diff --git a/apps/web/src/components/chat/MessagesTimeline.tsx b/apps/web/src/components/chat/MessagesTimeline.tsx
index 6d89140d1105..baff99d22c80 100644
--- a/apps/web/src/components/chat/MessagesTimeline.tsx
+++ b/apps/web/src/components/chat/MessagesTimeline.tsx
@@ -90,7 +90,13 @@ import {
   type TimelineLatestTurn,
 } from "./MessagesTimeline.logic";
 import { TerminalContextInlineChip } from "./TerminalContextInlineChip";
-import { Tooltip, TooltipPopup, TooltipTrigger } from "../ui/tooltip";
+import {
+  Tooltip,
+  TooltipPopup,
+  TooltipScrollDismissScope,
+  TooltipTrigger,
+  useTooltipScrollDismiss,
+} from "../ui/tooltip";
 import {
   deriveDisplayedUserMessageState,
   type ParsedTerminalContextEntry,
@@ -196,6 +202,8 @@ const TIMELINE_MAINTAIN_SCROLL_AT_END = {
     layout: true,
   },
 } as const;
+// Keys that scroll the focused list; anything else leaves tooltips alone.
+const SCROLL_DISMISS_KEYS = new Set(["PageUp", "PageDown", "Home", "End", "ArrowUp", "ArrowDown"]);
 
 // ---------------------------------------------------------------------------
 // Props (public API)
@@ -242,6 +250,38 @@ interface MessagesTimelineProps {
   loadEarlier?: { readonly loading: boolean; readonly onLoadEarlier: () => void } | null;
 }
 
+// Rendered inside TooltipScrollDismissScope: context is only visible to
+// descendants of its provider, so MessagesTimeline itself cannot consume it.
+// Tooltips here close on real input gestures only (wheel, touch, scroll keys,
+// presses inside the timeline). LegendList's maintainScrollAtEnd and minimap
+// scrollToIndex fire plain scroll events with no gesture behind them, so
+// streaming auto-follow never dismisses an open tooltip.
+function TooltipScrollDismissListener({ node }: { node: HTMLDivElement | null }) {
+  const dismissTooltips = useTooltipScrollDismiss();
+  useEffect(() => {
+    if (!node || !dismissTooltips) {
+      return;
+    }
+    const dismiss = () => dismissTooltips();
+    const handleKeyDown = (event: { key: string }) => {
+      if (SCROLL_DISMISS_KEYS.has(event.key)) {
+        dismissTooltips();
+      }
+    };
+    node.addEventListener("wheel", dismiss, { passive: true });
+    node.addEventListener("touchmove", dismiss, { passive: true });
+    node.addEventListener("pointerdown", dismiss, { passive: true });
+    node.addEventListener("keydown", handleKeyDown);
+    return () => {
+      node.removeEventListener("wheel", dismiss);
+      node.removeEventListener("touchmove", dismiss);
+      node.removeEventListener("pointerdown", dismiss);
+      node.removeEventListener("keydown", handleKeyDown);
+    };
+  }, [dismissTooltips, node]);
+  return null;
+}
+
 // ---------------------------------------------------------------------------
 // MessagesTimeline — list owner
 // ---------------------------------------------------------------------------
@@ -566,62 +606,65 @@ export const MessagesTimeline = memo(function MessagesTimeline({
   }
 
   return (
-    <TimelineRowCtx value={sharedState}>
-      <TimelineRowActivityCtx value={activityState}>
-        <div ref={setTimelineViewportElement} className="relative h-full min-h-0">
-          <LegendList<MessagesTimelineRow>
-            ref={listRef}
-            data={rows}
-            keyExtractor={keyExtractor}
-            getItemType={getItemType}
-            renderItem={renderItem}
-            estimatedItemSize={90}
-            initialScrollAtEnd
-            {...(anchoredEndSpace ? { anchoredEndSpace } : {})}
-            contentInsetEndAdjustment={contentInsetEndAdjustment}
-            maintainScrollAtEnd={
-              anchoredEndSpace || !liveFollowEnabled || disclosureToggleSettling
-                ? false
-                : TIMELINE_MAINTAIN_SCROLL_AT_END
-            }
-            maintainVisibleContentPosition={maintainVisibleContentPosition}
-            onScroll={handleScroll}
-            className={cn(
-              "scrollbar-gutter-both h-full min-h-0 overflow-x-hidden overscroll-y-contain px-3 [overflow-anchor:none] sm:px-5",
-              topFadeEnabled && "topbar-scroll-fade",
-            )}
-            ListHeaderComponent={
-              loadEarlier !== null ? (
-                <TimelineLoadEarlierHeader
-                  loading={loadEarlier.loading}
-                  onLoadEarlier={loadEarlier.onLoadEarlier}
-                  fade={topFadeEnabled}
-                />
-              ) : topFadeEnabled ? (
-                TIMELINE_LIST_FADE_HEADER
-              ) : (
-                TIMELINE_LIST_HEADER
-              )
-            }
-            ListFooterComponent={TIMELINE_LIST_FOOTER}
-          />
-          <TimelineMinimap
-            items={minimapItems}
-            hasPersistentGutter={minimapHasPersistentGutter}
-            hitStripWidth={minimapHitStripWidth}
-            stripMap={minimapStripMap}
-            onSelect={(item) => {
-              onManualNavigation();
-              void listRef.current?.scrollToIndex({
-                index: item.rowIndex,
-                animated: true,
-                viewOffset: 24,
-              });
-            }}
-          />
-        </div>
-      </TimelineRowActivityCtx>
-    </TimelineRowCtx>
+    <TooltipScrollDismissScope>
+      <TimelineRowCtx value={sharedState}>
+        <TimelineRowActivityCtx value={activityState}>
+          <div ref={setTimelineViewportElement} className="relative h-full min-h-0">
+            <TooltipScrollDismissListener node={timelineViewportElement} />
+            <LegendList<MessagesTimelineRow>
+              ref={listRef}
+              data={rows}
+              keyExtractor={keyExtractor}
+              getItemType={getItemType}
+              renderItem={renderItem}
+              estimatedItemSize={90}
+              initialScrollAtEnd
+              {...(anchoredEndSpace ? { anchoredEndSpace } : {})}
+              contentInsetEndAdjustment={contentInsetEndAdjustment}
+              maintainScrollAtEnd={
+                anchoredEndSpace || !liveFollowEnabled || disclosureToggleSettling
+                  ? false
+                  : TIMELINE_MAINTAIN_SCROLL_AT_END
+              }
+              maintainVisibleContentPosition={maintainVisibleContentPosition}
+              onScroll={handleScroll}
+              className={cn(
+                "scrollbar-gutter-both h-full min-h-0 overflow-x-hidden overscroll-y-contain px-3 [overflow-anchor:none] sm:px-5",
+                topFadeEnabled && "topbar-scroll-fade",
+              )}
+              ListHeaderComponent={
+                loadEarlier !== null ? (
+                  <TimelineLoadEarlierHeader
+                    loading={loadEarlier.loading}
+                    onLoadEarlier={loadEarlier.onLoadEarlier}
+                    fade={topFadeEnabled}
+                  />
+                ) : topFadeEnabled ? (
+                  TIMELINE_LIST_FADE_HEADER
+                ) : (
+                  TIMELINE_LIST_HEADER
+                )
+              }
+              ListFooterComponent={TIMELINE_LIST_FOOTER}
+            />
+            <TimelineMinimap
+              items={minimapItems}
+              hasPersistentGutter={minimapHasPersistentGutter}
+              hitStripWidth={minimapHitStripWidth}
+              stripMap={minimapStripMap}
+              onSelect={(item) => {
+                onManualNavigation();
+                void listRef.current?.scrollToIndex({
+                  index: item.rowIndex,
+                  animated: true,
+                  viewOffset: 24,
+                });
+              }}
+            />
+          </div>
+        </TimelineRowActivityCtx>
+      </TimelineRowCtx>
+    </TooltipScrollDismissScope>
   );
 });
 
diff --git a/apps/web/src/components/ui/tooltip.tsx b/apps/web/src/components/ui/tooltip.tsx
index 77b15a01e16b..38536deb96b6 100644
--- a/apps/web/src/components/ui/tooltip.tsx
+++ b/apps/web/src/components/ui/tooltip.tsx
@@ -1,4 +1,13 @@
 import { Tooltip as TooltipPrimitive } from "@base-ui/react/tooltip";
+import {
+  type ReactNode,
+  createContext,
+  use,
+  useEffect,
+  useMemo,
+  useRef,
+  type RefObject,
+} from "react";
 
 import { cn } from "~/lib/utils";
 
@@ -6,7 +15,103 @@ const TooltipCreateHandle = TooltipPrimitive.createHandle;
 
 const TooltipProvider = TooltipPrimitive.Provider;
 
-const Tooltip = TooltipPrimitive.Root;
+/**
+ * Tooltips rendered inside this scope close when the scope owner reports a
+ * user scroll gesture (via useTooltipScrollDismiss). Used around the chat
+ * timeline: its tooltips portal above other surfaces (like the composer), so
+ * one left open after its trigger scrolls out from under a stationary pointer
+ * would paint over them. Programmatic scrolls — streaming auto-follow,
+ * minimap jumps — never dismiss anything because only real input gestures
+ * trigger the dismissal. Keyboard-opened tooltips are exempt so keyboard
+ * users keep them until focus moves.
+ */
+interface TooltipScrollDismiss {
+  register: (close: () => void) => () => void;
+  dismissAll: () => void;
+}
+
+const TooltipScrollDismissContext = createContext<TooltipScrollDismiss | null>(null);
+
+function TooltipScrollDismissScope({ children }: { children: ReactNode }) {
+  const closeCallbacks = useRef(new Set<() => void>());
+  const dismiss = useMemo<TooltipScrollDismiss>(
+    () => ({
+      register: (close) => {
+        closeCallbacks.current.add(close);
+        return () => {
+          closeCallbacks.current.delete(close);
+        };
+      },
+      dismissAll: () => {
+        // Set iteration tolerates deletion of the in-flight entry, which is
+        // all a close callback ever does to the set.
+        for (const close of closeCallbacks.current) {
+          close();
+        }
+      },
+    }),
+    [],
+  );
+  return <TooltipScrollDismissContext value={dismiss}>{children}</TooltipScrollDismissContext>;
+}
+
+/** Dismisses every hover-opened tooltip under the nearest scope. Null outside one. */
+export function useTooltipScrollDismiss(): (() => void) | null {
+  const dismiss = use(TooltipScrollDismissContext);
+  return dismiss?.dismissAll ?? null;
+}
+
+function Tooltip(props: TooltipPrimitive.Root.Props) {
+  const { actionsRef: consumerActionsRef, onOpenChange, ...rootProps } = props;
+  const scrollDismiss = use(TooltipScrollDismissContext);
+  const actionsRef = useRef<TooltipPrimitive.Root.Actions>(null);
+  const registeredCloseRef = useRef<(() => void) | null>(null);
+  const consumerActionsRefMirror = useRef(consumerActionsRef);
+  consumerActionsRefMirror.current = consumerActionsRef;
+
+  useEffect(
+    () => () => {
+      registeredCloseRef.current?.();
+    },
+    [],
+  );
+
+  // Write through to a consumer-supplied actionsRef instead of dropping it.
+  const mergedActionsRef = useMemo<RefObject<TooltipPrimitive.Root.Actions | null>>(
+    () => ({
+      get current() {
+        return actionsRef.current;
+      },
+      set current(actions) {
+        actionsRef.current = actions;
+        const ref = consumerActionsRefMirror.current;
+        if (ref) {
+          ref.current = actions;
+        }
+      },
+    }),
+    [],
+  );
+
+  const handleOpenChange = (open: boolean, details: TooltipPrimitive.Root.ChangeEventDetails) => {
+    onOpenChange?.(open, details);
+    registeredCloseRef.current?.();
+    registeredCloseRef.current = null;
+    if (!scrollDismiss || !open || details.reason !== "trigger-hover") {
+      return;
+    }
+    const close = () => actionsRef.current?.close();
+    registeredCloseRef.current = scrollDismiss.register(close);
+  };
+
+  return (
+    <TooltipPrimitive.Root
+      {...rootProps}
+      actionsRef={mergedActionsRef}
+      onOpenChange={handleOpenChange}
+    />
+  );
+}
 
 function TooltipTrigger(props: TooltipPrimitive.Trigger.Props) {
   return <TooltipPrimitive.Trigger data-slot="tooltip-trigger" {...props} />;
@@ -61,4 +166,11 @@ function TooltipPopup({
   );
 }
 
-export { TooltipCreateHandle, TooltipProvider, Tooltip, TooltipTrigger, TooltipPopup };
+export {
+  TooltipCreateHandle,
+  TooltipProvider,
+  TooltipScrollDismissScope,
+  Tooltip,
+  TooltipTrigger,
+  TooltipPopup,
+};