Michał Pierzchała

@thymikee • 8,829 subscribers

Principal Engineer for Open Source @callstackio. Core @reactnative Community contributor. Building @agent_device, RN Testing Library, ex-maintainer Jest

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Michał Pierzchała

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Fable 5 made every app relaunch in agent-device 6× faster. 𝚘𝚙𝚎𝚗 --𝚛𝚎𝚕𝚊𝚞𝚗𝚌𝚑: 12s → 2s For an AI agent, that's 2.3x faster time-to-interaction. It's verifying and tapping in 5s instead of 13.

Introducing Agent Device: token‑efficient iOS &amp; Android automation for AI agents 𝚗𝚙𝚡 𝚊𝚐𝚎𝚗𝚝-𝚍𝚎𝚟𝚒𝚌𝚎

RNEF is now Rock 🎉 There are two hard things in computer science: naming and cache invalidation. While we've built React Native Enterprise Framework to tackle the latter, I admit, nailing the name was a challenge. So, we fixed it. 𝚗𝚙𝚖 𝚌𝚛𝚎𝚊𝚝𝚎 𝚛𝚘𝚌𝚔

What if your cloud agents could use iOS and Android devices just like that? Introducing Agent Device Cloud: hosted on your dusted Mac Mini, used through 𝚊𝚐𝚎𝚗𝚝-𝚍𝚎𝚟𝚒𝚌𝚎

This basically allows you to run any untrusted JavaScript in your app, whether it's written by 3rd party developers or AI agents

Videos

Watch Anya Live

Last week this session took 9 minutes and 150k tokens on Opus 4.6. Complex app navigation, network debugging, perf profiling on a production app. Justified, right? Not really. Same session today: 69k tokens. 6 minutes. Less than half. Here's how 🧵

anyone can optimize performance in React Native apps now, it's really just a single prompt

run Maestro tests 2x faster on Android with this tool » 𝚊𝚐𝚎𝚗𝚝-𝚍𝚎𝚟𝚒𝚌𝚎 𝚝𝚎𝚜𝚝

Upgrading React Native apps in 2026 couldn't be easier

Remote iOS Simulator control from a Linux agent container. One command on the Mac: » agent-device proxy Here’s a remote Claude container connecting to my Mac through a cloudflared tunnel and controlling Maps on an iOS Simulator like it’s local.

working on a faster boot, interactions, and test replay for agent-device. so far: → 3.4x faster than baseline → 1.5x faster than Maestro (yes, we're adding compatibility layer) shipping this in v0.15 once tested better

AI agents can now connect to real cloud devices🔥 agent-device now supports BrowserStack and AWS Device Farm. Test, inspect, and debug on real devices in cloud instead of stopping at local simulators. » agent-device connect browserstack » agent-device connect aws-device-farm

here’s codex controlling my physical iPhone because why not

agent-device v0.15 is out. faster than ever on iOS ⚡

there's something magical in using the tools your team ships: → Apex: an AI model fine-tuned for React Native dev → agent-device: mobile verification for AI agents → React Native: best mobile cross-platform lib Cost of Apex running this flow for 1 minute: $0.008876

what if your end-to-end tests: → were generated by agents → auto-fix as the app changes → run without AI involved » npx agent-device@latest

For a few weeks we've been building agents that are capable of understanding any app and then autonomously convert it to a React Native app. Powered by agent-device and react-native-best-practices skills from Callstack Engineers and some custom instructions DM if you're interested

The best build is no build.

Agents can now easily: → analyze a native crash → fix it → verify the fix without guessing » npx [email protected]

Introducing Agent Device: token‑efficient iOS & Android automation for AI agents 𝚗𝚙𝚡 𝚊𝚐𝚎𝚗𝚝-𝚍𝚎𝚟𝚒𝚌𝚎