diff --git a/web/src/attach.ts b/web/src/attach.ts
index f5be8bf..b512490 100644
--- a/web/src/attach.ts
+++ b/web/src/attach.ts
@@ -130,13 +130,17 @@ export function createAttachConnection(
   term.loadAddon(fit);
   term.open(body);
 
-  // Touch scrollback: xterm's built-in touch handling on the viewport is jittery
-  // (drags crawl a line at a time and stall after a few), so map finger drags to
-  // term.scrollLines ourselves. Skipped on the alternate screen (full-screen
-  // TUIs like tmux/Claude Code) — there's no scrollback to move and the app owns
-  // the gesture. `touch-action: pan-y` (CSS) tells the browser we handle Y.
+  // Touch scrolling: xterm's built-in touch handling is jittery (drags crawl a
+  // line at a time and stall), so map finger drags ourselves. Two routes:
+  //   • normal buffer  → term.scrollLines walks the scrollback.
+  //   • mouse-tracking apps (tmux, Claude Code on the alt screen) → synthesize
+  //     wheel events so xterm encodes them as mouse-wheel reports the app reads,
+  //     scrolling *its* content (the only scroll that exists on the alt screen).
+  //   • alt screen with no mouse tracking → nothing to do; the app owns input.
+  // `touch-action: pan-y` (CSS) tells the browser we handle the Y gesture.
   {
     const vp = el.querySelector(".xterm-viewport") as HTMLElement | null;
+    const screen = el.querySelector(".xterm-screen") as HTMLElement | null;
     const cellH = () => {
       const core = (term as unknown as {
         _core?: { _renderService?: { dimensions?: { css?: { cell?: { height: number } } } } };
@@ -145,12 +149,14 @@ export function createAttachConnection(
     };
     if (vp) {
       let lastY = 0;
+      let lastX = 0;
       let remainder = 0;
       vp.addEventListener(
         "touchstart",
         (e) => {
           if (e.touches.length !== 1) return;
           lastY = e.touches[0].clientY;
+          lastX = e.touches[0].clientX;
           remainder = 0;
         },
         { passive: true },
@@ -159,13 +165,34 @@ export function createAttachConnection(
         "touchmove",
         (e) => {
           if (e.touches.length !== 1) return;
-          if (term.buffer.active.type === "alternate") return; // app-owned
+          const ch = cellH();
           const y = e.touches[0].clientY;
           const px = lastY - y + remainder; // finger up → scroll toward newer
           lastY = y;
-          const lines = Math.trunc(px / cellH());
-          remainder = px - lines * cellH();
-          if (lines !== 0) {
+          const lines = Math.trunc(px / ch);
+          remainder = px - lines * ch;
+          if (lines === 0) return;
+          // term.modes.mouseTrackingMode is "none" unless the app turned mouse
+          // reporting on — that's the signal to forward instead of scrollback.
+          const mouseTracked = term.modes.mouseTrackingMode !== "none";
+          if (mouseTracked && screen) {
+            // One wheel event per crossed cell, dispatched at the touch point so
+            // xterm computes valid cell coords for the mouse report.
+            const dir = lines > 0 ? 1 : -1;
+            for (let i = 0; i < Math.abs(lines); i++) {
+              screen.dispatchEvent(
+                new WheelEvent("wheel", {
+                  deltaY: dir * ch,
+                  deltaMode: 0,
+                  clientX: lastX,
+                  clientY: y,
+                  bubbles: true,
+                  cancelable: true,
+                }),
+              );
+            }
+            e.preventDefault();
+          } else if (term.buffer.active.type !== "alternate") {
             term.scrollLines(lines);
             e.preventDefault();
           }