❗ NOTICE: stepfunctions-tasks: BedrockInvokeModel outputPath no longer passes output to next state

[clareliguori]

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Status: IN-PROGRESS

Overview:

Previously, the BedrockInvokeModel outputPath parameter could be used to select a portion of the model output to pass to the next state. This behavior aligns with how the parameter is documented "JSONPath expression to select select a portion of the state output to pass to the next state."
https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_stepfunctions_tasks.BedrockInvokeModel.html#outputpath

Now, the outputPath parameter is assumed to be an S3Uri where the model output should be saved. The parameter can no longer be used to select model output and pass it to the next state.

This behavior appears to have changed in f5dd73b

Complete Error Message:

Workaround:

Solution:

Revert existing code for encoding the path under S3Uri, and possibly introduce another variable in BedrockTaskProps instead of extending the existing TaskStateBaseProps.

Related Issues:

Regression Issue

• Select this option if this issue appears to be a regression.

Last Known Working CDK Version

2.150.0

Expected Behavior

In a BedrockInvokeModel task, set outputPath:

# Extract the response from the model
output_path="$.Body.content[0].text",

The Step Functions workflow definition is synthesized as:

"OutputPath": "$.Body.content[0].text",

When I execute the deployed Step Functions state machine, the model text output is passed as the output of the task.

"Here is a one sentence summary of ...."

Current Behavior

The outputPath parameter is synthesized as:

"Output": {
   "S3Uri": "$.Body.content[0].text"
}

When I execute the deployed Step Functions state machine, I get a validation exception:

The value for the S3Uri field is not recognized as a valid URI: $.Body.content[0].text

Reproduction Steps

This is my stack:
https://github.com/aws-samples/amazon-bedrock-serverless-prompt-chaining/blob/main/techniques/stacks/model_invocation.py

Possible Solution

I suggest reverting the change above, so that outputPath works as documented and expected. The input and output parameters were intended to distinguish between state that should be passed between states (inputPath/outputPath) vs destinations where input and output should be sourced from (input/output).

Additional Information/Context

No response

CDK CLI Version

2.155.0

Framework Version

No response

Node.js Version

v20.17.0

OS

Linux

Language

Python

Language Version

Python 3.12.3

Other information

No response

[pahud]

Hi @clareliguori

Thanks for the report. We've confirmed this a regression. We'll take actions immediately.

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[shikha372]

This issue has been fixed now in latest release (v2.156.0) under feature flag useNewS3UriParametersForBedrockInvokeModelTask which is enabled by default. New properties s3InputUri , s3OutputUri have been added under BedrockInvokeModelProps which can be used to populate S3 URI field dynamically the from previous runtime. To maintain the existing behaviour, you can set this feature flag to false but we recommend using the newly added properties.

Please let us know if you are still facing the issue.