fix(bedrock): Handle string or dict for guardContent.text

src/strands/models/bedrock.py

@@ -394,9 +394,21 @@ def _format_request_message_content(self, content: ContentBlock) -> dict[str, An
 
         # https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_GuardrailConverseContentBlock.html
         if "guardContent" in content:
-            guard = content["guardContent"]
-            guard_text = guard["text"]
-            result = {"text": {"text": guard_text["text"], "qualifiers": guard_text["qualifiers"]}}
+            # content["guardContent"] can be a dict-like structure. Annotate as Any for mypy.
+            guard: Any = content["guardContent"]
+            guard_text: Any = guard.get("text")
+
+            # Guard text may be provided either as a plain string or as a dict with 'text' and optional 'qualifiers'.
+            if isinstance(guard_text, str):
+                result = {"text": {"text": guard_text}}
+            else:
+                # treat as mapping-like when not a string, be defensive using .get()
+                text_val = guard_text.get("text") if isinstance(guard_text, dict) else None
+                result = {"text": {"text": text_val}}
+                qualifiers = guard_text.get("qualifiers") if isinstance(guard_text, dict) else None
+                if qualifiers is not None:
+                    result["text"]["qualifiers"] = qualifiers
+
             return {"guardContent": result}
 
         # https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_ImageBlock.html

tests/strands/models/test_bedrock.py

@@ -1600,6 +1600,48 @@ def test_format_request_filters_document_content_blocks(model, model_id):
     assert "metadata" not in document_block
 
 
+def test_format_request_guard_content_with_qualifiers(model, model_id):
+    """Test guardContent formatting when qualifiers are present."""
+    messages = [
+        {
+            "role": "user",
+            "content": [{"guardContent": {"text": {"text": "guarded text", "qualifiers": ["q1", "q2"]}}}],
+        }
+    ]
+
+    formatted = model.format_request(messages)
+    guard_block = formatted["messages"][0]["content"][0]["guardContent"]
+    assert guard_block == {"text": {"text": "guarded text", "qualifiers": ["q1", "q2"]}}
+
+
+def test_format_request_guard_content_without_qualifiers(model, model_id):
+    """Test guardContent formatting when qualifiers are not present."""
+    messages = [
+        {
+            "role": "user",
+            "content": [{"guardContent": {"text": {"text": "guarded text no qualifiers"}}}],
+        }
+    ]
+
+    formatted = model.format_request(messages)
+    guard_block = formatted["messages"][0]["content"][0]["guardContent"]
+    assert guard_block == {"text": {"text": "guarded text no qualifiers"}}
+
+
+def test_format_request_guard_content_text_as_string(model, model_id):
+    """Test guardContent formatting when the text field is a plain string."""
+    messages = [
+        {
+            "role": "user",
+            "content": [{"guardContent": {"text": "plain guard text"}}],
+        }
+    ]
+
+    formatted = model.format_request(messages)
+    guard_block = formatted["messages"][0]["content"][0]["guardContent"]
+    assert guard_block == {"text": {"text": "plain guard text"}}
+
+
 def test_format_request_filters_nested_reasoning_content(model, model_id):
     """Test deep filtering of nested reasoningText fields."""
     messages = [