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codesys-mcp-persistent

MCP serverCommunity

Keeps the CODESYS IDE open while an agent edits code, downloads to the PLC and reads or forces live variables. By luke-harriman.

96 starsUpdated 5 months agoGitHub data from 5 Nov 2026

At a glance

Type
MCP server
Works with
CODESYS
How it connects
Drives a running copy of the tool
Access
Can modify models
Tool versions
CODESYS V3.5 SP19 or SP20 for persistent mode; SP21 and later in headless mode only
Operating systems
Windows
Needs a CODESYS licence
Not stated in its documentation
Transport
Local (stdio)
AI clients documented
Claude Code
Licence
MIT
Language
Python

What it can do

  • 41 tools run through a watcher script inside one visible CODESYS instance, so changes appear in the IDE as they happen.
  • Creates POUs, DUTs, GVLs, methods and properties, searches code and renames symbols with a dry-run plan.
  • Logs in to the PLC runtime, downloads (online change or full), starts and stops the application, and reads, writes or monitors variables.

Limitations

  • Persistent mode works only on SP19 and SP20; newer versions spawn a headless CODESYS per call.
  • write_variable forces the value until it is unforced or the runtime restarts.
  • A developer tool, eval_python, runs arbitrary IronPython against the scripting engine.

Install

git clone <repository-url>
cd Codesys-MCP
npm install
npm run build
npm link

Source: github.com/luke-harriman/Codesys-MCP#install

MCP servers and skills run code on your computer. Review the source before installing.

AI-generated models, drawings and results must be checked by a qualified engineer before use.