rockwell-logix-mcp

An MCP server that exposes Rockwell Automation's Logix Designer SDK as 39 tools for programmatic ControlLogix / CompactLogix engineering — plus six skills that document how to use it well. Create and build Studio 5000 projects, generate L5X from a points list, read/write tags, resolve comm paths and (safely, confirm-gated) go online / download, publish or simulate telemetry over any protocol, and run FAT/SAT acceptance suites.

Unofficial / community project. Not affiliated with or endorsed by Rockwell Automation. "Logix Designer", "Studio 5000", "ControlLogix", "CompactLogix" are trademarks of Rockwell Automation. You must hold your own Studio 5000 and Logix Designer SDK licenses.

What's here

• server.py — the MCP server (Python mcp 2.x, stdio transport); 39 tools.

• l5xgen.py — pure-Python L5X code generation using a clone-and-splice approach.

• telemetry.py — any-protocol telemetry: simulate, publish (MQTT, OPC UA), live read (EtherNet/IP).

• fatsat.py — FAT/SAT assertion operators + report formatting.

• skills/ — six skills: rockwell-sdk-setup, rockwell-logix-mcp, rockwell-l5x-codegen, rockwell-build-commission, rockwell-telemetry, rockwell-fat-sat.

Related MCP server: LogixDesigner-MCP

Prerequisites (you provide these)

This server drives an installed Rockwell toolchain; it does not bundle it.

• Windows with Studio 5000 Logix Designer v37+ and the Logix Designer SDK 2.02+ installed. The SDK's LdSdkService must be running (gRPC, default port 53204).

• Python 3.12+ (64-bit).

• The LDSDK Python wheel from your SDK installation (not redistributed here):

  pip install "C:\Users\Public\Documents\Studio 5000\Logix Designer SDK\python\logix_designer_sdk-2.0.2-py3-none-any.whl"

• The rest: pip install -r requirements.txt

The two DOTNET_ROOT variables (the #1 setup gotcha)

The SDK loads .NET in-process (64-bit) and spawns a 32-bit helper (FtspAdapterLDSDK.exe), so set both machine-wide, pointing at the real runtime roots (modern .NET installs use an architecture subfolder, not dotnet\shared):

setx DOTNET_ROOT "C:\Program Files\dotnet\x64" /M
setx "DOTNET_ROOT(x86)" "C:\Program Files (x86)\dotnet" /M

Set only DOTNET_ROOT and the 32-bit helper tries to load the 64-bit host and dies with 0x800700C1, which surfaces in Python as LogixSdkError: The operation has timed out. The rockwell-sdk-setup skill has the full troubleshooting guide.

Run

run-mcp.cmd sets the env vars and starts the server over stdio. Register it with your MCP client as a stdio server (command: the path to run-mcp.cmd); the tools appear after the client reconnects.

Tools by area

• Lifecycle / build: create_project, open_project, convert_project, save_project, save_project_as, export_l5x, close_project, change_controller_type, build_project, get_processor_types, list_open_projects, server_info.

• L5X: partial_export_xml, partial_import_xml, partial_import_rungs, parse_l5x (enumerate — the SDK can't list tags), generate_project_from_points, validate_l5x, diff_l5x.

• Tags: read_tag, write_tag (OFFLINE project values or ONLINE live; bare names auto-resolve to the tag's XPath).

• Comms / online (confirm-gated): build_comm_path, set_comm_path, get_comm_path, read_connected_state, read_controller_mode, go_online, go_offline, change_controller_mode, download, upload, upload_to_new_project.

• Telemetry: simulate_telemetry, telemetry_selftest (in-process OPC UA round-trip, no hardware), publish_telemetry_mqtt, read_logix_telemetry.

• FAT/SAT: run_fat_suite, run_fat_suite_telemetry, controller_health.

Safety

Operations that change a controller — download, change_controller_mode, online writes, go_online, upload — are confirm-gated: without confirm=true they return a dry-run plan and do nothing. Always dry-run, confirm the exact target (IP + slot), then execute. A download overwrites the controller's running program; a move to RUN energizes outputs and actuates equipment.

How code generation works

l5xgen clones a bare, valid project (exported from the SDK) as a template and splices in generated <DataType>, <Tag>, and <Program> elements — so the result compiles, without hand-authoring the large controller/module boilerplate. Prove any generated project with validate_l5x, which opens and compiles it. See the rockwell-l5x-codegen skill.

License

MIT — see LICENSE.