CAIBI project benchmark: Watchy
Prompt version 1.0

Help me build Watchy using the existing creator project at https://github.com/sqfmi/Watchy. This is a CAIBI benchmark adaptation of the project build brief, not a claim about how the creator used AI.

Project context:
- A fully open-source ESP32-S3 e-paper watch sold as a small assembly kit and designed to be reprogrammed, modified and recased.
- Build context: Watchy PCB v3 with ESP32-S3FN8; 1.54 inch 200 x 200 e-paper display; 3.7 V 200 mAh LiPo battery; BMA423 three-axis accelerometer; Vibration motor and four physical buttons; Plastic enclosure and watch strap from the current kit; USB data cable and computer with Arduino IDE for custom firmware.
- Where AI helps: Watch-face code, Firmware changes, ESP32 troubleshooting, Power-use optimisation, Custom feature planning.
- Physical work: Connect display and battery, Assemble case, Enter bootloader mode, Flash and verify firmware, Protect and wear the hardware.
- Main limitation: Assembly is simple but the glass e-paper display and tiny ribbon connector need care. The stock experience is also deliberately basic, so much of the value depends on wanting to customise the firmware rather than simply wear a finished smartwatch.

Read the source first. Use its published design, files, dimensions and parts as the baseline; do not redesign it unless a missing detail requires a clearly labelled proposal. If you cannot access a source or verify a revision, say so.

Provide one practical build package:
1. Design and files: explain the source design, link the original editable files, and identify missing files or modifications.
2. Parts and fabrication: give quantities, exact variants and compatibility, plus a cutting or printing list where applicable. Preserve source dimensions; flag anything unconfirmed.
3. UK and US purchasing: direct product links, checked dates, stock, pack sizes, taxes, delivery and regional costs. Mark unverifiable details as unknown; do not invent links, prices or availability.
4. Assembly: an ordered guide covering fabrication, fitting, wiring or software as applicable, setup, checks and troubleshooting.
5. Cost and time: separate parts, fabrication, delivery, hands-on time and machine time, with assumptions and exclusions.
6. Function and ease: a test plan for the project's stated purpose, likely difficulties, required skills and any corrections or limitations.

Keep source facts, your proposals and items needing physical verification distinct. An estimate is not a measured build result. Do not claim to have built or tested hardware. Include failed attempts and omissions. If a section does not apply, say why.

Use the source as accessed during this run and record its revision or access date. The prompt is fixed; the linked source can change.