Apple’s Siri AI Can Be Swapped Out for Claude, ChatGPT, Code Shows
A developer named pdfu has dug through the code of iOS 27 and macOS Golden Gate and found something unusual: Siri’s brain is not fixed. The private frameworks he examined show Apple has built Siri to accept third-party AI models as drop-in replacements, and the evidence comes in the form of working demos that let Claude and ChatGPT step in for Siri’s own responses.
The findings were shared in a video posted to X, where pdfu walks through two distinct ways Apple has engineered Siri to work with external intelligence. One method is a simple menu choice. The other goes much deeper, letting Apple’s own server-side model be entirely replaced by another AI.
Menu Choice: Claude As a Siri Extension
The first mechanism is called Model Delegation. It works like an extension system, where Claude can appear as a Siri extension in the same way the built-in ChatGPT extension does. In the video, a macOS user opens the “Search or Ask” bar and picks Claude from an “Ask…” contextual menu.
Once the Claude extension is enabled, the user asks Siri to “Ask Claude” to set a reminder in Apple’s Reminders app. Claude interprets the natural language request, and Siri creates the reminder. The demo suggests that when the request touches an Apple system feature, Claude hands the task back to Siri to complete it.
The process is seamless to the user. They speak to Siri, Siri routes the request to Claude, Claude processes it, and Siri delivers the answer. The Claude extension acts as a filter between the user and the app.
Claude’s CSV Test
Another example shows Claude handling something Siri itself cannot manage on its own: creating a CSV file. In the video, Claude receives the request, processes it, and returns the result directly through the Siri app conversation window.
The test demonstrates that the delegation model works across different kinds of tasks. A reminder is a simple command. A CSV request is a data operation. Both work through the same Claude extension, routed through Siri.
Server-Side Swap Protocol
The second protocol goes further. It involves an inference provider in “Model Manager Services,” which appears to allow Apple’s server-side Siri model to be completely replaced by another model, such as GPT-5.6.
Here’s how it works:
- Apple sends its native Siri planner prompt and tool definitions to the external model.
- The external model processes the request and performs system actions.
- The model returns its results to Siri, which formats the answer and presents it using its own interface and voice.
The video shows this in action. The user asks the ChatGPT model, running within the Siri app, to search for emails about a specific topic, summarize their contents, and action points, then send a message to a person in the user’s contacts via the Messages app. The response is then shown as logged in OpenAI’s platform web interface.
What Is Actually Shown
The video demonstrates that Siri can route requests to an external AI and present the answers as its own. The Claude extension example is a user interface choice. The GPT-5.6 swap is a server-side configuration that the user never sees.
The distinction matters for developers. A menu choice is relatively easy to expose to users. A server-side model replacement is a different kind of integration, one that sits below the surface.
The EU Angle
The European Union’s Digital Markets Act may have shaped Apple’s approach here. The law requires Apple to give third parties effective access to iOS hardware and software features available to Apple’s own services, and the European Commission has said this principle extends to Siri.
Whether this code change was prompted by the law or arrived independently, the result is the same: Apple has engineered Siri to work with external AI models at a deep level.
What Is Not Yet Available
The “Ask…” implementation is currently limited to the ChatGPT extension in the macOS 27 Golden Gate Release Candidate, which is effectively the final version of the software set to be released later this month. Claude is not yet available through that menu.
Apple has not yet opened the model delegation entitlement to third parties, and it is not front-facing to users. The evidence is in the code, but the feature is not live for general use.
The Core Discovery
The findings suggest Apple is preparing for a world where Siri is not a fixed product but a platform. External AI models can be plugged in, swapped out, and exposed to users through familiar interfaces.
The implications are broad. Developers could build custom extensions that route requests to any AI they choose. Users could pick which model answers their questions. The server-side model replacement protocol opens the door to entirely custom Siri experiences, built on top of existing infrastructure.
The Wider Picture
The code exists. The video demonstrates it. The question now is whether Apple will open the model delegation entitlement to third parties and make these capabilities available to everyone.
“Model Delegation allows Claude to appear as a Siri extension in the same way as the existing built-in ChatGPT extension.”
That line, from pdfu’s description, captures the core of the discovery. Siri is no longer a single, fixed assistant. It is a framework that can host any AI model, and the user can choose which one answers.
The findings raise questions about what Siri is for, and who gets to define it. Apple has opened a door. Whether it stays open is the question worth watching.