diff --git a/Service-Bus.md b/Service-Bus.md
index 17cf426..4f1f1bc 100644
--- a/Service-Bus.md
+++ b/Service-Bus.md
@@ -154,6 +154,7 @@ Current topic families:
 | `identity.formed`                 | _reserved (clusterer)_ | `{identity_uuid, observation_uuids: [...], confidence, first_seen_at}` — clusterer creates a new identity from one or more observations |
 | `identity.observation.linked`     | _reserved (clusterer)_ | `{identity_uuid, observation_uuid, confidence_after}` — observation attached / re-attached to an identity |
 | `identity.merged`                 | _reserved (clusterer)_ | `{winner_uuid, loser_uuid, observation_uuids: [...], confidence_after}` — two identities collapsed; subscribers re-key cached references to the winner |
+| `identity.unmerged`               | _reserved (clusterer)_ | `{resurrected_uuid, former_winner_uuid, observation_uuids: [...], reason}` — revocable-merge undo: contradicting evidence cleared `merged_into_uuid`; subscribers should re-split cached references back to the resurrected side |
 | `system.log`                      | _reserved_ | — |
 | `system.bus.health`               | Bus worker heartbeat | `{ts, uptime_s}` |