Hi Take a look at the PersonAuthentication script where the intent id is set in the first place in the line identity.setWorkingParameter("openbanking_intent_id", "the value").
The flow is as follows
1. When /authorize endpoint is called, the openbanking_intent_id is set in the request object / URL parameters.
2. It is extracted in the person authentication script and set to session.
3. When the introspection scripts / update token script (for retaining id_token claims) are called, these values are set in the claims which are a part of access token , id_token respectively.