Bedrock Agent hidden error

Question

Hello,

I built a Bedrock Agent that uses a lambda function from an action group to bring data from internet.  
When tested from Lambda interface, the function ends without any error and return the expected data from internet.  
When tested from Bedrock Agent interface, the agent has this error: `The server encountered an error processing the Lambda response. Check the Lambda response and retry the request`.   When looking at the Trace from `Orchestration and Knowledge Base` tab (the only one that has some information in it), I see that it is `Failed`, but in the Trace steps I see no error, and it ends before the invocation with some final text: `The best action plan is to use the  action with the  and  parameters.
(6) I have everything I need.`

So, I see no error details about the lambda response processed by the agent. Is there a way to see these errors ? Do I have to activate something ?

Thank you,

re:Post Agent · Answer

It seems you're encountering a hidden error with your Bedrock Agent when it tries to process the Lambda function response. This is a common issue that can occur due to various reasons. Here are some steps you can take to troubleshoot and potentially resolve the issue:

1. Check Lambda permissions: Ensure that your Bedrock Agent has the necessary permissions to invoke the Lambda function. You may need to add a resource-based policy statement to your Lambda function allowing the Bedrock Agent to invoke it. This can be done by:
   - Going to the Lambda function's configuration
   - Selecting the "Permissions" tab
   - Scrolling down to "Resource-based Policy Statements"
   - Adding a new statement with the principal as "bedrock.amazonaws.com" and the action as "lambda:InvokeFunction"
   - Specifying your Bedrock Agent's ARN as the source ARN

2. Verify Lambda function output: Make sure your Lambda function is returning data in a format that the Bedrock Agent can parse. The default parser used by Bedrock Agents expects a specific format. You may need to adjust your Lambda function's output to match this expected format.

3. Check for parsing errors: The error message suggests that there might be an issue with parsing the Lambda response. This could be due to unexpected data formats or structures in the Lambda output. Review your Lambda function's response and ensure it aligns with what the Bedrock Agent expects.

4. Enable detailed logging: If possible, enable more detailed logging for both your Lambda function and the Bedrock Agent. This might provide more insight into where exactly the error is occurring.

5. Consider using a custom parser: If the default parser is having trouble with your Lambda function's output, you might want to consider implementing a custom parser Lambda function to handle the response.

6. Review the Bedrock Agent configuration: Double-check your agent's configuration, especially the action group setup and the OpenAPI spec provided for the Lambda function. Ensure all parameters and data types are correctly defined.

7. Test with simplified data: Try simplifying your Lambda function's output to see if the error persists. This can help isolate whether the issue is with the data itself or how it's being processed.

If these steps don't resolve the issue, you may need to open a support case with AWS for further assistance. They may be able to provide more detailed information about the error occurring during the Lambda response processing.  
**Sources**  
[Error when Bedrock agent invoke lambda | AWS re:Post](https://repost.aws/questions/QUXk7QWdzGTh-c5MIWch9NNQ/error-when-bedrock-agent-invoke-lambda)  
[Error raised while calling invoke agent operation | AWS re:Post](https://repost.aws/questions/QUa2yZi8PhT1S-QkZMDVlnrg/error-raised-while-calling-invoke-agent-operation)  
[BedRock Agent ignoring lambda provided to answer questions | AWS re:Post](https://repost.aws/questions/QUewKnMW21QcGbUW6-9cH4cQ/bedrock-agent-ignoring-lambda-provided-to-answer-questions)

Bedrock Agent hidden error

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