diff --git a/openhands/core/config/extended_config.py b/openhands/core/config/extended_config.py
index 324ba7cda952..14fc14cd2ee1 100644
--- a/openhands/core/config/extended_config.py
+++ b/openhands/core/config/extended_config.py
@@ -1,30 +1,43 @@
-class ExtendedConfig:
+from pydantic import BaseModel
+
+
+class ExtendedConfig(BaseModel):
     """Configuration for extended functionalities.
 
     Attributes:
         Values depend on the defined section
     """
 
-    extended: dict = {}
+    # No explicit fields are defined; extra keys will be allowed via the model configuration.
+
+    class Config:
+        extra = 'allow'  # allow arbitrary extra fields
 
-    def __str__(self):
+    def __str__(self) -> str:
+        # Build string representation using all model attributes
         attr_str = []
-        for attr_name, attr_value in self.extended.items():
+        # __dict__ contains both declared and extra attributes
+        for attr_name, attr_value in self.__dict__.items():
             attr_str.append(f'{attr_name}={repr(attr_value)}')
         return f"ExtendedConfig({', '.join(attr_str)})"
 
     @classmethod
     def from_dict(cls, extended_config_dict: dict) -> 'ExtendedConfig':
-        return cls(extended_config_dict)
+        # Create an instance using Pydantic V2's model validation
+        return cls.model_validate(extended_config_dict)
 
-    def __init__(self, dict=None):
-        self.extended = dict
-
-    def __repr__(self):
+    def __repr__(self) -> str:
         return self.__str__()
 
-    def __getitem__(self, key):
-        return self.extended[key]
-
-    def __getattr__(self, key):
-        return self.extended[key]
+    def __getitem__(self, key: str) -> object:
+        # Allow dictionary-like access to attributes
+        return self.__dict__[key]
+
+    def __getattr__(self, key: str) -> object:
+        # Fallback for attribute access if the attribute is not found normally
+        try:
+            return self.__dict__[key]
+        except KeyError as e:
+            raise AttributeError(
+                f"'ExtendedConfig' object has no attribute '{key}'"
+            ) from e