diff --git a/engraphis/service.py b/engraphis/service.py
index d2b439b..28dd4ad 100644
--- a/engraphis/service.py
+++ b/engraphis/service.py
@@ -40,7 +40,7 @@
 from engraphis.core.graph_layers import normalize_graph_layer
 from engraphis.core.ids import new_id as make_id
 from engraphis.core.interfaces import Edge, GraphLayer, MemoryType, Node, Scope, SearchFilter
-from engraphis.core.store import normalize_entity_name
+from engraphis.core.store import _loads, _merge_edge_provenance, normalize_entity_name
 from engraphis.graphdata import build_graph_payload, empty_graph
 
 # ── validation limits (memory-poisoning / resource-exhaustion guards) ──────────
@@ -2307,14 +2307,79 @@ def _new_repo(old_repo_id):
             )
 
         # 3) Edges: relabel workspace/repo, remapping any entity ids folded in step 2.
+        #    When a live source edge collides with an existing live target edge (same
+        #    src/dst/relation/layer/repo), merge metadata instead of violating the
+        #    partial unique index — mirrors Store._deduplicate_live_edges().
         src_edges = [dict(x) for x in c.execute(
-            "SELECT id, repo_id, src, dst FROM edges WHERE workspace_id=?", (wid_src,))]
+            "SELECT id, repo_id, src, dst, relation, layer, weight, provenance, "
+            "valid_from, ingested_at, valid_to, expired_at "
+            "FROM edges WHERE workspace_id=?", (wid_src,))]
         for ed in src_edges:
-            c.execute(
-                "UPDATE edges SET workspace_id=?, repo_id=?, src=?, dst=? WHERE id=?",
-                (wid_dst, _new_repo(ed["repo_id"]),
-                 entity_remap.get(ed["src"], ed["src"]), entity_remap.get(ed["dst"], ed["dst"]),
-                 ed["id"]))
+            new_src = entity_remap.get(ed["src"], ed["src"])
+            new_dst = entity_remap.get(ed["dst"], ed["dst"])
+            new_repo = _new_repo(ed["repo_id"])
+            is_live = ed["valid_to"] is None and ed["expired_at"] is None
+            target = None
+            if is_live:
+                # Check for a live target edge with the same identity.
+                if new_repo is not None:
+                    target = c.execute(
+                        "SELECT id, weight, provenance, valid_from, ingested_at "
+                        "FROM edges WHERE workspace_id=? AND repo_id=? AND src=? "
+                        "AND dst=? AND relation=? AND layer=? "
+                        "AND valid_to IS NULL AND expired_at IS NULL LIMIT 1",
+                        (wid_dst, new_repo, new_src, new_dst,
+                         ed["relation"], ed["layer"]),
+                    ).fetchone()
+                else:
+                    target = c.execute(
+                        "SELECT id, weight, provenance, valid_from, ingested_at "
+                        "FROM edges WHERE workspace_id=? AND repo_id IS NULL "
+                        "AND src=? AND dst=? AND relation=? AND layer=? "
+                        "AND valid_to IS NULL AND expired_at IS NULL LIMIT 1",
+                        (wid_dst, new_src, new_dst,
+                         ed["relation"], ed["layer"]),
+                    ).fetchone()
+            if target:
+                # Merge: keep target as survivor, retire source edge.
+                closed_at = time.time()
+                src_prov = _loads(ed["provenance"], {})
+                tgt_prov = _loads(target["provenance"], {})
+                merged_prov = _merge_edge_provenance(
+                    [tgt_prov, src_prov], merged_ids=[ed["id"]])
+                merged_weight = max(
+                    float(ed["weight"] or 0.0),
+                    float(target["weight"] or 0.0))
+                valid_vals = [v for v in (target["valid_from"], ed["valid_from"])
+                              if v is not None]
+                ingested_vals = [v for v in
+                                 (target["ingested_at"], ed["ingested_at"])
+                                 if v is not None]
+                c.execute(
+                    "UPDATE edges SET weight=?, provenance=?, "
+                    "valid_from=?, ingested_at=? WHERE id=?",
+                    (merged_weight,
+                     json.dumps(merged_prov, ensure_ascii=False),
+                     min(valid_vals) if valid_vals else None,
+                     min(ingested_vals) if ingested_vals else None,
+                     target["id"]))
+                # Move live edge_supports from source to target.
+                c.execute(
+                    "UPDATE edge_supports SET edge_id=? WHERE edge_id=? "
+                    "AND valid_to IS NULL AND expired_at IS NULL",
+                    (target["id"], ed["id"]))
+                # Bi-temporally close the source edge.
+                src_prov["canonical_deduplicated_into"] = target["id"]
+                c.execute(
+                    "UPDATE edges SET valid_to=?, expired_at=?, "
+                    "provenance=? WHERE id=?",
+                    (closed_at, closed_at,
+                     json.dumps(src_prov, ensure_ascii=False), ed["id"]))
+            else:
+                c.execute(
+                    "UPDATE edges SET workspace_id=?, repo_id=?, src=?, dst=? "
+                    "WHERE id=?",
+                    (wid_dst, new_repo, new_src, new_dst, ed["id"]))
 
         # 4) Memories / sessions / events: relabel workspace/repo per distinct repo_id
         #    bucket (ids, content and history are untouched).