diff --git a/letter_template/text.tex b/letter_template/text.tex
index f7d2e6d..ccec5cf 100644
--- a/letter_template/text.tex
+++ b/letter_template/text.tex
@@ -1,4 +1,14 @@
+% Tagged PDF (PDF/UA-2) accessibility setup.
+%
+% tagging=on is what actually builds the structure tree: it loads the
+% kernel code that tags paragraphs, headings, lists, tables, and
+% floats. Declaring pdfstandard=ua-2 on its own only writes the claim
+% into the metadata; without tagging=on the PDF is marked as UA-2 but
+% carries no structure for a screen reader to read. This needs TeX
+% Live 2025 or later --- on Overleaf, set it in Menu > Settings >
+% TeX Live version.
 \DocumentMetadata{
+  tagging=on,
   pdfversion=2.0,
   pdfstandard=ua-2,
   lang=en-US,
@@ -23,9 +33,6 @@
 
 \usepackage[letterpaper,left=1.3in,right=1.3in,top=0.8in,bottom=0.8in]{geometry}
 
-\usepackage{tagpdf}
-\tagpdfsetup{activate-all}
-
 \usepackage{hyperref}
 \hypersetup{unicode=true,
     pdftitle={Letter},
diff --git a/memo_template/text.tex b/memo_template/text.tex
index a47ccbe..9fbe5c7 100644
--- a/memo_template/text.tex
+++ b/memo_template/text.tex
@@ -1,7 +1,16 @@
 % Tagged PDF (PDF/UA-2) accessibility setup. The article class works
-% with the LaTeX tagging-project, so we use the full \DocumentMetadata
+% with the LaTeX tagging project, so we use the full \DocumentMetadata
 % path here.
+%
+% tagging=on is what actually builds the structure tree: it loads the
+% kernel code that tags paragraphs, headings, lists, tables, and
+% floats. Declaring pdfstandard=ua-2 on its own only writes the claim
+% into the metadata; without tagging=on the PDF is marked as UA-2 but
+% carries no structure for a screen reader to read. This needs TeX
+% Live 2025 or later --- on Overleaf, set it in Menu > Settings >
+% TeX Live version.
 \DocumentMetadata{
+  tagging=on,
   pdfversion=2.0,
   pdfstandard=ua-2,
   lang=en-US,
@@ -10,8 +19,6 @@
 \documentclass[12pt]{article}
 
 \usepackage{cdsc-memo}
-\usepackage{tagpdf}
-\tagpdfsetup{activate-all}
 
 \usepackage{fontspec}
 % fontspec disables the classic TeX input ligatures by default