diff --git a/src/anthropic/lib/bedrock/_auth.py b/src/anthropic/lib/bedrock/_auth.py
index 0a8b2109d..77e74aa68 100644
--- a/src/anthropic/lib/bedrock/_auth.py
+++ b/src/anthropic/lib/bedrock/_auth.py
@@ -56,8 +56,9 @@ def get_auth_headers(
     # The connection header may be stripped by a proxy somewhere, so the receiver
     # of this message may not see this header, so we remove it from the set of headers
     # that are signed.
+    # Note: HTTP/2 requests don't have a Connection header, so we safely remove it only if present.
     headers = headers.copy()
-    del headers["connection"]
+    headers.pop("connection", None)
 
     request = AWSRequest(method=method.upper(), url=url, headers=headers, data=data)
     credentials = session.get_credentials()
diff --git a/src/anthropic/lib/tools/_beta_runner.py b/src/anthropic/lib/tools/_beta_runner.py
index f466c1534..562e3cf6f 100644
--- a/src/anthropic/lib/tools/_beta_runner.py
+++ b/src/anthropic/lib/tools/_beta_runner.py
@@ -88,6 +88,8 @@ def set_messages_params(
         if callable(params):
             params = params(self._params)
         self._params = params
+        self._cached_tool_call_response = None
+        self._messages_modified = True
 
     def append_messages(self, *messages: BetaMessageParam | BetaMessage) -> None:
         """Add one or more messages to the conversation history.