diff --git a/src/app/social/__init__.py b/src/app/social/__init__.py
index de83e63..9ce3708 100644
--- a/src/app/social/__init__.py
+++ b/src/app/social/__init__.py
@@ -26,7 +26,7 @@ class SocialAPIsTool(SocialWrapper, Toolkit):
         """
 
         wrappers = [RedditWrapper]
-        self.wrapper_handler: WrapperHandler[SocialWrapper] = WrapperHandler(wrappers)
+        self.wrapper_handler: WrapperHandler[SocialWrapper] = WrapperHandler.build_wrappers(wrappers)
 
         Toolkit.__init__(
             self,
@@ -38,7 +38,7 @@ class SocialAPIsTool(SocialWrapper, Toolkit):
 
     # TODO Pensare se ha senso restituire i post da TUTTI i wrapper o solo dal primo che funziona
     # la modifica è banale, basta usare try_call_all invece di try_call
-    def get_top_crypto_posts(self, limit:int = 5) -> list[SocialPost]:
+    def get_top_crypto_posts(self, limit: int = 5) -> list[SocialPost]:
         return self.wrapper_handler.try_call(lambda w: w.get_top_crypto_posts(limit))
 
 
diff --git a/src/app/social/base.py b/src/app/social/base.py
index 1b66c1d..dd894f5 100644
--- a/src/app/social/base.py
+++ b/src/app/social/base.py
@@ -17,6 +17,7 @@ class SocialWrapper:
     Base class for social media API wrappers.
     All social media API wrappers should inherit from this class and implement the methods.
     """
+
     def get_top_crypto_posts(self, limit: int = 5) -> list[SocialPost]:
         """
         Get top cryptocurrency-related posts, optionally limited by total.
diff --git a/src/app/social/reddit.py b/src/app/social/reddit.py
index 730f862..8f3867f 100644
--- a/src/app/social/reddit.py
+++ b/src/app/social/reddit.py
@@ -35,19 +35,19 @@ class RedditWrapper(SocialWrapper):
     """
 
     def __init__(self):
-        self.client_id = os.getenv("REDDIT_API_CLIENT_ID")
-        assert self.client_id is not None, "REDDIT_API_CLIENT_ID environment variable is not set"
+        client_id = os.getenv("REDDIT_API_CLIENT_ID")
+        assert client_id is not None, "REDDIT_API_CLIENT_ID environment variable is not set"
 
-        self.client_secret = os.getenv("REDDIT_API_CLIENT_SECRET")
-        assert self.client_secret is not None, "REDDIT_API_CLIENT_SECRET environment variable is not set"
+        client_secret = os.getenv("REDDIT_API_CLIENT_SECRET")
+        assert client_secret is not None, "REDDIT_API_CLIENT_SECRET environment variable is not set"
 
         self.tool = Reddit(
-            client_id=self.client_id,
-            client_secret=self.client_secret,
+            client_id=client_id,
+            client_secret=client_secret,
             user_agent="upo-appAI",
         )
 
-    def get_top_crypto_posts(self, limit:int = 5) -> list[SocialPost]:
+    def get_top_crypto_posts(self, limit: int = 5) -> list[SocialPost]:
         subreddit = self.tool.subreddit("CryptoCurrency")
         top_posts = subreddit.top(limit=limit, time_filter="week")
         return [create_social_post(post) for post in top_posts]
diff --git a/src/app/utils/wrapper_handler.py b/src/app/utils/wrapper_handler.py
index ecc0e11..7d16c6c 100644
--- a/src/app/utils/wrapper_handler.py
+++ b/src/app/utils/wrapper_handler.py
@@ -24,6 +24,8 @@ class WrapperHandler(Generic[W]):
             try_per_wrapper (int): Number of retries per wrapper before switching to the next.
             retry_delay (int): Delay in seconds between retries.
         """
+        assert not WrapperHandler.__check(wrappers), "All wrappers must be instances of their respective classes. Use `build_wrappers` to create the WrapperHandler."
+
         self.wrappers = wrappers
         self.retry_per_wrapper = try_per_wrapper
         self.retry_delay = retry_delay
@@ -87,6 +89,10 @@ class WrapperHandler(Generic[W]):
             raise Exception("All wrappers failed")
         return results
 
+    @staticmethod
+    def __check(wrappers: list[W]) -> bool:
+        return all(w.__class__ is type for w in wrappers)
+
     @staticmethod
     def build_wrappers(constructors: Iterable[Type[W]], try_per_wrapper: int = 3, retry_delay: int = 2) -> 'WrapperHandler[W]':
         """
@@ -102,6 +108,8 @@ class WrapperHandler(Generic[W]):
         Raises:
             Exception: If no wrappers could be initialized.
         """
+        assert WrapperHandler.__check(constructors), f"All constructors must be classes. Received: {constructors}"
+
         result = []
         for wrapper_class in constructors:
             try:
diff --git a/tests/utils/test_wrapper_handler.py b/tests/utils/test_wrapper_handler.py
index d95d928..154d3dc 100644
--- a/tests/utils/test_wrapper_handler.py
+++ b/tests/utils/test_wrapper_handler.py
@@ -25,6 +25,29 @@ class FailingWrapperWithParameters(MockWrapperWithParameters):
 
 @pytest.mark.wrapper
 class TestWrapperHandler:
+    def test_init_failing(self):
+        with pytest.raises(AssertionError) as exc_info:
+            WrapperHandler([MockWrapper, MockWrapper2])
+        assert exc_info.type == AssertionError
+
+    def test_init_failing_empty(self):
+        with pytest.raises(AssertionError) as exc_info:
+            WrapperHandler.build_wrappers([])
+        assert exc_info.type == AssertionError
+
+    def test_init_failing_with_instances(self):
+        with pytest.raises(AssertionError) as exc_info:
+            WrapperHandler.build_wrappers([MockWrapper(), MockWrapper2()])
+        assert exc_info.type == AssertionError
+
+    def test_init_not_failing(self):
+        handler = WrapperHandler.build_wrappers([MockWrapper, MockWrapper2])
+        assert handler is not None
+        assert len(handler.wrappers) == 2
+        handler = WrapperHandler([MockWrapper(), MockWrapper2()])
+        assert handler is not None
+        assert len(handler.wrappers) == 2
+
     def test_all_wrappers_fail(self):
         wrappers = [FailingWrapper, FailingWrapper]
         handler: WrapperHandler[MockWrapper] = WrapperHandler.build_wrappers(wrappers, try_per_wrapper=2, retry_delay=0)