705: Relentless in a Gentle Way

What It Covers

Marco Arment launches Unforgettable, a $20/year iOS and Mac reminder app built for ADHD-style brains that relentlessly re-notifies until tasks are completed, reads and writes directly to Apple's Reminders database, and uses CloudKit with a custom SkyBridge sync layer. The episode also covers Home Assistant for HVAC integration, Apple ID security throttling, and Anthropic's EU-mandated AI text watermarking via seeded pseudo-random number generation.

Key Questions Answered

• •ADHD-Focused App Design: When building productivity tools for users with attention difficulties, removing the ability to create undated tasks entirely — rather than offering a "someday" bucket — produces better outcomes. Roughly half of Unforgettable's beta users who initially complained about undated tasks being surfaced immediately ended up setting real dates or completing them, validating the design choice to force a due date or deletion rather than enable indefinite deferral.
• •Notification Spacing and Randomization: To prevent notification stack overwhelm — a common failure mode where iOS collapses multiple simultaneous alerts into a summary — Unforgettable spaces reminders by a user-configurable interval (default: 15 minutes) and randomizes daily delivery order using a date-seeded pseudo-random number generator. The same seed is shared across Mac and iPhone so both devices present tasks in identical randomized order, ensuring no task stays buried at the bottom indefinitely.
• •CloudKit as Metadata Layer for EventKit: Apple's EventKit API for Reminders exposes no mechanism to attach arbitrary metadata to tasks — no URL fields, no custom properties. Unforgettable solves this by maintaining a parallel CloudKit-backed Blackbird database (via an AI-generated SkyBridge sync layer) that stores per-task metadata like last-used snooze interval and delayed location trigger offsets, while leaving the canonical task data in the system Reminders database for full interoperability.
• •Mac App as Background Push Relay: iOS background refresh intervals create a gap where a reminder dictated to Siri may not appear in a third-party app for minutes. Unforgettable's Mac app monitors the Reminders database continuously and sends a CloudKit silent push notification to the iPhone app the moment a new task appears, dramatically reducing detection latency. Keeping the Mac app running persistently — rather than quitting it — is the recommended configuration for fastest cross-device sync.
• •Home Assistant vs. Homebridge for HVAC Integration: Homebridge functions as a thin HomeKit facade for non-native devices, while Home Assistant is a full automation platform with a steep initial learning curve but near-unlimited capability once understood. For a Daikin multi-zone mini-split system with a poor proprietary app, the recommended path is a $200 Home Assistant Green hardware device — plug into Ethernet, configure via browser — then install the Daikin integration and expose thermostats to HomeKit for voice control without touching Docker or Mac mini hosting.
• •AI Text Watermarking via Seeded Randomness: Anthropic's EU-compliant text watermarking works by replacing the standard arbitrary random number generator — used during word selection when multiple candidates are roughly equally probable — with a keyed pseudo-random generator. The resulting word choices are statistically indistinguishable to readers but detectable by anyone holding the key. Detection returns a probability score rather than a binary result, and reliability increases with output length, with approximately 200 words cited as a practical detection threshold.
• •App Store Naming and Search Optimization: Searching for a unique productivity app name in 2025 is constrained by thousands of live trademarks across task management, collaboration, and organization categories. Every common metaphor — elephants, nudge, waves, beacon, kona — resolves to an existing active product. LLM-generated name suggestions are consistently poor for this task. Once a name is chosen, omitting a clean title in favor of keyword-stuffed title and subtitle fields is necessary because App Store search ranking weights phrase proximity across title and subtitle fields heavily.