Developer "pdfu" discovered after digging into the underlying code of iOS 27 and macOS Golden Gate that Apple has designed the new Siri's AI architecture to be an open format capable of deep collaboration with third-party models within its private frameworks. His demonstration video shows that Anthropic's Claude and OpenAI's GPT-5.6 can be integrated into the Siri framework.

The first mechanism is called "Model Delegation," which allows Claude to appear as a Siri extension, similar in form to the currently built-in ChatGPT extension. In the video, a macOS user opens the "Search or Ask" bar, selects Claude from the "Ask…" menu; then the user asks Siri to "let Claude" create a reminder in the Reminders app. Claude is responsible for parsing this natural language request and then handing the task back to Siri to create the actual reminder—when it comes to Apple system functions, third-party models return the execution authority to Siri. In another example, Claude received a request to create a CSV file within the Siri conversation window. This task cannot be done by Siri itself, but Claude successfully returned the result, meaning third-party models can fill in the capability gaps of Siri.

Even more significant is the second protocol, "Model Management Service," which includes an Inference Provider. Its openness is much higher, allowing users to completely replace the on-device Siri model on Apple devices with external models like GPT-5.6. In this mode, ChatGPT can fully take over Apple's Siri planner and tool definitions, independently request system operations, receive returned personal data, and generate answers that are delivered by Siri using its own interface and voice. In the demonstration, the user asked ChatGPT to search for emails on a specific topic within the Siri app, summarize the content and tasks, and then send messages through the Messages app to contacts. The relevant responses were simultaneously displayed in the logs on the OpenAI platform's web interface.

Most media believe that the EU's Digital Markets Act is the behind-the-scenes force driving this change. The regulation requires Apple to provide third parties with equivalent access to iOS hardware and software functions as its own services. The European Commission has clearly stated that this principle also applies to the Siri AI.

However, these capabilities have not yet been truly made available to users. The implementation of "Ask…" is currently limited to the ChatGPT extension in the macOS 27 Golden Gate candidate release version, while Claude is still unavailable; Apple has also not yet opened up model delegation authorization to third parties, and related features are not shown to users. But the code makes one thing clear—the Apple has already made quite in-depth engineering preparations for future model interoperability.