character-sheet

Tips

Mobile workflow

The app is fully mobile-friendly. The main friction point is getting JSON from your AI into the app. Inline JSON in chat is hard to select and copy on mobile.

The fix: ask your AI to write the update as a file rather than pasting it into chat.

“Write my updated data.json as a downloadable file.”

Claude (and most other AIs) will attach a data.json file to the message. Tap to download it, then:

1. Open character-sheet.html in your mobile browser (saved to Files, or the GitHub Pages demo)
2. Tap ↑ (bottom right) to open the import modal
3. Tap ↑ data.json (bottom right of the modal) and select the downloaded file
4. Tap Apply

If your AI doesn’t support file attachments, the next best option is to ask it to output a short partial update (see below): less JSON to select and copy.

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Keeping token usage low

• Start a new chat each session. Most important. Every message in a conversation re-sends the entire history, so costs compound fast.
• Use project knowledge. instructions.md and data.json load once at the start, not per message.
• Use partial updates. Instead of asking for a full data.json, ask: “Give me a partial update for what changed.” The AI will output only the fields that changed. Much smaller and cheaper to generate. See Partial updates below.
• Keep data.json concise. It loads every session. Push back if the AI makes it verbose.
• One topic per session. Focused sessions produce leaner JSON updates.

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Partial updates

A partial update is a smaller JSON that contains only the top-level fields that changed, rather than the full data.json. The app merges it into your existing data.

When to use it: any session where only a few things changed (XP, a quest or two, a status read). No need to re-output skills, allies, enemies, and everything else that didn’t move.

How to request one: ask the AI: “Give me a partial update JSON for what changed this session.”

What the AI outputs (example):

{
  "_partial": true,
  "_instructionsVersion": "1.4.0",
  "xp": 520,
  "sessionCount": 12,
  "lastSession": "2026-04-10",
  "health": 72,
  "mana": 68,
  "healthAvg": 65,
  "manaAvg": 63,
  "sideQuests": [...]
}

How to import it: exactly the same as a full update. Click ↑, paste, Import. The app detects the "_partial": true flag and merges rather than replaces.

What gets merged vs replaced: partial updates do a shallow merge at the top level. If you include "sideQuests", the entire sideQuests array is replaced. If you omit it, it stays untouched. The same applies to any other top-level key.

The diff toast shows “Partial update” as the first item so you can confirm what changed before the modal closes.

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What does and doesn’t persist

What	Where	Survives browser restart?	Survives clearing browser data?	AI knows?
Everything imported via ↑	localStorage	✅	❌	Yes
Edits made in the app	localStorage	✅	❌	Only if you export ↓
Practice timer / checkbox / number	localStorage	✅	❌	No
Practice history (graphs)	localStorage	✅	❌	No
Status sliders	localStorage	✅	❌	No
Core skills sliders	localStorage	✅	❌	No
XP log	localStorage	✅	❌	No
Completed quests	localStorage	✅	❌	Only when newly completed in a session
data.json	Project knowledge	✅	✅	Yes

localStorage is not session storage. It survives closing and reopening the browser. Risks are: clearing browser data, switching browser, opening the file from a different path, or a new device.

The safe habit: end every session by asking the AI to update your data.json, replace it in project knowledge, and import the new version. That way the AI and the app always match.

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Updating to a new version

1. Export first: click ↓ (bottom right). Use Full Migration Backup to download migration.json. This preserves practice history, status history, and XP log.
2. Re-download character-sheet.html.
3. Clear old localStorage:
   • Firefox: about:preferences#privacy → Manage Data → search for the file name → Remove
   • Chrome: Open the old file → DevTools (F12) → Application → Local Storage → right-click → Clear
   • Quickest: open browser console (F12 → Console) and run localStorage.clear(), then refresh
4. Re-import your data: open the new file, click ↑, paste your data.json. (migration.json is not for the import modal. It’s a backup only.)
5. Re-download instructions.md and replace it in your AI project knowledge.