cmux-copilot-integration-plugin

Copilot CLI plugin that integrates with cmux to provide visual feedback when agents are working, finish, or need user input.

Features

• Tab marked in-progress — tab shows active indicator while the agent is working
• Tab highlighted on finish — tab flashes and is marked unread when the agent stops
• Notification on finish — OS notification with the agent's last message
• Notification on user input — OS notification + tab flash when the agent asks a question

Requirements

• cmux must be installed and running
• Copilot CLI with plugin support

Install

copilot plugin marketplace add demorgi/cmux-copilot-integration-plugin
copilot plugin install cmux-copilot-integration-plugin@cmux-copilot-plugins

Test

bash tests/integration_test.sh

How it works

Hook	What happens
preToolUse (any tool)	Marks the current tab as active via cmux claude-hook active
preToolUse (ask_user)	Sends notification with the question, flashes tab, marks unread
agentStop	Marks tab idle via cmux claude-hook stop, sends notification with last agent message, flashes tab, marks unread

All state is per-tab using CMUX_SURFACE_ID — multiple agents across tabs work independently.

Debug logging

Set CMUX_COPILOT_INTEGRATION_PLUGIN_DEBUG=1 to enable debug logging. Hook payloads are appended to /tmp/cmux-hook-debug.log with UTC timestamps.

export CMUX_COPILOT_INTEGRATION_PLUGIN_DEBUG=1

Developer notes

• plugin.json — Plugin metadata
• hooks.json — Registers preToolUse and agentStop hooks
• scripts/cmux-integration.sh — Reads hook payload from stdin, calls cmux commands