How to Replace Siri With ChatGPT, Claude, or Gemini

9 min read By FindSkill Team

iOS 27's Extensions let you swap Siri for ChatGPT, Claude, or Gemini. Here's exactly how the new default-assistant setting works — and the honest catch.

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A few weeks ago, “you’ll be able to swap Siri’s brain for another AI” was a rumor. A well-sourced one, but still a rumor. Now it’s on a keynote slide. At WWDC 2026, Apple confirmed iOS 27 includes a system called Extensions that lets you point Siri at ChatGPT, Claude, or Gemini instead of Apple’s own model.

Which means the most common question we’ve gotten all spring — “I don’t like Siri, can I just use ChatGPT?” — finally has a real answer. Yes. Here’s how it works, and the catch nobody’s putting in the headline.

What Extensions actually is (now that it’s official)

Until now, your iPhone had exactly one outside AI it could call on: ChatGPT, baked in since iOS 18.2 back in 2024. You’d ask Siri something hard, it’d offer to “Ask ChatGPT,” and that was the only option on the menu.

Extensions blows that open. Apple is turning the single ChatGPT deal into an open lane any qualifying AI app can join through the App Store. So instead of being stuck with Apple’s model, you install the AI app you actually like — ChatGPT, Claude, Gemini — and set it as your phone’s go-to.

Here’s the framing one viral post on X nailed: Siri “doesn’t compete — it turns them into its providers.” Apple isn’t trying to out-ChatGPT ChatGPT. It’s making your phone the place where the AI you already trust does the talking.

iOS 27’s Extensions settings, where you choose a default AI service Source: Tom’s Guide

How to replace Siri, step by step

The mechanic is genuinely simple. Three moves.

Swapping Siri's brain in iOS 27
Install the AI app you want ChatGPT, Claude, or Gemini
Settings → Apple Intelligence & Siri find Default AI Service
Pick your default Siri hands eligible requests to it
Reported flow based on the iOS 27 developer beta — final UI may shift before fall.
  1. Install the app. Get ChatGPT, Claude, or Gemini from the App Store (free accounts are fine to start). The app has to support Apple’s new Extensions feature — the big three are on board.
  2. Open the setting. Go to Settings → Apple Intelligence & Siri. Reports point to a “Default AI Service” option there where your installed AI apps show up.
  3. Choose your assistant. Pick the one you want. From then on, Siri, the Writing Tools popover, and Image Playground route eligible requests to that model instead of Apple’s.

One nice touch that’s been reported: Apple plans to give third-party AI responses a different voice, so you can actually tell whether Apple’s Siri or your chosen model just answered. Small thing. Genuinely helpful.

A quick honesty flag on the exact menu: the concept is confirmed by Apple, but the precise “Default AI Service” wording and screens are coming from Bloomberg reporting and early-beta walkthroughs, not a finished Apple support page. Expect the labels to settle by the fall release.

Which one should you actually pick?

Short version, because this deserves its own page (and has one): each model has a personality. Gemini leans research and Google-ecosystem stuff. Claude is the careful writer and explainer. ChatGPT is the do-everything generalist most people already know. Some reports even suggest you’ll be able to route different request types to different models — Gemini for a search, Claude for a rewrite — though that part’s still firming up.

If you want the full “who’s good at what, and who should pick which” breakdown, we wrote it here: Claude, Gemini, or ChatGPT: Choose Your iOS 27 Siri. This page is the how; that one is the which.

What this means for you

If you’re a die-hard ChatGPT user. This is the upgrade you’ve wanted since 2024. Set ChatGPT as your default and your iPhone basically becomes a ChatGPT remote — no more opening the app every time.

If you live in the EU. Pay attention, because this matters more for you than anyone. Apple confirmed the new Siri AI won’t ship on iPhone or iPad in the EU at launch (a Digital Markets Act standoff). Extensions and third-party assistants are your most likely path to a modern AI assistant on an EU iPhone — though whether the full setup arrives untouched there is still worth watching.

If you’ve never used Claude or Gemini. No rush to switch. The default Siri AI is genuinely capable. But it’s nice to know that if it annoys you, you’re not trapped — you can change the brain, not the phone.

If you find all of this overwhelming. Totally fair. You don’t have to pick on day one. Apple will set a sensible default and you can change it whenever — or never.

The honest catch

Read this part before you get excited.

  • It’s not live for most people yet. Extensions ships with iOS 27 in the fall. Right now it’s only in the developer beta. So “you can replace Siri today” is true only if you’re running beta software on a supported iPhone.
  • The exact setup could change. The settings screen and the per-task routing are based on reporting and early builds. Apple tweaks this stuff right up to release.
  • You still need a recent iPhone. Same Apple Intelligence hardware rules apply — iPhone 15 Pro, 16, or newer.
  • Free tiers have limits. Setting ChatGPT or Claude as your default doesn’t unlock their paid features. Heavy use may still hit free-plan caps.

The bottom line

For the first time, the AI in your iPhone is a choice, not a sentence. iOS 27’s Extensions let you keep Siri or hand the keys to ChatGPT, Claude, or Gemini — your call, changeable anytime. The setup is three taps. The catch is that it lands for everyone this fall, not today.

The bigger point: the model matters less than knowing how to use it. A great assistant with lazy prompts still gives lazy answers. If you want to get genuinely good at talking to any of these — Siri, ChatGPT, Claude, Gemini — start with our ChatGPT vs Claude course to learn what each one is actually best at. First two lessons are free, no signup.

Sources

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