TLDR Tech / Dev
How Expensify Uses Agent-Device for Mobile Bug Evidence and Profiling
Expensify uses agent-device, a tool that gives AI agents “hands and eyes” on real devices by hiding platform fragmentation behind one API and returning the screen as a structured accessibility tree rather than a screenshot (richer and cheaper in tokens). They apply it to three repeated chores: an agent-device-evidence skill that reproduces a bug, distills the steps into a replayable script, and captures before/after recordings for PRs; automated Sentry span measurement across multiple runs; and one-prompt React profiling that returns component-specific render data.
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