How to use Codex to build an offline iPhone player
Dean Hipkiss built a SwiftUI music player with Codex in Xcode, using a design brief to guide AVPlayer, background audio, AirPlay and project-specific debugging.
deanhipkiss.com
Original prompt
Shared by the source author. See source notes for context.
Is this the right architecture for what I’m building?
Reach people exploring AI agents
See placements →Evidence at a glance
Sourced account- Source author
- Dean Hipkiss
- Original account
- Read the source ↗
- Published
- Source link checked
- Reported result
- Author reports local albums playing on iPhone and through AirPlay.
- Human involvement
- Author set goals and architecture, imported artwork/music, and exercised playback.
A linked account supports attribution. It does not mean we independently reproduced its result.
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How the agent did it
- Wrote design brief with screens/navigation/playback behavior.
- Codex structured SwiftUI models/viewmodels and AVPlayer manager.
- Implemented background playback, remote controls and AirPlay.
Dean Hipkiss built a personal iPhone music player to use local albums instead of depending on a streaming subscription. He began with a SwiftUI template and a design brief covering features, screens, navigation and playback behavior. The project section explicitly identifies GPT-5.3-Codex inside Xcode.
Codex helped organize Track and Album models, an AVPlayer-based playback manager and a ViewModel layer. The requested experience included local MP3 and FLAC importing, album artwork, artist and album grouping, playlists, background playback and AirPlay. The author used the design brief to discuss architectural refinements rather than asking only for isolated snippets.
Audio behavior introduced configuration and debugging work. Hipkiss pasted compilation errors and behavior problems into Codex with the project context intact. The account discusses file-URL permissions, Info.plist settings, background audio modes and AirPlay routing, including interruption and remote-control handling.
Hipkiss reports using the finished app on his iPhone, sending audio to a HiFi through AirPlay and listening through headphones. This is a personal-use report, not an independent compatibility test or an App Store release claim.
Prompt
Original prompt
Source: Blog · Dean Hipkiss
Frequently asked questions
How did the author set direction?
He wrote a design brief describing the app's core features, screen layouts, navigation and playback interactions before sharing it with Codex.
Which playback technology was used?
The source describes AVFoundation and an AVPlayer-based playback manager, with SwiftUI views and a ViewModel layer.
What result did Hipkiss actually report?
He describes local albums playing on his iPhone and audio sent through AirPlay or headphones. The article does not establish an App Store release.
More details
Remaining steps
- Author pasted compilation/behavior errors to debug in project context.
About this account
Codex structured SwiftUI models and playback code, reasoned about the project architecture and investigated supplied compilation and behavior errors.
Primary first-person account opened and checked on 2026-10-14. Personal use report; article inconsistently uses 'Codex 3.5' elsewhere, so retain explicit GPT-5.3-Codex attribution in project section. Outcomes and test claims are attributed to the source and were not independently reproduced. Original prompt excerpt: reproduced verbatim from the first-person account.
Credit: Dean Hipkiss on Blog
Source published
Added to Agents In Use
Source checked
Tools and topics
Codex · Xcode · SwiftUI · AVFoundation · AVPlayer · AirPlay
Personal music · SwiftUI · Offline app
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.