diff --git a/.changeset/certain-nice-caracara.md b/.changeset/certain-nice-caracara.md
new file mode 100644
index 00000000..9ffabdba
--- /dev/null
+++ b/.changeset/certain-nice-caracara.md
@@ -0,0 +1,5 @@
+---
+"stagehand": patch
+---
+
+fix: invalid_request_error when using anthropic cua client
diff --git a/stagehand/agent/anthropic_cua.py b/stagehand/agent/anthropic_cua.py
index df6c7a23..664edf0e 100644
--- a/stagehand/agent/anthropic_cua.py
+++ b/stagehand/agent/anthropic_cua.py
@@ -295,9 +295,13 @@ def _process_provider_response(
         if hasattr(response, "content") and isinstance(response.content, list):
             # Serialize Pydantic models from response.content for history
             try:
-                raw_assistant_content_blocks = [
-                    block.model_dump() for block in response.content
-                ]
+                for block in response.content:
+                    block_dict = block.model_dump()
+                    if isinstance(block_dict, dict):
+                        # Anthropic beta responses include a `caller` field on tool_use blocks
+                        # but the API rejects that key on subsequent requests.
+                        block_dict.pop("caller", None)
+                    raw_assistant_content_blocks.append(block_dict)
             except Exception as e:
                 self.logger.error(
                     f"Could not model_dump response.content blocks: {e}",
diff --git a/stagehand/context.py b/stagehand/context.py
index cd4b13c5..27ee327a 100644
--- a/stagehand/context.py
+++ b/stagehand/context.py
@@ -147,6 +147,7 @@ async def _handle_page_close(self, closing_page: StagehandPage):
         Uses the page switch lock to prevent race conditions with ongoing operations.
         """
         try:
+
             async def handle_with_lock():
                 async with self.stagehand._page_switch_lock:
                     if self.active_stagehand_page is not closing_page: