autoPromotionEnabled: true, not auto promoting with minimal promotionTemplate

[lknite]

I'm using the verification step to perform work within the analysistemplate, triggering a job when there is new freight.

Because I'm focused on the verification step, and taking advantage of kargo's freight mechanism, I just need the minimum in the promotionTemplate.

Currently I have:

  promotionTemplate:
    spec:
      steps:
      - uses: http
        config:
          url: https://redacted:6443
          successExpression: response.status == 401
          failureExpression: response.status == 123
          insecureSkipTLSVerify: true

projectconfig.yaml:

apiVersion: kargo.akuity.io/v1alpha1
kind: ProjectConfig
metadata:
  name: kargo-addons-cert-manager-promote-containers
spec:
  promotionPolicies:
  - stage: dev
    autoPromotionEnabled: true
  - stage: staging
    autoPromotionEnabled: true
  - stage: prod
    autoPromotionEnabled: true

Auto promotion isn't working, but if I click to promote things the promotion is successful.

What's the minimum required for the autoPromotionEnabled to work?