Unexpected Bedrock Agent Behavior: Post-Processing Prompt Overridden and Ignored During Knowledge Base Orchestration

The behavior you're experiencing with your Bedrock Agent is indeed unexpected and seems to be inconsistent with the intended functionality. Based on the information provided, there are a few potential explanations and steps you can take to address this issue:

1. Prompt Override: The unexpected overwriting of your custom post-processing prompt with the default prompt is concerning. This should not happen without user intervention. It's possible that there was an unannounced update or a bug in the system that caused this. To address this:

   • Double-check your agent configuration to ensure the custom post-processing prompt is still in place.
   • If it has been overwritten, restore your custom prompt and save the changes.
   • Document the exact time and date when you notice any unexpected changes to your configuration.

2. Post-Processing Ignored During Knowledge Base Search: The behavior where the post-processing step is bypassed when a knowledge base search is involved is not the intended functionality of Bedrock Agents. Normally, the post-processing step should be applied to all responses, including those generated from knowledge base searches. To troubleshoot this:

   • Verify that the post-processing prompt state is set to "ENABLED" in your agent configuration.
   • Check if there have been any recent changes to your knowledge base or orchestration settings that might be interfering with the post-processing step.
   • Review your orchestration prompt to ensure it's not inadvertently instructing the agent to bypass post-processing.

3. Prompt Configuration: Ensure that your prompt configuration is correctly set up:

   • Confirm that the "Override template defaults" option is turned on for your post-processing prompt.
   • Verify that both the orchestration and knowledge base response generation steps are set to "ENABLED".
   • Check if the "promptCreationMode" is set to "OVERRIDE" for your post-processing step.

4. Custom Parser: If you're using a custom parser Lambda function, ensure it's correctly configured and functioning as expected. The parser plays a crucial role in how the agent processes and formats its final response.

5. Logging and Monitoring: Enable detailed logging for your agent if you haven't already. This can help you track the flow of information through the various processing steps and identify where the breakdown is occurring.

6. Test with Simplified Scenarios: Try testing your agent with simple queries that don't require knowledge base access. This can help isolate whether the issue is specific to knowledge base interactions or if it's a more general problem with the post-processing step.

7. Contact AWS Support: Given that this behavior appeared suddenly without changes on your end, and it's significantly impacting your application's core functionality, it would be advisable to contact AWS Support. They can investigate if there have been any recent changes or known issues with Bedrock Agents that might explain this behavior.

Remember, Bedrock Agents is a relatively new service and may still be evolving. It's possible that recent updates or changes have inadvertently affected your specific use case. Documenting your observations in detail and sharing them with AWS support can help both in resolving your immediate issue and in improving the service for all users.

In the meantime, you might consider implementing a temporary workaround in your application logic to enforce the Socratic style responses, even if the agent's output doesn't match your expectations. This could involve post-processing the agent's responses on your application server before presenting them to the end-user.

Sources
Configure advanced prompts - Amazon Bedrock
PromptConfiguration - Amazon Bedrock
PromptConfiguration - Amazon Bedrock