AppKit Inspector

AppKit Inspector is a Debug-only bridge for inspecting a live native macOS AppKit interface from Codex. It captures the application's content view in-process, maps a clicked point to its NSView, shows hierarchy and geometry, and prepares precise visual feedback for a coding task.

Public Preview: APIs, plugin packaging, and presentation behavior may change before 1.0. Codex Browser is the supported default surface. Fullscreen remains experimental and disabled by default.

Features

• Inspect a real AppKit window without Accessibility or Screen Recording permission.

• Click the captured interface and identify the deepest native NSView.

• Review class names, frames, accessibility metadata, and ancestor paths.

• Copy a feedback package containing the selected view, geometry, note, and private local artifacts.

• Keep discovery and transport authenticated on 127.0.0.1.

• Compile the probe out of active Release behavior with #if DEBUG.

Requirements

• macOS 14 or later;

• Xcode 26 or later with Swift 6.2;

• Node.js 22 or later;

• a current Codex desktop installation for the plugin workflow.

Quick start

Clone and verify the project:

git clone https://github.com/JaminZhou/AppKitInspector.git
cd AppKitInspector
npm ci
npm run check

Install the cloned repository as a local Codex marketplace and enable the plugin:

codex plugin marketplace add "$PWD"
codex plugin add appkit-inspector@appkit-inspector-dev

Start the included AppKit demo:

make demo

Start a new Codex task so it loads the newly installed MCP tools, then ask:

Use AppKit Inspector to connect to the running demo and open it in Codex Browser.

The default open_appkit_inspector tool creates a 60-second, single-use loopback URL for the current task's right Browser panel. It never requests fullscreen or invokes the system browser automatically. The external browser window is an explicit fallback.

Add the probe to an AppKit project

Add the package in Xcode with:

https://github.com/JaminZhou/AppKitInspector.git

Or declare it in Package.swift:

.package(
    url: "https://github.com/JaminZhou/AppKitInspector.git",
    from: "0.1.1"
)

Add AppKitInspectorProbe only to a Debug target or Debug configuration, then start it after the application has launched:

#if DEBUG
import AppKitInspectorProbe

_ = try? AppKitInspectorProbe.start()
#endif

Never add or start the probe in Release, archive, TestFlight, or App Store builds.

Presentation modes

• Codex Browser: default and supported.

• External local window: explicit fallback opened in the system default browser.

• MCP App fullscreen: experimental, disabled by default, and available only when the MCP server starts with APPKIT_INSPECTOR_EXPERIMENTAL_FULLSCREEN=1.

No presentation failure automatically opens another window.

Repository layout

• native/ — reusable Swift probe, demo application, and native tests.

• packages/mcp/ — local MCP server, discovery, and authenticated transport.

• packages/app/ — Inspector browser interface and local client.

• plugins/appkit-inspector/ — installable Codex plugin, generated distribution, and skill.

• TODO.md — deferred work and experimental fullscreen acceptance.

Development

npm ci
npm run check
swift build -c release

For a live bridge check, run make demo in one terminal and npm run test:live in another. After changing packages/app/ or packages/mcp/, run npm run build and include the matching generated files under plugins/appkit-inspector/dist/.

Security and privacy

The probe and Inspector servers bind only to loopback, require random credentials, and write user-private discovery data. Codex Browser launch links are single-use and become HttpOnly, same-site sessions. The project uses public AppKit and Foundation APIs and does not use injection, Accessibility automation, private frameworks, or Screen Recording.

Captured screenshots, hierarchy data, notes, and review artifacts are sensitive. When used through Codex they may become part of the Codex task under the user's product and workspace data controls. Read SECURITY.md before integrating the probe and use private security advisories for vulnerability reports.

Contributing

See CONTRIBUTING.md. Contributions intentionally submitted to the project are licensed under Apache License 2.0.

License

Copyright 2026 Jamin Zhou.

Licensed under the Apache License, Version 2.0. Bundled dependency attributions are documented in THIRD_PARTY_NOTICES.md.