1 files changed, 3 insertions, 1 deletions
diff --git a/README.md b/README.md
index 7b01711..b47ab51 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,8 @@ using the following tools:
 * Asciidoctor 1.5.5 or later ([Asciidoctor](https://asciidoctor.org))
 * Asciidoctor-pdf
 * GNU Make 4.1 or later
+* xmllint
+* Python 3.8 or later
 
 The default `make` build creates both an html and a pdf version of the specification
 in out/html and out/pdf
@@ -19,4 +21,4 @@ in out/html and out/pdf
 If only an html build is required, `make html` will build only the html file,
 and asciidoctor-pdf is not needed.
 
-If only a pdf build is required, `make pdf` will build only the pdf.
-\ No newline at end of file
+If only a pdf build is required, `make pdf` will build only the pdf.