Anthropic just put the Claude Hardware Buddy code on GitHub, confirming every detail researchers dug out of the desktop app binary. The reference build uses an M5StickC Plus—an ESP32 board with a 135×240 color screen, two buttons, an accelerometer and USB-C charging—for about $20–30. After cloning the repo and flashing via PlatformIO, you pair over Bluetooth Low Energy using Claude Desktop’s developer mode. From there the device auto-reconnects and shows seven animation states—sleep, idle, busy, attention, celebrate, dizzy and heart—reflecting Claude’s current activity. The real value lies in the two physical buttons. When Claude hits a permission checkpoint—like running a bash script or writing a file—you see a hint such as “bash: rm -rf /tmp/foo” on the Buddy. Press A to approve or B to deny, and Claude continues even if you’re away from your laptop. That keeps sessions moving without opening a dialog on your main screen. Behind the scenes, JSON messages shuttle over the Nordic UART Service: heartbeat snapshots flow from Claude with fields like total tasks, running tasks and pending approvals, and button presses send permission decisions back. Anthropic also published the full BLE protocol, so you can swap the M5StickC for any Nordic UART Service-capable hardware. They laid out five alternative builds: a three-LED traffic light for status alerts, an analog gauge for token burn rate, an e-ink transcript display, a single-button CI/CD puck, or a vibrating wristband. All use the same JSON heartbeat and permission commands. You can even upload custom GIF characters—96px wide, seven states, up to 1.8 MB—to swap in your own desk pet.