add no cover

Author: Wh1isper

pydantic_ai_slim/pydantic_ai/models/anthropic.py

@@ -686,9 +686,11 @@ async def _map_message(  # noqa: C901
             content = m['content']
             if isinstance(content, str):
                 # Convert string content to structured format with cache_control
-                # This typically happens with assistant messages containing plain text
-                m['content'] = [
-                    {'text': content, 'type': 'text', 'cache_control': BetaCacheControlEphemeralParam(type='ephemeral')}
+                # This typically happens with tool responses
+                m['content'] = [  # pragma: no cover
+                    BetaTextBlockParam(
+                        text=content, type='text', cache_control=BetaCacheControlEphemeralParam(type='ephemeral')
+                    )
                 ]
             else:
                 # For structured content (lists), add cache_control to the last block