ak.realm.set_default_strand· realm· active- wire scope
- durable_event
- reducer input
- yes
- payload
- Sets / changes the Realm's authoritative default discussion Strand pointer. payload = {realm_id, strand_id}; reducer projects payload.strand_id into the Realm projection default_strand_id (single authoritative pointer; avoids multi-default dirty state). Reducer MUST verify the referenced strand_id already exists in this Realm (a projected, non-tombstoned Strand); a dangling reference MUST be rejected with failed_precondition. Strand-side is_default is a derived marker (strand_id == realm.default_strand_id), never independent storage; clients discover the default Strand deterministically from the Realm projection default_strand_id or the Strand projection is_default, NOT from any shared-token implementation detail. Authorization is the standard Realm-admin gate (hold ak.realm.admin, or the same-name action ak.realm.set_default_strand).