IFC Core MCP Server

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MCP server for IFC4.3 specification reference — search and retrieve IFC entity definitions, attributes, inheritance hierarchies, and PropertySets.

Unlike existing IFC-related MCP servers that operate on IFC model files (parse, extract, modify), this server provides access to the IFC specification itself as a structured reference. It enables AI to look up the correct definitions of entities, attributes, types, and constraints defined in the IFC4.3 standard (ISO 16739-1:2024).

Key Features

• Entity Search — find IFC entities by name or description keyword

• Entity Definition — retrieve complete definitions with attributes, inheritance, WHERE rules, and documentation

• Inheritance Tree — visualize ancestor chains and descendant hierarchies

• PropertySet Lookup — get or search PropertySet definitions with full documentation

• Dual Output — every tool supports both Markdown (human-readable) and JSON (structured) formats

• Pagination — configurable limit/offset for large result sets

Related MCP server: rdf-mcp

Available Tools

Scope

What this MCP provides

• IFC4.3 specification reference: entity definitions, attributes, inheritance, WHERE rules, PropertySet definitions

• Structured lookup of the IFC standard (ISO 16739-1:2024) — a vocabulary/dictionary for AI

• Dual output (Markdown / JSON) suitable for both human reading and programmatic consumption

What this MCP does NOT provide

• IFC file (.ifc) parsing or extraction — use IfcOpenShell (Python) or web-ifc (TypeScript/WebAssembly) instead

• Geometry rendering or 3D visualization

• Schema version migration (IFC2x3 / IFC4 → IFC4.3) — currently IFC4.3 only

• Quantity information (Qto_*) — planned for a future release

If you need to operate on actual .ifc files at runtime, combine this MCP (for specification lookup) with a file-operation library (for data extraction).

Installation

npm (global)

npm install -g @shuji-bonji/ifc-core-mcp

Claude Desktop

Add the following to your claude_desktop_config.json:

{
  "mcpServers": {
    "ifc-core": {
      "command": "npx",
      "args": ["-y", "@shuji-bonji/ifc-core-mcp"]
    }
  }
}

Claude Code

claude mcp add ifc-core -- npx -y @shuji-bonji/ifc-core-mcp

From source

git clone https://github.com/shuji-bonji/ifc-core-mcp.git
cd ifc-core-mcp
npm install
npm run build
node dist/index.js

Running manually (after global install)

After npm install -g @shuji-bonji/ifc-core-mcp, the server can be started with:

ifc-core-mcp

The process communicates over stdio (MCP standard transport) and is intended to be launched by an MCP client (Claude Desktop, Claude Code, etc.) rather than invoked directly for interactive use.

Example Usage

Once installed, you can ask an MCP-enabled LLM (e.g., Claude) questions such as:

• "What attributes does IfcSpace have in IFC4.3?"

• "Show me the inheritance hierarchy from IfcBuildingElement down to leaf subtypes."

• "Find all IFC entities related to HVAC."

• "What PropertySets apply to IfcWall, and what properties do they contain?"

• "What is the definition of IfcMapConversion, and which attributes store CRS information?"

The LLM will invoke the appropriate tool (ifc_search_entity, ifc_get_entity, ifc_get_inheritance, or ifc_get_propertyset) and return structured results.

Data Coverage

The server covers the complete IFC4.3 schema:

Entities are organized across 4 IFC layers:

Architecture

Build time (one-time, Python):
  IFC.exp (EXPRESS schema) → ifc4x3-schema.json
  IFC4.3.x-development Markdown → ifc4x3-descriptions-*.json

Runtime (TypeScript MCP server):
  Pre-built JSON files → Map-based indexes → MCP tools

The server loads three pre-built JSON data files at startup and builds in-memory indexes (Maps) for O(1) entity lookups by name. The EXPRESS schema provides structural data (types, attributes, inheritance, WHERE rules), while the Markdown documentation provides semantic data (definitions, usage, history).

Data Sources & Licenses

• EXPRESS schema (IFC.exp) — from buildingSMART/IFC4.3.x-output

• Markdown documentation — from buildingSMART/IFC4.3.x-development

• IFC specification content is licensed under CC BY-ND 4.0 by buildingSMART International

Development

Prerequisites

• Node.js >= 22.12 (22 and 24 are verified in CI)

• Python 3 + IfcOpenShell (only for data regeneration)

Commands

npm run build          # Compile TypeScript
npm run dev            # Watch mode with tsx
npm test               # Run all tests (unit + e2e)
npm run test:unit      # Unit tests only
npm run test:e2e       # E2E integration tests
npm run lint           # Biome lint
npm run format         # Biome formatting
npm run check          # Biome lint + format + import order (used in CI)
npm run prepare-data   # Regenerate data from raw sources (requires Python)

Connecting a local build to Claude Desktop

To test changes before publishing, point Claude Desktop at the built file instead of the npm package. Add an entry with a distinct name (for example ifc-core-dev) to claude_desktop_config.json, using the absolute path to your clone:

{
  "mcpServers": {
    "ifc-core-dev": {
      "command": "node",
      "args": ["/absolute/path/to/ifc-core-mcp/dist/index.js"]
    }
  }
}

Notes:

• dist/ is not rebuilt automatically. After editing src/, run npm run build and restart Claude Desktop. (npm run dev keeps stdio for its own watcher, so it cannot be used as the Desktop entry point.)

• Claude Desktop is launched from the GUI, so node installed via nvm / volta may not be on its PATH. If the server fails to start, replace "command": "node" with the absolute path printed by which node.

Tech Stack

• Runtime: TypeScript 7 (strict), Node.js

• MCP SDK: @modelcontextprotocol/server v2 (serveStdio; serves both the 2025 and 2026-07-28 protocol revisions)

• Validation: Zod 4

• Testing: Vitest (unit + e2e with actual MCP client)

• Linting / Formatting: Biome

• CI/CD: GitHub Actions (lint → test → build → publish)

Roadmap

This server focuses on the IFC4.3 schema itself. Potential future directions under consideration:

• QuantitySet (Qto_*) support — add quantity definitions alongside PropertySets

• ifcJSON schema — complement the current EXPRESS-derived data

• Cross-version lookup — map IFC2x3 / IFC4 → IFC4.3 entities

• Sister MCP for IFC file operations — a separate project (planned, not yet released) for parsing and querying actual .ifc files, designed to pair with this reference server

Feedback and use-case reports are welcome via GitHub Issues.

Related Projects

• w3c-mcp — MCP server for W3C/WHATWG/IETF web specifications

• rfcxml-mcp — MCP server for IETF RFC documents (XML-based)

• epsg-mcp — MCP server for EPSG coordinate reference systems (useful when combined with IfcMapConversion)

License

MIT