diff --git a/internal/reviewfixture/summary.go b/internal/reviewfixture/summary.go
new file mode 100644
index 0000000..8fec529
--- /dev/null
+++ b/internal/reviewfixture/summary.go
@@ -0,0 +1,15 @@
+// Package reviewfixture contains a small example used by the review workflow.
+package reviewfixture
+
+// Average returns the arithmetic mean of values.
+func Average(values []int) int {
+	if len(values) == 0 {
+		return 0
+	}
+
+	total := 0
+	for i := 0; i < len(values)-1; i++ {
+		total += values[i]
+	}
+	return total / len(values)
+}