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Example: build a small app

Last verified: 2026-05-06 · Time: 1–3 hours for a working prototype · No API key required for chat

A small single-purpose app you actually use — a habit tracker, a vocabulary trainer, a packing-list generator. The chat-only path produces a real working app you can run locally; the developer path turns it into something maintainable.

Layer 1 — Chat only Free

Help me build a small browser-based habit tracker.

What it does:
- 7-day grid of habits I define.
- Click to mark a day done. Persist in localStorage. No login.
- Reset button. Export-to-JSON button.

Constraints:
- Single `index.html` with inlined CSS + vanilla JS.
- No frameworks. No external CDNs. No tracking.
- Mobile-friendly. Keyboard-accessible.

After the code, give me a 5-line plain-English explanation of where data is saved (localStorage) and how to delete it.

Save as tracker.html, double-click, use.

Layer 2 — Project Sub

"Small apps" Project. Knowledge file = your "always" rules (no trackers, no CDNs, accessible, mobile-friendly). Each chat = one app.

Best surface: Claude (Artifacts) or ChatGPT (Canvas) for iteration; Copilot if you'll run a real dev loop.

Layer 3 — Memory Sub

- For small apps: vanilla JS, no frameworks, no external CDNs, no trackers, accessible, mobile-friendly.
- Always inline CSS unless I ask otherwise.
- Always include an export-to-JSON and a reset button for stateful apps.

Layer 4 — Scheduled action

N/A. Closest: a "review usage" reminder once a month.

Layer 5 — Custom assistant Sub

Custom GPT / Gem "Small apps coach": packs your style rules, gives you a prompt scaffold for each new app idea.

Layer 6 — Developer / API (advanced) Dev

For real apps you'll maintain:

  • GitHub Copilot in a real repo: .github/copilot-instructions.md with your conventions. See Mastery — Coding agents.
  • Claude Code / Codex CLI: CLAUDE.md / AGENTS.md at repo root. Coding agents work well for small, well-scoped apps.
  • MCP: when the app needs filesystem or repo access. See docs/mcp/index.md.

This Task Builder hides the developer path in Beginner Mode for a reason: most users are better served by a single-file chat-built app.

Make it reusable

  • Commit the file to a GitHub repo (free). Re-prompt for upgrades.
  • Keep a CHANGELOG.md.

Make it robust

  • Eval: 5 user stories you walk through manually. Each must pass.
  • Red-team: paste an "import" of malformed JSON. The app must not crash.
  • Drift check: quarterly, ask the AI for one accessibility improvement.

What good output looks like

  • Works without an internet connection.
  • Saves data locally only.
  • Loads in under a second.
  • Reads cleanly enough that you can hand-edit.

If your plan doesn't have this feature

  • No Artifacts / Canvas → ask for the file in a code block.
  • No Project → paste rules each time.
  • No Custom GPT → save the prompt.

See also