Captures CPU profiles from running Valdi apps via the Hermes debug protocol.
npx skills add https://github.com/Snapchat/Valdi --skill valdi-profile
Please help me install this Agent Skill. Skill: valdi-profile Source: https://github.com/Snapchat/Valdi/tree/main/ai-skills/skills/valdi-profile Command: npx skills add https://github.com/Snapchat/Valdi --skill valdi-profile
Diagnosing slow renders and hot functions in a Valdi app requires visibility into what the JavaScript thread is actually doing, which is impossible without a CPU profile of the Hermes runtime.
Ask the assistant to capture a 5-second CPU profile of the running Valdi app while you trigger the slow interaction, then open the resulting .cpuprofile in Chrome DevTools.
High-intent search queries and answers about installing and using this skill.
Build the app with the Hermes engine, start valdi hotreload from the project directory, then run valdi profile capture --duration 5 while triggering the interaction you want to measure. The command outputs a .cpuprofile file path as JSON.
Open the .cpuprofile in Chrome DevTools via the Performance tab's upload button, drag it into speedscope.app, or use the VS Code JS Profile Visualizer extension. The file uses the standard Chrome DevTools CPU profile format.
This error means the app was built with the default QuickJS engine instead of Hermes, or the hot-reloader is not running. Rebuild with the Hermes bazel args and ensure valdi hotreload is active to create the port 13595 tunnel.
No, physical iOS devices are not supported in V1 because Hermes debugging there requires idb tunnelling. Use an iOS simulator, or an Android device or emulator, for CPU profiling.
An empty profile means the app was idle during the capture window with no JS activity. Trigger the interaction you want to profile while the capture is running, since only active JavaScript execution appears in the profile.
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