1 files changed, 2 insertions, 0 deletions
diff --git a/build b/build
index bcab9a26..09208271 100755
--- a/build
+++ b/build
@@ -148,5 +148,7 @@ exit 0
 
 # scenarios considered:
 #   no output when nothing needs updating
+#     no output for mu.cc when .mu files modified
+#     touch mu.cc but don't modify it; no output on second build
 #   only a single layer is recompiled when changing a C++ function
 #   stop immediately after failure in tangle