isValidForRead

Whether this level is valid as the regular (non-serial) consistency of a read operation.

EACH_QUORUM is the only level here Cassandra/Scylla reject for reads — it's a write-only, multi-DC level; the coordinator errors out server-side ("EACH_QUORUM ConsistencyLevel is only supported for writes") rather than executing the read. Every other level, including SERIAL/LOCAL_SERIAL (which perform a linearizable read), is valid here.

See resolveReadConsistency in kandra-runtime's StatementBuilder (validated at the point a read consistency is resolved from a per-call override / @ReadConsistency / defaultRead) and kandra-ktor's Kandra plugin (validated eagerly for consistency { defaultRead = ... } at install time, before any query runs).