diff --git a/README.md b/README.md
index 26f4c352..6b65cda2 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@ Langfun is *simple and elegant*:
 *   An intuitive programming model, graspable in 5 minutes;
 *   Plug-and-play into any Python codebase, making an immediate difference;
 *   Comprehensive LLMs under a unified API: Gemini, GPT, Claude, Llama3, and more.
-*   Designed for agile developement: offering intellisense, easy debugging, with minimal overhead;
+*   Designed for agile development: offering intellisense, easy debugging, with minimal overhead;
 
 ## Hello, Langfun
 
diff --git a/langfun/core/agentic/action.py b/langfun/core/agentic/action.py
index 80419275..0b52b076 100644
--- a/langfun/core/agentic/action.py
+++ b/langfun/core/agentic/action.py
@@ -780,10 +780,11 @@ def append(self, item: TracedItem) -> None:
 
   def remove(self, item: TracedItem) -> None:
     """Removes an item from the sequence."""
-    index = self.items.index(item)
-    if index == -1:
-      raise ValueError(f'Item not found in execution trace: {item!r}')
-
+    try:
+      index = self.items.index(item)
+    except ValueError as exc:
+      raise ValueError(f'Item not found in execution trace: {item!r}') from exc
+    
     with pg.notify_on_change(False):
       self.items.pop(index)