feat: enable retrieval tool by default, update tool spec prompt

Author: lizradway

src/strands/vended_plugins/context_offloader/plugin.py

@@ -42,7 +42,7 @@
 from ...tools.decorator import tool
 from ...types.content import Message
 from ...types.tools import ToolContext, ToolResult, ToolResultContent
-from .storage import InMemoryStorage, Storage
+from .storage import Storage
 
 if TYPE_CHECKING:
     from ...agent.agent import Agent
@@ -88,7 +88,7 @@ class ContextOffloader(Plugin):
         max_result_tokens: Offload results whose estimated token count exceeds this threshold.
         preview_tokens: Number of tokens to keep as a text preview in context.
         include_retrieval_tool: Whether to register the ``retrieve_offloaded_content`` tool.
-            Defaults to False.
+            Defaults to True.
 
     Example:
         ```python
@@ -109,7 +109,7 @@ def __init__(
         max_result_tokens: int = _DEFAULT_MAX_RESULT_TOKENS,
         preview_tokens: int = _DEFAULT_PREVIEW_TOKENS,
         *,
-        include_retrieval_tool: bool | None = None,
+        include_retrieval_tool: bool = True,
     ) -> None:
         """Initialize the ContextOffloader plugin.
 
@@ -121,9 +121,7 @@ def __init__(
                 Uses tiktoken for exact slicing when available, falls back to
                 chars/4 heuristic. Defaults to ``_DEFAULT_PREVIEW_TOKENS`` (1,000).
             include_retrieval_tool: Whether to register the ``retrieve_offloaded_content``
-                tool so the agent can fetch offloaded content. Defaults to True for
-                ``InMemoryStorage`` (where the retrieval tool is the only access
-                method) and False for other backends.
+                tool so the agent can fetch offloaded content. Defaults to True.
 
         Raises:
             ValueError: If max_result_tokens is not positive, preview_tokens is negative,
@@ -136,9 +134,6 @@ def __init__(
         if preview_tokens >= max_result_tokens:
             raise ValueError("preview_tokens must be less than max_result_tokens")
 
-        if include_retrieval_tool is None:
-            include_retrieval_tool = isinstance(storage, InMemoryStorage)
-
         self._storage = storage
         self._max_result_tokens = max_result_tokens
         self._preview_tokens = preview_tokens
@@ -278,7 +273,10 @@ async def _handle_tool_result(self, event: AfterToolCallEvent) -> None:
             "Use your available tools to selectively access the data you need."
         )
         if self._include_retrieval_tool:
-            guidance += "\nYou can also use retrieve_offloaded_content with a reference to get the full content."
+            guidance += (
+                "\nOnly use retrieve_offloaded_content as a fallback"
+                " if the data cannot be accessed using your existing tools."
+            )
 
         preview_text = (
             f"[Offloaded: {len(content)} blocks, ~{token_count:,} tokens]\n"

tests/strands/vended_plugins/context_offloader/test_plugin.py

@@ -468,14 +468,14 @@ def test_retrieval_tool_registered_when_enabled(self, plugin):
         tool_names = [t.tool_name for t in plugin.tools]
         assert "retrieve_offloaded_content" in tool_names
 
-    def test_retrieval_tool_registered_by_default_for_inmemory(self):
+    def test_retrieval_tool_registered_by_default(self):
         plugin = ContextOffloader(storage=InMemoryStorage())
         plugin.init_agent(MagicMock())
         tool_names = [t.tool_name for t in plugin.tools]
         assert "retrieve_offloaded_content" in tool_names
 
-    def test_retrieval_tool_not_registered_by_default_for_file_storage(self, tmp_path):
-        plugin = ContextOffloader(storage=FileStorage(artifact_dir=str(tmp_path)))
+    def test_retrieval_tool_not_registered_when_disabled(self):
+        plugin = ContextOffloader(storage=InMemoryStorage(), include_retrieval_tool=False)
         plugin.init_agent(MagicMock())
         tool_names = [t.tool_name for t in plugin.tools]
         assert "retrieve_offloaded_content" not in tool_names