Manage saved work

Molt autosaves cell identity, type, order, and source. It does not save output or live execution state.

Locate the saved files

On macOS, Molt uses the standard Application Support configuration directory:

~/Library/Application Support/molt/

The directory contains:

File	Purpose
config.toml	Interpreter and application settings
notebooks.json	Autosaved cell source for all four tabs

Older repository prose refers to ~/.config/molt/, but the released code uses macOS’s Application Support directory.

Understand autosave

After a store change, Molt waits about 1.5 seconds and writes a new JSON snapshot when the persistable fields changed. It also attempts to flush a pending write when the React application unmounts.

Saved fields are limited to:

• File schema version.
• Tab index.
• Cell ID.
• Cell type.
• Cell source.

On relaunch, Molt resets outputs, execution labels, cell states, notebook counters, and all Python kernels.

Back up your scratchpads

Quit Molt, then copy the persistence file:

mkdir -p "$HOME/Documents/Molt Backups"
cp "$HOME/Library/Application Support/molt/notebooks.json" \
  "$HOME/Documents/Molt Backups/notebooks-$(date +%Y-%m-%d-%H%M%S).json"

A backup taken while Molt is running may miss the most recent 1.5-second debounce window.

Restore a backup

1. Quit Molt.
2. Preserve the current file.
3. Copy the backup into place.
4. Relaunch Molt.

mv "$HOME/Library/Application Support/molt/notebooks.json" \
  "$HOME/Library/Application Support/molt/notebooks.before-restore.json"
cp "$HOME/Documents/Molt Backups/notebooks-2026-08-31-190000.json" \
  "$HOME/Library/Application Support/molt/notebooks.json"

Molt loads the restored cell source on startup.

Reset all saved cells

Quit Molt and move the persistence file out of the way:

mv "$HOME/Library/Application Support/molt/notebooks.json" \
  "$HOME/Library/Application Support/molt/notebooks.reset-backup.json"

On the next launch, Molt starts each tab with one empty cell. The old file remains available for recovery.

Recover from malformed JSON

If notebooks.json cannot be parsed, Molt logs an error and opens with default empty notebooks. It does not show a dedicated recovery dialog. A later store change can cause those defaults to be written over the malformed file.

1. Quit Molt promptly and copy the malformed file for analysis if it still exists.

2. Preserve that copy before relaunching or editing.

3. Validate it with Python:

   python3 -m json.tool \
     "$HOME/Library/Application Support/molt/notebooks.json"

4. Correct the JSON or restore a backup.

5. Relaunch Molt.

The Files and schemas reference provides the exact version 1 structure.

Recover one cell manually

Because source is plain JSON, you can extract text from a backup without restoring the entire file:

python3 - <<'PYTHON'
import json
from pathlib import Path

path = Path.home() / "Documents" / "Molt Backups" / "notebooks-backup.json"
data = json.loads(path.read_text())
for tab in data["tabs"]:
    for index, cell in enumerate(tab["cells"], start=1):
        print(f"--- Tab {tab['tabIndex'] + 1}, cell {index} ---")
        print(cell["source"])
PYTHON

Copy the required source back into Molt rather than hand-editing live data while the app is running.