Your Instagram carousel designer is now a Claude subprocess

What it does

A local-first Next.js app where you design Instagram carousels by chatting with Claude. The in-app agent is literally the Claude CLI spawned as a subprocess from /api/chat — it reads your brand config, writes each slide as a complete HTML/CSS string, and POSTs it back to the app’s own API. Slides stream into a three-panel editor with live preview and a drag-reorderable filmstrip, then export as a zip of PNGs at exact Instagram dimensions (1:1, 4:5, 9:16).

The interesting bit

The same wrapper function, wrapSlideHtml() in src/lib/slide-html.ts, feeds both the sandboxed preview iframe and the Puppeteer export — so what you see is pixel-for-pixel what you ship. And slides are plain HTML rather than a JSON DSL or canvas, which means Claude’s strongest skill (writing markup) is the whole design engine.

Key highlights

• Reuses your existing Claude Code authentication — no separate API keys or accounts.
• Brand config (palette, fonts, logo, style keywords) is injected into the system prompt before every generation.
• Reference images: drop in carousels you admire and Claude matches the style.
• Per-slide version history with undo, safe-zone overlay for Instagram’s crop-prone UI, and a captions/hashtag generator.
• Storage is JSON files with async-mutex and atomic tmp-file-then-rename writes — no database, no cloud.

Caveats

• Requires Claude Code installed and authenticated; without it you get the editor and export but no AI chat.
• First run downloads ~300 MB of Chromium for Puppeteer export.
• Single-user by design — it’s a localhost app talking to local files, not a deployable service.

Verdict

Worth a look if you post carousels regularly and already pay for Claude — it’s a genuinely clever use of the CLI as an agent. Skip it if you need multi-user, hosted, or non-Anthropic tooling.