fix: retain existing bound params

Author: kurtisvg

packages/toolbox-core/src/toolbox_core/tool.py

@@ -240,7 +240,8 @@ def add_auth_token_getters(
         )
 
     def bind_parameters(
-        self, bound_params: Mapping[str, Union[Callable[[], Any], Any]]
+        self,
+        bound_params: Mapping[str, Union[Callable[[], Any], Any]]
     ) -> "ToolboxTool":
         """
         Binds parameters to values or callables that produce values.
@@ -261,10 +262,13 @@ def bind_parameters(
         for p in self.__params:
             if p.name not in bound_params:
                 new_params.append(p)
+        
+        all_bound_params = dict(self.__bound_parameters)
+        all_bound_params.update(bound_params)
 
         return self.__copy(
             params=new_params,
-            bound_params=bound_params,
+            bound_params=types.MappingProxyType(all_bound_params),
         )