diff --git a/.github/workflows/check_headers_installed.yml b/.github/workflows/check_headers_installed.yml
new file mode 100644
index 00000000000..9037733ec87
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+++ b/.github/workflows/check_headers_installed.yml
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+#------------------------------------------------------------------------------
+# © 2021-2025. Triad National Security, LLC. All rights reserved.  This
+# program was produced under U.S. Government contract 89233218CNA000001
+# for Los Alamos National Laboratory (LANL), which is operated by Triad
+# National Security, LLC for the U.S.  Department of Energy/National
+# Nuclear Security Administration. All rights in the program are
+# reserved by Triad National Security, LLC, and the U.S. Department of
+# Energy/National Nuclear Security Administration. The Government is
+# granted for itself and others acting on its behalf a nonexclusive,
+# paid-up, irrevocable worldwide license in this material to reproduce,
+# prepare derivative works, distribute copies to the public, perform
+# publicly and display publicly, and to permit others to do so.
+#------------------------------------------------------------------------------
+name: Check Headers Installed
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+    check-headers-installed:
+      name: Check every header has register_headers install logic
+      runs-on: ubuntu-24.04
+
+      steps:
+        - name: Checkout code
+          uses: actions/checkout@v3
+        - name: check headers are registered for install
+          run: ./utils/scripts/check_headers_installed.sh
diff --git a/utils/scripts/check_headers_installed.sh b/utils/scripts/check_headers_installed.sh
new file mode 100755
index 00000000000..d8c1c60286f
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+++ b/utils/scripts/check_headers_installed.sh
@@ -0,0 +1,65 @@
+#!/bin/bash
+
+#------------------------------------------------------------------------------
+# © 2021-2025. Triad National Security, LLC. All rights reserved.  This
+# program was produced under U.S. Government contract 89233218CNA000001
+# for Los Alamos National Laboratory (LANL), which is operated by Triad
+# National Security, LLC for the U.S.  Department of Energy/National
+# Nuclear Security Administration. All rights in the program are
+# reserved by Triad National Security, LLC, and the U.S. Department of
+# Energy/National Nuclear Security Administration. The Government is
+# granted for itself and others acting on its behalf a nonexclusive,
+# paid-up, irrevocable worldwide license in this material to reproduce,
+# prepare derivative works, distribute copies to the public, perform
+# publicly and display publicly, and to permit others to do so.
+#------------------------------------------------------------------------------
+
+# Report singularity-eos headers that are missing install logic.
+#
+# Every .hpp under singularity-eos/ is meant to be installed, which means it
+# must appear as an argument to a register_headers(...) call in some
+# CMakeLists.txt (see cmake/plugins.cmake). A header that is never registered
+# is silently left out of the install. This script flags any such header so
+# it can be wired into CI as a guard (non-zero exit when any are found).
+
+set -euo pipefail
+
+# Move to the repo root (two levels up from utils/scripts/).
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd "${SCRIPT_DIR}/../.." && pwd)"
+cd "${REPO_ROOT}"
+
+# Directory whose headers must all be installed.
+HEADER_ROOT="singularity-eos"
+
+# Collect the text of every CMakeLists.txt so we can search registrations.
+CMAKE_FILES=$(find . -name CMakeLists.txt -not -path './build/*' -not -path './.git/*')
+
+missing=0
+for f in $(find "${HEADER_ROOT}" -name '*.hpp' | sed "s|^${HEADER_ROOT}/||" | sort); do
+  base=$(basename "$f")
+  # A header is considered registered if either its path relative to the
+  # header root, or just its file name, appears in a CMakeLists.txt. The
+  # register_headers() paths are relative to the calling CMakeLists.txt, so
+  # matching on the basename keeps this robust without re-implementing
+  # CMake's path resolution.
+  if ! grep -rqF "$f" ${CMAKE_FILES} && ! grep -rqF "$base" ${CMAKE_FILES}; then
+    if [ "$missing" -eq 0 ]; then
+      echo "Headers missing register_headers() install logic:"
+    fi
+    echo "  ${HEADER_ROOT}/$f"
+    missing=$((missing + 1))
+  fi
+done
+
+if [ "$missing" -eq 0 ]; then
+  echo "OK: every ${HEADER_ROOT} header has register_headers() install logic."
+  exit 0
+fi
+
+echo ""
+echo "${missing} header(s) have no register_headers call."
+echo "Add each to a register_headers(...) call in the appropriate CMakeLists.txt"
+echo "(with the matching build condition if it is only needed under an option),"
+echo "or exclude it deliberately."
+exit 1