I have checked that the SDK documentation doesn't solve my issue.

• Yes I've checked them.

I have checked that the API documentation doesn't solve my issue.

• Yes I've checked them.

I have checked that the Box Developer Forums doesn't solve my issue.

• Yes I've checked them.

I have searched Issues in this repo and my issue isn't already reported.

• Yes I've checked them.

Describe the bug

API request errors, for example, are missing on stderr as process.stderr.setEncoding('utf8') is incorrectly called as below:

process.stderr doesn't have setEncoding so this line should be removed.

Expected behavior

API request errors are correctly emitted on stderr.

Steps to reproduce

Upload the same file twice:

$ box files:upload --parent-id=0 foo.txt > 1 2> 2
$ box files:upload --parent-id=0 foo.txt > 1 2> 2
$ cat 2

where 2 should have the entry like below, but doesn't.

Conflicts:
    Type: file
    ID: '.............'
    File Version:
        Type: file_version
        ID: '.............'
        SHA1: ........................................
    Sequence ID: '0'
    ETag: '0'
    SHA1: ........................................
    Name: foo.txt

Authentication method used in your application

User Authentication (OAuth 2.0)

App Access Level

App Access Only

What is Box CLI Version and Node used?

@box/cli/4.0.1 darwin-arm64 node-v22.14.0

What is your Operating System Version?

macOS Sequoia 15.3.2