servers for the design. People are now building the "did that write land, and where" guard by hand.Error Index
- A local MCP server driving AutoCAD over COM, tried on a real 42-sheet drawing set. Write tools require an expected_document and return DOCUMENT_CHANGED without writing if the user switched tabs. Writes run once, never retried, and a timeout mid-call returns UNKNOWN_COMMIT. The author says they studied three community AutoCAD MCP servers for the design. People are now building the "did that write land, and where" guard by hand.Error Index
- An agent deleted VIEWPORT on a sheet it had just made, removing the layout's main viewport, while strict validation, validate_drawing and AutoCAD AUDIT all reported 0 errors, and AutoCAD 2027 then stops with ePermanentlyErased on open.Error Index
- An AutoCAD Electrical agent skill kept failing because ACADE rejects COM calls while busy, mid-batch, and right after closing drawings.Error Index
- DXF files from AutoCAD came in without layer colours, lineweights, linetypes or blocks, and a 13 MB file with 21,455 objects held the window for minutes because the session journal wrote each object out as its own temp file.Error Index
Sources
Not verified
- Pricing: none stated on the repo.
- No independent user voice found: the repo lists no public issues.
- No GitHub releases exist, so latest release fields are null.
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.