AWS Bedrock Nova model produces different results based on line ending format

[MaxRepin]

Checkboxes for prior research

• I've gone through Developer Guide and API reference
• I've checked AWS Forums and StackOverflow.
• I've searched for previous similar issues and didn't find any solution.

Describe the bug

Description:

• Using \n (Unix) line endings produces incorrect responses
• Using \r\n (Windows) line endings produces correct responses
• Same prompt content, only line ending format differs
• Affects structured prompts with sections and rules

Impact:

• Inconsistent behavior between environments
• Forces developers to normalize line endings
• Could affect other users with similar issues

Test Case:

• Model: amazon.nova-lite-v1:0
• Region: eu-west-2
• Same prompt with \n vs \r\n produces different reasoning and responses

Regression Issue

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

SDK version number

@aws-sdk/package-name@version, ...

Which JavaScript Runtime is this issue in?

Node.js

Details of the browser/Node.js/ReactNative version

@aws-sdk/client-bedrock-runtime@3.891.0

Reproduction Steps

• Model: amazon.nova-lite-v1:0
• Region: eu-west-2

Observed Behavior

• Same prompt with \n vs \r\n produces different reasoning and responses

Expected Behavior

Most modern systems normalize line endings. Same prompt with \n vs \r\n should produce identical reasoning and responses.

Possible Solution

normalize line endings

Additional Information/Context

No response

[aBurmeseDev]

Hi @MaxRepin - thanks for reporting this.

I'm not sure if this's SDK issue but let me check against service model. Can you share your sample code and responses?

[github-actions]

This issue has not received a response in 1 week. If you still think there is a problem, please leave a comment to avoid the issue from automatically closing.