brick-bacnet-mcp

A read-only BACnet/IP gateway that exposes building automation point databases to LLM agents via MCP, with Brick + Project Haystack semantic tagging at ingest time.

Why this exists

The research note this implementation came out of is at https://habchy.dev/research/bacnet-msi-semantic-gap. A version of the same article is also published at AutomatedBuildings.com (link will be added when the AB.com edition goes live).

Short version: vendor agentic platforms (JCI OpenBlue, Honeywell Forge, Siemens Building X, Tridium Niagara 5) keep their semantic AI layer inside their own controls portfolios. Independent MSIs running mixed-vendor 5-50 building portfolios have BACnet point databases but no clean way to expose them in semantic-tagged form to external LLM agents. This gateway is one answer to that gap.

ezhuk/bacnet-mcp does read and write at the BACnet protocol layer with no semantic normalization. This project sits beside it: it adds the Brick + Haystack tagging step at ingest and restricts the v0.1 surface to read-only for a tighter compliance footprint.

What it does (v0.1)

• Discovers BACnet/IP devices on the local broadcast domain (Who-Is, I-Am)
• Enumerates objects per device (AI, AO, AV, BI, BO, BV, MSI, MSO, MSV, Schedule, Calendar)
• Reads present-value, units, and description per object
• Tags each object with a Brick class and a Haystack tag set using rule-based mapping (rules are extensible via YAML)
• Exposes the tagged topology to any MCP host via four tools: list_devices, list_objects, get_object_value, get_tagged_topology

What it isn't (v0.1)

• Not a write path. WriteProperty is intentionally out of v0.1 for the compliance-surface reasons noted in the research article.
• Not a Niagara station integration. Fox protocol / Niagara module wrapping is a separate design.
• Not an FDD or analytics platform. The tagged topology is meant to be consumed by downstream FDD or LLM-agent workflows. This gateway is the ingest layer only.
• Not a UI. Output is MCP only. Pair it with Claude Desktop, Cursor, or any other MCP host.
• Not BACnet/SC. v0.1 is BACnet/IP only. Secure Connect is a v0.2 consideration.
• Not 223P full schema parity. v0.1 uses the simplified Brick + Haystack mapping. Full 223P entity model is a v0.2 candidate.
• Not multi-site federated. v0.1 handles one broadcast domain at a time.
• Not authenticated. v0.1 runs in a trusted local network environment.

Install

pip install brick-bacnet-mcp

Or from source:

git clone https://github.com/Yveshby27/brick-bacnet-mcp
cd brick-bacnet-mcp
pip install -e .

Python 3.11 or later required.

Quick start

Create a config file config.yaml:

bacnet:
  local_device_instance: 555001
  broadcast_address: 192.168.1.255
  polling_interval_seconds: 30
rules:
  brick: src/brick_bacnet_mcp/rules/brick_rules.yaml
  haystack: src/brick_bacnet_mcp/rules/haystack_rules.yaml
mcp:
  transport: stdio  # or "http" for a hosted MCP host
  http_port: 8080   # only if transport == http
log_level: INFO

Run the MCP server:

brick-bacnet-mcp --config config.yaml

Or wire it into Claude Desktop:

{
  "mcpServers": {
    "brick-bacnet": {
      "command": "brick-bacnet-mcp",
      "args": ["--config", "/path/to/config.yaml"]
    }
  }
}

Example interaction

With the server running and the simulator active (or a real BACnet/IP network reachable), an MCP-capable LLM can run:

User: List all the air-handling units across the building.

Agent (via MCP tool): calls get_tagged_topology(filter="brick:AHU")

Agent response: Found 3 AHUs. AHU-1 has 5 child points (discharge_air_temp, return_air_temp, supply_fan_status, mixed_air_damper_position, outside_air_temp). AHU-2 ... AHU-3 ...

See examples/ for full runnable scripts.

Checking coverage on your building

The starte

... View full README on GitHub