# 260614 — Jupyter Notebooks deep dive

Date: 2026-06-14 · Source: **SHARD-WP-0004 T3**

## What this is

A deep dive into **Jupyter Notebooks**: the **`.ipynb` JSON** document (ordered cells:
markdown / code+outputs / raw), **kernels**, **embedded computed outputs** (MIME bundles),
and **execution-count provenance**. The dominant modern computational document and the
concrete case where the **derived output is captured and stored *inside* the source** with
real-but-fragile provenance.

## Why it matters

- Tests the T1 **replication- vs derivation-projection** split on the dominant real artifact
  and adds the wrinkle that **outputs are stored back inside the source** — the source/
  projection line runs *through* the document.
- The page model (T12) must carry a **notebook shape**: ordered cells with code cells owning
  embedded computed outputs that have **weak execution provenance** (run order, environment
  not captured).
- Non-Markdown + lossy translation (T15): JSON+MIME bundles; nbconvert→Markdown is lossy and
  directional. JSON diffs are noisy → Jupytext text-pairing / nbdime (T13).

## Yield

- **UC-84** (new): attach/project a computational notebook preserving cell structure +
  embedded outputs, surfacing outputs as **snapshots with weak execution provenance**;
  re-execution **capability-gated**, default = present snapshot + static render.
- Enrich **UC-54, UC-55, UC-59, UC-35**; links **UC-32, UC-83, UC-79**.

## Contents

| Path | Role |
|------|------|
| `findings.md` | `.ipynb` model, kernels/execution-count fragility, ecosystem (nbconvert/Jupytext/papermill/nbdime/nbstripout), capability profile, INTENT mapping, UC seed, architecture notes, open questions |