LCS CAD MCP

An MCP (Model Context Protocol) server that exposes Pre-DCR and Auto-DCR building scrutiny workflows as AI-consumable tools. Designed to let AI assistants (Claude, etc.) open DXF drawings, validate layer conventions, compute areas, run regulatory rule checks, and generate compliance reports — all via natural language.

What it does

• PreDCR setup — creates standardised layers (PREDCR-WALL-EXT, PREDCR-PLOT, etc.) and validates drawings against authority naming conventions

• Entity management — draws polylines, lines, arcs, circles, text and blocks; moves, copies, deletes and queries entities

• Area computation — calculates plot area, built-up area, carpet area, FSI and ground coverage using Shapely polygons

• AutoDCR scrutiny — evaluates FSI, ground coverage, setbacks, parking ratios and height restrictions against loaded DCR rule configs

• Report generation — produces PDF, DOCX and JSON compliance reports

• Workflow archival — stores scrutiny runs, tool events and audit trails in SQLite

Related MCP server: AutoCAD MCP Pro

Architecture

src/lcs_cad_mcp/
├── modules/
│   ├── cad/          # Drawing lifecycle (open, new, save, backend selection)
│   ├── layers/       # Layer CRUD + property management
│   ├── predcr/       # PreDCR layer catalog and validation
│   ├── entities/     # Entity draw/query/edit tools
│   ├── verification/ # Closure, containment, naming and count checks
│   ├── area/         # FSI, coverage and area computation (Shapely)
│   ├── config/       # DCR rule config load and validation
│   ├── autodcr/      # Rule evaluation engine + dry-run mode
│   ├── reports/      # PDF/DOCX/JSON report generation
│   └── workflow/     # Pipeline orchestration and audit trail
├── backends/
│   ├── ezdxf_backend.py   # Cross-platform DXF backend (primary)
│   └── com_backend.py     # Windows AutoCAD COM backend (optional)
├── rule_engine/      # DCRConfig Pydantic models + RuleEvaluator
├── archive/          # SQLAlchemy ORM models + repository
└── session/          # DrawingSession context + SnapshotManager

Transport: stdio (default) and SSE supported via FastMCP 3.x.

Requirements

• Python 3.11+

• uv (recommended) or pip

Installation

git clone <repo-url>
cd lcs-cad-mcp
uv sync

For development dependencies (pytest, ruff):

uv sync --extra dev

Running the server

stdio (for Claude Desktop / MCP clients)

uv run python -m lcs_cad_mcp

SSE

uv run python -m lcs_cad_mcp --transport sse --port 8000

Claude Desktop integration

See docs/claude-desktop-config.md for the full config snippet. Quick version:

{
  "mcpServers": {
    "lcs-cad": {
      "command": "uv",
      "args": ["run", "--project", "/path/to/lcs-cad-mcp", "python", "-m", "lcs_cad_mcp"]
    }
  }
}

DCR Rule configs

YAML or JSON configs define the regulatory rules evaluated during scrutiny. Example:

version: "1.0.0"
authority: "MCGM"
effective_date: "2024-01-01"
rules:
  - rule_id: "FSI_001"
    name: "Max FSI"
    rule_type: "FSI"
    threshold: 1.5
    unit: "ratio"
    zone_applicability: ["R1", "R2"]

Sample configs are in dcr_configs/. Full schema: docs/dcr-config-schema.md.

Available MCP tools

Full API reference: docs/tool-api-reference.md.

Testing

uv run pytest

173 tests across unit and integration suites. Backends, services, rule engine and archive are all covered.

Windows / AutoCAD COM backend

The COM backend enables live interaction with a running AutoCAD instance on Windows. See docs/windows-deployment-guide.md.