> ## Documentation Index
> Fetch the complete documentation index at: https://docs.paperline.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Development Environment

> Paperline Doctor automatically configures Xcode, iOS Simulator, and build tools. One-click setup for Swift and SwiftUI development on Mac.

## Paperline Doctor

Paperline Doctor runs automatically every time you launch the app to verify your development environment. During first launch, it's part of the onboarding flow. After that, if any tools are missing, a warning appears below the chat input so you can fix issues without interrupting your workflow.

### System Checks

Paperline Doctor checks three main components:

<AccordionGroup>
  <Accordion title="Xcode">
    **Required**: Xcode 16 or later

    Xcode is Apple's development environment. Paperline uses Xcode's build tools to compile Swift code and run the iOS Simulator.

    **If not installed:**

    * Click "Open App Store" button in Paperline
    * Or search for "Xcode" in Mac App Store
    * Download takes approximately 12GB
    * Open Xcode once after installation to accept the license
  </Accordion>

  <Accordion title="Xcode Command Line Tools">
    Compilers and build utilities required for iOS development.

    Click "Install" button and Paperline handles the rest.
  </Accordion>

  <Accordion title="iPhone Simulator & iOS Version">
    **Required**: iOS SDK and at least one iPhone simulator

    * **iOS Runtime** — The iOS SDK for building apps
    * **iPhone Simulator** — Virtual iPhone for testing (e.g., iPhone 17 Pro)

    Click "Install" and Paperline will:

    1. Download the latest iOS runtime via `xcodebuild -downloadPlatform iOS`
    2. Create an iPhone 17 Pro simulator automatically
  </Accordion>
</AccordionGroup>

## Status Indicators

| Status  | Meaning                                 |
| ------- | --------------------------------------- |
| Green   | Component is installed and ready        |
| Red     | Component is missing — click to install |
| Pulsing | Installation in progress                |

## Troubleshooting

<AccordionGroup>
  <Accordion title="Xcode won't open after installation">
    Open Xcode from Applications folder and accept the license agreement. You may need to enter your Mac password.
  </Accordion>

  <Accordion title="iOS Runtime installation takes too long">
    iOS runtime download is several GB. It can take 10-30 minutes depending on your internet connection. Progress is shown
    in the Paperline UI.
  </Accordion>

  <Accordion title="Simulator not showing devices">
    1. Open Xcode 2. Go to **Window → Devices and Simulators** 3. Click **+** to add a new simulator 4. Click "Check
       tools" in Paperline to refresh
  </Accordion>
</AccordionGroup>