代理平台
macOS 27’s Private Inference Interface Can Replace Siri’s Planning Model, but It Is Not Yet a Third-Party API
Reverse-engineering experiments show that macOS 27’s `Inference Providing` path can pass Siri’s planning prompts, tool definitions, and execution results to an external model. The demo requires disabling system protections and using a private Apple entitlement, so it should not be interpreted as meaning users can now officially replace Siri’s model.
A macOS 27 reverse-engineering experiment that drew community attention on September 14 shows that the new Siri AI contains at least two internal levels of model replacement. The shallower `Model Delegation` level allows Claude to take over when Siri cannot handle a request, similar to the existing ChatGPT extension. The deeper `Inference Providing` level can replace Siri’s server-side planning model. In the demo, GPT‑5.6 Terra received Apple’s native planner prompt and 20 tool definitions, allowing it to ask the system to search email, access personal data returned by tools, send messages, and then present the results through Siri’s interface and voice.
Technically, this design separates the language model from the operating system’s execution layer: Apple retains control of tool implementations, permissions, and the UI, while the external model handles planning and generates tool calls. If Apple makes this capability public in the future, developers could replace cloud or on-device models without rebuilding an entire desktop agent. The same layer could also serve as a centralized policy gateway that determines which data may be sent externally and which actions require confirmation. At the same time, it expands the sensitive-data boundary because an external provider could gain access to Siri’s system prompts, email content, contact information, and tool results. The model provider’s own privacy settings alone would not be sufficient.
The current limitations are clear. The experiment uses the unpublished ExtensionKit endpoint `com.apple.modelmanager.inferenceprovider`, requires a private Apple entitlement, and also requires SIP and AMFI to be disabled during development. The official macOS 27 “Ask…” interface currently still supports only ChatGPT. Apple has not formally committed to opening full planner replacement, so this is a validation of capabilities in a framework that has already shipped—not a product launch. Engineers should now watch whether Apple makes the entitlement public, whether tool permissions are granted individually, whether personal data can remain on-device, and what logging, revocation, and audit models will apply to third-party providers.