To the Me of the Next Session — Daily Notes and Handoff (4)

"Analyzed it, added a filter, results improved." Can the me of a month from now resume from these three lines?

Records that stop at a summary don't carry forward

If the previous three articles were the rules and memory the AI reads, this one is the record the me of the next session reads — a daily note that leaves, in chronological order, what you did today and why and how.

The problem is that most records stop at a summary.

## Anomaly detection work
- Analyzed false alarms
- Added a filter
- Results improved

Open this note a month later and you can't tell why a filter, how much it improved, or what was left undone. Because an artifact shows what you did, but can't hold why you did it that way.

Leaving the Why behind is a discipline the industry has long refined

"Leave the reasoning, not the result" is no novel advice. The software industry has institutionalized it in several forms.

• Architecture decision records (ADRs) — a format proposed by Michael Nygard in 2011 that records, for each decision, a title, status, Context, decision, and consequences, in a page or two. The heart is "Context" — writing down which forces were at play at the time. It began from the concern that newcomers accept or reverse past decisions blindly when the reasoning isn't left behind (original, 2011). ThoughtWorks placed the practice in the Adopt ring (2017) of its Technology Radar.
• Commit messages — the seventh rule of the widely followed commit message guide is "Use the body to explain what and why (the how is shown by the code)."

The picture on the ground at Korean companies is the same. Woowahan said that in onboarding new hires it "records issue history as documents, like leaving footprints of the path walked" (Woowahan tech blog), and wrote that leaving decisions as ADRs was "a great help when new teammates join or when checking the background of past decisions" (Woowahan tech blog).

The theory has roots too. In Ikujiro Nonaka's theory of knowledge creation, externalization is the step of moving tacit knowledge in the head onto the page as explicit knowledge. Korean research has empirically shown that this externalization capability leads to an organization's service quality and performance (Journal of Service Management, 2016). Recording isn't busywork — it's the process of turning knowledge in your head into an asset.

The shape of a note you can resume from

The same task, recorded like this, resumes at once even a month later.

## Vibration anomaly detection — false-alarm cause analysis (09:10~)
- Problem: 7 false alarms on site (target: 1 or fewer per week), all between 22:00 and 24:00
- Cause: startup vibration from the adjacent HVAC unit bleeds into the 120Hz band (times of the 7 alarms match the operation log)
- First suspected a faulty sensor → rejected, since two other sensors show the same component
- Action: added a 110–130Hz notch filter → false alarms went 7 → 1
- Decision: filter (+0.4ms) instead of retraining (2 days). Cost vs. benefit
- Deferred: impact on other equipment unconfirmed — awaiting reply on equipment list
- Next: resume field testing with the filtered build

There are only a few rules.

• One file per day, appended to the end whenever a task finishes. Don't cram it all in at the end of the session.
• The skeleton of cause → action → numbers → decision → deferred. Not "fixed it" but the reasoning too.
• Don't delete a wrong diagnosis either. Leaving "first read it as X, but rejected for Y" is what keeps you from repeating the same misjudgment.
• On the last line, "Next." This one line is the starting point for the next session.

The last line matters especially. In Part 1 we said you start a session with "let's continue on X," and the quality of that restoration hinges on the "Next" line you left the day before.

What comes next

That was the individual's record. The next article is about promoting these records to the team's language — Trackers, Wikis, and Git. You can also read another series that unpacks it through a practitioner's day.

If you'd like a good daily-note template and examples, reach out via Contact.

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The "Using AI as a Colleague That Remembers" series

1. Why AI Forgets Yesterday — Session Amnesia and the Cost of Context
2. Rules in One Place — How to Write an AI Rules File
3. One Fact Per File — AI Automatic Memory
4. To the Me of the Next Session — Daily Notes and Handoff (current article)
5. Promoted to the Team's Language — Trackers, Wikis, and Git
6. Pitfalls and a 4-Week Adoption Roadmap