Since we cannot directly reuse the schema's from Home Assistant (they're in Python), this repository contains a 'copy' of the most used schema's... In Typescript. This means that every time Home Assistant updates their schema's, they have to be updated here as well. So let's quickly go through that process;

Find all the typings in the src/language-service/src/schemas/ folder. They're logically grouped by domain. Create or update the missing classes/properties in one of the Typescript files.

These Typescript files need to be transformed to JSON schema's, these JSON schema files are not part of the codebase. To test your changes, they need to be generated locally at least once. Because this generation takes ±10 seconds, this happens only the first time when running npm run compile. To re-run this generation (to test updates of the typescript files) run npm run schema.