Sprint 3: Privacy-First Spatial Intelligence

A diary isn't just a list of events; it's a narrative of space and time. In Sprint 3, we bridged the gap between raw data and visual storytelling by integrating CoreLocation, MapKit, and the Photos framework.

Spatial context: more than just coordinates

We implemented a custom location provider that identifies significant locations visited throughout the day. Instead of just logging GPS coordinates, the local processing pipeline turns these into meaningful "Significant Locations" (e.g., "Michigan Central Station" vs. "2001 15th St").

Key achievements in Sprint 3:

• MapKit integration: the new timeline view features an interactive map showing the day's journey.
• Privacy-first geofencing: all location processing happens on-device. No location data is sent to external APIs for reverse geocoding; Apple's native frameworks keep the "where" private.

Visual context: reliving the moment

A photo is worth a thousand words, and in the diary app, it's the anchor of the narrative. We integrated the Photos framework to fetch relevant highlights from the user's library for each diary entry.

• Dynamic highlights: the diary automatically pairs photos with the locations and events they correspond to.
• Zero-knowledge photos: we only store local identifiers (PHAsset IDs). The actual image data never leaves the encrypted on-device storage.

Narrative generation, on-device

The most significant technical leap in this sprint is the upgrade to the summary service. A local model-context server now acts as a compute delegate, generating narratives that weave together:

• The music you listened to
• The meetings you attended
• The places you visited
• The photos you took

The result is a cohesive summary of the day that reads naturally but is entirely automated and private.

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This is a private project. No App Store release is planned.