Full Breakdown
Apple Shows Private “Model Delegation” API Can Run Claude as a Siri Extension on macOS
By Drooid · · How we work
Demonstration of Claude as a Siri Extension
On September 13, 2026, developer pdfu used Apple’s private Model Delegation API to run Anthropic’s Claude model as a Siri extension on macOS Golden Gate. In the video, the user selects Claude from an “Ask…” contextual menu, asks Siri to “Ask Claude” to set a reminder, and Claude processes the natural-language request while Siri executes the system action. A second example shows Claude generating a CSV file—something Siri cannot do—then returning the result to the user. The demonstration proves that a third-party model can handle generative tasks while Siri retains control of native system functions.
Technical Mechanism: Model Delegation API
Apple’s App Intents framework contains a private Model Delegation API that lets an authorized app add a Siri Extension and replace Siri’s server-side AI model with an external one. The integration requires a special entitlement normally reserved for Apple’s own services. When a request involves a system capability (e.g., creating a reminder), Siri intercepts the request, performs the action, and hands the response back to the third-party model for final wording. A separate “Inference Providing” protocol in Model Manager Services can even swap Apple’s server model entirely, allowing a model such as GPT-5.6 to receive Siri’s planner prompt and tool definitions, request system actions, and return answers that Siri vocalizes.
Implications and Limitations
The setup illustrates a deep level of interoperability that could broaden the AI ecosystem for Apple devices. However, the Model Delegation entitlement is not publicly available, and the feature is limited to the ChatGPT extension in the macOS 27 Golden Gate Release Candidate. Claude is not yet offered to users, and Apple has not opened the entitlement to third-party developers. The European Union’s Digital Markets Act, which obliges Apple to grant effective access to iOS hardware and software features, may have influenced this direction, as the European Commission has indicated the principle extends to Siri. Privacy considerations arise because requests processed by Claude would leave Apple’s Private Cloud Compute environment and be sent to Anthropic’s servers.
Timeline
- September 13, 2026 – Developer pdfu demonstrates Claude running as a Siri extension on macOS Golden Gate via the private Model Delegation API.
- macrumors reports that the implementation is currently limited to the ChatGPT extension in the macOS 27 Golden Gate Release Candidate and that Apple has not yet exposed the model-delegation entitlement to third parties.