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Data + AI case study

Dayline
A clearer picture

Turns Family Link and YouTube activity into a nightly record, historical trends, app changes, and age-aware video review.

Explore Dayline See the data flow
PythonFastAPIGeminiGrok
Week view for Saturday 3 October, 4h 49m.
64 videos need a look
A missing night is not a zero
The problem

The day is split across two places.

Screen time is in Family Link. Video history is in YouTube.

  1. Family LinkScreen time and apps
  2. YouTubeVideo history
  3. Manual comparisonTime-consuming and inconsistent
  4. Missed contextHard to see the bigger picture
The solution

One evening.
Both sources.

Each night the record is stored. Through the day, videos are judged. Grok then writes the evening note and the app ideas from that stored night.

Family LinkDevice time, apps
YouTubeVideo history
Nightly collectorPulls and stores data
HistoryKeeps earlier days
GeminiThrough the day
GrokNote and ideas
DaylineOne view of the day
01 The evening note

A single grounded note for each night.

  • Stored through the cutoff
  • The day is not marked complete
  • Apps that held the time
  • A missing night is not a zero
Apps that night, and the total for the week.
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How it works

Family Link and YouTube are stored that night, through a cutoff.

A night that was not stored is left as a gap.

Grok writes the note from that stored night.

The day is not marked complete.

02 History & trends

Follow patterns across stored days.

  • Stored days only
  • A gap is a missing night
  • The day total is against the average of stored days
Year trends, stored days, and time against the week before.
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How the week is counted

The chart shows stored days only.

An empty day is a missing night, not a zero.

Today can be shown, and it is left out of the average because the day is not over.

03 Apps & change

Find apps that showed up, and the time they took.

  • New apps flagged
  • Time per app
  • Time over the last 7 stored days
  • Nothing is changed on the device
Apps from the last 7 stored days, including apps new on the device.
Recommendations: Worms Zone and Snake.io.
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Where the app list comes from

App time comes from Family Link.

A new app is one that was not there on the last pull.

Each row is that app's time over the last 7 stored days, not one night.

The list is a record. Nothing is changed on the device.

04 YouTube review

Video flags include a reason.

  • Gemini watches the opening
  • Needs a look is not a no
  • The reason sits next to the verdict
  • Grok does not judge the video
YouTube review of a video that needs a look.
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What the flag means

Gemini watches the opening and writes the reason.

Needs a look is not a no.

The reason sits on the row.

Grok writes the evening note. Grok does not judge the video.

AI does the repetitive reading.
The system keeps the context.

Gemini

Video review

Looks at videos through the day and writes a reason for each one, including when it is fine.

Grok

Evening intelligence

Writes the evening note from the stored night, and suggests apps from apps already used.

Technologies
  • Python
  • FastAPI
  • Jinja
  • Gemini API
  • Grok
  • Family Link
  • YouTube
Key takeaways
  • The night stores the record. Videos are judged through the day.
  • Missing days stay missing.
  • Gemini judges the videos and says why. Grok writes the note and the app ideas.