diff --git a/tools/README.md b/tools/README.md
index ecb1df2..0cda5c9 100644
--- a/tools/README.md
+++ b/tools/README.md
@@ -19,3 +19,7 @@ A prototypical compiler for the B language
 ## mkfs7
 
 Makes a PDP-7 filesystem image for SimH
+
+## sdump
+
+A tool to dump the contents of the ../build/image.fs filesystem