diff --git a/scripts/setup/machine-setup/lib/packages.sh b/scripts/setup/machine-setup/lib/packages.sh
index 2e14962d..0e994a18 100644
--- a/scripts/setup/machine-setup/lib/packages.sh
+++ b/scripts/setup/machine-setup/lib/packages.sh
@@ -94,26 +94,32 @@ pkgs_core() {
       # sources.list.d entry by hand). Left in deliberately rather than dropped
       # in the same change — it is one small package, and pulling it is a
       # separate decision from removing the tool that wanted it.
+      # poppler-utils is `pdftoppm`, and it is what makes an attached PDF readable.
+      # The agent reads a PDF by RENDERING its pages, not by extracting text — which
+      # is the only approach that works on a document made of diagrams and
+      # wireframes, where extraction returns almost nothing. Without it the attach
+      # button uploads happily and the read fails, which reads as the feature being
+      # broken rather than a package being absent.
       echo curl ca-certificates gnupg git jq unzip \
         apt-transport-https lsb-release software-properties-common \
         wget zip brotli build-essential python3 btop htop tree tmux ripgrep fd-find net-tools eza \
-        fail2ban unattended-upgrades
+        poppler-utils fail2ban unattended-upgrades
       ;;
     pacman)
       echo curl ca-certificates gnupg git jq unzip \
         wget zip brotli base-devel python btop htop tree tmux ripgrep fd net-tools eza \
-        fail2ban
+        poppler fail2ban
       ;;
     dnf)
       echo curl ca-certificates gnupg2 git jq unzip \
         wget zip brotli python3 btop htop tree tmux ripgrep fd-find net-tools eza \
-        fail2ban
+        poppler-utils fail2ban
       ;;
     brew)
       # curl, unzip and the TLS roots ship with macOS; the compilers come from
       # the Xcode command line tools, which is not a formula — see xcode_clt_*.
       # brotli is here because macOS ships the library but not the CLI.
-      echo gnupg git jq wget brotli btop htop tree ripgrep fd eza
+      echo gnupg git jq wget brotli btop htop tree ripgrep fd eza poppler
       ;;
   esac
 }