feat(cache): add TTL support to CachePoint for prompt caching

src/strands/models/bedrock.py

@@ -492,7 +492,11 @@ def _format_request_message_content(self, content: ContentBlock) -> dict[str, An
         """
         # https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_CachePointBlock.html
         if "cachePoint" in content:
-            return {"cachePoint": {"type": content["cachePoint"]["type"]}}
+            cache_point = content["cachePoint"]
+            result = {"type": cache_point["type"]}
+            if "ttl" in cache_point:
+                result["ttl"] = cache_point["ttl"]
+            return {"cachePoint": result}
 
         # https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_DocumentBlock.html
         if "document" in content:

src/strands/types/content.py

@@ -8,7 +8,7 @@
 
 from typing import Literal
 
-from typing_extensions import TypedDict
+from typing_extensions import NotRequired, TypedDict
 
 from .citations import CitationsContentBlock
 from .media import DocumentContent, ImageContent, VideoContent
@@ -66,9 +66,11 @@ class CachePoint(TypedDict):
 
     Attributes:
         type: The type of cache point, typically "default".
+        ttl: Optional TTL duration for cache entries. Valid values are "5m" (5 minutes) or "1h" (1 hour).
     """
 
     type: str
+    ttl: NotRequired[Literal["5m", "1h"]]
 
 
 class ContentBlock(TypedDict, total=False):

tests/strands/models/test_bedrock.py

@@ -2050,6 +2050,53 @@ def test_format_request_filters_cache_point_content_blocks(model, model_id):
     assert "extraField" not in cache_point_block
 
 
+def test_format_request_preserves_cache_point_ttl(model, model_id):
+    """Test that format_request preserves the ttl field in cachePoint content blocks."""
+    messages = [
+        {
+            "role": "user",
+            "content": [
+                {
+                    "cachePoint": {
+                        "type": "default",
+                        "ttl": "1h",
+                    }
+                },
+            ],
+        }
+    ]
+
+    formatted_request = model._format_request(messages)
+
+    cache_point_block = formatted_request["messages"][0]["content"][0]["cachePoint"]
+    expected = {"type": "default", "ttl": "1h"}
+    assert cache_point_block == expected
+    assert cache_point_block["ttl"] == "1h"
+
+
+def test_format_request_cache_point_without_ttl(model, model_id):
+    """Test that cache points work without ttl field (backward compatibility)."""
+    messages = [
+        {
+            "role": "user",
+            "content": [
+                {
+                    "cachePoint": {
+                        "type": "default",
+                    }
+                },
+            ],
+        }
+    ]
+
+    formatted_request = model._format_request(messages)
+
+    cache_point_block = formatted_request["messages"][0]["content"][0]["cachePoint"]
+    expected = {"type": "default"}
+    assert cache_point_block == expected
+    assert "ttl" not in cache_point_block
+
+
 def test_config_validation_warns_on_unknown_keys(bedrock_client, captured_warnings):
     """Test that unknown config keys emit a warning."""
     BedrockModel(model_id="test-model", invalid_param="test")