Native Android proof: Pixel 9, Android 16/API 36, development client installed using mobile:install; Metro serves the head checkout. Fresh synthetic environment paired through the normal Add Environment route.
Open the synthetic Site copy proof thread, tap One tab open, then Take control. The tab was created through the agent's thread-scoped preview_open tool (see replay-browser-open.diff and after-agent-open.json).
Tap Copy with writeText on the streamed page. The native alert reads 127.0.0.1:14203 wants to copy text, with Not now and Copy. Capture the alert twice at least 500 ms apart, requiring identical files.
Tap Copy, close Browser, long-press the empty unsent composer, tap native Paste. Observed composer value: site-copy-test.
Then fill the native composer with LOCAL-MARKER-UNCHANGED, long-press, Select all, Copy, and clear the composer. Reopen Browser and Take control, reload the page, tap Copy with execCommand. Observe the same native alert; tap Not now. Close Browser, long-press the empty composer and Paste. Observed composer value: LOCAL-MARKER-UNCHANGED. The recording includes the execCommand offer and dismissal; its still pair crossed a status-clock minute, so that still is not submitted as evidence.
Native head evidence supplements the full web two-commit comparison. Native base and iOS clipboard behavior were not completed.