Foundation Models framework dyld symbol errors after macOS 26 Beta 2 - LanguageModelSession constructor missing

Foundation Models framework worked perfectly on macOS 26 Beta 2, but starting from Beta 3 and continuing through Beta 6 (latest), I get dyld symbol errors even with the exact code from Apple's documentation.

Environment:

• macOS 26.0 Beta 6 (25A5351b)
• Xcode 26 Beta 6
• M4 Max MacBook Pro
• Apple Intelligence enabled and downloaded

Error Details: dyld[Process]: Symbol not found: _$s16FoundationModels20LanguageModelSessionC5model10guardrails5tools12instructionsAcA06SystemcD0C_AC10GuardrailsVSayAA4Tool_pGAA12InstructionsVSgtcfC Referenced from: <UUID> /path/to/app.debug.dylib Expected in: <UUID> /System/Library/Frameworks/FoundationModels.framework/Versions/A/FoundationModels

Code Used (Exact from Documentation): import FoundationModels

// This worked on Beta 2, crashes on Beta 3+ let model = SystemLanguageModel.default let session = LanguageModelSession(model: model) let response = try await session.respond(to: "Hello")

What I've Verified:

1. FoundationModels.framework exists in /System/Library/Frameworks/
2. Framework is properly linked in Xcode project
3. Apple Intelligence is enabled and working
4. Same code works in older beta versions
5. Issue persists even with completely fresh Xcode projects

Analysis: The dyld error suggests the LanguageModelSession(model:) constructor is missing. The symbol shows it's looking for a constructor with parameters (model:guardrails:tools:instructions:), but the documentation still shows the simple (model:) constructor.

Questions:

1. Has the LanguageModelSession API changed since Beta 2?
2. Should we now use the constructor with guardrails/tools/instructions parameters?
3. Is this a known issue with recent betas?
4. Are there updated code samples for the current API?

Additional Context: This affects both basic SystemLanguageModel usage AND custom adapter loading. The same dyld symbol errors occur when trying to create SystemLanguageModel(adapter: adapter) as well.

Any guidance on the correct API usage for current betas would be greatly appreciated. The documentation appears to be out of sync with the actual framework implementation.