Hi, I just upgraded my macOS with beta 2. After upgrade, the SwiftTranscriptionSampleApp it's stopped working, in Xcode console I read: "The connection to service named com.apple.modelcatalog.catalog was invalidated: failed at lookup with error 159 - Sandbox restriction." Note: in beta 1 worked fine

I've created the following Foundation Models Tool, which uses the .anyOf guide to constrain the LLM's generation of suitable input arguments. When calling the tool, the model is only allowed to request one of a fixed set of sections, as defined in the sections array. struct SectionReader: Tool { let article: Article let sections: [String] let name: String = "readSection" let description: String = "Read a specific section from the article." var parameters: GenerationSchema { GenerationSchema( type: GeneratedContent.self, properties: [ GenerationSchema.Property( name: "section", description: "The article section to access.", type: String.self, guides: [.anyOf(sections)] ) ] ) } func call(arguments: GeneratedContent) async throws -> String { let requestedSectionName = try arguments.value(String.self, forProperty: "section") ... } } However, I have found that the model will sometimes call the tool with invalid (but plausible) section names, meaning that .anyOf is not actually doing its job (i.e. requestedSectionName is sometimes not a member of sections). The documentation for the .anyOf guide says, "Enforces that the string be one of the provided values." Is this a bug or have I made a mistake somewhere? Many thanks for any help you provide!

Context I trained a LoRA adapter for Apple’s on-device language model using the Foundation Models Adapter Training Toolkit v0.2.0 on macOS 26 beta 4. Although training completes successfully, loading the resulting .fmadapter package fails with: Adapter is not compatible with the current system base model. What I’ve Observed, Hard-coded Signature: In export/constants.py, the toolkit sets, BASE_SIGNATURE = "9799725ff8e851184037110b422d891ad3b92ec1" Metadata Injection: The export_fmadapter.py script writes this value into the adapter’s metadata: self_dict[MetadataKeys.BASE_SIGNATURE] = BASE_SIGNATURE Compatibility Check: At runtime, the Foundation Models framework compares the adapter’s baseModelSignature against the OS’s system model signature, and reports compatibleAdapterNotFound if they don’t match—without revealing the expected signature. Questions Signature Generation - What exactly does the toolkit hash to derive BASE_SIGNATURE? Is it a straight SHA-1 of base-model.pt, or is there an additional transformation? Recomputing for Beta 4 - Is there a way to locally compute the correct signature for the macOS 26 beta 4 system model? Toolkit Updates - Will Apple release Adapter Training Toolkit v0.3.0 with an updated BASE_SIGNATURE for beta 4, or is there an alternative workaround to generate it myself? Any guidance on how the Foundation Models framework derives and verifies the base model signature—or how to regenerate it for beta 4—would be greatly appreciated.

I have been able to train an adapter on Google's Colaboratory. I am able to start a LanguageModelSession and load it with my adapter. The problem is that after one simple prompt, the context window is 90% full. If I start the session without the adapter, the same simple prompt consumes only 1% of the context window. Has anyone encountered this? I asked Claude AI and it seems to think that my training script needs adjusting. Grok on the other hand is (wrongly, I tried) convinced that I just need to tweak some parameters of LanguageModelSession or SystemLanguageModel. Thanks for any tips.

Greetings! I was trying to get a response from the LanguageModelSession but I just keep getting the following: Error getting response: Model Catalog error: Error Domain=com.apple.UnifiedAssetFramework Code=5000 "There are no underlying assets (neither atomic instance nor asset roots) for consistency token for asset set com.apple.MobileAsset.UAF.FM.Overrides" UserInfo={NSLocalizedFailureReason=There are no underlying assets (neither atomic instance nor asset roots) for consistency token for asset set com.apple.MobileAsset.UAF.FM.Overrides} This occurs both in macOS 15.5 running the new Xcode beta with an iOS 26 simulator, and also on a macOS 26 with Xcode beta. The simulators are both Pro iPhone 16s. I was wondering if anyone had any advice?

Hi all, I'm working on an app that utilizes the FoundationModels found in iOS 26. I updated my phone to iOS 26 beta 3 and am now receiving the following error when trying to run code that worked in beta 2: Al Error: The operation couldn't be completed. (FoundationModels.LanguageModelSession.Genera- tionError error 2.) I admit I'm a bit of a new developer, but any idea if this is an issue with beta 3 or work that I'll need to do to adapt my code to some changes in the AI API? Thank you!