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Configuration

Shared settings live at %ProgramData%\TwinCat-MCP\settings.json and can be edited from the TwinCat-MCP toolbar Options button (gear icon) — a dockable, tabbed window with General, Safety & Target, Connection, and UserMode Runtime pages (plus Licensing).

Settings

Setting Default Description
ServiceHttpPort 3001 HTTP port for the MCP endpoint. Requires a Service restart to take effect.
ServicePipeName twincat-mcp-service Named pipe used by the plugin to register with the Service.
HeartbeatIntervalSeconds 30 Plugin → Service keep-alive interval.
RequireConfirmation true Prompt before dangerous operations on real hardware.
PreferUmr false Automatically use the UserMode Runtime for dangerous tools, even without an explicit useUmr flag.
CustomInstructions "" Custom prompt text sent to AI agents on connect.

Changing the port

If you change ServiceHttpPort, restart the Service and update your agent's endpoint URL (see Agent Connection) to match the new port.