Hi @BENNIE_ALIBANGA, I had a look into this for you.
No, there’s no extra toml field. When a discount function is linked to a settings UI extension through the [extensions.ui] handle like yours, Shopify shows the extension in the discount type picker and registers the app intent for you. Your description matches that documented flow, and since discountAutomaticAppCreate, the settings form, and the function all work, nothing in what you’ve shared points at a configuration gap.
That leaves the picker itself. Similar reports of app discount types intermittently missing from the Create discount menu are being investigated. A hard refresh may not be enough in that kind of case, so open the same store with the same admin account in a fresh private/incognito window and see whether your type shows up. A session that starts without your usual admin data makes it a useful comparison either way.
If it’s still missing that way, this’d be worth opening a ticket with our Support team. You can do so via the Partner Help Center → “Chat with a human”