TcKit

AI-assisted development toolchain for TwinCAT 3 PLC engineering.

TcKit connects Claude Code to TwinCAT 3 projects via MCP (Model Context Protocol). Claude can read project structure, write ST code, trigger builds, deploy to targets, run TcUnit tests, and iterate autonomously on failures.

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What it does

Capability	Status
Read project structure, POU interfaces, method bodies	Phase 1
Search Beckhoff infosys documentation	Phase 1
Generate Sphinx docs from RST-commented ST code	Phase 1
Write ST code, add POUs and methods	Phase 2
Build projects, get structured errors	Phase 2
Run TcUnit tests and iterate autonomously	Phase 3

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Quick start

# Clone the repo
git clone https://github.com/turb5/tckit
cd tckit

# Configure
cp docker/.env.example docker/.env
# Edit docker/.env with your paths

# Start the MCP server
docker compose -f docker/docker-compose.yml up

Then add TcKit to your Claude Code MCP config:

{
  "mcpServers": {
    "tckit": {
      "url": "http://localhost:8000/sse"
    }
  }
}

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Design philosophy

TcKit uses a ports & adapters (hexagonal) architecture. Every external concern is abstracted behind a port (Python ABC). Adapters implement ports. The MCP server only calls ports.

The one hard rule: adapters may only import from ports and stdlib. Never from each other.

This means when Beckhoff ships new tooling, you write a new adapter and change one config value. Nothing else changes.

See Architecture → Overview for the full picture.