Merge pull request #19919 from lizhen921/fix/anthropic-cache-control-null-issue

fix(anthropic): remove explicit cache_control null in tool_result content

litellm/litellm_core_utils/prompt_templates/factory.py

@@ -1677,13 +1677,16 @@ def convert_to_anthropic_tool_result(
         ] = []
         for content in content_list:
             if content["type"] == "text":
-                anthropic_content_list.append(
-                    AnthropicMessagesToolResultContent(
-                        type="text",
-                        text=content["text"],
-                        cache_control=content.get("cache_control", None),
-                    )
-                )
+                # Only include cache_control if explicitly set and not None
+                # to avoid sending "cache_control": null which breaks some API channels
+                text_content: AnthropicMessagesToolResultContent = {
+                    "type": "text",
+                    "text": content["text"],
+                }
+                cache_control_value = content.get("cache_control")
+                if cache_control_value is not None:
+                    text_content["cache_control"] = cache_control_value
+                anthropic_content_list.append(text_content)
             elif content["type"] == "image_url":
                 format = (
                     content["image_url"].get("format")