Unrecognized configuration parameter when using set_config(text, text, boolean) in CTE

I'm trying to implement a simple ABAC system using row level security, with main policy defined as following:

CREATE policy resource_access ON resourceUSING (  (    org_id::varchar = current_setting('scope.org.id', true)  )  AND   (    acl_read && regexp_split_to_array(current_setting('scope.acl'), ',')::varchar[]  ))

Issuing queries akin to:

WITH   acl AS (SELECT set_config('scope.acl', 'ACL', true) "__acl"),   result AS ( ... )SELECT * FROM acl, result

With the main reason to use WITH is to avoid multiple statements when queries are later PREPAREd and EXECUTEd by the Postgres driver I'm using.

The result in example above can contain any arbitrary queries required by the application. To ensure that set_config is executed in the query, it's also added to the final SELECT.

However, I still do consistently encounter the following error:

QueryFailedError: unrecognized configuration parameter "scope.acl"

Which appears to be caused by executing the subquery from WITH in isolation from the result query.

So the main questions are:

• Is there any elegant way to ensure running set_config before the main query (the one in result) is executed?
• Is there any better way to construct queries for the application side, to avoid using WITH, but keeping them as a single SQL statement?

Thank you!