Autocomplete Extra: Anthropic Is Building a Physical Device. It’s Called Buddy

And It’s Already in the Code.

I’ve written about Claude’s desktop app internals before. When we first found Buddy in the codebase a few weeks ago, it was a handful of references, enough to know something hardware-related existed, not enough to understand what it was.

Version 1.2773.0 changes that. The Buddy infrastructure has expanded significantly. There’s now enough code, UUIDs, telemetry fields, and UI strings to reconstruct what Anthropic is building.

What Buddy is, based on the code

Buddy is a Bluetooth Low Energy companion device that pairs with the Claude desktop app. The main-process class is BuddyBleTransport, which handles all BLE communication. There’s a dedicated renderer window (buddy_window/), a menu item (BuddyMenuItem), and a preference key (claude.buddy).

The BLE stack uses the Nordic UART Service, which is the standard protocol for communicating with Nordic Semiconductor nRF chips and ESP32 boards. Three UUIDs handle the connection:

RX:      6e400002-b5a3-f393-e0a9-e50e24dcca9e
TX:      6e400003-b5a3-f393-e0a9-e50e24dcca9e
Control: 6e400001-b5a3-f393-e0a9-e50e24dcca9e

There’s also a custom Anthropic service UUID: 94406324-c0b4-4cac-9147-14e1bbaa0de9. This is Anthropic’s own BLE service, separate from the standard Nordic UART, likely handling device-specific commands that go beyond serial data transfer.

The Info.plist contains the privacy string: “Claude uses Bluetooth to connect to hardware accessories.” Apple requires this declaration for any app that accesses Bluetooth. It’s present in the shipping app.