fix: ignore self and cls from method params

Author: Unshure

src/strands/hooks/_type_inference.py

@@ -44,9 +44,9 @@ def infer_event_types(callback: "HookCallback[TEvent]") -> "list[type[TEvent]]":
     if not params:
         raise ValueError("callback has no parameters | cannot infer event type, please provide event_type explicitly")
 
-    # Skip 'self' parameter for methods
+    # Skip 'self' and 'cls' parameters for methods
     first_param = params[0]
-    if first_param.name == "self" and len(params) > 1:
+    if first_param.name in ("self", "cls") and len(params) > 1:
         first_param = params[1]
 
     type_hint = hints.get(first_param.name)

tests/strands/plugins/test_hook_decorator.py

@@ -92,6 +92,17 @@ def handler3(event: AfterInvocationEvent):
         assert AfterModelCallEvent in handler2._hook_event_types
         assert AfterInvocationEvent in handler3._hook_event_types
 
+    def test_hook_skips_cls_parameter(self):
+        """Test that @hook skips 'cls' parameter for classmethods."""
+
+        class MyClass:
+            @classmethod
+            @hook
+            def handler(cls, event: BeforeModelCallEvent):
+                pass
+
+        assert BeforeModelCallEvent in MyClass.handler._hook_event_types
+
 
 class TestHookDecoratorUnionTypes:
     """Tests for union type support in @hook decorator."""