diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/Chevron.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/Chevron.kt
new file mode 100644
index 0000000..0d7cdf7
--- /dev/null
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/Chevron.kt
@@ -0,0 +1,53 @@
+package com.example.aiapp
+
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.width
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.StrokeCap
+import androidx.compose.ui.unit.dp
+
+/**
+ * A chevron, pointing up or down.
+ *
+ * Drawn rather than set in a font: a chevron from an icon font is one of the glyphs a system font
+ * may simply not have, and the reader who gets an empty box instead is never the one who wrote it.
+ *
+ * One composable for both directions rather than two that differ by a minus sign -- the pair would
+ * drift, and the drift would be a bug in exactly one direction.
+ *
+ * It draws no label of its own, so every caller owes it a `contentDescription`: this is the whole
+ * of what assistive technology has to go on, and it is also the answer to "what was that arrow
+ * for" six months from now.
+ */
+@Composable
+fun Chevron(
+    pointingUp: Boolean,
+    modifier: Modifier = Modifier,
+    colour: Color = MaterialTheme.colorScheme.onSurfaceVariant,
+) {
+    Canvas(modifier.width(20.dp).height(10.dp)) {
+        val inset = 2.dp.toPx()
+        val point = if (pointingUp) inset else size.height - inset
+        val ends = if (pointingUp) size.height - inset else inset
+        val stroke = 2.dp.toPx()
+        drawLine(
+            colour,
+            Offset(inset, ends),
+            Offset(size.width / 2, point),
+            strokeWidth = stroke,
+            cap = StrokeCap.Round,
+        )
+        drawLine(
+            colour,
+            Offset(size.width / 2, point),
+            Offset(size.width - inset, ends),
+            strokeWidth = stroke,
+            cap = StrokeCap.Round,
+        )
+    }
+}
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
index 664a144..0bcf7de 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
@@ -28,6 +28,10 @@ import androidx.compose.material3.FilledTonalButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.OutlinedTextField
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material3.Surface
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
@@ -660,16 +664,29 @@ fun SessionScreen(
 
             // Only while the newest message is off-screen. Reading back
             // through a conversation is a place to be, not a state to be
-            // rescued from, so this waits to be wanted -- and says where it
-            // goes rather than drawing an arrow, since an arrow in a list
-            // that is laid out upside down is the one thing nobody should
-            // have to reason about.
+            // rescued from, so this waits to be wanted.
+            //
+            // Down, and the same chevron a tool group collapses with: the
+            // list is built upside down internally, but nobody reading it
+            // knows that -- on screen the newest message is at the bottom,
+            // which is where this goes. The name is carried in the
+            // description, since an arrow alone says nothing to a screen
+            // reader and nothing to whoever finds this in six months.
             if (!followTail) {
-                FilledTonalButton(
+                Surface(
                     onClick = { scope.launch { listState.animateScrollToItem(0) } },
-                    modifier = Modifier.align(Alignment.BottomCenter).padding(bottom = 12.dp),
+                    shape = CircleShape,
+                    color = MaterialTheme.colorScheme.surfaceContainerHigh,
+                    modifier =
+                        Modifier.align(Alignment.BottomCenter)
+                            .padding(bottom = 12.dp)
+                            .semantics { contentDescription = "Jump to latest" },
                 ) {
-                    Text("Jump to latest", style = MaterialTheme.typography.bodySmall)
+                    Chevron(
+                        pointingUp = false,
+                        colour = MaterialTheme.colorScheme.onSurface,
+                        modifier = Modifier.padding(horizontal = 16.dp, vertical = 12.dp),
+                    )
                 }
             }
         }
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/ToolRows.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/ToolRows.kt
index 3e1661f..2eabe12 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/ToolRows.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/ToolRows.kt
@@ -132,25 +132,7 @@ private fun CollapseBar(onToggle: () -> Unit) {
             .padding(vertical = 10.dp),
         horizontalArrangement = Arrangement.Center,
     ) {
-        // Drawn rather than set in a font: a chevron from an icon font is one of the glyphs a
-        // system font may simply not have, and the reader who gets the empty box is never me.
-        androidx.compose.foundation.Canvas(Modifier.width(20.dp).height(10.dp)) {
-            val inset = 2.dp.toPx()
-            drawLine(
-                colour,
-                Offset(inset, size.height - inset),
-                Offset(size.width / 2, inset),
-                strokeWidth = 2.dp.toPx(),
-                cap = StrokeCap.Round,
-            )
-            drawLine(
-                colour,
-                Offset(size.width / 2, inset),
-                Offset(size.width - inset, size.height - inset),
-                strokeWidth = 2.dp.toPx(),
-                cap = StrokeCap.Round,
-            )
-        }
+        Chevron(pointingUp = true, colour = colour)
     }
 }