Free, open-source local MCP gateway: register each server once, share it with every AI client, and cut tool-definition tokens by up to 91%.
Summary
Open-source GUI coding agent whose sessions are branching, resumable documents instead of a linear chat transcript.
Screenshots
Description
Juggler is a visual workbench for AI coding agents, built by Julian Storer — the developer behind the JUCE framework, the Tracktion DAW, and the Cmajor DSP language. It is a deliberate argument against the terminal transcript as the interface for agentic coding.
A session is a document, not a log
Each session is a CRDT document stored on disk. Any point in it can branch into a sub-thread, and sub-threads can branch again, so you can explore several approaches side by side without losing the context that produced them. Quit and relaunch, or reconnect from another device, and the session rehydrates exactly where it was — including an agent paused mid-run waiting on your approval.
Built to be inspected
A Finder-style Miller-column interface exposes the structure directly: navigate threads, read individual tool calls, review diffs before approving an edit, examine item properties, and read the raw context JSON the model actually received. This is the tool for people who want to see what the agent is doing to their codebase rather than trust it.
Everything is an extension
Context items such as read-file, replace-text, and bash, LLM loop strategies like plan and research, and slash commands like /clear and /compact are all JavaScript plugins with their own interfaces — so the agent loop itself is something you can modify.
Local, multi-client, bring your own key
It ships as a native desktop app for macOS and Windows plus a headless server for Linux and remote sessions, and several desktop or browser clients can attach to one live session at once. The backend is a single Go binary built on Wails — explicitly not Electron, with no Node runtime. The server binds to localhost by default. There is no signup and no telemetry: bring your own key for Claude Code, OpenAI or Codex, Gemini, Ollama, OpenRouter, Z.AI, DeepSeek, Mistral, or OpenCode Zen.
Licensing and status
The extension SDK and the bundled extensions are Apache-2.0; the Go server, desktop app, and web UI are AGPL-3.0-or-later. Juggler launched on Hacker News on July 12, 2026 and is still alpha, with no paid tier today.
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