diff --git a/tools/diag/README b/tools/diag/README
new file mode 100644
index 000000000000..44ef7ada9e55
--- /dev/null
+++ b/tools/diag/README
@@ -0,0 +1,7 @@
+This directory is for diagnostic programs.
+
+A diagnostic program is one that will inform you that something is wrong
+somewhere, for instance by traversing a kernel-structure and verifying
+the integrity.
+
+Please make a subdir per program, and add a brief description to this file.