diff --git a/api/README b/api/README
index 846e31e..d8746d3 100644
--- a/api/README
+++ b/api/README
@@ -15,4 +15,4 @@
 fuchsia.txt lists Fuchsia specific features. After a full build, this
 list can be regenerated with
 
-    $(fx get-build-dir)/host-tools/goroot/bin/go tool api | grep -e '^pkg syscall/zx' > third_party/go/api/fuchsia.txt
+    $(fx get-build-dir)/host-tools/goroot/bin/go tool api | grep -e '^pkg syscall/zx' > ${FUCHSIA_DIR}/third_party/go/api/fuchsia.txt