File

File is a built-in Home Assistant integration that writes notifications to a local file and reads values from files into sensors. It adds a notifier that appends messages to a chosen file path, with an option to add a timestamp to each notification. It also adds a sensor that takes its value from a local file, with a unit of measurement and a value template that renders the state from the file content. A read file action returns the contents of a file, which is useful in automations and scripts. Everything runs locally, and setup and later changes to options happen in the UI.