Newly surfaced code inside iOS 27 and macOS Golden Gate suggests Apple has built its overhauled Siri to work alongside — and even defer to — third-party AI models such as Anthropic's Claude and OpenAI's ChatGPT. The findings, shared by developer and code sleuth "pdfu" on X, point to private frameworks that go well beyond the assistant's current capabilities.

How the model delegation works

According to the demonstration, one mechanism called Model Delegation lets Claude appear as a Siri extension, mirroring the way the existing ChatGPT integration operates. In a video posted to X, a macOS user opens the "Search or Ask" bar and selects Claude through an "Ask..." contextual menu.

Once the Claude extension is enabled, the user asks Siri to "Ask Claude" to create a reminder in Apple's Reminders app. Claude interprets the natural-language request, and Siri then completes the task. The setup implies that when a request needs access to an Apple system feature, the third-party model hands control back to Siri. In another example, Claude generates a CSV file inside a Siri conversation window — something Siri cannot do on its own — and returns the result.

Replacing Siri's server model entirely

A second protocol demonstrated in the video appears to go considerably further. An inference provider within "Model Manager Services" reportedly allows Apple's own server-side Siri model to be swapped out completely for another model, such as GPT-5.6.

In that scenario, ChatGPT receives Apple's Siri planner prompt and its tool definitions. That lets the external model request system actions, receive the resulting personal data, and craft a response that Siri presents using its own interface and voice. In one example, the ChatGPT model is asked to find emails on a specific topic, summarize their content and action points, then send a message to a contact through the Messages app. The interaction is shown logged in OpenAI's own platform web interface.

Why the EU may be a factor

The architecture may reflect regulatory pressure as much as engineering ambition. The European Union's Digital Markets Act requires Apple to give third parties effective access to iOS hardware and software features that its own services can use. The European Commission has specifically said that principle extends to Siri, which could push Apple toward deeper interoperability.

For now, the capabilities remain largely hidden. The "Ask..." implementation is currently limited to the ChatGPT extension in the macOS 27 Golden Gate Release Candidate — effectively the final build — so Claude is not yet selectable. Apple has also not opened the model delegation entitlement to outside developers, and none of this is exposed to everyday users.

What it means for users

Even in an unfinished state, the code shows how extensively Apple has engineered Siri for future model interoperability. If the company eventually enables these paths for third parties, users could route requests to whichever AI model suits a task while still relying on Siri for system-level actions and personal data access. That would mark a significant shift for an assistant historically built around Apple's own technology. As with any pre-release discovery, the features could change or be removed before a public rollout.