Worked out from what I already leave behind.
A short film about this is coming.
It builds a picture of what is going on from things I already leave behind. So it almost never has to ask me anything.
Three parts, and not one of them is my phone.
One place everything lands: mail, chats, meetings, sleep, commits, what I read.
One writer, so it is the record and not a copy. Nothing is ever edited: a change lands as a new row beside the old one, and the history stays. Nothing downstream goes back to the original — it reads what already landed.
I talk more than I type. Most of what I take on goes out as a voice note.
Those notes are transcribed and kept as text beside the message. Chats too. Before that, a spark said out loud on Tuesday evaporated on Tuesday.
That text is what the miners read.
I wanted to know where I am without changing how I live. So it reads small clues instead of tracking me. Each clue is a vote, and each vote carries how sure it is. It asks one question, and only when the votes disagree.
For a week in Provincetown the planner kept prescribing a gym 250 miles away. Both ways it had to know I had left were blind: Provincetown is in my home timezone, and my calendar entry for the trip is one word, ptown. A line in my own notes had said where I was. Nothing read it.
what it looks at
one answer
A place, how long it holds, and how sure it is.
Two clues that agree carry it. One alone hedges. Two that disagree take the majority, and ask. A failed feed counts as a clue, so a dead calendar never reads as a week at home.
what it changes
Two lines of its constitution decided the shape.
The hedge rides the answer. Nothing downstream re-derives it.
NEVER inferred: GPS, Find My, network beacons, photo EXIF, IP geolocation, or another person’s calendar read as his location. the first lines of the module, above the code that does the work
GPS was never the easy option. Where I have been in a day is not where I will sleep, and sleeping is the question. A useful reading means a ping late at night, which wakes the phone and burns battery — and makes the whole thing depend on my phone.
It does not geocode either: a geocoder that turns “Stay at a bed & breakfast” into a plausible wrong point is the confident wrong answer this exists to stop. The place names come from a short list inside the system.
It never asks whether I am home, never about a trip more than a day out, never twice about the same trip.
This page is not where I am. It is how the answer gets made. The other four ideas are on the home page.