Apple iOS 27 Extensions Opens Third-Party AI Marketplace at WWDC 2026 — Claude, ChatGPT, and Gemini Can Replace Siri as Default Across All Apple Intelligence Features

Distinct from the already-announced Siri-on-Gemini backend deal, Apple's WWDC 2026 keynote on June 8 introduces iOS 27 Extensions — a framework that opens Siri, Writing Tools, and Image Playground to third-party AI providers via a dedicated App Store marketplace. Users can set Claude, ChatGPT, Google Gemini, or Grok as their preferred AI across Apple Intelligence system features through Settings, with Apple ending its single-provider ChatGPT model in favor of an open competitive platform. The move gives Anthropic, OpenAI, and Google direct distribution to over 1 billion Apple device users, with Apple testing Claude and Gemini as the first two third-party partners alongside the existing ChatGPT integration.