# Lesson #001 — PPTX speaker-note bug

**Date:** 2026-05-24
**Trigger:** PPTX export missing speaker notes when slide layout = "Title-Only"
**Cost:** 14 min debug, 1 user reroll

## What went wrong
python-pptx defaults `notes_slide` to *not auto-created* on Title-Only layouts.
Joe's `compose_deck()` assumed it always existed → silent dropped notes.

## Root cause (修復)
`slide.has_notes_slide` returns False until `.notes_slide` is accessed once.

## Corrected pattern (進化)
```python
def ensure_notes(slide):
    _ = slide.notes_slide  # touch to materialize
    return slide.notes_slide
```

## Guard added
- Unit test `test_speaker_notes_persist.py` in `applelai001/joe`
- Lint rule: any `slide.notes_slide` access must go through `ensure_notes()`

## Promotion path
After 3 occurrences this graduates into `joe/SOUL.md` as a canonical pattern.

---
*Joe lesson notes feed a self-improving agent loop (skill: proactive-self-improving-agent).*