diff --git a/skywipe/operations.py b/skywipe/operations.py
index f0c0600..6cc91c0 100644
--- a/skywipe/operations.py
+++ b/skywipe/operations.py
@@ -52,7 +52,16 @@ class OperationContext:
 
 
 class BaseStrategy:
-    def get_cursor(self, response):
+    def fetch(self, context: OperationContext, cursor: str | None = None) -> Any:
+        raise NotImplementedError
+
+    def extract_items(self, response: Any) -> list[Any]:
+        raise NotImplementedError
+
+    def process_item(self, item: Any, context: OperationContext) -> None:
+        raise NotImplementedError
+
+    def get_cursor(self, response: Any) -> str | None:
         return response.cursor
 
 
@@ -60,7 +69,7 @@ class RecordDeletionStrategy(BaseStrategy):
     def __init__(self, collection: str):
         self.collection = collection
 
-    def fetch(self, context: OperationContext, cursor: str | None = None):
+    def fetch(self, context: OperationContext, cursor: str | None = None) -> Any:
         list_params = models.ComAtprotoRepoListRecords.Params(
             repo=context.did,
             collection=self.collection,
@@ -69,10 +78,10 @@ class RecordDeletionStrategy(BaseStrategy):
         )
         return context.client.com.atproto.repo.list_records(params=list_params)
 
-    def extract_items(self, response):
+    def extract_items(self, response: Any) -> list[Any]:
         return response.records
 
-    def process_item(self, record, context: OperationContext):
+    def process_item(self, record: Any, context: OperationContext) -> None:
         record_uri = record.uri
         rkey = record_uri.rsplit("/", 1)[-1]
         delete_data = {
@@ -85,34 +94,34 @@ class RecordDeletionStrategy(BaseStrategy):
 
 
 class FeedStrategy(BaseStrategy):
-    def fetch(self, context: OperationContext, cursor: str | None = None):
+    def fetch(self, context: OperationContext, cursor: str | None = None) -> Any:
         if cursor:
             return context.client.get_author_feed(
                 actor=context.did, limit=context.batch_size, cursor=cursor
             )
         return context.client.get_author_feed(actor=context.did, limit=context.batch_size)
 
-    def extract_items(self, response):
+    def extract_items(self, response: Any) -> list[Any]:
         return response.feed
 
-    def process_item(self, post, context: OperationContext):
+    def process_item(self, post: Any, context: OperationContext) -> None:
         uri = post.post.uri
         context.client.delete_post(uri)
         context.logger.debug(f"Deleted post: {uri}")
 
 
 class BookmarkStrategy(BaseStrategy):
-    def fetch(self, context: OperationContext, cursor: str | None = None):
+    def fetch(self, context: OperationContext, cursor: str | None = None) -> Any:
         get_params = models.AppBskyBookmarkGetBookmarks.Params(
             limit=context.batch_size,
             cursor=cursor
         )
         return context.client.app.bsky.bookmark.get_bookmarks(params=get_params)
 
-    def extract_items(self, response):
+    def extract_items(self, response: Any) -> list[Any]:
         return response.bookmarks
 
-    def process_item(self, bookmark, context: OperationContext):
+    def process_item(self, bookmark: Any, context: OperationContext) -> None:
         bookmark_uri = self._extract_bookmark_uri(bookmark)
         if not bookmark_uri:
             raise ValueError("Unable to find bookmark URI")
@@ -122,7 +131,7 @@ class BookmarkStrategy(BaseStrategy):
         context.client.app.bsky.bookmark.delete_bookmark(data=delete_data)
         context.logger.debug(f"Deleted bookmark: {bookmark_uri}")
 
-    def _extract_bookmark_uri(self, bookmark):
+    def _extract_bookmark_uri(self, bookmark: Any) -> str | None:
         if hasattr(bookmark, "uri"):
             return bookmark.uri
 
@@ -148,6 +157,7 @@ class Operation:
         self.filter_fn = filter_fn
         self._client = client
         self._config_data = config_data
+        self.strategy: BaseStrategy
 
         if strategy_type == "record":
             if not collection: