Boto3 bedrock.list_guardrails() failing if passing the retrieved nextToken among with a guardrail_id

[FraqMasq]

Describe the bug

Bedrock ListGuardrails API fails on pagination

Description

When attempting to paginate through guardrails using the Bedrock list_guardrails API, the second API call fails when passing the received nextToken. The first call succeeds and returns a nextToken, but using this token in a subsequent request results in an error. Notice that the very same code, invoked without passing the guardrailIdentifier is working correctly.

Current Code

First call succeeds
response = bedrock.list_guardrails( guardrailIdentifier=guardrail_id, maxResults=100, )
Second call fails when using the nextToken from the first response
response = bedrock.list_guardrails( guardrailIdentifier=guardrail_id, maxResults=100, nextToken=next_token # Token received from previous response )

Regression Issue

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

Expected Behavior

second invocation should retrieve correctly the guardrails versions.

Current Behavior

Second invocation of API, passing the nextToken just retrieved, result in error:

Error

An error occurred (InternalServerException) when calling the ListGuardrails operation (reached max retries: 4): The system encountered an unexpected error during processing.

Reproduction Steps

`
def get_latest_guardrail_version(guardrail_id, guardrail_region):
try:
bedrock = boto3.client("bedrock", region_name=guardrail_region)
next_token = None

    while True:
        if not next_token:
            response = bedrock.list_guardrails(
                guardrailIdentifier=guardrail_id,
                maxResults=10,
            )
        else:
            response = bedrock.list_guardrails(
                guardrailIdentifier=guardrail_id,
                maxResults=10,
                nextToken=next_token
            )

        next_token = response.get("nextToken")
        if not next_token:
            break

`

Possible Solution

No response

Additional Information/Context

No response

SDK version used

1.35.97

Environment details (OS name and version, etc.)

Python 3.9, Windows 11

[RyanFitzSimmonsAK]

Hi @FraqMasq, thanks for reaching out. The Bedrock service team is aware of this bug, and is working on a fix. I'll put any updates in this issue.

Ticket # for internal use : P155609965

[RyanFitzSimmonsAK]

This issue has been resolved by a fix from the service team. Thanks for reporting this, please feel free to re-open this issue if you're still having problems.