feat: add additional error case where no tool uses were fixed

Author: dbschmigelski

src/strands/agent/conversation_manager/recover_tool_use_on_max_tokens_reached.py

@@ -38,6 +38,7 @@ async def recover_tool_use_on_max_tokens_reached(agent: "Agent", exception: MaxT
         raise exception
 
     valid_content: list[ContentBlock] = []
+    has_corrected_content = False
     for content in incomplete_message["content"]:
         tool_use: ToolUse | None = content.get("toolUse")
         if not tool_use:
@@ -57,10 +58,15 @@ async def recover_tool_use_on_max_tokens_reached(agent: "Agent", exception: MaxT
                     f"to maximum token limits being reached."
                 }
             )
+            has_corrected_content = True
         else:
             # ToolUse was invalid for an unknown reason. Cannot correct, return without modifying
             raise exception
 
+    if not has_corrected_content:
+        # No ToolUse were modified, meaning this method could not have resolved the root cause
+        raise exception
+
     valid_message: Message = {"content": valid_content, "role": incomplete_message["role"]}
     agent.messages.append(valid_message)
     agent.hooks.invoke_callbacks(MessageAddedEvent(agent=agent, message=valid_message))

tests/strands/agent/conversation_manager/test_recover_tool_use_on_max_tokens_reached.py

@@ -128,23 +128,30 @@ async def test_recover_tool_use_on_max_tokens_reached_with_valid_tool_use():
     mock_invoke_callbacks.assert_not_called()
 
 
+@pytest.mark.parametrize(
+    "content,description",
+    [
+        ([], "empty content"),
+        ([{"text": "Just some text with no tools to edit."}], "text-only content"),
+    ],
+)
 @pytest.mark.asyncio
-async def test_recover_tool_use_on_max_tokens_reached_with_empty_content():
+async def test_recover_tool_use_on_max_tokens_reached_with_empty_content(content, description):
     """Test that an exception that is raised without recoverability, re-raises exception."""
     agent = Agent()
     # Mock the hooks.invoke_callbacks method
     mock_invoke_callbacks = Mock()
     agent.hooks.invoke_callbacks = mock_invoke_callbacks
     initial_message_count = len(agent.messages)
 
-    incomplete_message: Message = {"role": "assistant", "content": []}
+    incomplete_message: Message = {"role": "assistant", "content": content}
 
     exception = MaxTokensReachedException(message="Token limit reached", incomplete_message=incomplete_message)
 
     with pytest.raises(MaxTokensReachedException):
         await recover_tool_use_on_max_tokens_reached(agent, exception)
 
-    # Should not add any message since content is empty
+    # Should not add any message since there's nothing to recover
     assert len(agent.messages) == initial_message_count
 
     # Verify that the MessageAddedEvent callback was NOT invoked