Technical Overview

claude-wrist (cw) is an edge-engineering bridge that turns a smartwatch (Huawei Watch Fit 4 Pro) into a physical remote control for an autonomous coding agent. When running long agentic workflows in Claude Code inside Termux on Android, dangerous tool calls (bash executions, file modifications) require human approval. Rather than keeping a terminal open, approvals and terminal tails are piped directly to the user's wrist.

Technical Flow & Relay Architecture

[ Huawei Watch Fit 4 Pro ]
      │  Bluetooth LE (P2P Packets)
      ▼
[ Android Bridge APK ] (Kotlin + Huawei Wear Engine)
      │  HTTP Long-Poll (localhost:8742)
      ▼
[ cw-hub ] (Zero-dep Node.js Server in Termux)
   ├── Hooks Listener (receives tool_approval events from Claude CLI)
   └── tmux Controller (sends keystrokes 'y' / 'n' to attached session)
      ▼
[ Claude Code TUI ] (Running in tmux session)

1. Core Principle (Zero Added Latency / No Extra LLMs): The watch does not run an LLM, nor does the bridge query external APIs. The watch functions strictly as a hardware I/O peripheral for an existing local Claude Code session.
2. cw-hub (The Local Coordinator): A zero-dependency Node.js HTTP server running on localhost:8742 inside the phone’s Termux environment:

• Approval Hooks: Hooks into Claude Code lifecycle events (pre-tool-call). When a tool requires permission, Claude CLI executes a hook script that POSTs approval metadata (tool name, target file, command diff) to cw-hub.
• tmux Integration: Communicates with the background tmux process via Unix commands (tmux send-keys -t claude:0 ...), injecting approvals without needing direct TUI interaction.

1. Android Relay Bridge (Kotlin): A native Android service utilizing the Huawei Wear Engine SDK:

• Maintains a low-power persistent long-poll connection to cw-hub on localhost:8742.
• Encodes approval payloads into compact binary packets transmitted over Bluetooth LE to the paired smartwatch.
• Translates wrist taps (Approve / Deny) back into HTTP responses to cw-hub.

1. Watch UI (HarmonyOS / Lite Wearable): Lightweight wearable interface displaying tool details, proposed commands, and two tactile buttons (Approve / Reject), plus a live stream of the terminal's last 5 log lines.