Custom Fields created via API don't appear on new tickets

I'm having an issue where custom fields I'm creating via the API aren't appearing on new tickets as I would expect them to. This JSON is the result of querying my custom fields via the API, the first record having been created by the API and the second manually. When I create a new task in the (ID 'IEAE5CVJI4YSTAUN') space, I see the second custom field but not the first. Let me know where I'm going wrong.

Thanks,
Scott

          {'accountId': 'IEAE5CVJ',
           'id': 'IEAE5CVJJUACTVMY',
           'settings': {'inheritanceType': 'All', 'readOnly': False},
           'sharedIds': [],
           'spaceId': 'IEAE5CVJI4YSTAUN',
           'title': 'clientName',
           'type': 'Text'}

          {'accountId': 'IEAE5CVJ',
           'id': 'IEAE5CVJJUACTVON',
           'settings': {'inheritanceType': 'All', 'readOnly': False},
           'sharedIds': [],
           'spaceId': 'IEAE5CVJI4YSTAUN',
           'title': 'projectName',
           'type': 'Text'}

And here's what my query to create a custom field looks like.

import httpx
import os
from dotenv import load_dotenv
from pprint import pprint

# Load the bearer token from .env
load_dotenv()
BEARER_TOKEN = os.getenv("WRIKE_BEARER_TOKEN")
HEADERS = {"Authorization": "bearer " + BEARER_TOKEN}

url = "https://app-us2.wrike.com/api/v4"

def main():
    # Add clientName customField
    query = "/customfields"
    data = {
        "title": "clientName",
        "type": "Text",
        "spaceId": "IEAE5CVJI4YSTAUN",
    }
    type = "POST"

    r = httpx.post(url + query, headers=HEADERS, data=data)

    pprint(r.json())

if __name__ == "__main__":
    main()