Build firmware for an e-ink fridge shopping list without writing code

To test whether an agent could handle unfamiliar hardware, a Hacker News poster had Claude Code write all of the roughly 2,400 lines of C++ firmware for a small ESP32 e-ink touchscreen, plus a phone web app. The device shows the family shopping list, lets you tick items off by touch, syncs over Wi-Fi when touched and works offline, using partial screen refreshes and deep sleep to save battery. An MCP server added later lets an AI plan meals and push items to it. It's stuck to the fridge and used every week, nothing on the board was damaged, and typing on it is clunky, hence the web app.