# Siri's brain can be swapped out

> Hidden iOS 27 code shows Apple built Siri to run on Claude or ChatGPT, not just Apple's own model.
- Title: Siri's brain can be swapped out · MacRumors | Shortify
- Summary: Hidden iOS 27 code shows Apple built Siri to run on Claude or ChatGPT, not just Apple's own model. Apple has quietly engineered Siri as a shell that any AI…
- Keywords: siri, apple, claude, chatgpt, ios 27, technology, startups, Siri's, brain, swapped, MacRumors
- Source: MacRumors — https://macrumors.com/2026/09/14/siri-can-be-swapped-out-for-chatgpt-claude
- Published: 2026-09-14T11:37:17+00:00
- Read time: 1 min
- Topics: siri, apple, claude, chatgpt, ios 27, technology, startups
## A code sleuth goes digging
Researcher "pdfu" pulled apart private frameworks in iOS 27 and macOS Golden Gate. What they found: Apple's new Siri was designed for third-party AI models at a deep level.
## Claude as a Siri extension
A mechanism called Model Delegation lets Claude show up next to the built-in ChatGPT extension. On macOS you open the "Search or Ask" bar and pick Claude from an "Ask..." menu.
## The handoff back to Siri
Asked to set a reminder, Claude parses the natural language and Siri actually creates it. Anything touching an Apple system feature gets handed back to Siri.
## Doing what Siri cannot
In another demo, Claude takes a request inside the Siri conversation window to build a CSV file and returns it. Siri has never been able to do that on its own.
## Replacing Siri's brain entirely
An inference provider in Model Manager Services lets a model like GPT-5.6 replace Apple's server-side Siri model. It gets Apple's planner prompt and tool definitions, then answers in Siri's voice and interface.

> GPT-5.6 receives Apple's native Siri planner prompt and tool definitions.
## Regulators may be the reason
The EU's Digital Markets Act forces Apple to give third parties real access to iOS features, and the Commission said that covers Siri. For now the entitlement stays closed to outside developers.
## Key takeaway

Apple has quietly engineered Siri as a shell that any AI model can plug into, even if users cannot flip that switch yet.