diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/DebugStats.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/DebugStats.kt
index 3d36bd4..145b1a5 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/DebugStats.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/DebugStats.kt
@@ -33,6 +33,15 @@ object DebugStats {
         at(counts, name).addAndGet(by)
     }
 
+    /** Keeps [name] at the largest value it has been given, for a high-water mark. */
+    fun atLeast(name: String, value: Long) {
+        val slot = at(counts, name)
+        while (true) {
+            val had = slot.get()
+            if (value <= had || slot.compareAndSet(had, value)) break
+        }
+    }
+
     /** Records one occurrence of [name] that took [elapsed] nanoseconds. */
     fun record(name: String, elapsed: Long) {
         count(name)
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptScroll.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptScroll.kt
index d2f2bc8..c35cdc1 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptScroll.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptScroll.kt
@@ -138,8 +138,20 @@ class TranscriptScroll(internal val scroll: ScrollState) {
         val top = tops.getOrNull(index) ?: return true
         val viewportTop = scroll.maxValue - scroll.value
         val margin = scroll.viewportSize
-        return top + height >= viewportTop - margin &&
-            top <= viewportTop + scroll.viewportSize + margin
+        val near =
+            top + height >= viewportTop - margin &&
+                top <= viewportTop + scroll.viewportSize + margin
+        // Counted so that "drawing costs too much" can be told apart from "drawing was skipped and
+        // still costs too much". They need opposite fixes: the first is a row that should not have
+        // been drawn, the second is a single row too tall to record cheaply -- and one enormous
+        // reply on screen records as many glyph runs as a hundred short ones.
+        if (near) {
+            DebugStats.count("row drawn")
+            DebugStats.atLeast("tallest drawn row px", height.toLong())
+        } else {
+            DebugStats.count("row skipped")
+        }
+        return near
     }
 
     /** Where the last touch went down, in the content's own coordinates. */