diff --git a/src/pybroker/config.py b/src/pybroker/config.py
index 91b73590..c595b1fc 100644
--- a/src/pybroker/config.py
+++ b/src/pybroker/config.py
@@ -29,8 +29,6 @@ class StrategyConfig:
                 :class:`pybroker.common.FeeInfo`.
             - ``None``: Fees are disabled (default).
         fee_amount: Brokerage fee amount.
-        subtract_fees: Whether to subtract fees from the cash balance after an
-            order is filled. Defaults to ``False``.
         enable_fractional_shares: Whether to enable trading fractional shares.
             Set to ``True`` for crypto trading. Defaults to ``False``.
         round_fill_price: Whether to round fill prices to the nearest cent.
diff --git a/src/pybroker/strategy.py b/src/pybroker/strategy.py
index bcde212c..63d86a43 100644
--- a/src/pybroker/strategy.py
+++ b/src/pybroker/strategy.py
@@ -73,6 +73,10 @@
     Optional,
     Union,
 )
+from typing_extensions import Concatenate, ParamSpec
+
+
+P = ParamSpec("P")
 
 
 def _between(
@@ -904,12 +908,12 @@ def set_slippage_model(self, slippage_model: Optional[SlippageModel]):
 
     def add_execution(
         self,
-        fn: Optional[Callable[[ExecContext], None]],
+        fn: Optional[Callable[Concatenate[ExecContext, P], None]],
         symbols: Union[str, Iterable[str]],
         models: Optional[Union[ModelSource, Iterable[ModelSource]]] = None,
         indicators: Optional[Union[Indicator, Iterable[Indicator]]] = None,
-        *args: Any,
-        **kwargs: Any,
+        *args: P.args,
+        **kwargs: P.kwargs,
     ):
         r"""Adds an execution to backtest.