diff --git a/py/routes/handlers/misc_handlers.py b/py/routes/handlers/misc_handlers.py
index 91526ec4..398f7089 100644
--- a/py/routes/handlers/misc_handlers.py
+++ b/py/routes/handlers/misc_handlers.py
@@ -2470,6 +2470,7 @@ class ModelLibraryHandler:
             }
             scanner = scanner_map.get(found_type or "")
             if scanner:
+                scanner.bump_cache_version()
                 persist: Any = getattr(scanner, "_persist_current_cache", None)
                 if persist:
                     await persist()
diff --git a/py/services/checkpoint_scanner.py b/py/services/checkpoint_scanner.py
index 4d1e2900..707a0d0d 100644
--- a/py/services/checkpoint_scanner.py
+++ b/py/services/checkpoint_scanner.py
@@ -242,6 +242,7 @@ class CheckpointScanner(ModelScanner):
                     if entry.get("file_path") == file_path:
                         entry["sha256"] = sha256.lower()
                         entry["hash_status"] = "completed"
+                        self.bump_cache_version()
                         break
 
             logger.info(f"Hash calculated for checkpoint: {file_path}")
diff --git a/py/services/model_lifecycle_service.py b/py/services/model_lifecycle_service.py
index 54189bed..3f7e6318 100644
--- a/py/services/model_lifecycle_service.py
+++ b/py/services/model_lifecycle_service.py
@@ -138,6 +138,9 @@ class ModelLifecycleService:
                 item for item in cache.raw_data if item.get("file_path") != file_path
             ]
             await cache.resort()
+            bump_cache_version = getattr(self._scanner, "bump_cache_version", None)
+            if callable(bump_cache_version):
+                bump_cache_version()
 
         if hasattr(self._scanner, "_hash_index") and self._scanner._hash_index:
             self._scanner._hash_index.remove_by_path(file_path)
@@ -244,6 +247,9 @@ class ModelLifecycleService:
                 item for item in cache.raw_data if item["file_path"] != file_path
             ]
             await cache.resort()
+            bump_cache_version = getattr(self._scanner, "bump_cache_version", None)
+            if callable(bump_cache_version):
+                bump_cache_version()
 
         excluded = getattr(self._scanner, "_excluded_models", None)
         if isinstance(excluded, list):
diff --git a/py/services/model_scanner.py b/py/services/model_scanner.py
index c9add7df..8409abcc 100644
--- a/py/services/model_scanner.py
+++ b/py/services/model_scanner.py
@@ -79,6 +79,7 @@ class ModelScanner:
         self.model_class = model_class
         self.file_extensions = file_extensions
         self._cache: Any = None
+        self._cache_version: int = 0
         self._hash_index = hash_index or ModelHashIndex()
         self._tags_count = {}  # Dictionary to store tag counts
         self._is_initializing = False  # Flag to track initialization state
@@ -98,6 +99,25 @@ class ModelScanner:
         # Register this service
         asyncio.create_task(self._register_service())
 
+    @property
+    def cache_version(self) -> int:
+        """Monotonic version counter for the in-memory cache.
+
+        Every write path that mutates scanner cache state calls
+        :meth:`bump_cache_version`, so consumers (e.g. RecipeScanner) can
+        detect when a cached derivation of the raw data is stale. Reads never
+        bump.
+        """
+        return self._cache_version
+
+    def bump_cache_version(self) -> None:
+        """Invalidate derived caches by incrementing the cache version.
+
+        Public because external services (model lifecycle, route handlers)
+        rewrite scanner raw_data directly and must be able to invalidate it.
+        """
+        self._cache_version += 1
+
     def on_library_changed(self) -> None:
         """Reset caches when the active library changes."""
         self._persistent_cache = get_persistent_cache()
@@ -107,6 +127,7 @@ class ModelScanner:
         self._excluded_models = []
         self._is_initializing = False
         self._name_display_mode = self._resolve_name_display_mode()
+        self.bump_cache_version()
 
         try:
             loop = asyncio.get_running_loop()
@@ -1030,6 +1051,7 @@ class ModelScanner:
             logger.error(f"{self.model_type.capitalize()} Scanner: Error reconciling cache: {e}", exc_info=True)
         finally:
             self._is_initializing = False # Unset flag
+            self.bump_cache_version()
     
     def is_initializing(self) -> bool:
         """Check if the scanner is currently initializing"""
@@ -1267,6 +1289,8 @@ class ModelScanner:
 
         self._log_duplicate_filename_summary()
 
+        self.bump_cache_version()
+
     def _log_duplicate_filename_summary(self) -> None:
         """Log a batched summary of duplicate filename conflicts once per scan."""
         # Duplicate filename detection is only relevant for LoRAs, which use
@@ -1498,6 +1522,7 @@ class ModelScanner:
                 metadata_dict.get('autov3') or None,
             )
             await self._persist_current_cache()
+            self.bump_cache_version()
             return True
         except Exception as e:
             logger.error(f"Error adding model to cache: {e}")
@@ -1702,6 +1727,7 @@ class ModelScanner:
 
         if cache_modified:
             await self._persist_current_cache()
+            self.bump_cache_version()
 
         if metadata and cache_entry is not None:
             return cache_entry
@@ -1828,6 +1854,7 @@ class ModelScanner:
         # ---- In-place update of the cache entry ----
         existing_entry.clear()
         existing_entry.update(desired_entry)
+        self.bump_cache_version()
 
         # ---- Incremental tag count update ----
         new_tags: set[str] = set(desired_entry.get("tags") or [])
@@ -1966,6 +1993,7 @@ class ModelScanner:
                 payload['autov3'] = entry['autov3'] or None
                 await MetadataManager.save_metadata(metadata_path, payload)
 
+            self.bump_cache_version()
             return True
         except Exception as exc:
             logger.warning("Failed to update AutoV3 for %s: %s", file_path, exc)
@@ -2298,6 +2326,8 @@ class ModelScanner:
 
             await self._persist_current_cache()
 
+            self.bump_cache_version()
+
             return True
             
         except Exception as e:
diff --git a/tests/services/test_recipe_scanner.py b/tests/services/test_recipe_scanner.py
index 2c222707..d1f849a2 100644
--- a/tests/services/test_recipe_scanner.py
+++ b/tests/services/test_recipe_scanner.py
@@ -8,8 +8,13 @@ from typing import Any, Dict
 import pytest
 
 from py.config import config
+from py.services import model_scanner as model_scanner_module
+from py.services.model_cache import ModelCache
+from py.services.model_hash_index import ModelHashIndex
+from py.services.model_scanner import CacheBuildResult, ModelScanner
 from py.services.recipe_scanner import RecipeScanner
 from py.services import settings_manager as settings_manager_module
+from py.utils.models import BaseModelMetadata
 from py.utils.utils import calculate_recipe_fingerprint
 
 
@@ -1106,3 +1111,382 @@ async def test_remove_recipe_clears_image_id_map(recipe_scanner):
 
     assert "111" not in cache.image_id_map
     assert cache.image_id_map["222"] == "recipe-b"
+
+
+# ---------------------------------------------------------------------------
+# cache_version — ModelScanner write-path bump coverage (plan todo 1)
+# ---------------------------------------------------------------------------
+
+
+class DummyScanner(ModelScanner):
+    """Minimal ModelScanner subclass exercising the base-class write paths."""
+
+    def __init__(self, root: str):
+        self._root = root
+        super().__init__(
+            model_type="dummy",
+            model_class=BaseModelMetadata,
+            file_extensions={".txt"},
+            hash_index=ModelHashIndex(),
+        )
+
+    def get_model_roots(self) -> list[str]:
+        return [self._root]
+
+    async def _process_model_file(
+        self,
+        file_path: str,
+        root_path: str,
+        *,
+        hash_index: ModelHashIndex | None = None,
+        excluded_models: list[str] | None = None,
+    ) -> Dict[str, Any] | None:
+        hash_index = hash_index or self._hash_index
+        excluded_models = excluded_models if excluded_models is not None else self._excluded_models
+        name = os.path.splitext(os.path.basename(file_path))[0]
+        if name.startswith("skip"):
+            excluded_models.append(file_path.replace(os.sep, "/"))
+            return None
+        return {
+            "file_path": file_path.replace(os.sep, "/"),
+            "folder": os.path.dirname(os.path.relpath(file_path, root_path)).replace(os.path.sep, "/"),
+            "sha256": f"hash-{name}",
+            "tags": [],
+            "model_name": name,
+            "file_name": name,
+            "size": 1,
+            "modified": 1.0,
+        }
+
+
+class DummyScannerB(DummyScanner):
+    """A second ModelScanner subclass so per-class versions are independent."""
+
+
+class DummyScannerC(DummyScanner):
+    """A third ModelScanner subclass (embedding stand-in for the misc route test)."""
+
+
+async def _empty_metadata_loader(path: str) -> Dict[str, Any]:
+    return {}
+
+
+class DummyMetadataManagerForLifecycle:
+    async def load_metadata_payload(self, file_path: str) -> Dict[str, Any]:
+        return {}
+
+    async def save_metadata(self, file_path: str, metadata: Dict[str, Any]) -> None:
+        return None
+
+
+def _make_scanner(raw_data: list[Dict[str, Any]], root: str) -> DummyScanner:
+    scanner = DummyScanner(root)
+    scanner._cache = ModelCache(raw_data=[dict(item) for item in raw_data], folders=[])
+    return scanner
+
+
+def _normalize(root_path: str) -> str:
+    return root_path.replace(os.sep, "/")
+
+
+async def test_cache_version_starts_at_zero(tmp_path: Path):
+    scanner = DummyScanner(str(tmp_path))
+    assert scanner.cache_version == 0
+
+
+async def test_scan_apply_bumps_cache_version(tmp_path: Path):
+    scanner = _make_scanner([], str(tmp_path))
+    result = CacheBuildResult(
+        raw_data=[{"file_path": "a.txt", "folder": "", "sha256": "abc", "tags": []}],
+        hash_index=ModelHashIndex(),
+        tags_count={},
+        excluded_models=[],
+    )
+    assert scanner.cache_version == 0
+    await scanner._apply_scan_result(result)
+    assert scanner.cache_version == 1
+    assert scanner._cache.raw_data == result.raw_data
+
+
+async def test_add_model_to_cache_bumps_cache_version(tmp_path: Path):
+    scanner = _make_scanner([], str(tmp_path))
+    assert scanner.cache_version == 0
+    ok = await scanner.add_model_to_cache(
+        {"file_path": "x.txt", "folder": "", "sha256": "abc", "tags": []}
+    )
+    assert ok is True
+    assert scanner.cache_version == 1
+    assert len(scanner._cache.raw_data) == 1
+
+
+async def test_update_single_model_cache_bumps_cache_version(tmp_path: Path):
+    scanner = _make_scanner(
+        [{"file_path": "old.txt", "folder": "", "sha256": "abc", "tags": [], "model_name": "m", "file_name": "old"}],
+        str(tmp_path),
+    )
+    await scanner._cache.resort()
+    assert scanner.cache_version == 0
+    result = await scanner.update_single_model_cache(
+        "old.txt",
+        "new.txt",
+        {"sha256": "def", "tags": [], "model_name": "new", "file_name": "new"},
+    )
+    assert result is not None
+    assert scanner.cache_version == 1
+    assert [item["file_path"] for item in scanner._cache.raw_data] == ["new.txt"]
+
+
+async def test_sync_cache_from_metadata_sha256_change_bumps_cache_version(tmp_path: Path):
+    scanner = _make_scanner(
+        [{"file_path": "m.txt", "folder": "", "sha256": "oldsha", "tags": [], "model_name": "m", "file_name": "m"}],
+        str(tmp_path),
+    )
+    await scanner._cache.resort()
+    assert scanner.cache_version == 0
+    changed = await scanner._sync_cache_from_metadata_impl(
+        "m.txt",
+        {"sha256": "newsha", "tags": [], "model_name": "m", "file_name": "m", "size": 1, "modified": 1.0},
+    )
+    assert changed is True
+    assert scanner.cache_version == 1
+    assert scanner._cache.raw_data[0]["sha256"] == "newsha"
+
+
+async def test_update_autov3_for_model_bumps_cache_version(tmp_path: Path):
+    scanner = _make_scanner(
+        [{"file_path": "m.txt", "folder": "", "sha256": "abc", "tags": [], "model_name": "m", "file_name": "m", "autov3": ""}],
+        str(tmp_path),
+    )
+    assert scanner.cache_version == 0
+    ok = await scanner.update_autov3_for_model("dummy", "m.txt", "AAA12BBB34CD")
+    assert ok is True
+    assert scanner.cache_version == 1
+    assert scanner._cache.raw_data[0]["autov3"] == "aaa12bbb34cd"
+
+
+async def test_batch_remove_bumps_cache_version(tmp_path: Path):
+    scanner = _make_scanner(
+        [{"file_path": "gone.txt", "folder": "", "sha256": "abc", "tags": [], "model_name": "gone", "file_name": "gone"}],
+        str(tmp_path),
+    )
+    assert scanner.cache_version == 0
+    updated = await scanner._batch_update_cache_for_deleted_models(["gone.txt"])
+    assert updated is True
+    assert scanner.cache_version == 1
+    assert scanner._cache.raw_data == []
+
+
+async def test_reconcile_cache_append_only_bumps_cache_version(tmp_path: Path):
+    root = tmp_path / "models"
+    root.mkdir()
+    (root / "new.txt").write_text("data", encoding="utf-8")
+    scanner = _make_scanner([], str(root))
+    assert scanner.cache_version == 0
+    await scanner._reconcile_cache()
+    assert scanner.cache_version == 1
+    assert len(scanner._cache.raw_data) == 1
+
+
+async def test_reconcile_cache_bumps_unconditionally(tmp_path: Path):
+    root = tmp_path / "models"
+    root.mkdir()
+    scanner = _make_scanner([], str(root))
+    assert scanner.cache_version == 0
+    await scanner._reconcile_cache()
+    assert scanner.cache_version == 1
+
+
+async def test_get_cached_data_read_does_not_bump_cache_version(tmp_path: Path):
+    scanner = _make_scanner([], str(tmp_path))
+    assert scanner.cache_version == 0
+    cache = await scanner.get_cached_data()
+    assert cache is scanner._cache
+    assert scanner.cache_version == 0
+    _ = scanner.cache_version
+    assert scanner.cache_version == 0
+
+
+async def test_scanner_versions_are_independent(tmp_path: Path):
+    root = tmp_path / "models"
+    root.mkdir()
+    lora = DummyScanner(str(root))
+    checkpoint = DummyScannerB(str(root))
+    assert lora.cache_version == 0
+    assert checkpoint.cache_version == 0
+    lora.bump_cache_version()
+    assert lora.cache_version == 1
+    assert checkpoint.cache_version == 0
+
+
+async def test_on_library_changed_bumps_cache_version(tmp_path: Path, monkeypatch):
+    scanner = DummyScanner(str(tmp_path))
+    assert scanner.cache_version == 0
+
+    async def _noop_initialize() -> None:
+        pass
+
+    monkeypatch.setattr(scanner, "initialize_in_background", _noop_initialize)
+    scanner.on_library_changed()
+    assert scanner.cache_version == 1
+
+
+async def test_checkpoint_lazy_hash_bumps_cache_version(tmp_path: Path, monkeypatch):
+    from py.services.checkpoint_scanner import CheckpointScanner
+
+    checkpoints_root = tmp_path / "checkpoints"
+    checkpoints_root.mkdir()
+    checkpoint_file = checkpoints_root / "test_model.safetensors"
+    checkpoint_file.write_text("fake content", encoding="utf-8")
+
+    normalized_root = _normalize(str(checkpoints_root))
+    normalized_file = _normalize(str(checkpoint_file))
+
+    monkeypatch.setattr(
+        model_scanner_module.config, "base_models_roots", [normalized_root], raising=False
+    )
+    monkeypatch.setattr(
+        model_scanner_module.config, "checkpoints_roots", [normalized_root], raising=False
+    )
+
+    scanner = CheckpointScanner()
+    scanner._cache = ModelCache(
+        raw_data=[
+            {
+                "file_path": normalized_file,
+                "folder": "",
+                "sha256": "",
+                "hash_status": "pending",
+                "tags": [],
+                "model_name": "test_model",
+                "file_name": "test_model",
+            }
+        ],
+        folders=[],
+    )
+    assert scanner.cache_version == 0
+    hash_result = await scanner.calculate_hash_for_model(normalized_file)
+    assert hash_result is not None
+    assert scanner.cache_version == 1
+    assert scanner._cache.raw_data[0]["sha256"] == hash_result.lower()
+
+
+async def test_lifecycle_delete_model_bumps_cache_version(tmp_path: Path):
+    from py.services.model_lifecycle_service import ModelLifecycleService
+
+    root = tmp_path / "loras"
+    root.mkdir()
+    model = root / "model.safetensors"
+    model.write_bytes(b"data")
+
+    scanner = _make_scanner(
+        [{"file_path": str(model), "folder": "", "sha256": "abc", "tags": [], "model_name": "m", "file_name": "m"}],
+        str(root),
+    )
+    service = ModelLifecycleService(
+        scanner=scanner,
+        metadata_manager=DummyMetadataManagerForLifecycle(),
+        metadata_loader=_empty_metadata_loader,
+    )
+    assert scanner.cache_version == 0
+    result = await service.delete_model(str(model))
+    assert result["success"] is True
+    assert scanner.cache_version == 1
+    assert scanner._cache.raw_data == []
+
+
+async def test_lifecycle_exclude_model_bumps_cache_version(tmp_path: Path):
+    from py.services.model_lifecycle_service import ModelLifecycleService
+
+    root = tmp_path / "loras"
+    root.mkdir()
+    model = root / "model.safetensors"
+    model.write_bytes(b"data")
+
+    scanner = _make_scanner(
+        [{"file_path": str(model), "folder": "", "sha256": "abc", "tags": [], "model_name": "m", "file_name": "m"}],
+        str(root),
+    )
+    service = ModelLifecycleService(
+        scanner=scanner,
+        metadata_manager=DummyMetadataManagerForLifecycle(),
+        metadata_loader=_empty_metadata_loader,
+    )
+    assert scanner.cache_version == 0
+    result = await service.exclude_model(str(model))
+    assert result["success"] is True
+    assert scanner.cache_version == 1
+    assert scanner._cache.raw_data == []
+
+
+async def test_misc_delete_model_version_bumps_cache_version(tmp_path: Path):
+    from aiohttp.test_utils import make_mocked_request
+
+    from py.routes.handlers.misc_handlers import ModelLibraryHandler, ServiceRegistryAdapter
+
+    root = tmp_path / "loras"
+    root.mkdir()
+    model = root / "model.safetensors"
+    model.write_bytes(b"data")
+
+    lora_scanner = _make_scanner(
+        [
+            {
+                "file_path": str(model),
+                "folder": "",
+                "sha256": "abc",
+                "tags": [],
+                "model_name": "m",
+                "file_name": "m",
+                "civitai": {"id": 42, "modelId": 7, "name": "m"},
+            }
+        ],
+        str(root),
+    )
+    lora_scanner._cache.rebuild_version_index()
+    # Use distinct scanner classes: ModelScanner is a per-class singleton, so
+    # re-instantiating DummyScanner would return the same instance and clobber
+    # the lora cache set above.
+    checkpoint_scanner = DummyScannerB(str(root))
+    checkpoint_scanner._cache = ModelCache(raw_data=[], folders=[])
+    embedding_scanner = DummyScannerC(str(root))
+    embedding_scanner._cache = ModelCache(raw_data=[], folders=[])
+
+    deleted: list[tuple[str, int]] = []
+
+    async def history_factory():
+        class FakeHistory:
+            async def mark_as_deleted(self, model_type: str, model_version_id: int) -> None:
+                deleted.append((model_type, model_version_id))
+
+        return FakeHistory()
+
+    async def lora_factory():
+        return lora_scanner
+
+    async def checkpoint_factory():
+        return checkpoint_scanner
+
+    async def embedding_factory():
+        return embedding_scanner
+
+    async def _noop_metadata_provider() -> Any:
+        return None
+
+    handler = ModelLibraryHandler(
+        ServiceRegistryAdapter(
+            get_lora_scanner=lora_factory,
+            get_checkpoint_scanner=checkpoint_factory,
+            get_embedding_scanner=embedding_factory,
+            get_downloaded_version_history_service=history_factory,
+        ),
+        metadata_provider_factory=_noop_metadata_provider,
+    )
+
+    request = make_mocked_request("GET", "/api/models/versions/delete?modelVersionId=42")
+    assert lora_scanner.cache_version == 0
+    response = await handler.delete_model_version(request)
+    assert response.status == 200
+    assert lora_scanner.cache_version == 1
+    assert checkpoint_scanner.cache_version == 0
+    assert embedding_scanner.cache_version == 0
+    assert deleted == [("lora", 42)]