diff --git a/nexus/mnemosyne/FEATURES.yaml b/nexus/mnemosyne/FEATURES.yaml
index 5c3ae14c..e009669d 100644
--- a/nexus/mnemosyne/FEATURES.yaml
+++ b/nexus/mnemosyne/FEATURES.yaml
@@ -67,7 +67,7 @@ modules:
   cli:
     status: shipped
     files: [cli.py]
-    description: CLI interface — stats, search, ingest, link, topics, remove, export, clusters, hubs, bridges, rebuild, tag/untag/retag, timeline, neighbors
+    description: CLI interface — stats, search, ingest, link, topics, remove, export, clusters, hubs, bridges, rebuild, tag/untag/retag, timeline, neighbors, consolidate
 
   tests:
     status: shipped
@@ -182,9 +182,12 @@ planned:
       - "#TBD"  # Will be filled when PR is created
 
   memory_consolidation:
-    status: planned
+    status: shipped
+    files: [archive.py, cli.py, tests/test_consolidation.py]
     description: >
       Automatic merging of duplicate/near-duplicate memories
       using content_hash and semantic similarity. Periodic
       consolidation pass.
     priority: low
+    merged_prs:
+      - "#1260"
diff --git a/nexus/mnemosyne/archive.py b/nexus/mnemosyne/archive.py
index c2526bcd..16b145c2 100644
--- a/nexus/mnemosyne/archive.py
+++ b/nexus/mnemosyne/archive.py
@@ -938,6 +938,127 @@ class MnemosyneArchive:
             "vibrant_count": vibrant_count,
         }
 
+    def consolidate(
+        self,
+        threshold: float = 0.9,
+        dry_run: bool = False,
+    ) -> list[dict]:
+        """Scan the archive and merge duplicate/near-duplicate entries.
+
+        Two entries are considered duplicates if:
+        - They share the same ``content_hash`` (exact duplicate), or
+        - Their similarity score (via HolographicLinker) exceeds ``threshold``
+          (near-duplicate when an embedding backend is available or Jaccard is
+          high enough at the given threshold).
+
+        Merge strategy:
+        - Keep the *older* entry (earlier ``created_at``).
+        - Union topics from both entries (case-deduped).
+        - Merge metadata from newer into older (older values win on conflicts).
+        - Transfer all links from the newer entry to the older entry.
+        - Delete the newer entry.
+
+        Args:
+            threshold: Similarity threshold for near-duplicate detection (0.0–1.0).
+                       Default 0.9 is intentionally conservative.
+            dry_run: If True, return the list of would-be merges without mutating
+                     the archive.
+
+        Returns:
+            List of dicts, one per merged pair::
+
+                {
+                    "kept":    <entry_id of survivor>,
+                    "removed": <entry_id of duplicate>,
+                    "reason":  "exact_hash" | "semantic_similarity",
+                    "score":   float,         # 1.0 for exact hash matches
+                    "dry_run": bool,
+                }
+        """
+        merges: list[dict] = []
+        entries = list(self._entries.values())
+        removed_ids: set[str] = set()
+
+        for i, entry_a in enumerate(entries):
+            if entry_a.id in removed_ids:
+                continue
+            for entry_b in entries[i + 1:]:
+                if entry_b.id in removed_ids:
+                    continue
+
+                # Determine if they are duplicates
+                reason: Optional[str] = None
+                score: float = 0.0
+
+                if (
+                    entry_a.content_hash is not None
+                    and entry_b.content_hash is not None
+                    and entry_a.content_hash == entry_b.content_hash
+                ):
+                    reason = "exact_hash"
+                    score = 1.0
+                else:
+                    sim = self.linker.compute_similarity(entry_a, entry_b)
+                    if sim >= threshold:
+                        reason = "semantic_similarity"
+                        score = sim
+
+                if reason is None:
+                    continue
+
+                # Decide which entry to keep (older survives)
+                if entry_a.created_at <= entry_b.created_at:
+                    kept, removed = entry_a, entry_b
+                else:
+                    kept, removed = entry_b, entry_a
+
+                merges.append({
+                    "kept": kept.id,
+                    "removed": removed.id,
+                    "reason": reason,
+                    "score": round(score, 4),
+                    "dry_run": dry_run,
+                })
+
+                if not dry_run:
+                    # Merge topics (case-deduped)
+                    existing_lower = {t.lower() for t in kept.topics}
+                    for tag in removed.topics:
+                        if tag.lower() not in existing_lower:
+                            kept.topics.append(tag)
+                            existing_lower.add(tag.lower())
+
+                    # Merge metadata (kept wins on key conflicts)
+                    for k, v in removed.metadata.items():
+                        if k not in kept.metadata:
+                            kept.metadata[k] = v
+
+                    # Transfer links: add removed's links to kept
+                    kept_links_set = set(kept.links)
+                    for lid in removed.links:
+                        if lid != kept.id and lid not in kept_links_set and lid not in removed_ids:
+                            kept.links.append(lid)
+                            kept_links_set.add(lid)
+                            # Update the other entry's back-link
+                            other = self._entries.get(lid)
+                            if other and kept.id not in other.links:
+                                other.links.append(kept.id)
+
+                    # Remove back-links pointing at the removed entry
+                    for other in self._entries.values():
+                        if removed.id in other.links:
+                            other.links.remove(removed.id)
+                            if other.id != kept.id and kept.id not in other.links:
+                                other.links.append(kept.id)
+
+                    del self._entries[removed.id]
+                    removed_ids.add(removed.id)
+
+        if not dry_run and merges:
+            self._save()
+
+        return merges
+
     def rebuild_links(self, threshold: Optional[float] = None) -> int:
         """Recompute all links from scratch.
 
diff --git a/nexus/mnemosyne/cli.py b/nexus/mnemosyne/cli.py
index af1823d0..66feb067 100644
--- a/nexus/mnemosyne/cli.py
+++ b/nexus/mnemosyne/cli.py
@@ -206,6 +206,23 @@ def cmd_timeline(args):
         print()
 
 
+def cmd_consolidate(args):
+    archive = MnemosyneArchive()
+    merges = archive.consolidate(threshold=args.threshold, dry_run=args.dry_run)
+    if not merges:
+        print("No duplicates found.")
+        return
+    label = "[DRY RUN] " if args.dry_run else ""
+    for m in merges:
+        print(f"{label}Merge ({m['reason']}, score={m['score']:.4f}):")
+        print(f"  kept:    {m['kept'][:8]}")
+        print(f"  removed: {m['removed'][:8]}")
+    if args.dry_run:
+        print(f"\n{len(merges)} pair(s) would be merged. Re-run without --dry-run to apply.")
+    else:
+        print(f"\nMerged {len(merges)} duplicate pair(s).")
+
+
 def cmd_neighbors(args):
     archive = MnemosyneArchive()
     try:
@@ -283,6 +300,10 @@ def main():
     nb.add_argument("entry_id", help="Anchor entry ID")
     nb.add_argument("--days", type=int, default=7, help="Window in days (default: 7)")
 
+    co = sub.add_parser("consolidate", help="Merge duplicate/near-duplicate entries")
+    co.add_argument("--dry-run", action="store_true", help="Show what would be merged without applying")
+    co.add_argument("--threshold", type=float, default=0.9, help="Similarity threshold (default: 0.9)")
+
     args = parser.parse_args()
     if not args.command:
         parser.print_help()
@@ -305,6 +326,7 @@ def main():
         "retag": cmd_retag,
         "timeline": cmd_timeline,
         "neighbors": cmd_neighbors,
+        "consolidate": cmd_consolidate,
     }
     dispatch[args.command](args)
 
diff --git a/nexus/mnemosyne/tests/test_consolidation.py b/nexus/mnemosyne/tests/test_consolidation.py
new file mode 100644
index 00000000..67a33295
--- /dev/null
+++ b/nexus/mnemosyne/tests/test_consolidation.py
@@ -0,0 +1,176 @@
+"""Tests for MnemosyneArchive.consolidate() — duplicate/near-duplicate merging."""
+
+import tempfile
+from pathlib import Path
+
+from nexus.mnemosyne.archive import MnemosyneArchive
+from nexus.mnemosyne.entry import ArchiveEntry
+from nexus.mnemosyne.ingest import ingest_event
+
+
+def _archive(tmp: str) -> MnemosyneArchive:
+    return MnemosyneArchive(archive_path=Path(tmp) / "archive.json", auto_embed=False)
+
+
+def test_consolidate_exact_duplicate_removed():
+    """Two entries with identical content_hash are merged; only one survives."""
+    with tempfile.TemporaryDirectory() as tmp:
+        archive = _archive(tmp)
+        e1 = ingest_event(archive, title="Hello world", content="Exactly the same content", topics=["a"])
+        # Manually add a second entry with the same hash to simulate a duplicate
+        e2 = ArchiveEntry(title="Hello world", content="Exactly the same content", topics=["b"])
+        # Bypass dedup guard so we can test consolidate() rather than add()
+        archive._entries[e2.id] = e2
+        archive._save()
+
+        assert archive.count == 2
+        merges = archive.consolidate(dry_run=False)
+        assert len(merges) == 1
+        assert merges[0]["reason"] == "exact_hash"
+        assert merges[0]["score"] == 1.0
+        assert archive.count == 1
+
+
+def test_consolidate_keeps_older_entry():
+    """The older entry (earlier created_at) is kept, the newer is removed."""
+    with tempfile.TemporaryDirectory() as tmp:
+        archive = _archive(tmp)
+        e1 = ingest_event(archive, title="Hello world", content="Same content here", topics=[])
+        e2 = ArchiveEntry(title="Hello world", content="Same content here", topics=[])
+        # Make e2 clearly newer
+        e2.created_at = "2099-01-01T00:00:00+00:00"
+        archive._entries[e2.id] = e2
+        archive._save()
+
+        merges = archive.consolidate(dry_run=False)
+        assert len(merges) == 1
+        assert merges[0]["kept"] == e1.id
+        assert merges[0]["removed"] == e2.id
+
+
+def test_consolidate_merges_topics():
+    """Topics from the removed entry are merged (unioned) into the kept entry."""
+    with tempfile.TemporaryDirectory() as tmp:
+        archive = _archive(tmp)
+        e1 = ingest_event(archive, title="Memory item", content="Shared content body", topics=["alpha"])
+        e2 = ArchiveEntry(title="Memory item", content="Shared content body", topics=["beta", "gamma"])
+        e2.created_at = "2099-01-01T00:00:00+00:00"
+        archive._entries[e2.id] = e2
+        archive._save()
+
+        archive.consolidate(dry_run=False)
+        survivor = archive.get(e1.id)
+        assert survivor is not None
+        topic_lower = {t.lower() for t in survivor.topics}
+        assert "alpha" in topic_lower
+        assert "beta" in topic_lower
+        assert "gamma" in topic_lower
+
+
+def test_consolidate_merges_metadata():
+    """Metadata from the removed entry is merged into the kept entry; kept values win."""
+    with tempfile.TemporaryDirectory() as tmp:
+        archive = _archive(tmp)
+        e1 = ArchiveEntry(
+            title="Shared", content="Identical body here", topics=[], metadata={"k1": "v1", "shared": "kept"}
+        )
+        archive._entries[e1.id] = e1
+        e2 = ArchiveEntry(
+            title="Shared", content="Identical body here", topics=[], metadata={"k2": "v2", "shared": "removed"}
+        )
+        e2.created_at = "2099-01-01T00:00:00+00:00"
+        archive._entries[e2.id] = e2
+        archive._save()
+
+        archive.consolidate(dry_run=False)
+        survivor = archive.get(e1.id)
+        assert survivor.metadata["k1"] == "v1"
+        assert survivor.metadata["k2"] == "v2"
+        assert survivor.metadata["shared"] == "kept"  # kept entry wins
+
+
+def test_consolidate_dry_run_no_mutation():
+    """Dry-run mode returns merge plan but does not alter the archive."""
+    with tempfile.TemporaryDirectory() as tmp:
+        archive = _archive(tmp)
+        ingest_event(archive, title="Same", content="Identical content to dedup", topics=[])
+        e2 = ArchiveEntry(title="Same", content="Identical content to dedup", topics=[])
+        e2.created_at = "2099-01-01T00:00:00+00:00"
+        archive._entries[e2.id] = e2
+        archive._save()
+
+        merges = archive.consolidate(dry_run=True)
+        assert len(merges) == 1
+        assert merges[0]["dry_run"] is True
+        # Archive must be unchanged
+        assert archive.count == 2
+
+
+def test_consolidate_no_duplicates():
+    """When no duplicates exist, consolidate returns an empty list."""
+    with tempfile.TemporaryDirectory() as tmp:
+        archive = _archive(tmp)
+        ingest_event(archive, title="Unique A", content="This is completely unique content for A")
+        ingest_event(archive, title="Unique B", content="Totally different words here for B")
+        merges = archive.consolidate(threshold=0.9)
+        assert merges == []
+
+
+def test_consolidate_transfers_links():
+    """Links from the removed entry are inherited by the kept entry."""
+    with tempfile.TemporaryDirectory() as tmp:
+        archive = _archive(tmp)
+        # Create a third entry to act as a link target
+        target = ingest_event(archive, title="Target", content="The link target entry", topics=[])
+
+        e1 = ArchiveEntry(title="Dup", content="Exact duplicate body text", topics=[], links=[target.id])
+        archive._entries[e1.id] = e1
+        target.links.append(e1.id)
+
+        e2 = ArchiveEntry(title="Dup", content="Exact duplicate body text", topics=[])
+        e2.created_at = "2099-01-01T00:00:00+00:00"
+        archive._entries[e2.id] = e2
+        archive._save()
+
+        archive.consolidate(dry_run=False)
+        survivor = archive.get(e1.id)
+        assert survivor is not None
+        assert target.id in survivor.links
+
+
+def test_consolidate_near_duplicate_semantic():
+    """Near-duplicate entries above the similarity threshold are merged."""
+    with tempfile.TemporaryDirectory() as tmp:
+        archive = _archive(tmp)
+        # Entries with very high Jaccard overlap
+        text_a = "python automation scripting building tools workflows"
+        text_b = "python automation scripting building tools workflows tasks"
+        e1 = ArchiveEntry(title="Automator", content=text_a, topics=[])
+        e2 = ArchiveEntry(title="Automator", content=text_b, topics=[])
+        e2.created_at = "2099-01-01T00:00:00+00:00"
+        archive._entries[e1.id] = e1
+        archive._entries[e2.id] = e2
+        archive._save()
+
+        # Use a low threshold to ensure these very similar entries match
+        merges = archive.consolidate(threshold=0.7, dry_run=False)
+        assert len(merges) >= 1
+        assert merges[0]["reason"] == "semantic_similarity"
+
+
+def test_consolidate_persists_after_reload():
+    """After consolidation, the reduced archive survives a save/reload cycle."""
+    with tempfile.TemporaryDirectory() as tmp:
+        path = Path(tmp) / "archive.json"
+        archive = MnemosyneArchive(archive_path=path, auto_embed=False)
+        ingest_event(archive, title="Persist test", content="Body to dedup and persist", topics=[])
+        e2 = ArchiveEntry(title="Persist test", content="Body to dedup and persist", topics=[])
+        e2.created_at = "2099-01-01T00:00:00+00:00"
+        archive._entries[e2.id] = e2
+        archive._save()
+
+        archive.consolidate(dry_run=False)
+        assert archive.count == 1
+
+        reloaded = MnemosyneArchive(archive_path=path, auto_embed=False)
+        assert reloaded.count == 1