# Session 2026-04-28T14:02

## User goal
Refactor the `JournalWriter` class — the `write()` method had grown to ~120 lines.

## What happened
- Read `src/runtime/journal.ts` end-to-end before touching anything.
- Extracted `formatEntry()`, `validateEntry()`, and `appendToFile()` as private methods.
- Kept the public `write()` signature unchanged so callers were unaffected.
- Updated unit tests to cover each new private method via the public surface.

## Outcome
Tests pass. Single commit on a feature branch, ready for review.

## Pattern noted
Read the full file before refactoring. Keep the public API stable. Verify with the existing test suite before declaring done.