MCP Connector for Civil 3D Documentation

MCP Connector for Civil 3D connects AI assistants to a live Autodesk Civil 3D session on your machine. Once connected, your AI can read and author the drawing: surfaces, alignments, profiles, pipe networks, COGO points, sample lines and sections, alongside the full AutoCAD drawing tool set for geometry, layers, blocks, external references, annotation and layouts. Two parts ship together and talk over a local connection: an MCP server your AI client launches, and a plug-in that loads inside Civil 3D. Nothing needs to be configured between them.

251 tools are served by default: 189 inherited from the AutoCAD drawing surface and 62 that exist only because the host is Civil 3D. 39 of the 189 are free and read-only. Every Civil tool needs a Pro licence, and every tool that edits objects in bulk previews the change before it writes.

Supported Civil 3D Versions

• Civil 3D 2024
• Civil 3D 2025
• Civil 3D 2026
• Civil 3D 2027

Civil 3D 2023 and earlier are not supported. Autodesk does not publish a managed Civil 3D API package for those releases, so there is nothing to build against. Windows 10 or 11, 64-bit.

If you work in plain AutoCAD rather than Civil 3D, use MCP Connector for Civil 3D instead. That one covers AutoCAD 2022 to 2027. This connector already contains the whole AutoCAD tool set, so you do not need both.

AI Applications

• Claude Desktop
• ChatGPT Desktop
• Cursor
• Claude Code
• VS Code (GitHub Copilot agent mode)
• Visual Studio 2022 17.14+ / 2026 (GitHub Copilot)
• GitHub Copilot CLI
• Grok Build (xAI CLI)

Installation

Enabling MCP Connector for Civil 3D

After installation, click the MCP Connector button in the Add-ins tab to open the connector dialog, then toggle Enable MCP to start the connection. No licence key is needed for the free tools - the key only unlocks the Pro set.

The dialog shows the status of detected AI applications:

• Ready (Running) - The AI application is configured to reach Civil 3D and is currently open
• Ready - Configured, but the application is not running right now
• Detected - The application is installed but not yet configured; toggle Enable MCP to configure it
• Not Detected - The AI application is not installed on this machine

The indicator at the top of the dialog reads Disabled, Waiting, or Active. Toggling Enable MCP off again removes the connector from every detected client's configuration.

Configuration

MCP Connector for Civil 3D includes one-click auto-configuration for supported AI applications. Toggling Enable MCP in the connector dialog writes the configuration for every detected application at once. The installer also registers the server on install, so in most cases there is nothing to do by hand.

Claude Desktop

The config file is located at:

ChatGPT Desktop

ChatGPT appears in the dialog when it is installed on your machine. The config file is located at:

This file is shared with the Codex CLI, so configuring ChatGPT Desktop makes the Civil 3D tools available in Codex CLI as well. After configuring, fully quit ChatGPT and reopen it. With AutoCAD open and a drawing loaded, a quick test is to ask ChatGPT to "ping AutoCAD".

Use Work, not Chat. ChatGPT Desktop loads MCP servers from this config file in its Work area only - regular Chat conversations cannot see the AutoCAD tools. If ChatGPT replies that the AutoCAD MCP is not connected, check you are in Work first, then start a fresh conversation - the MCP connection is per-conversation and drops after sitting idle.

Cursor

The config file is located at:

GitHub Copilot

GitHub Copilot appears in the dialog when VS Code, Visual Studio, or the Copilot CLI is installed on your machine. The config files are located at:

Grok Build

Toggle Enable MCP and the connector writes its entry into xAI's Grok Build CLI configuration automatically. The config file is located at:

Grok Build also reads Claude Code's and Cursor's MCP config, so if you have already configured either of those the connector shows up in Grok Build with no extra step.

Claude Code & other MCP clients

MCP Connector for Civil 3D exposes a standard MCP stdio server, so it also works with Claude Code, VS Code, and any other MCP-compatible client. The server is a single executable installed with the plug-in bundle:

Register it in Claude Code from a terminal:

Manual configuration (any MCP client)

Add this to your client's MCP server configuration:

{
  "mcpServers": {
    "AUTOM8LABS_Civil3D": {
      "command": "C:\\Program Files\\Autodesk\\ApplicationPlugins\\AUTOM8LABS.MCPConnectorCivil3D.bundle\\Contents\\Bridge\\MCPConnectorCivil3D.Bridge.exe"
    }
  }
}

VS Code

VS Code uses a slightly different shape. Add the server to your MCP configuration (for example .vscode/mcp.json in a workspace):

{
  "servers": {
    "AUTOM8LABS_Civil3D": {
      "type": "stdio",
      "command": "C:\\Program Files\\Autodesk\\ApplicationPlugins\\AUTOM8LABS.MCPConnectorCivil3D.bundle\\Contents\\Bridge\\MCPConnectorCivil3D.Bridge.exe"
    }
  }
}

Optional: raw command execution

Two tools can drive the host directly: execute_command runs a raw command string as if typed at the command line, and execute_lisp evaluates an AutoLISP expression. Because they can drive anything, both are disabled by default: they are neither listed nor callable until you opt in on that machine by setting MCP_CONNECTOR_ENABLE_COMMAND_EXEC=1 in the MCP client configuration. Even when enabled, code-loading and shell verbs (NETLOAD, APPLOAD, SCRIPT, SHELL, AutoLISP load) are blocked. Both tools are Pro, so a licence is needed as well as the opt-in.

After saving the configuration, fully quit and reopen your AI client - quit it from the system tray rather than just closing the window, or it keeps the old environment and the two tools still will not appear. To turn them off again, remove the setting and restart the client the same way.

{
  "mcpServers": {
    "AUTOM8LABS_Civil3D": {
      "command": "C:\\Program Files\\Autodesk\\ApplicationPlugins\\AUTOM8LABS.MCPConnectorCivil3D.bundle\\Contents\\Bridge\\MCPConnectorCivil3D.Bridge.exe",
      "env": {
        "MCP_CONNECTOR_ENABLE_COMMAND_EXEC": "1"
      }
    }
  }
}

Optional: read-only session

A read-only session withholds every tool that can change a drawing, leaving the free read-only set: query, inspect, measure and navigate. A withheld tool is not listed to the AI client at all, and is refused by name if it is called anyway, so the AI cannot reach a write.

It is worth using whenever the drawings belong to a client rather than to you. DWG is usually the format that arrives from someone else. An in-session change can still be undone in Civil 3D, but the folder tools save each drawing as they go, so those edits are on disk already - and an unwanted change does not always announce itself on screen.

Turn it on with the Read-Only Session checkbox in the connection dialog, or by running MCPCONNECTORC3D_READONLY at the Civil 3D command line. Either way, reconnect your AI client afterwards so it refreshes its tool list.

Locking it on for a team. An administrator can enforce read-only across a machine, so it applies to every user and cannot be switched off locally. That is a deployment setting rather than something to set up per seat - get in touch and we will send you the policy and how to apply it.

Claude Desktop Settings

MCP Connector for Civil 3D exposes 189 tools, plus two optional command-execution tools that stay disabled until you opt in. In Claude Desktop, enable Load tools when needed so tools are loaded on demand rather than all at once.

Use Chat, not Cowork

Claude Desktop has a mode selector at the bottom of the message box: Chat and Cowork. MCP connectors run in Chat conversations. In Cowork, your AutoCAD requests will not reach the connector and Claude behaves as if AutoCAD is not connected - even though the connector is configured correctly. Before you start, check the selector is set to Chat.

Note this is the opposite way round to ChatGPT Desktop, where the Civil 3D tools are available in Work rather than regular Chat.

Operator Skill

An operator skill is a plain text playbook Claude reads before touching your drawing. It teaches Claude to use the connector efficiently: read in bulk instead of one entity at a time, verify answers with counts, batch edits in one call, and say so instead of guessing when something cannot be done. The result is fewer calls, fewer dead chats, and far less of your usage allowance burned on a single question.

The free AutoCAD operator skill covers the drawing tools this connector inherits, which is most of the tool set, so it is worth installing. A skill for the Civil design tools is in progress.

Install in Claude Desktop:

1. Download the skill: autocad-connector.zip
2. In Claude Desktop, go to Settings > Skills > Add > Upload a skill and select the zip.
3. That is it - Claude picks the skill up automatically in new chats. If you ever find it has not, mention it in your prompt, for example "Follow the autocad-connector skill".

Using Claude Code or Cursor instead? Install steps for both are in the mcp-connector-skills repository, which also hosts free skills for the rest of the MCP Connector family.

Quickstart

Tool Reference

MCP Connector for Civil 3D serves two sets of tools, grouped by category below. The Civil design tools come first, then the AutoCAD drawing tools the connector inherits, including a read-only free tier that works without a licence. Every tool name shown is the exact identifier exposed to your AI client. The Edition column shows whether a tool is available in the free edition or needs a Pro licence. A tool marked Opt-in does not register at all until you enable it - see raw command execution. Under each description is an example prompt showing how to ask for it in natural language - click any prompt to copy it, paste it into your AI client, and adjust the names and numbers to suit your drawing.

Civil design objects

These tools exist only because the host is Civil 3D. Every one of them needs a Pro licence. Anything that edits objects in bulk previews the change and reports what it would do before it writes, so you approve the edit rather than discover it.

Civil: Overview

Civil: Surfaces

Civil: Alignments

Civil: Profiles and profile views

Civil: Pipe and duct networks

Civil: Crossings and clearance

Civil: COGO points

Civil: Sample lines and sections

Civil: Corridors, parcels and feature lines

Civil: Styles, layers and standards

Civil: Labels

Civil: Export and utility

Connectivity

Drawing and Document

Entities and Selection

Geometry Creation

3D Solids

Modification

Layers

Blocks

Annotation

Views and Navigation

Layouts and Plotting

Styles

External References

UCS

Search and Text

Utility and Measurement

Management Pack

Folder-batch tools for whole-project maintenance. Each one runs over every drawing in a folder using a side database, so your open drawing is never disturbed. Write operations are safe by default: a dry-run mode previews what would change without modifying any file.

Troubleshooting

The AI says it is not connected to Civil 3D

• Civil 3D must be running with a drawing open. The connector talks to a live session; it cannot open Civil 3D for you.
• In Civil 3D, run MCPCONNECTORC3D_STATUS to check the plug-in state. If it reports not running, run MCPCONNECTORC3D_START.
• Ask your AI to run the ping tool. It reports whether the link is up and, if not, why.

The plug-in did not load

• The plug-in auto-loads when Civil 3D starts. If the AUTOM8LABS ribbon is missing, restart Civil 3D, then run MCPCONNECTORC3D_START at the command line.
• Confirm the bundle exists at C:\Program Files\Autodesk\ApplicationPlugins\AUTOM8LABS.MCPConnectorCivil3D.bundle. If it is missing, re-run the installer.
• Check that your Civil 3D release is 2024, 2025, 2026 or 2027. Earlier releases are not supported.

Pro tools are missing after activating

• The MCP server reads the edition once, when the AI client starts it. Restart the AI client after activating and the full tool list appears.
• Confirm the licence state in Civil 3D via Manage Licence on the AUTOM8LABS ribbon.

The AI client does not list the server

• Restart the client completely after installing; a window reload is not always enough.
• For clients other than Claude Desktop, ChatGPT Desktop, and Cursor, add the manual configuration yourself.

execute_command or execute_lisp is not available

• Both tools are off by default and do not register at all until you opt in. Set MCP_CONNECTOR_ENABLE_COMMAND_EXEC=1 in the MCP client configuration, then fully quit and reopen the client from the system tray. See Raw command execution.
• They are Pro tools, so they also need an active licence. If the opt-in is set and they still do not appear, check the licence first.

FAQ

Changelog