Validations:

The name field is required. If only the name is provided without additional data, a custom set will be created with no items, and access will be granted to all teams within the organization.
If the teams field is provided, it must contain valid team IDs belonging to the organization.
If an items field is included in the data property:
- The items will appear in the custom set in the same order they were specified.
- Each item must include an item_name field, which is required.
- Other fields within each item (e.g., reference_id, score, color, is_flagged) are optional.

When to expect errors:

400 Bad Request:

401 Unauthorized

The provided API key is invalid or missing.
You attempt to create a custom set for a team that you do not have permission to access.

404 Not Found