Add Private Feature Flag

Overview

Adds a new private feature flag to Ghost. Private flags appear in Labs settings under the "Private features" tab, visible only when developer experiments are enabled.

Read and follow the canonical feature flag guide before adding a flag. The guide covers when a Labs flag is appropriate, safe gating across server and Admin, testing, and the cleanup lifecycle.

Steps

1. Add the flag to ghost/core/core/shared/labs.js

   • Add the flag name (camelCase string) to the PRIVATE_FEATURES array.

2. Add a UI toggle in apps/admin/src/settings/advanced/labs/private-features.tsx

   • Add a new entry to the features array with title, description, and flag (must match the string in labs.js).

3. Run tests and update the config API snapshot

   • Unit: cd ghost/core && pnpm test:single test/unit/shared/labs.test.js
   • Update snapshots: cd ghost/core && pnpm test:single test/e2e-api/admin/config.test.js -u && pnpm test:single test/e2e-api/admin/settings.test.js -u
   • Review both snapshot diffs to confirm only your new flag was added.

Notes

• No database migration is needed. Labs flags are stored in a single JSON labs setting.
• The flag name must be identical in labs.js, private-features.tsx, and the snapshots.
• Flags are camelCase strings (e.g. welcomeEmailDesignCustomization).
• For public beta flags (visible to all users), add to PUBLIC_BETA_FEATURES in labs.js instead and add the toggle to apps/admin/src/settings/advanced/labs/beta-features.tsx.