Codesys MCP Server

A Model Context Protocol (MCP) server for CODESYS V3 programming environments.

Local serverstdioPython

What is the Codesys MCP server?

Codesys mcp server connects Codesys to AI assistants that speak the Model Context Protocol. A Model Context Protocol (MCP) server for CODESYS V3 programming environments.

What Codesys does

A Model Context Protocol (MCP) server for CODESYS V3 programming environments. This toolkit enables seamless interaction between MCP clients (like Claude Desktop) and CODESYS, allowing automation of project management, POU creation, code editing, and compilation tasks via the CODESYS Scripting Engine.

Tools it exposes

Once connected, the assistant can call these 4 tools directly:

  • codesys — //project/status: Check scripting status and currently open project state
  • Node.js — Version 18.0.0 or later is recommended
  • Cause — ** This typically happens when the tool is launched via npx within an environment like Claude Desktop. The execution environment (PATH variable) provided to
  • Solution — ** Configure your MCP Client to run the command directly ("command": "codesys-mcp-tool") instead of using "command": "npx". See the **Recommended

Installing the codesys mcp server

The server is distributed via npm as @codesys/mcp-toolkit, so most clients can run it without a manual build step. Add it to your MCP client's configuration and restart the client to pick it up — the copy-paste configs for Claude Desktop, Claude Code and Cursor are on this page.

Configuration

The server reads one environment variable: CODESYS_PATH. Keep credentials in your client's env block or a secrets manager rather than committing them.

Where it fits

Developer-tool servers are usually the first ones people connect, because they turn "help me with this code" into an assistant that can actually read the repo and act on it. Codesys sits in that group, and the shape of its toolset — codesys, Node.js, Cause among others — tells you what it is really for. Worth comparing against the other developer tools servers in this directory before you commit to one, since several overlap in scope but differ sharply in setup cost and permissions.

Practical notes

  • This server runs locally, so it operates with whatever access your machine and its credentials already have. Scope that deliberately rather than by default.
  • Written in Python.
  • MCP clients ask for confirmation before each tool call by default. Keep that on while you learn what the codesys mcp server actually does with your data.
  • Every entry in this directory is reviewed by hand before it goes live, and details are checked against the project's own documentation.

Available tools

ToolWhat it does
codesys//project/status: Check scripting status and currently open project state.
Node.jsVersion 18.0.0 or later is recommended.
Cause** This typically happens when the tool is launched via npx within an environment like Claude Desktop. The execution environment (PATH variable) provided to the process likely causes an internal CODESYS command (like run
Solution** Configure your MCP Client to run the command **directly** ("command": "codesys-mcp-tool") instead of using "command": "npx". See the **Recommended Configuration Method** section above.

How to install the Codesys MCP server

{
  "mcpServers": {
    "codesys-mcp-toolkit": {
      "command": "npx",
      "args": ["-y", "@codesys/mcp-toolkit"],
      "env": {
        "CODESYS_PATH": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
CODESYS_PATHFilesystem location the server is allowed to use.Optional

Example prompts to try

  • Use Codesys to codesys.
  • Use Codesys to Node.js.
  • Use Codesys to Cause.

Frequently asked questions

It connects Codesys to MCP-compatible AI assistants such as Claude and Cursor, exposing 4 tools (codesys, Node.js, Cause, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Codesys directly.