WP-CLI, the WordPress REST API, and the new Abilities API serve different callers at different layers of the same stack. WP-CLI runs PHP directly on the server for bulk operations, migrations, and deploys. The REST API exposes WordPress over HTTP for browsers, mobile apps, and headless frontends. The Abilities API, introduced in WordPress 6.9, lets plugins register named, schema-described capabilities that AI agents can safely discover and execute without needing raw endpoint access. Rather than competing, the three layers complement each other: Abilities often surface over REST, which runs on the same PHP WP-CLI drives. The decision rule is simple — the closer and more trusted the caller, the lower in the stack you go; the more autonomous and remote, the higher you climb.
