iOS 27 and macOS Golden Gate have private hooks that let apps add Siri Extensions and replace Siri AI’s server backend with third-party models.
First, here’s Claude running as a Siri Extension using the Model Delegation API in App Intents. Claude can appear in Siri’s “Ask…” menu and supports the same underlying flow as the built-in ChatGPT extension.
In some cases, Siri Extensions can be more powerful than Siri AI. For example, Siri can’t create a CSV, but Claude can easily return one when asked.
When system interaction is required, such as setting a reminder, Claude can relay the original or a modified request back to Siri, which completes the request.
Requires the private com\.apple.developer.model-delegation entitlement. (1/2)
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And here’s an app extension replacing Siri AI’s server model with GPT-5.6 Terra. It uses the Inference Providing protocol in Model Manager Services.
GPT-5.6 receives Apple’s native Siri planner prompt and tool definitions. It can make tool calls that perform system actions, and receive tool call results with personal data. Finally, GPT-5.6 can return a response through Siri AI’s UI and voice, including interactive elements.
Siri AI has a local “Skimmer” planner with limited capabilities that hands off most tasks to Apple’s server models, but that’s for another day.
Watch until the end to see requests being logged on OpenAI’s platform. Uses a private ExtensionKit extension point: com\.apple.modelmanager.inferenceprovider.
GPT-5.6 receives Apple’s native Siri planner prompt and tool definitions. It can make tool calls that perform system actions, and receive tool call results with personal data. Finally, GPT-5.6 can return a response through Siri AI’s UI and voice, including interactive elements.
Siri AI has a local “Skimmer” planner with limited capabilities that hands off most tasks to Apple’s server models, but that’s for another day.
Watch until the end to see requests being logged on OpenAI’s platform. Uses a private ExtensionKit extension point: com\.apple.modelmanager.inferenceprovider.
1:06 PM UTC · Sep 13, 2026 · 31.6K Views
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