Shopify 藉助 Agent 轉離 React Native，Expo 用 Agent 修復 React Native；作者指關鍵在可測試性

Shopify used AI agents to get off React Native. Expo shipped an AI agent that fixes React Native bugs.
Both came out the same month. Same bet, pointed in opposite directions.
The bet: agents make large-scale mobile work cheap.

What each one did

Shopify's Helix is the internal tooling behind their move to Swift and Kotlin. They rebuilt the Shop app in 12 weeks, and now they're working through the main app, which has 300+ screens.
Expo's agent starts when someone adds a label to a GitHub issue. It reproduces the bug on a cloud simulator, fixes it and opens a PR with before and after recordings.

The wrong lesson

Everyone will read the Shopify post as "native won." I don't think that's the lesson.
Helix doesn't one-shot a spec. It works in small checkpoints, and each one has to pass gates: behaviour tests, UI review, two adversarial agent reviews, then a human.
That only works if logic and UI are separable enough to test on their own.

The real lesson

That's a testability problem, not a React Native problem. Most RN codebases I've seen in 10 years have it too.
Every native vs cross-platform cycle I've lived through was decided by team shape, not framework quality. This one is being decided by which codebase an agent can safely navigate.
So I wouldn't migrate on Monday. I'd measure how much of my app an agent can touch without breaking something. That number matters more than the framework.
How much of your app could an agent safely change today?