Apple on Monday unveiled “Siri AI,” a ground-up rebuild of its voice assistant running on a custom 1.2-trillion-parameter Google Gemini model, at the 37th Worldwide Developers Conference. The disclosure ends nearly two years of unmet Apple promises on artificial intelligence and inaugurates the company’s deepest external dependency inside a flagship consumer product, as The Washington Post framed it.

It was also Tim Cook’s last WWDC keynote as chief executive. On September 1, Cook transitions to executive chairman and hardware engineering chief John Ternus takes over, a handoff that now arrives bolted to a strategic concession Apple spent two years avoiding.

The architecture, first reported by Bloomberg’s Mark Gurman, is a three-tier routing arrangement. On-device requests stay on the iPhone; mid-complexity queries run on Apple Private Cloud Compute servers powered by Nvidia Blackwell B200 GPUs; the hardest requests are tokenized, anonymized, and shipped to Google Cloud, where the custom Gemini model handles them without either Apple staff or Google being able to link queries to individual users. The partnership was first disclosed in January 2026, per the Post.

The framing matters. Apple’s internal leadership meetings, Bloomberg reported, had concluded the company was behind OpenAI, Google, Anthropic, and Meta on generative AI deployment, and the Gemini deal is the structural admission of that gap. The branding “Siri AI” is itself narrative management, a way to relaunch a product that Apple already paid $250 million to settle with iPhone 16 buyers who said features advertised at WWDC 2024 never shipped.

Cook, speaking from Apple Park, described the moment as a defining one for Apple and positioned Siri AI as the delivery on commitments first made two years ago, NPR reported.

The rollout is uneven. Siri AI ships in a public beta in July and goes general with iOS 27 and iPadOS 27 in September alongside the iPhone 18. It won’t launch in China, and Apple said in a statement carried by CNBC: “Unfortunately, due to the Digital Markets Act (DMA), Apple will not be able to ship Siri AI in the European Union with the release of iOS 27 and iPadOS 27.” Under iOS 27 Extensions, TechCrunch reported, users will also be able to set a third-party AI model as their default assistant, a concession unimaginable from Apple a decade ago.

Apple also previewed homeOS and the HomePad, a smart-home hub combining a HomePod speaker, a 7-inch display, and an A18 chip. Developer betas for all six refreshed operating systems were seeded Monday.

The keynote belonged to Cook on paper. The underlying transaction belonged to Google.

Sources