OpenID connect and JWT plugin integration

I’m trying to connect Caddy with JWT plugin to external auth provider what implements OpenID Connect protocol (keycloak).

The problem is the external provider after successful login redirects back with an issued token in URI fragment, like:
Location: https://myhost/#access_token=token_here&param1=value1
While the JWT plugin accepts tokens only in header, cookie or query.

My question: is where any hint / solution to transform fragment from URI into a cookie on the Caddy side?
OR should I write my own plugin to support this communication?

Thanks for your time!