DWG MCP Server

DWG MCP Server is an MCP server for inspecting AutoCAD DWG files with AI agents and assistants. It provides read-only access to drawing contents as queryable objects. Agents can open a DWG, inspect available types, fetch objects by handle, and query properties, scopes, and references.

Quick Start

Use DWG MCP Server from the MCP client of your choice. The npm package launches the published Docker image. The Docker launcher mounts $HOME by default. For drawings outside $HOME, set DWG_MCP_DOCKER_MOUNTS.

If your MCP client, AI agent, or test harness does not support MCP roots, set DWG_MCP_ALLOWED_ROOTS to the folders that should be accessible.

Codex

codex mcp add dwg-mcp \
  --env DWG_MCP_ALLOWED_ROOTS="$HOME" \
  -- npx -y @dmytro-prototypes/dwg-mcp-server

Codex does not currently provide MCP client roots to stdio MCP servers. Configure explicit allowed roots for the folders that contain your drawings.

Claude

claude mcp add --scope user --transport stdio dwg-mcp -- npx -y @dmytro-prototypes/dwg-mcp-server

Claude Code provides MCP roots, so no extra path variable is usually needed.

Cursor

{
  "mcpServers": {
    "dwg-mcp": {
      "command": "npx",
      "args": ["-y", "@dmytro-prototypes/dwg-mcp-server"]
    }
  }
}

Exposed Tools

A typical flow is:

1. Discover available folders with dwg.list_roots.
2. Open a file from one of those folders with dwg.open_file.
3. Inspect supported or file-local types with dwg.list_types, dwg.list_file_types, or dwg.describe_type.
4. Fetch known handles with dwg.get_objects or search the drawing with dwg.query_objects.
5. Close the session with dwg.close_file.

Architecture

Runtime model

In the packaged deployment, DWG MCP Server is a stdio MCP server implemented in Python and typically run inside a Linux container. The Python host exposes the MCP tools, validates file access, and manages document sessions.

Each dwg.open_file call starts a dedicated Rust dwg-worker process for that DWG and returns a host-side documentId. All later file-scoped calls use that document id. dwg.close_file terminates the worker for that session.

Worker and query model

The Rust worker speaks newline-delimited JSON over stdin and stdout. When it opens a DWG through LibreDWG, it first builds an in-memory indexed document. That upfront indexing step is central to the design: the server pays the cost once when the file is opened, then answers later requests against the index instead of rescanning the DWG each time.

The indexed model stores object handles, kinds, type names, generic types, summary and full properties, and derived block, layout, and space membership. It also stores supported type metadata such as aliases, default projections, and property definitions.

When you request full object records, responses also include that derived membership under extendedData, including container block, layout, and model or paper space when known.

dwg.get_objects is direct lookup by handle. dwg.query_objects runs over indices for handle, type, generic type, kind, exact property values, block, layout, and space, then applies filters,

... View full README on GitHub