Also running the same exact code that runs fine on the mac simulator on iPhone simulators with iOS 26 result in this error: guardrailViolation(FoundationModels.LanguageModelSession.GenerationError.Context(debugDescription: "Safety guardrail was triggered after consecutive failures during streaming.", underlyingErrors: []))

The issue seem to persist on the Tahoe Beta 3 @DTS Engineer I will submit the report shortly.

Fixed on Xcode beta 2

Hello Benjamin, I hope you’re doing well. Several posts by the developers, including myself, have raised concerns about an issue that seems to have arisen since installing iOS 26 Beta 3. Specifically, FoundationModels is intermittently throwing guardrail violations on otherwise harmless prompts. For example, Apple’s own sample app from the “Foundation Code-Along” session now fails with the same error. FoundationModels guardrailViolation on Beta 3 Community members on the forums have tested a variety of queries and found wildly inconsistent results—asking “What’s the population of New York?” succeeds, whereas “What’s the population of Sweden?” triggers a guardrailViolation or a GenerationError (see these threads for details): "FoundationModels GenerationError error 2" on iOS 26 beta 3 So far, the only official responses have been generic reminders about prompt safety, which don’t explain why simple factual questions are being blocked. Given Apple’s two-week beta cadence, I’m optimistic that this behavior will be addressed in the next release.

I encounter the same issues. Also some strange haptics errors?

I am also experiencing issues with tool calling. Not sure what is the issue yet, but what has been answered to you is checked on my code. It used to work perfectly before the change to the new tool output format.

Even though this doesn’t provide a direct solution for cross-device real-time database persistence, it may simulate the behavior you’re looking for. If both devices are on the same network, you can leverage the MultipeerConnectivity framework to send data to other devices immediately and then persist it locally. This way you can achieve a “live update” experience within the Apple ecosystem, while still using SwiftData for storage.