direct_conversation_slot_already_committed· reason_code· applies to service_call, federation_transactionThe founder's current Station already closed its local (founder_id, trust_domain_id, pair_key) founding slot with a different unit, so this unit is refused with zero writes. Carried under conflict. The caller MUST re-resolve the existing coordinates through ak.self.direct_conversation.read.resolve.v1 instead of authoring another unit; the service MUST NOT accept a second unit, degrade it to a partial acceptance or quarantine it. A byte-identical replay of the committed unit is not this code: it returns the same four byte-identical source RealmCommits without changing the fourth committed_at. See zh/identity/contact-and-direct-conversation.md section 5.5.