Private Cloud Compute (iOS 27)

PrivateCloudComputeLanguageModel is Apple’s larger, server-based model running on Private Cloud Compute (PCC). It supports longer contexts and more capabilities than the on-device model, with Apple’s PCC privacy guarantees.

Entitlement

Apple: “To develop with PCC you must meet certain eligibility requirements. To learn more and request access to the managed entitlement, see Accessing Private Cloud Compute.”

This package never bypasses or fakes the entitlement. Once Apple grants it, add it with the config plugin using the exact key Apple provides (the package intentionally does not hard-code it):

{
  "expo": {
    "plugins": [["@fourlyn/apple-foundation-models", { "entitlements": { "<entitlement key from Apple>": true } }]]
  }
}

Bare React Native: add it in Xcode → Signing & Capabilities.

Usage

const info = await AppleFoundationModels.getPrivateCloudComputeInfo(); // never throws
// { availability, isAvailable, quota, contextSize, supportedLanguages, capabilities }

const session = await createSession({ model: 'privateCloudCompute' });

model: 'privateCloudCompute' never falls back. If PCC is unavailable, createSession rejects with PRIVATE_CLOUD_COMPUTE_UNAVAILABLE (details.reason: DEVICE_NOT_ELIGIBLE | SYSTEM_NOT_READY).

Quota

info.quota = {
  status: 'belowLimit' | 'limitReached',
  isLimitReached: boolean,
  isApproachingLimit: boolean,
  resetDate: string | null,           // ISO-8601
  canRequestLimitIncrease: boolean,   // Apple offers the user a way to raise their limit
};

Requests over quota fail with QUOTA_LIMIT_REACHED (details.resetDate, details.canRequestLimitIncrease). Other PCC errors: NETWORK_FAILURE, PRIVATE_CLOUD_COMPUTE_UNAVAILABLE (SERVICE_UNAVAILABLE).

Missing entitlement

try {
  await session.respond(prompt);
} catch (error) {
  const missingEntitlement =
    isAppleFoundationModelsError(error, 'ENTITLEMENT_REQUIRED') ||
    (isAppleFoundationModelsError(error, 'PRIVATE_CLOUD_COMPUTE_UNAVAILABLE') && error.details.reason === 'ENTITLEMENT_REQUIRED');
  if (missingEntitlement) showSetupHint();
}

Apple’s SDK has no dedicated error or availability reason for a missing entitlement. The package recognises it from the text of Apple’s error (a description mentioning an entitlement):

Because this depends on Apple’s wording, treat it as a hint. The original description is always in error.message and error.details.debugDescription. It is also possible for an app without the entitlement to simply see PCC as unavailable (SYSTEM_NOT_READY / DEVICE_NOT_ELIGIBLE); this has not been verified on an entitled or unentitled device yet.

model: 'auto' (Fourlyn abstraction, not an Apple API)

const session = await createSession({ model: 'auto' });
session.model; // 'system' or 'privateCloudCompute'

Resolution order: on-device system model if available → PCC if available → MODEL_UNAVAILABLE. It is resolved once, at session creation.

Privacy