Description
Muster is a free and open-source Mac menu bar application that enhances the interaction with AI coding assistants like Claude Code, Codex, and Cursor. It addresses the common challenge of silently waiting AI agents by providing real-time notifications and an intuitive interface for managing multiple sessions.
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The core functionality of Muster revolves around its ability to monitor your AI agent sessions and alert you when an agent requires input or completes a task. This includes showing which Claude Code, Codex, or Cursor session needs your attention directly in the menu bar and through desktop alerts. Users can then allow or deny commands from these alerts without needing to switch applications, significantly streamlining their workflow.
For more detailed interactions, Muster allows users to unfold alerts with a keyboard shortcut (⌥↓) to view the agent's reasoning, the full command, file changes, or all available options for a question. Responses can be selected using simple key combinations (⌥1, ⌥2, ⌥3, or ⌥↩). The application also features a quick session switcher (⌥Tab) that lists all active sessions from the last three hours, prioritizing those awaiting your input. This switcher allows users to jump directly to the relevant application window or terminal.
Beyond basic interaction, Muster provides valuable insights into token usage and estimated API costs per session, helping users understand which interactions are more resource-intensive. It is built natively for macOS, adhering to system aesthetics and supporting both light and dark modes. The app is designed to be private by default, reading session files locally and keeping all questions and answers on localhost, with optional update checks and no account or app analytics. An upcoming version 1.4 will introduce optional SSH monitoring for remote Claude Code sessions, with summaries kept on the user's Mac.
Muster is open-source under the MIT License, emphasizing transparency and user control. It integrates with tools like Raycast and Alfred via custom URLs for enhanced automation. The app ensures that its shortcuts do not interfere with other applications, only taking control when a prompt or switcher is active on screen. It also intelligently handles sessions stopped by usage limits, moving them out of the way and indicating when the limit resets.
- CategoryAI Coding Assistants
- Pricing ModelFree
- DeploymentDesktop App
- PlatformsmacOS
Muster's Core Features
Real-time notifications for Claude Code, Codex, and Cursor sessions
Allow or deny AI agent commands directly from alerts
View agent's reasoning, full commands, or question options in alerts
Quickly switch between active sessions using ⌥Tab
Search and filter sessions from the last three hours
Display token usage and estimated API costs per session
Native macOS menu bar application with system theme support
Opens the correct application window or terminal for a session
Supports remote Claude Code sessions over SSH
Customizable keyboard shortcuts for ⌥Tab and ⌃⌥Space
Raycast and Alfred integration via custom URLs
Sessions remain marked unread until opened
Privacy-focused: no accounts, no analytics, local data storage
Open-source under MIT License
Handles sessions stopped by usage limits
How to use Muster?
Install Muster: Download and install the Muster application on your macOS device.
Monitor Sessions: Muster will automatically appear in your Mac's menu bar and begin monitoring Claude Code, Codex, and Cursor sessions.
Receive Alerts: Get desktop alerts and a menu bar count when an AI agent needs your attention or completes a task.
Interact with Alerts: Press ⌥↓ on an alert to view details like the agent's reason or full command, then use ⌥↩ or ⌥1-⌥9 to respond.
Switch Sessions: Hold ⌥ and tap Tab to view a list of all active sessions and quickly jump to any one.
Search Sessions: Type in the session switcher to narrow down and find specific sessions from the last three hours.
Muster's Use Cases
- AI Agent Interaction
- Multi-Session Management
- Code Approval Workflow
- Productivity Enhancement
- Cost Monitoring
- Remote Development
