How Expensify Uses Agent-Device for Mobile Bug Evidence and Profiling
TLDR Dev
Expensify built agent-device, a tool that gives AI coding agents the ability to see and interact with mobile apps through structured accessibility trees and platform-agnostic commands, rather than just screenshots and coordinates. The company created agent-device-evidence to automatically reproduce bugs and collect before/after video evidence across platforms by parsing issue descriptions and replaying saved scripts, reducing what took five minutes per platform to automation. This frees developers from manual testing loops, allowing agents to handle mobile workflows like bug reproduction, performance measurement, and React profiling while engineers focus on building product features.
Why it matters
Expensify uses agent-device to give AI agents hands and eyes on real devices by returning the screen as a structured accessibility tree, applying it to bug reproduction, span measurement, and React profiling.
