Why does the assistant throw a MIME type error for CSV files?

Below is some background and a couple of suggestions to help troubleshoot the issue.

Background

According to the documentation, CSV files are supported for Assistants and the Code Interpreter. In the Supported Files lists, CSV files appear with MIME types such as text/csv (and in one table, also with application/csv). However, even though CSV is a supported format, the error

  Failed to index file: Unsupported file file-h58JiHmhtRMps5ZGB4vxzhZ0 type: application/csv

indicates that the file’s MIME type wasn’t accepted in your particular case.

Suggestions

1. Verify File Encoding and Content-Type
    Ensure that your CSV file is encoded in one of the accepted encodings (UTF-8, UTF-16, or ASCII). Although CSV is listed as supported, if the file encoding isn’t one of these, the file might be rejected.
    Also, verify that when you upload the file, the content type is correctly set (for instance, forcing it to be text/csv rather than application/csv).

2. Review File Upload Parameters
    Make sure that the file is being uploaded with the correct purpose (e.g., purpose='assistants' as in the provided example) and that no extra headers or parameters are inadvertently changing the MIME type.

3. If the Issue Persists
    This could be due to how the file is auto-detected on the backend. In that case, consider re-saving or re-encoding the CSV file and trying again. If you continue to get the error, it might be useful to reach out to support with details of your file’s encoding and headers.

Following these steps should help resolve the MIME type mismatch causing the error.