Code researcher “pdfu” has uncovered evidence that Apple has engineered its new Siri architecture to support third-party AI models at a deep technical level, according to analysis of iOS 27 and macOS Golden Gate private frameworks.
The architecture includes at least two distinct mechanisms for AI model integration. The first, called Model Delegation, allows third-party AI models like Claude to appear as Siri extensions alongside the existing ChatGPT extension. In a demonstration video shared on X, a macOS user selected Claude from an “Ask…” contextual menu in the “Search or Ask” bar. When asked to set a reminder, Claude interpreted the natural language request, and Siri subsequently created the reminder in Apple’s Reminders app. For tasks requiring Claude’s capabilities—such as generating a CSV file—Claude handles the request directly.
A second, more extensive protocol operates through “Model Manager Services,” which appears to allow Apple’s server-side Siri model to be completely replaced by alternative models like GPT-5.6. In this scenario, the third-party model receives Apple’s Siri planner prompt and tool definitions, enabling it to request system actions, access personal data, and formulate responses that Siri presents through its own interface and voice. According to pdfu’s demonstration, this allows ChatGPT to perform complex tasks like finding emails on a specific topic, summarizing their contents, identifying action points, and sending messages through the Messages app.
Apple has not yet enabled the Model Delegation entitlement for third parties, and the feature remains non-public-facing. The “Ask…” implementation in the macOS 27 Golden Gate Release Candidate currently supports only the ChatGPT extension, with Claude not yet available through this mechanism.
The European Union’s Digital Markets Act may have influenced Apple’s approach. The regulation requires Apple to provide third parties effective access to iOS and macOS hardware and software features available to Apple’s own services. The European Commission has explicitly stated this principle extends to Siri.
Key facts
- Code analysis reveals two mechanisms for third-party AI integration in Apple’s new Siri architecture
- Model Delegation allows AI models like Claude to function as Siri extensions
- A second protocol can replace Apple’s server-side Siri model entirely with alternatives like GPT-5.6
- Model Delegation entitlements have not yet been opened to third parties
- The EU’s Digital Markets Act may have influenced Apple’s design approach