I suppose all-or-none could work in my case. So I could “query” the schema if it’s using keyword keys.. It looks like :encode is only handed the key so it wouldn’t have the context to decide what to turn it into (keyword or leave as-is).

by default, it encodes/decodes all keys. the transformers can see the schema, so it’s not hard to create a variant / option just to use the keys defined. m/strip-extra-keys-transformer is an example of looking into defined keys