Developer Builds Self-Deleting macOS launchd Job to Auto-Handle Future API Change

A developer has shared a technique for scheduling a one-time macOS launchd job that automatically executes on a specific future date and then removes itself. The approach was designed to handle the end-of-life of the Fable 5 AI model on July 7, 2026, by rewriting a configuration file to switch to a different model. The solution uses three components: a date gate that skips execution until the target day, a safe JSON rewrite using jq with a backup and temp-file verification, and a self-unload command that removes the job after it runs. Because launchd cannot natively schedule a truly one-time calendar event, the script compensates with idempotency checks to prevent redundant rewrites. The method offers an alternative to calendar reminders or always-on daemons for managing known, future breaking changes in software configurations.