Show HN: Juggler – An open source GUI coding agent made by the creator of JUCE

Juggler is a GUI-based coding agent designed to go beyond a simple chat interface, letting users visually see and control what the LLM is doing to the codebase.

Key features include:

• Visual Workbench: A Finder-style Miller column view lets you hierarchically browse and edit tool calls, item properties, and nested sub-threads.
• Tree-structured sessions: Instead of a simple transcript, it uses a Yjs-based document structure, making it easy to branch, rewind, and compare threads.
• Extensibility and flexibility: All components (context items, slash commands, LLM loop strategies, etc.) are implemented as JavaScript extensions, which users can modify or replace themselves.
• Broad model support: Supports a wide range of major LLM models and APIs, including Claude Code, OpenAI, Gemini, Ollama, and Deepseek.
• Multi-client support: Multiple clients, such as a local desktop app and a web browser, can connect to and work on the same server session simultaneously.

Users can install it as a desktop app or run it as a headless server on macOS, Windows, and Linux.