AutoCAD AI: connect Claude to AutoCAD & Civil 3D over MCP

The Model Context Protocol is an open standard for connecting AI assistants to real tools. Instead of pasting context into a chat, an MCP client — Claude Desktop or Claude Code — connects to an MCP server that exposes concrete actions, and the assistant calls them directly. It is a common plug between your LLM and the software you already use.

HMK CAD Pilot runs that server inside AutoCAD, so the assistant reads and edits the live drawing. Nothing is exported, round-tripped or re-imported.

Around eighty general AutoCAD actions, covering the everyday work:

• Geometry — draw and modify lines, polylines, arcs, circles, rectangles and hatches; move, copy, rotate, scale, mirror, offset and erase.
• Layers — list, create, set current, change properties, isolate and delete.
• Blocks — list, insert, and read or write block attributes.
• Text and annotation — create text and MText, find and replace across the drawing, add linear and aligned dimensions.
• Drawing context — what is open, what is selected, entity properties, counts by type, layouts.
• Output — plot to PDF and export DWG.

Civil 3D runs in the same host as AutoCAD, so one install serves both — and this is where the depth is. Roughly fifty Civil-specific actions sit on top of the AutoCAD set, and they are hidden automatically when you are working in plain AutoCAD:

• Alignments — create from a polyline, offset alignments, read geometry, convert between station/offset and coordinates, add labels.
• Profiles — surface profiles, layout profiles with PVIs, and profile views.
• Surfaces — create TIN and volume surfaces, add points, breaklines, boundaries and contours, sample elevations, read statistics.
• Corridors — create from an alignment, profile and assembly, rebuild, and read the result.
• Feature lines, COGO points, sample line groups and pipe networks.

The whole road pipeline is there end to end — alignment, profile, assembly, corridor — so the assistant can take a design from a polyline to a rebuilt corridor without you leaving the chat. Verified on Civil 3D 2023 and 2026.

With Dynamo open, ask the assistant to work on the graph directly. It reports what Dynamo is doing, opens or starts a graph, searches the node library — including packages you have installed, such as Civil3DToolkit — adds and wires nodes, writes Code Block and Python, runs the graph and reads the computed values and node warnings back.

That makes it useful in both directions: building a script from a description, and explaining why an existing one is failing.

• “List every alignment in this drawing with its length and start station.”
• “Create a surface profile for Alignment A along the EG surface, then a profile view for it.”
• “Move everything on layer C-ROAD to C-ROAD-NEW and set it to colour 3.”
• “What is the elevation of the EG surface at station 2+400, offset 12 left?”
• “Plot all layouts in this drawing to PDF.”

Connecting an LLM to a CAD session usually means hand-editing claude_desktop_config.json and restarting everything. HMK CAD Pilot writes that configuration for you — one click for Claude Desktop, one for Claude Code — and preserves any MCP servers you already use. You bring your own Claude account; there is no separate AI fee.

The catalogue the assistant sees is deliberately curated rather than exhaustive: tool selection degrades once a model is shown more than about fifty tools, so the niche actions ship switched off and you turn on whichever you want in Settings.

The same suite covers Revit, where you additionally get a chat panel built into the ribbon rather than driving it only through Claude. See Revit MCP for that side, or browse the whole toolbox.