Based on my research, when calling Apple Intelligence from Swift APIs using the Foundation Models framework, only on-device AFM (Apple Foundation Models) is available. Neither PCC (Private Cloud Compute) nor ChatGPT can be accessed programmatically through Apple's APIs.
The Foundation Models framework provides developers with access exclusively to the on-device ~3B parameter language model. According to Apple's official developer forums, inference is entirely on-device and PCC is never used when calling the Foundation Models framework.[1][2][3]
Key characteristics:
- Zero cloud communication: No user data is transferred to PCC when using the Foundation Models API[3]
- Enhanced privacy: Apple doesn't log input prompts or outputs - only counts that your app called the model[3]
- Swift-native access: Available through a clean, type-safe Swift API with features like
@Generablemacros, guided generation, and tool calling[2][4][1]
While PCC powers certain Apple Intelligence features for end-users when tasks exceed on-device capabilities, there is currently no API for developers to access PCC. A developer asking about PCC access received this direct response from Apple:[5]
"Users may use it indirectly when using Apple Intelligence, but there is currently no API for developers to access PCC."[5]
PCC remains a user-facing infrastructure that:
- Automatically handles complex requests from Apple's own features (Writing Tools, Siri, etc.)
- Runs larger foundation models on Apple's custom server hardware[6][7]
- Maintains end-to-end encryption with stateless computation[7][8]
The ChatGPT integration announced for iOS 18.2+ operates as a user-facing extension, not a developer API. It works through:[9][10][11]
- Siri queries: Users can ask Siri to consult ChatGPT, but developers cannot programmatically invoke this
- Writing Tools: ChatGPT powers the "Compose" feature in system-wide Writing Tools
- User permission model: Each ChatGPT request requires explicit user consent[12][9]
Developers cannot call ChatGPT through Apple Intelligence APIs. If you need ChatGPT functionality in your app, you must integrate OpenAI's API directly using third-party Swift packages.[13]
For production apps requiring AI capabilities beyond on-device processing:
- Check availability of Foundation Models on the device (
SystemLanguageModel.default.isAvailable)[14][15] - Implement graceful fallbacks to cloud-based LLMs (OpenAI, Anthropic, Google Gemini) when Foundation Models aren't available[16][17][15]
- Use hybrid architectures that prefer on-device when possible, with cloud fallback for unsupported devices or regions[17]
Several developers have created open-source solutions for this hybrid approach, including unified APIs that switch seamlessly between Apple's on-device models and cloud providers.[18][16]
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