opencode's TUI runs on the ALTERNATE SCREEN (measured on 1.18.31: tmux
`alternate_on=1`, `history_size=0`), so tmux keeps no history for the pane and
the browser's normal buffer never grows past one screen (`baseY === 0`). The
plain wheel therefore scrolled a buffer with nothing in it — dead in every
opencode tab, on desktop and touch alike.
opencode is not a forwarding candidate: it IGNORES SGR wheel reports (six
`\x1b[<64;…M` reports against an idle pane left the capture byte-identical),
but it does page its own transcript on PageUp/PageDown (`messages_page_up/down`,
verified on the same pane). The hollow-buffer rescue already sends exactly those
keys — it was just gated to `claude`. Widen the gate to opencode so the wheel
and touch gestures reach the CLI's own transcript instead of a no-op.
Every other mode stays out: shell/pi own real terminal scrollback, and
codex/gemini/antigravity/grok/deepseek/omp page-key behaviour is unverified
(docs/scrollback-fix-plan.md).
Test: test/terminal-scroll-routing.test.ts — new opencode case (Red before the
fix, Green after); the "real local scrollback is untouched" case now also pins
antigravity as not-paged.
Randalix
5a0018fc86