🔭 Treescope
MIT licensed · zero-install browser viewer

Put your view tree under the scope — SwiftUI included.

An open-source runtime view inspector for UIKit, AppKit and SwiftUI. Your app serves a browser viewer over loopback — browse the unified tree, inspect properties, see snapshots and an exploded 3D view, and edit live.

Get started View on GitHub

A free, open alternative to Lookin — with first-class SwiftUI inspection.

Treescope viewer
SwiftUI
declaration tree, open
0 deps
in your app binary
Browser
macOS · Linux · Windows
iOS + macOS
simulator & desktop

Everything you need to inspect a running app

🌳

Unified hierarchy tree

UIKit/AppKit views, SwiftUI nodes and CALayers in one tree, colour-coded by framework, with search, filtering and keyboard navigation.

🟠

Open SwiftUI inspection

Recovers the real declaration tree — VStack, Text content, modifiers, @State — using only public reflection.

🧊

Exploded 3D canvas

Wireframes + rendered snapshots, drag-to-orbit 3D with angle & depth controls, zoom/pan, and click-to-select synced with the tree.

✏️

Live editing

Change alpha, hidden, corner radius, colours, text and layer properties — on views and CALayers — and watch the app update.

🌐

Zero-install viewer

The app hosts the viewer itself over loopback HTTP + WebSocket. Open a URL in any browser — nothing to install, easy to share.

🔒

Debug-only, no deps

The embedded server is built on Network.framework + CryptoKit only — no third-party code enters your app, and it's excluded from Release.

🤖

CLI, Python & MCP for agents

treescope screenshot lets a coding agent see the whole screen; tree/find/inspect/set drive the hierarchy. Ships as an npm CLI, a pip install treescope-cli Python client, an MCP server, and a ready Claude Code skill.

See the layers, literally.

Toggle the exploded 3D view to fan the hierarchy out in depth. Drag to orbit, tune the X/Y angle and layer spacing, and the selected node stays in sync with the tree and inspector.

  • ✓ Drag to orbit · ⌥-drag to pan · ⌘-scroll to zoom
  • ✓ Per-axis angle sliders + depth control
  • ✓ Rendered snapshots layered in 3D
Exploded 3D view
🤖 Built for coding agents

Let an agent see your UI

The same in-app server powers a CLI, a Python client and an MCP server. Claude Code and friends can screenshot the screen, walk the hierarchy, find views and live-edit — no browser needed.

npm: treescope-cli PyPI: treescope-cli

Register the MCP server

One line — Node or Python, no local build:

# Node (npm)
claude mcp add treescope -- npx -y treescope-cli mcp

# Python (PyPI)
pip install treescope-cli
claude mcp add treescope -- treescope mcp

Tools: screenshot · get_tree · find_nodes · inspect_node · get_snapshot · set_attribute · status.

…or drive the CLI directly

A typical agent loop:

treescope status                 # is the app reachable?
treescope screenshot -o ui.png   # SEE the whole screen
treescope tree --depth 3         # token-friendly hierarchy
treescope find LoginButton       # locate a node → #obj:42
treescope inspect obj:42         # properties + editable keys
treescope set obj:42 alpha 0.5   # live-edit, then re-screenshot

🛠️ A ready-made Claude Code skill

Drop .claude/skills/treescope/ into your project and your agent learns the whole loop — status → screenshot → tree/find → inspect → set — plus how to start the server and recover when the app isn't running.

Quick start

Three steps to inspect your running app.

  1. 1

    Add the package (Debug only)

    Add Treescope to your Package.swift dependencies:

    .package(url: "https://github.com/everettjf/treescope", from: "0.1.0")
// target dependency:
.product(name: "TreescopeServer", package: "treescope")
  2. 2

    Start the server early

    Guard it for Debug builds so it never ships in Release:

    import TreescopeServer

#if DEBUG
Treescope.start()   // serves http://127.0.0.1:50067
#endif
  3. 3

    Open the viewer

    Run your app (Simulator or Mac), then open the URL in any browser:

    open http://127.0.0.1:50067

    The iOS Simulator shares the host network stack, so loopback reaches the app.

On a physical device? Forward over USB

The server listens on 127.0.0.1 only. On a real iPhone/iPad that loopback is the device, not your Mac — so tunnel it over USB with iproxy (from libimobiledevice): 

brew install libimobiledevice

# with the device plugged in over USB and the app running:
iproxy 50067 50067           # Mac:50067 → device 127.0.0.1:50067
open http://127.0.0.1:50067  # inspect it from your Mac browser

iproxy tunnels through usbmuxd to the device's loopback, so no app changes are needed. Leave it running for the session.

Try it in 30 seconds

Clone and run the bundled demo:

git clone https://github.com/everettjf/treescope
cd treescope
swift run TreescopeDemo      # a sample app that embeds the server
open http://127.0.0.1:50067  # inspect it

How it works

📸

Capture

A debug-only engine walks UIWindow/NSWindow → views → layers, and reflects SwiftUI by opening any View with Mirror.

🔌

Serve

A tiny loopback HTTP + WebSocket server streams the tree, snapshots and edits — built on Apple frameworks only.

🖥️

Inspect

A React viewer renders the tree, 3D canvas and property inspector — in any browser, no install.

Read more in the README · contribute via CONTRIBUTING.md

Open source. Built from scratch.

MIT licensed. Built from scratch — no code copied from other inspectors. Contributions welcome.

Star Treescope on GitHub