diff --git a/ix/runnable/output_parser.py b/ix/runnable/output_parser.py
index 1c57f112..002b7ca5 100644
--- a/ix/runnable/output_parser.py
+++ b/ix/runnable/output_parser.py
@@ -23,6 +23,9 @@ def invoke(
         config: Optional[RunnableConfig] = None,
         **kwargs: Any,
     ) -> FunctionCall:
+        if isinstance(input, dict):
+            input = AIMessage(**input)
+
         additional_kwargs = input.additional_kwargs
         if "function_call" in additional_kwargs:
             function_call = additional_kwargs["function_call"]
@@ -42,6 +45,9 @@ async def ainvoke(
         config: Optional[RunnableConfig] = None,
         **kwargs: Any,
     ) -> FunctionCall:
+        if isinstance(input, dict):
+            input = AIMessage(**input)
+
         additional_kwargs = input.additional_kwargs
         if "function_call" in additional_kwargs:
             function_call = additional_kwargs["function_call"]
diff --git a/ix/skills/types.py b/ix/skills/types.py
index fcbd318c..efd0e519 100644
--- a/ix/skills/types.py
+++ b/ix/skills/types.py
@@ -15,7 +15,7 @@ class SkillBase(BaseModel):
     name: str = Field(max_length=128)
     description: Optional[str] = None
     code: str
-    tags: List[str] = Field(default_factory=list)
+    tags: Optional[List[str]] = Field(default_factory=list)
     func_name: Optional[str] = None
     input_schema: Optional[dict[str, Any]] = None
 
@@ -31,12 +31,6 @@ class EditSkill(SkillBase):
     class Config:
         from_attributes = True
 
-    @model_validator(mode="before")
-    def default_tags(cls, values):
-        if not values["tags"]:
-            values["tags"] = []
-        return values
-
     @model_validator(mode="before")
     def parse_code_and_set_fields(cls, values):
         code = values.get("code", None)