[BUG] Claude Code support for AWS credentials with MFA support

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Details -

• current claude code version

``
$ claude --version
2.0.73 (Claude Code)
``

• current aws cli version

``
$ aws --version
aws-cli/2.28.10 Python/3.13.6 Darwin/24.1.0 source/x86_64
``

• here are my aws environment settings,
• users have iam accounts with access-key, secret-key and mfa enabled.
• temporary credentials are created using the mfa token and the following properties are set,

```
# ensure no previous settings exists
unset AWS_ACCESS_KEY_ID; unset AWS_SECRET_ACCESS_KEY; unset AWS_SESSION_TOKEN

# set aws-account profile using existing aws credentials
export AWS_PROFILE=aws-account-profile-1

# generate temporary credentials with mfa
aws sts assume-role --role-arn arn:aws:iam::${AWS_ACCOUNT_ID}:role/${ROLE_NAME} --role-session-name ${SESSION_NAME} --serial-number arn:aws:iam::${AWS_ACCOUNT_ID}:mfa/mfa-device --duration-seconds 43200 --token-code xxxxx > /tmp/aws-token.json

# sample file - /tmp/aws-token.json
{
"Credentials": {
"AccessKeyId": "xxxxx",
"SecretAccessKey": "xxxxx",
"SessionToken": "xxxx",
"Expiration": "2025-12-19T05:57:00+00:00"
},
}

# set the temporary values from the tokens generated
export AWS_ACCESS_KEY_ID=$(cat /tmp/aws-token.json | jq -r .Credentials.AccessKeyId); export AWS_SECRET_ACCESS_KEY=$(cat /tmp/aws-token.json | jq -r .Credentials.SecretAccessKey); export AWS_SESSION_TOKEN=$(cat /tmp/aws-token.json | jq -r .Credentials.SessionToken);

# confirmed the aws cli is working using the temporary tokens

$ aws sts get-caller-identity
{
"UserId": "xxxx:xxxx",
"Account": "xxxx",
"Arn": "arn:aws:sts::xxxxx:assumed-role/xxxx/xxxxx"
}
```

• while starting up claude code and trying to use the anthropic modes from aws bedrock, I get the following error -

``
API Error: Profile ${AWS_ACCOUNT_NAME} requires multi-factor authentication, but no MFA code callback was provided.
``

• so far whatever I have researched, it seems claude code does honor these environment properties, so I am not sure why above issue will happen.

``
AWS_ACCESS_KEY_ID
AWS_SECRET_ACCESS_KEY
AWS_SESSION_TOKEN
``

What Should Happen?

The expectation is that like any other application, claude code will be able to honor the aws credentials with mfa authentication process.

Error Messages/Logs

Steps to Reproduce

The steps listed in the bug description, describes on how to reproduce the issue.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.73

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_