diff --git a/.env.example b/.env.example
index 8481562..b2fc3f2 100644
--- a/.env.example
+++ b/.env.example
@@ -152,9 +152,10 @@ PUSH_HTTP_RECEIVE_TIMEOUT_MS=
 PUSH_HTTP_CONNECT_TIMEOUT_MS=
 PUSH_HTTP_RETRY_DELAY_MS=
 
-# Direct browser Web Push. Generate one VAPID key pair per environment and
-# keep the private key only in that environment's .env. The subject must be a
-# mailto: or HTTPS contact owned by the operator.
+# Direct browser Web Push. Generate one VAPID key pair per environment with
+# scripts/generate-vapid-env.sh and keep the private key only in that
+# environment's .env. The subject must be a mailto: or HTTPS contact owned by
+# the operator.
 WEB_PUSH_VAPID_PUBLIC_KEY=
 WEB_PUSH_VAPID_PRIVATE_KEY=
 WEB_PUSH_VAPID_SUBJECT=
diff --git a/docs/operations.md b/docs/operations.md
index 5f88f3d..3f656bd 100644
--- a/docs/operations.md
+++ b/docs/operations.md
@@ -213,6 +213,9 @@ Provider downloads can be imported into that same file without placing
 secrets on a command line or printing them:
 
 ```bash
+./scripts/generate-vapid-env.sh \
+  .env mailto:contact@YOUR_DOMAIN
+
 chmod 600 /secure/downloads/google-oauth-client.json
 ./scripts/import-google-oauth-client.sh \
   .env /secure/downloads/google-oauth-client.json
@@ -225,10 +228,19 @@ chmod 600 /secure/downloads/fcm-service-account.json
   .env /secure/downloads/fcm-service-account.json
 ```
 
+The VAPID helper runs the exact locked `web_push_elixir` generator in an
+isolated, network-disabled container, imports the result atomically, removes
+its one-run image tag and temporary files, and never prints either key. It
+refuses to replace an existing VAPID identity because an unplanned rotation
+invalidates existing browser subscriptions.
+
 The importers validate the exact OAuth callback, Android package, Firebase
 project relationship, and required service-account fields before atomically
 replacing existing keys. They preserve mode `0600` and never create another
-permanent environment file. OAuth and service-account downloads still contain
+permanent environment file. Provider and initializer values that cannot be
+represented as one unquoted Compose `.env` line are rejected before mutation.
+Literal dollar signs are stored as `$$`, which Compose resolves back to one
+`$` inside the container. OAuth and service-account downloads still contain
 private credentials after import; deliberately move them to protected backup
 storage or remove them after verification.
 
diff --git a/scripts/generate-vapid-env.sh b/scripts/generate-vapid-env.sh
new file mode 100755
index 0000000..a288bbb
--- /dev/null
+++ b/scripts/generate-vapid-env.sh
@@ -0,0 +1,161 @@
+#!/bin/sh
+set -eu
+umask 077
+
+if [ "$#" -ne 2 ]; then
+  echo "Usage: $0 ENV_FILE VAPID_SUBJECT" >&2
+  exit 1
+fi
+
+ROOT=$(CDPATH='' cd -- "$(dirname -- "$0")/.." && pwd)
+env_file=$1
+subject=$2
+
+if [ ! -f "$env_file" ]; then
+  echo "Environment file does not exist: $env_file" >&2
+  exit 1
+fi
+
+if [ "$(stat -c '%a' "$env_file")" != 600 ]; then
+  echo "Environment file must have mode 0600: $env_file" >&2
+  exit 1
+fi
+
+case "$subject" in
+  mailto:?* | https://?*) ;;
+  *)
+    echo "VAPID_SUBJECT must be a non-empty mailto: or https:// URI without whitespace." >&2
+    exit 1
+    ;;
+esac
+
+case "$subject" in
+  *'
+'*)
+    echo "VAPID_SUBJECT must be a non-empty mailto: or https:// URI without whitespace." >&2
+    exit 1
+    ;;
+esac
+
+if printf '%s' "$subject" | LC_ALL=C grep -q '[[:space:]]'; then
+  echo "VAPID_SUBJECT must be a non-empty mailto: or https:// URI without whitespace." >&2
+  exit 1
+fi
+
+for command in awk chmod date docker grep mktemp rm stat; do
+  if ! command -v "$command" >/dev/null 2>&1; then
+    echo "Required command is unavailable: $command" >&2
+    exit 1
+  fi
+done
+
+for key in \
+  WEB_PUSH_VAPID_PUBLIC_KEY \
+  WEB_PUSH_VAPID_PRIVATE_KEY \
+  WEB_PUSH_VAPID_SUBJECT; do
+  key_count=$(
+    awk -F= -v key="$key" '$1 == key { count++ } END { print count + 0 }' \
+      "$env_file"
+  )
+  if [ "$key_count" -ne 1 ]; then
+    echo "Environment must contain exactly one $key entry before VAPID generation." >&2
+    exit 1
+  fi
+
+  existing_value=$(
+    awk -F= -v key="$key" '
+      $1 == key {
+        print substr($0, index($0, "=") + 1)
+        exit
+      }
+    ' "$env_file"
+  )
+  if [ -n "$existing_value" ]; then
+    echo "Refusing to rotate an existing VAPID identity: $key is already configured." >&2
+    exit 1
+  fi
+done
+unset existing_value
+
+env_dir=$(CDPATH='' cd -- "$(dirname -- "$env_file")" && pwd)
+temporary_dir=$(mktemp -d "$env_dir/.vapid-generation.XXXXXX")
+chmod 700 "$temporary_dir"
+raw_keys="$temporary_dir/generated.txt"
+values_file="$temporary_dir/values.env"
+generator_image=${WNH_VAPID_GENERATOR_IMAGE:-}
+owned_image=false
+run_id="$(date -u +%Y%m%d%H%M%S)-$$"
+generator_container="wnh-vapid-tool-$run_id"
+
+cleanup() {
+  trap - EXIT HUP INT TERM
+  rm -rf "$temporary_dir"
+  docker rm --force "$generator_container" >/dev/null 2>&1 || true
+  if [ "$owned_image" = true ]; then
+    docker image rm "$generator_image" >/dev/null 2>&1 || true
+  fi
+}
+
+cleanup_on_exit() {
+  exit_status=$?
+  cleanup
+  exit "$exit_status"
+}
+
+trap cleanup_on_exit EXIT
+trap 'cleanup; exit 129' HUP
+trap 'cleanup; exit 130' INT
+trap 'cleanup; exit 143' TERM
+
+if [ -z "$generator_image" ]; then
+  generator_image="who-need-help:vapid-tool-$run_id"
+  owned_image=true
+  docker build --quiet --target test --tag "$generator_image" "$ROOT" >/dev/null
+fi
+
+docker image inspect "$generator_image" >/dev/null
+docker run --rm \
+  --name "$generator_container" \
+  --network none \
+  --read-only \
+  --tmpfs /tmp:rw,noexec,nosuid,size=16m \
+  --entrypoint mix \
+  "$generator_image" \
+  generate.vapid.keys >"$raw_keys"
+chmod 600 "$raw_keys"
+
+if ! awk -F'"' -v subject="$subject" '
+  /^[[:space:]]*vapid_private_key:/ {
+    private_count++
+    private_key = $2
+  }
+  /^[[:space:]]*vapid_public_key:/ {
+    public_count++
+    public_key = $2
+  }
+  END {
+    valid_private = private_key ~ /^[A-Za-z0-9_-]+$/
+    valid_public = public_key ~ /^[A-Za-z0-9_-]+$/
+
+    if (private_count != 1 ||
+      public_count != 1 ||
+      !valid_private ||
+      !valid_public ||
+      private_key == public_key) {
+      exit 40
+    }
+
+    print "WEB_PUSH_VAPID_PUBLIC_KEY=" public_key
+    print "WEB_PUSH_VAPID_PRIVATE_KEY=" private_key
+    print "WEB_PUSH_VAPID_SUBJECT=" subject
+  }
+' "$raw_keys" >"$values_file"; then
+  echo "The pinned web_push_elixir generator returned an unexpected key format." >&2
+  exit 1
+fi
+chmod 600 "$values_file"
+
+"$ROOT/scripts/set-env-values.sh" "$env_file" "$values_file" >/dev/null
+
+echo "Generated a new environment-specific VAPID identity without printing its keys."
+echo "Updated the single mode-0600 environment file: $env_file"
diff --git a/scripts/import-fcm-service-account.sh b/scripts/import-fcm-service-account.sh
index 11364b9..a2a7559 100755
--- a/scripts/import-fcm-service-account.sh
+++ b/scripts/import-fcm-service-account.sh
@@ -26,8 +26,10 @@ esac
 
 if ! jq --exit-status '
   .type == "service_account"
-    and (.project_id | type == "string" and length > 0)
-    and (.client_email | type == "string" and length > 0)
+    and (.project_id
+      | type == "string" and length > 0 and test("^[^\r\n]+$"))
+    and (.client_email
+      | type == "string" and length > 0 and test("^[^\r\n]+$"))
     and (.private_key | type == "string" and length > 0)
 ' "$service_account_file" >/dev/null; then
   echo "FCM service-account JSON is incomplete." >&2
diff --git a/scripts/import-firebase-android-config.sh b/scripts/import-firebase-android-config.sh
index cf2d6b6..fcd875c 100755
--- a/scripts/import-firebase-android-config.sh
+++ b/scripts/import-firebase-android-config.sh
@@ -38,12 +38,16 @@ if ! jq --exit-status --arg package "$package_name" '
     | select(.client_info.android_client_info.package_name == $package)
   ] as $clients
   | ($clients | length == 1)
-    and (.project_info.project_id | type == "string" and length > 0)
-    and (.project_info.project_number | type == "string" and length > 0)
-    and ($clients[0].client_info.mobilesdk_app_id | type == "string" and length > 0)
+    and (.project_info.project_id
+      | type == "string" and length > 0 and test("^[^\r\n]+$"))
+    and (.project_info.project_number
+      | type == "string" and length > 0 and test("^[^\r\n]+$"))
+    and ($clients[0].client_info.mobilesdk_app_id
+      | type == "string" and length > 0 and test("^[^\r\n]+$"))
     and ($clients[0].client_info.mobilesdk_app_id
       | startswith("1:" + $project_number + ":android:"))
-    and ($clients[0].api_key[0].current_key | type == "string" and length > 0)
+    and ($clients[0].api_key[0].current_key
+      | type == "string" and length > 0 and test("^[^\r\n]+$"))
 ' "$client_file" >/dev/null; then
   echo "Firebase Android configuration does not contain exactly one complete client for package $package_name." >&2
   exit 1
diff --git a/scripts/init-production-env.sh b/scripts/init-production-env.sh
index 17efdc3..c8157be 100755
--- a/scripts/init-production-env.sh
+++ b/scripts/init-production-env.sh
@@ -10,6 +10,31 @@ usage() {
   echo "Usage: $0 DOMAIN [OUTPUT_FILE]" >&2
 }
 
+require_single_line_env_value() {
+  value_name=$1
+  value=$2
+
+  case "$value" in
+    *'
+'*)
+      echo "$value_name must not contain control characters because .env stores one value per line." >&2
+      exit 1
+      ;;
+  esac
+
+  if printf '%s' "$value" | LC_ALL=C grep -q '[[:cntrl:]]'; then
+    echo "$value_name must not contain control characters because .env stores one value per line." >&2
+    exit 1
+  fi
+
+  case "$value" in
+    ' '* | *' ' | \"* | \'* | *' #'*)
+      echo "$value_name cannot be represented safely as an unquoted Compose .env value." >&2
+      exit 1
+      ;;
+  esac
+}
+
 if [ -z "$domain" ]; then
   usage
   exit 1
@@ -69,6 +94,30 @@ test_upstream=${PRODUCTION_TEST_UPSTREAM:-who-need-help-test:4000}
 edge_compose_project_name=${PRODUCTION_EDGE_COMPOSE_PROJECT_NAME:-who_need_help_edge}
 git_sha=$(git -C "$ROOT" rev-parse --short=12 HEAD)
 
+require_single_line_env_value PRODUCTION_DATABASE_MODE "$database_mode"
+require_single_line_env_value PRODUCTION_APP_TOPOLOGY "$app_topology"
+require_single_line_env_value PRODUCTION_COMPOSE_PROJECT_NAME "$compose_project_name"
+require_single_line_env_value PRODUCTION_PUBLIC_EDGE_ENABLED "$public_edge_enabled"
+require_single_line_env_value PRODUCTION_PUBLIC_EDGE_NETWORK "$public_edge_network"
+require_single_line_env_value PRODUCTION_PUBLIC_UPSTREAM_NAME "$public_upstream_name"
+require_single_line_env_value PRODUCTION_CODEX_SESSION_ID "$codex_session_id"
+require_single_line_env_value PRODUCTION_GOOGLE_OAUTH_CLIENT_ID "$google_oauth_client_id"
+require_single_line_env_value PRODUCTION_GOOGLE_OAUTH_CLIENT_SECRET "$google_oauth_client_secret"
+require_single_line_env_value PRODUCTION_WEB_PUSH_VAPID_PUBLIC_KEY "$web_push_vapid_public_key"
+require_single_line_env_value PRODUCTION_WEB_PUSH_VAPID_PRIVATE_KEY "$web_push_vapid_private_key"
+require_single_line_env_value PRODUCTION_WEB_PUSH_VAPID_SUBJECT "$web_push_vapid_subject"
+require_single_line_env_value PRODUCTION_WNH_FIREBASE_APPLICATION_ID "$firebase_application_id"
+require_single_line_env_value PRODUCTION_WNH_FIREBASE_API_KEY "$firebase_api_key"
+require_single_line_env_value PRODUCTION_WNH_FIREBASE_PROJECT_ID "$firebase_project_id"
+require_single_line_env_value PRODUCTION_WNH_FIREBASE_GCM_SENDER_ID "$firebase_sender_id"
+require_single_line_env_value PRODUCTION_FCM_PROJECT_ID "$fcm_project_id"
+require_single_line_env_value PRODUCTION_FCM_SERVICE_ACCOUNT_JSON_BASE64 "$fcm_service_account_json_base64"
+require_single_line_env_value PRODUCTION_ANDROID_APP_LINKS_PACKAGE_NAME "$android_app_links_package_name"
+require_single_line_env_value PRODUCTION_ANDROID_APP_LINKS_SHA256_CERT_FINGERPRINTS "$android_app_links_fingerprints"
+require_single_line_env_value PRODUCTION_TEST_DOMAIN "$test_domain"
+require_single_line_env_value PRODUCTION_TEST_UPSTREAM "$test_upstream"
+require_single_line_env_value PRODUCTION_EDGE_COMPOSE_PROJECT_NAME "$edge_compose_project_name"
+
 if [ -z "$codex_session_id" ]; then
   echo "PRODUCTION_CODEX_SESSION_ID is required for the Build Week feedback page." >&2
   exit 1
@@ -87,6 +136,7 @@ if { [ -n "$android_app_links_package_name" ] || [ -n "$android_app_links_finger
 fi
 
 firebase_values="$firebase_application_id $firebase_api_key $firebase_project_id $firebase_sender_id"
+firebase_configured=false
 if printf '%s\n' "$firebase_values" | grep -q '[^[:space:]]'; then
   for value in "$firebase_application_id" "$firebase_api_key" \
     "$firebase_project_id" "$firebase_sender_id"; do
@@ -95,6 +145,15 @@ if printf '%s\n' "$firebase_values" | grep -q '[^[:space:]]'; then
       exit 1
     }
   done
+
+  firebase_prefix="1:$firebase_sender_id:android:"
+  if ! printf '%s\n' "$firebase_sender_id" | grep -Eq '^[0-9]+$' ||
+    [ "${firebase_application_id#"$firebase_prefix"}" = "$firebase_application_id" ] ||
+    [ -z "${firebase_application_id#"$firebase_prefix"}" ]; then
+    echo "Production Firebase application ID must belong to the configured numeric sender/project number." >&2
+    exit 1
+  fi
+  firebase_configured=true
 fi
 
 vapid_values="$web_push_vapid_public_key $web_push_vapid_private_key $web_push_vapid_subject"
@@ -106,6 +165,14 @@ if printf '%s\n' "$vapid_values" | grep -q '[^[:space:]]'; then
       exit 1
     }
   done
+
+  case "$web_push_vapid_subject" in
+    mailto:?* | https://?*) ;;
+    *)
+      echo "Production WEB_PUSH_VAPID_SUBJECT must be a non-empty mailto: or https:// URI." >&2
+      exit 1
+      ;;
+  esac
 fi
 
 if { [ -n "$fcm_project_id" ] || [ -n "$fcm_service_account_json_base64" ]; } &&
@@ -114,6 +181,7 @@ if { [ -n "$fcm_project_id" ] || [ -n "$fcm_service_account_json_base64" ]; } &&
   exit 1
 fi
 
+fcm_credential_project_id=
 if [ -n "$fcm_service_account_json_base64" ]; then
   for command in base64 jq; do
     command -v "$command" >/dev/null 2>&1 || {
@@ -121,17 +189,38 @@ if [ -n "$fcm_service_account_json_base64" ]; then
       exit 1
     }
   done
-  if ! printf '%s' "$fcm_service_account_json_base64" |
+  if ! fcm_credential_project_id=$(printf '%s' "$fcm_service_account_json_base64" |
     base64 --decode 2>/dev/null |
-    jq -e '
-      .type == "service_account" and
-      (.project_id | type == "string" and length > 0) and
-      (.client_email | type == "string" and length > 0) and
-      (.private_key | type == "string" and length > 0)
-    ' >/dev/null 2>&1; then
+    jq -er '
+      . as $credential
+      | (
+          ($credential.type == "service_account") and
+          ($credential.project_id | type == "string" and length > 0) and
+          ($credential.client_email | type == "string" and length > 0) and
+          ($credential.private_key | type == "string" and length > 0)
+        )
+      | if . then $credential.project_id else error("incomplete service account") end
+    ' 2>/dev/null); then
     echo "Production FCM credential is not a complete service-account JSON document." >&2
     exit 1
   fi
+
+  if [ "$fcm_credential_project_id" != "$fcm_project_id" ]; then
+    echo "Production FCM service-account project must match PRODUCTION_FCM_PROJECT_ID." >&2
+    exit 1
+  fi
+
+  if [ "$firebase_configured" = true ] &&
+    [ "$fcm_project_id" != "$firebase_project_id" ]; then
+    echo "Production Firebase Android client and FCM service account must use the same project." >&2
+    exit 1
+  fi
+fi
+
+if [ -n "$android_app_links_package_name" ] &&
+  [ "$android_app_links_package_name" != org.whoneedhelp.mobile ]; then
+  echo "Production Android App Links package must be org.whoneedhelp.mobile." >&2
+  exit 1
 fi
 
 case "$compose_project_name" in
@@ -203,6 +292,22 @@ smtp_ssl=${PRODUCTION_SMTP_SSL:-false}
 email_from_address=${PRODUCTION_EMAIL_FROM_ADDRESS:-"contact@$domain"}
 support_inbox_address=${PRODUCTION_SUPPORT_INBOX_ADDRESS:-}
 
+require_single_line_env_value PRODUCTION_DATABASE_URL "$database_url"
+require_single_line_env_value PRODUCTION_DATABASE_SOCKET_DIR "$database_socket_dir"
+require_single_line_env_value PRODUCTION_HTTP_BIND_ADDRESS "$http_bind_address"
+require_single_line_env_value PRODUCTION_HTTP_PORT "$http_port"
+require_single_line_env_value PRODUCTION_TRAEFIK_TRUSTED_IPS "$trusted_proxy_ips"
+require_single_line_env_value PRODUCTION_EMAIL_DELIVERY_PROVIDER "$email_delivery_provider"
+require_single_line_env_value PRODUCTION_SMTP_RELAY "$smtp_relay"
+require_single_line_env_value PRODUCTION_SMTP_PORT "$smtp_port"
+require_single_line_env_value PRODUCTION_SMTP_USERNAME "$smtp_username"
+require_single_line_env_value PRODUCTION_SMTP_PASSWORD "$smtp_password"
+require_single_line_env_value PRODUCTION_SMTP_AUTH "$smtp_auth"
+require_single_line_env_value PRODUCTION_SMTP_TLS "$smtp_tls"
+require_single_line_env_value PRODUCTION_SMTP_SSL "$smtp_ssl"
+require_single_line_env_value PRODUCTION_EMAIL_FROM_ADDRESS "$email_from_address"
+require_single_line_env_value PRODUCTION_SUPPORT_INBOX_ADDRESS "$support_inbox_address"
+
 [ "$email_delivery_provider" = smtp ] || {
   echo "PRODUCTION_EMAIL_DELIVERY_PROVIDER must be smtp." >&2
   exit 1
@@ -326,6 +431,10 @@ TEST_UPSTREAM_VALUE=$test_upstream \
       replacement["WNH_ANDROID_DEVELOPMENT_SIGNING_KEY_ALIAS"] = ""
       replacement["WNH_ANDROID_STAGING_SIGNING_KEY_ALIAS"] = ""
       replacement["CODEX_SESSION_ID"] = ENVIRON["CODEX_SESSION_ID_VALUE"]
+
+      for (key in replacement) {
+        gsub(/\$/, "$$", replacement[key])
+      }
     }
     {
       separator = index($0, "=")
@@ -347,6 +456,7 @@ unset postgres_password secret_key_base handover_secret release_cookie metrics_t
 unset smtp_password
 unset google_oauth_client_secret
 unset web_push_vapid_private_key firebase_api_key fcm_service_account_json_base64
+unset fcm_credential_project_id
 unset android_app_links_fingerprints
 
 echo "Generated independent deployment secrets without printing them."
diff --git a/scripts/init-test-env.sh b/scripts/init-test-env.sh
index a01a3c4..f798130 100755
--- a/scripts/init-test-env.sh
+++ b/scripts/init-test-env.sh
@@ -11,6 +11,27 @@ if [[ -z "$domain" ]]; then
   exit 1
 fi
 
+require_single_line_env_value() {
+  local value_name=$1
+  local value=$2
+
+  if [[ "$value" == *$'\n'* ]]; then
+    echo "$value_name must not contain control characters because .env stores one value per line." >&2
+    exit 1
+  fi
+
+  if printf '%s' "$value" | LC_ALL=C grep -q '[[:cntrl:]]'; then
+    echo "$value_name must not contain control characters because .env stores one value per line." >&2
+    exit 1
+  fi
+
+  if [[ "$value" == ' '* || "$value" == *' ' ||
+    "$value" == \"* || "$value" == \'* || "$value" == *' #'* ]]; then
+    echo "$value_name cannot be represented safely as an unquoted Compose .env value." >&2
+    exit 1
+  fi
+}
+
 if [[ ! "$domain" =~ ^[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?(\.[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?)+$ ]]; then
   echo "DOMAIN must be a lowercase ASCII DNS hostname without a scheme, port, or path." >&2
   exit 1
@@ -20,7 +41,7 @@ if [[ "$target" != /* ]]; then
   target="$ROOT/$target"
 fi
 
-for command in awk docker git mktemp openssl stat; do
+for command in awk docker git grep mktemp openssl stat; do
   command -v "$command" >/dev/null 2>&1 || {
     echo "Required command is unavailable: $command" >&2
     exit 1
@@ -67,6 +88,29 @@ android_app_links_fingerprints=${TEST_ANDROID_APP_LINKS_SHA256_CERT_FINGERPRINTS
 support_inbox_address=${TEST_SUPPORT_INBOX_ADDRESS:-}
 git_sha=$(git -C "$ROOT" rev-parse --short=12 HEAD)
 
+require_single_line_env_value TEST_COMPOSE_PROJECT_NAME "$compose_project_name"
+require_single_line_env_value TEST_PUBLIC_EDGE_NETWORK "$public_edge_network"
+require_single_line_env_value TEST_PUBLIC_UPSTREAM_NAME "$public_upstream_name"
+require_single_line_env_value TEST_HTTP_BIND_ADDRESS "$http_bind_address"
+require_single_line_env_value TEST_HTTP_PORT "$http_port"
+require_single_line_env_value TEST_MAILPIT_BIND_ADDRESS "$mailpit_bind_address"
+require_single_line_env_value TEST_MAILPIT_PORT "$mailpit_port"
+require_single_line_env_value TEST_CODEX_SESSION_ID "$codex_session_id"
+require_single_line_env_value TEST_GOOGLE_OAUTH_CLIENT_ID "$google_oauth_client_id"
+require_single_line_env_value TEST_GOOGLE_OAUTH_CLIENT_SECRET "$google_oauth_client_secret"
+require_single_line_env_value TEST_WEB_PUSH_VAPID_PUBLIC_KEY "$web_push_vapid_public_key"
+require_single_line_env_value TEST_WEB_PUSH_VAPID_PRIVATE_KEY "$web_push_vapid_private_key"
+require_single_line_env_value TEST_WEB_PUSH_VAPID_SUBJECT "$web_push_vapid_subject"
+require_single_line_env_value TEST_WNH_FIREBASE_APPLICATION_ID "$firebase_application_id"
+require_single_line_env_value TEST_WNH_FIREBASE_API_KEY "$firebase_api_key"
+require_single_line_env_value TEST_WNH_FIREBASE_PROJECT_ID "$firebase_project_id"
+require_single_line_env_value TEST_WNH_FIREBASE_GCM_SENDER_ID "$firebase_sender_id"
+require_single_line_env_value TEST_FCM_PROJECT_ID "$fcm_project_id"
+require_single_line_env_value TEST_FCM_SERVICE_ACCOUNT_JSON_BASE64 "$fcm_service_account_json_base64"
+require_single_line_env_value TEST_ANDROID_APP_LINKS_PACKAGE_NAME "$android_app_links_package_name"
+require_single_line_env_value TEST_ANDROID_APP_LINKS_SHA256_CERT_FINGERPRINTS "$android_app_links_fingerprints"
+require_single_line_env_value TEST_SUPPORT_INBOX_ADDRESS "$support_inbox_address"
+
 [[ "$compose_project_name" =~ ^[a-zA-Z0-9_-]+$ ]] || {
   echo "TEST_COMPOSE_PROJECT_NAME contains unsupported characters." >&2
   exit 1
@@ -98,6 +142,7 @@ if [[ -n "$android_app_links_package_name" || -n "$android_app_links_fingerprint
 fi
 
 firebase_values="$firebase_application_id $firebase_api_key $firebase_project_id $firebase_sender_id"
+firebase_configured=false
 if grep -q '[^[:space:]]' <<<"$firebase_values"; then
   for value in "$firebase_application_id" "$firebase_api_key" \
     "$firebase_project_id" "$firebase_sender_id"; do
@@ -106,6 +151,14 @@ if grep -q '[^[:space:]]' <<<"$firebase_values"; then
       exit 1
     }
   done
+
+  firebase_prefix="1:$firebase_sender_id:android:"
+  if [[ ! "$firebase_sender_id" =~ ^[0-9]+$ ||
+    "$firebase_application_id" != "$firebase_prefix"?* ]]; then
+    echo "Test Firebase application ID must belong to the configured numeric sender/project number." >&2
+    exit 1
+  fi
+  firebase_configured=true
 fi
 
 vapid_values="$web_push_vapid_public_key $web_push_vapid_private_key $web_push_vapid_subject"
@@ -117,6 +170,12 @@ if grep -q '[^[:space:]]' <<<"$vapid_values"; then
       exit 1
     }
   done
+
+  if [[ "$web_push_vapid_subject" != mailto:?* &&
+    "$web_push_vapid_subject" != https://?* ]]; then
+    echo "Test WEB_PUSH_VAPID_SUBJECT must be a non-empty mailto: or https:// URI." >&2
+    exit 1
+  fi
 fi
 
 if [[ (-n "$fcm_project_id" || -n "$fcm_service_account_json_base64") &&
@@ -125,6 +184,7 @@ if [[ (-n "$fcm_project_id" || -n "$fcm_service_account_json_base64") &&
   exit 1
 fi
 
+fcm_credential_project_id=
 if [[ -n "$fcm_service_account_json_base64" ]]; then
   for command in base64 jq; do
     command -v "$command" >/dev/null 2>&1 || {
@@ -132,17 +192,38 @@ if [[ -n "$fcm_service_account_json_base64" ]]; then
       exit 1
     }
   done
-  if ! printf '%s' "$fcm_service_account_json_base64" |
+  if ! fcm_credential_project_id=$(printf '%s' "$fcm_service_account_json_base64" |
     base64 --decode 2>/dev/null |
-    jq -e '
-      .type == "service_account" and
-      (.project_id | type == "string" and length > 0) and
-      (.client_email | type == "string" and length > 0) and
-      (.private_key | type == "string" and length > 0)
-    ' >/dev/null 2>&1; then
+    jq -er '
+      . as $credential
+      | (
+          ($credential.type == "service_account") and
+          ($credential.project_id | type == "string" and length > 0) and
+          ($credential.client_email | type == "string" and length > 0) and
+          ($credential.private_key | type == "string" and length > 0)
+        )
+      | if . then $credential.project_id else error("incomplete service account") end
+    ' 2>/dev/null); then
     echo "Test FCM credential is not a complete service-account JSON document." >&2
     exit 1
   fi
+
+  if [[ "$fcm_credential_project_id" != "$fcm_project_id" ]]; then
+    echo "Test FCM service-account project must match TEST_FCM_PROJECT_ID." >&2
+    exit 1
+  fi
+
+  if [[ "$firebase_configured" == true &&
+    "$fcm_project_id" != "$firebase_project_id" ]]; then
+    echo "Test Firebase Android client and FCM service account must use the same project." >&2
+    exit 1
+  fi
+fi
+
+if [[ -n "$android_app_links_package_name" &&
+  "$android_app_links_package_name" != org.whoneedhelp.mobile.staging ]]; then
+  echo "Test Android App Links package must be org.whoneedhelp.mobile.staging." >&2
+  exit 1
 fi
 
 for pair in "HTTP:$http_port" "MAILPIT:$mailpit_port"; do
@@ -267,6 +348,10 @@ CODEX_SESSION_ID_VALUE=$codex_session_id \
       replacement["WNH_ANDROID_DEVELOPMENT_SIGNING_KEY_ALIAS"] = ""
       replacement["WNH_ANDROID_STAGING_SIGNING_KEY_ALIAS"] = "who-need-help-staging"
       replacement["CODEX_SESSION_ID"] = ENVIRON["CODEX_SESSION_ID_VALUE"]
+
+      for (key in replacement) {
+        gsub(/\$/, "$$", replacement[key])
+      }
     }
     {
       separator = index($0, "=")
@@ -282,6 +367,7 @@ trap - EXIT HUP INT TERM
 unset postgres_password secret_key_base handover_secret release_cookie metrics_token
 unset google_oauth_client_secret
 unset web_push_vapid_private_key firebase_api_key fcm_service_account_json_base64
+unset fcm_credential_project_id
 unset android_app_links_fingerprints
 
 "$ROOT/scripts/compose.sh" "$target" config --quiet
diff --git a/scripts/quality.sh b/scripts/quality.sh
index 938ec8f..428111e 100755
--- a/scripts/quality.sh
+++ b/scripts/quality.sh
@@ -105,7 +105,8 @@ chmod 600 "$credential_env"
 credential_values="$scan_dir/credential-values"
 printf '%s\n' \
   'GOOGLE_OAUTH_CLIENT_ID=quality-imported-client' \
-  'GOOGLE_OAUTH_CLIENT_SECRET=quality-imported-secret' >"$credential_values"
+  'GOOGLE_OAUTH_CLIENT_SECRET=quality-imported-secret' \
+  "SMTP_PASSWORD=quality\$literal" >"$credential_values"
 chmod 600 "$credential_values"
 credential_output=$(
   ./scripts/set-env-values.sh "$credential_env" "$credential_values"
@@ -117,6 +118,32 @@ fi
 test "$(stat -c '%a' "$credential_env")" = 600
 grep -Fx 'GOOGLE_OAUTH_CLIENT_ID=quality-imported-client' "$credential_env" >/dev/null
 grep -Fx 'GOOGLE_OAUTH_CLIENT_SECRET=quality-imported-secret' "$credential_env" >/dev/null
+grep -Fx "SMTP_PASSWORD=quality\$\$literal" "$credential_env" >/dev/null
+
+compose_env_probe="$scan_dir/compose-env-probe.yaml"
+printf '%s\n' \
+  'services:' \
+  '  probe:' \
+  "    image: $SHELLCHECK_IMAGE" \
+  '    network_mode: none' \
+  '    entrypoint: ["/usr/bin/env"]' \
+  '    environment:' \
+  "      SMTP_PASSWORD: \${SMTP_PASSWORD}" \
+  >"$compose_env_probe"
+resolved_smtp_password=$(
+  docker compose \
+    --project-name "$project" \
+    --env-file "$credential_env" \
+    --file "$compose_env_probe" \
+    run --rm --no-deps probe |
+    awk -F= '
+      $1 == "SMTP_PASSWORD" {
+        print substr($0, index($0, "=") + 1)
+        exit
+      }
+    '
+)
+test "$resolved_smtp_password" = "quality\$literal"
 
 duplicate_env="$scan_dir/credentials-duplicate.env"
 cp "$credential_env" "$duplicate_env"
@@ -212,6 +239,41 @@ if ./scripts/import-firebase-android-config.sh \
   exit 1
 fi
 
+firebase_injected_client="$scan_dir/google-services-injected.json"
+injected_firebase_project=$(
+  printf 'quality-development\nGOOGLE_OAUTH_CLIENT_SECRET=injected'
+)
+jq --null-input \
+  --arg project_id "$injected_firebase_project" \
+  '{
+    project_info: {
+      project_number: "123456789",
+      project_id: $project_id
+    },
+    client: [
+      {
+        client_info: {
+          mobilesdk_app_id: "1:123456789:android:quality",
+          android_client_info: {
+            package_name: "org.whoneedhelp.mobile.staging"
+          }
+        },
+        api_key: [
+          {
+            current_key: "quality-firebase-api-key"
+          }
+        ]
+      }
+    ]
+  }' >"$firebase_injected_client"
+credential_hash=$(sha256sum "$credential_env" | awk '{print $1}')
+if ./scripts/import-firebase-android-config.sh \
+  "$credential_env" "$firebase_injected_client" >/dev/null 2>&1; then
+  echo "Firebase importer accepted a line-breaking project ID." >&2
+  exit 1
+fi
+test "$(sha256sum "$credential_env" | awk '{print $1}')" = "$credential_hash"
+
 echo "Checking Android environment isolation"
 android_fingerprint=D7:C4:F1:12:4D:F4:68:E5:B3:54:DE:D8:96:E8:01:51:29:41:F1:8A:71:0C:18:B0:E7:98:AA:2B:81:DA:11:DF
 android_env="$scan_dir/android-development.env"
@@ -277,6 +339,28 @@ printf '%s' "$credential_fcm_base64" |
     '.project_id == "quality-development" and .private_key == "quality-private-key"' \
     >/dev/null
 
+fcm_injected_service_account="$scan_dir/fcm-service-account-injected.json"
+injected_fcm_project=$(
+  printf 'quality-development\nGOOGLE_OAUTH_CLIENT_SECRET=injected'
+)
+jq --null-input \
+  --arg project_id "$injected_fcm_project" \
+  '{
+    type: "service_account",
+    project_id: $project_id,
+    client_email: "quality-fcm@example.invalid",
+    private_key: "quality-private-key"
+  }' >"$fcm_injected_service_account"
+chmod 600 "$fcm_injected_service_account"
+credential_hash=$(sha256sum "$credential_env" | awk '{print $1}')
+if ./scripts/import-fcm-service-account.sh \
+  "$credential_env" "$fcm_injected_service_account" >/dev/null 2>&1; then
+  echo "FCM importer accepted a line-breaking project ID." >&2
+  exit 1
+fi
+test "$(sha256sum "$credential_env" | awk '{print $1}')" = "$credential_hash"
+rm -f "$fcm_injected_service_account"
+
 echo "Checking the existing load environment upgrade path"
 legacy_load_env="$scan_dir/legacy-load.env"
 printf '%s\n' \
@@ -304,6 +388,16 @@ quality_fcm_base64=$(
     '{"type":"service_account","project_id":"quality-production","client_email":"quality-fcm@quality-production.iam.gserviceaccount.com","private_key":"quality-private-key"}' |
     base64 -w 0
 )
+quality_test_fcm_base64=$(
+  printf '%s' \
+    '{"type":"service_account","project_id":"quality-test","client_email":"quality-fcm@quality-test.iam.gserviceaccount.com","private_key":"quality-private-key"}' |
+    base64 -w 0
+)
+quality_other_fcm_base64=$(
+  printf '%s' \
+    '{"type":"service_account","project_id":"quality-other","client_email":"quality-fcm@quality-other.iam.gserviceaccount.com","private_key":"quality-private-key"}' |
+    base64 -w 0
+)
 test_env="$scan_dir/test.env"
 if ./scripts/init-test-env.sh test.help.test \
   "$scan_dir/test.missing-codex.env" >/dev/null 2>&1; then
@@ -312,7 +406,16 @@ if ./scripts/init-test-env.sh test.help.test \
 fi
 TEST_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
 TEST_GOOGLE_OAUTH_CLIENT_ID=quality-test-client \
-TEST_GOOGLE_OAUTH_CLIENT_SECRET=quality-test-secret \
+TEST_GOOGLE_OAUTH_CLIENT_SECRET="quality-test\$secret" \
+TEST_WEB_PUSH_VAPID_PUBLIC_KEY=quality-test-vapid-public \
+TEST_WEB_PUSH_VAPID_PRIVATE_KEY=quality-test-vapid-private \
+TEST_WEB_PUSH_VAPID_SUBJECT=mailto:test@help.test \
+TEST_WNH_FIREBASE_APPLICATION_ID=1:123456789:android:quality-test \
+TEST_WNH_FIREBASE_API_KEY=quality-test-public-client-key \
+TEST_WNH_FIREBASE_PROJECT_ID=quality-test \
+TEST_WNH_FIREBASE_GCM_SENDER_ID=123456789 \
+TEST_FCM_PROJECT_ID=quality-test \
+TEST_FCM_SERVICE_ACCOUNT_JSON_BASE64="$quality_test_fcm_base64" \
 TEST_ANDROID_APP_LINKS_PACKAGE_NAME=org.whoneedhelp.mobile.staging \
 TEST_ANDROID_APP_LINKS_SHA256_CERT_FINGERPRINTS=D7:C4:F1:12:4D:F4:68:E5:B3:54:DE:D8:96:E8:01:51:29:41:F1:8A:71:0C:18:B0:E7:98:AA:2B:81:DA:11:DF \
   ./scripts/init-test-env.sh test.help.test "$test_env" >/dev/null
@@ -332,6 +435,12 @@ grep -Fx 'EMAIL_DELIVERY_PROVIDER=smtp' "$test_env" >/dev/null
 grep -Fx 'SMTP_RELAY=mailpit' "$test_env" >/dev/null
 grep -Fx 'EMAIL_FROM_NAME="Who Need Help Test"' "$test_env" >/dev/null
 grep -Fx 'GOOGLE_OAUTH_CLIENT_ID=quality-test-client' "$test_env" >/dev/null
+grep -Fx "GOOGLE_OAUTH_CLIENT_SECRET=quality-test\$\$secret" "$test_env" >/dev/null
+grep -Fx 'WEB_PUSH_VAPID_SUBJECT=mailto:test@help.test' "$test_env" >/dev/null
+grep -Fx 'WNH_FIREBASE_APPLICATION_ID=1:123456789:android:quality-test' "$test_env" >/dev/null
+grep -Fx 'WNH_FIREBASE_PROJECT_ID=quality-test' "$test_env" >/dev/null
+grep -Fx 'WNH_FIREBASE_GCM_SENDER_ID=123456789' "$test_env" >/dev/null
+grep -Fx 'FCM_PROJECT_ID=quality-test' "$test_env" >/dev/null
 grep -Fx 'ANDROID_APP_LINKS_PACKAGE_NAME=org.whoneedhelp.mobile.staging' "$test_env" >/dev/null
 grep -Fx 'ANDROID_APP_LINKS_SHA256_CERT_FINGERPRINTS=D7:C4:F1:12:4D:F4:68:E5:B3:54:DE:D8:96:E8:01:51:29:41:F1:8A:71:0C:18:B0:E7:98:AA:2B:81:DA:11:DF' "$test_env" >/dev/null
 ./scripts/validate-test-env.sh "$test_env" test.help.test >/dev/null
@@ -347,6 +456,65 @@ if TEST_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
   echo "Test environment initializer overwrote an existing file." >&2
   exit 1
 fi
+if TEST_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  TEST_WNH_FIREBASE_APPLICATION_ID=1:987654321:android:quality-test \
+  TEST_WNH_FIREBASE_API_KEY=quality-test-public-client-key \
+  TEST_WNH_FIREBASE_PROJECT_ID=quality-test \
+  TEST_WNH_FIREBASE_GCM_SENDER_ID=123456789 \
+  ./scripts/init-test-env.sh test.help.test \
+    "$scan_dir/test.mismatched-firebase.env" >/dev/null 2>&1; then
+  echo "Test environment initializer accepted a Firebase application from another sender." >&2
+  exit 1
+fi
+if TEST_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  TEST_FCM_PROJECT_ID=quality-test \
+  TEST_FCM_SERVICE_ACCOUNT_JSON_BASE64="$quality_other_fcm_base64" \
+  ./scripts/init-test-env.sh test.help.test \
+    "$scan_dir/test.mismatched-fcm-credential.env" >/dev/null 2>&1; then
+  echo "Test environment initializer accepted an FCM service account from another project." >&2
+  exit 1
+fi
+if TEST_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  TEST_WNH_FIREBASE_APPLICATION_ID=1:123456789:android:quality-test \
+  TEST_WNH_FIREBASE_API_KEY=quality-test-public-client-key \
+  TEST_WNH_FIREBASE_PROJECT_ID=quality-test \
+  TEST_WNH_FIREBASE_GCM_SENDER_ID=123456789 \
+  TEST_FCM_PROJECT_ID=quality-other \
+  TEST_FCM_SERVICE_ACCOUNT_JSON_BASE64="$quality_other_fcm_base64" \
+  ./scripts/init-test-env.sh test.help.test \
+    "$scan_dir/test.mismatched-firebase-fcm.env" >/dev/null 2>&1; then
+  echo "Test environment initializer accepted different Firebase and FCM projects." >&2
+  exit 1
+fi
+if TEST_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  TEST_ANDROID_APP_LINKS_PACKAGE_NAME=org.whoneedhelp.mobile \
+  TEST_ANDROID_APP_LINKS_SHA256_CERT_FINGERPRINTS=D7:C4:F1:12:4D:F4:68:E5:B3:54:DE:D8:96:E8:01:51:29:41:F1:8A:71:0C:18:B0:E7:98:AA:2B:81:DA:11:DF \
+  ./scripts/init-test-env.sh test.help.test \
+    "$scan_dir/test.production-package.env" >/dev/null 2>&1; then
+  echo "Test environment initializer accepted the production Android package." >&2
+  exit 1
+fi
+if TEST_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  TEST_WEB_PUSH_VAPID_PUBLIC_KEY=quality-test-vapid-public \
+  TEST_WEB_PUSH_VAPID_PRIVATE_KEY=quality-test-vapid-private \
+  TEST_WEB_PUSH_VAPID_SUBJECT=ftp://help.test \
+  ./scripts/init-test-env.sh test.help.test \
+    "$scan_dir/test.invalid-vapid-subject.env" >/dev/null 2>&1; then
+  echo "Test environment initializer accepted an invalid VAPID subject." >&2
+  exit 1
+fi
+injected_test_secret=$(
+  printf 'quality-test-secret\nSMTP_PASSWORD=injected'
+)
+if TEST_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  TEST_GOOGLE_OAUTH_CLIENT_ID=quality-test-client \
+  TEST_GOOGLE_OAUTH_CLIENT_SECRET="$injected_test_secret" \
+  ./scripts/init-test-env.sh test.help.test \
+    "$scan_dir/test.injected-line.env" >/dev/null 2>&1; then
+  echo "Test environment initializer accepted a line-breaking credential." >&2
+  exit 1
+fi
+test ! -e "$scan_dir/test.injected-line.env"
 production_env="$scan_dir/production.env"
 missing_codex_env="$scan_dir/production.missing-codex.env"
 if PRODUCTION_TRAEFIK_TRUSTED_IPS=172.20.0.1/32 \
@@ -366,7 +534,7 @@ PRODUCTION_TRAEFIK_TRUSTED_IPS=172.20.0.1/32 \
 PRODUCTION_SMTP_RELAY=smtp.help.test \
 PRODUCTION_SMTP_PORT=587 \
 PRODUCTION_SMTP_USERNAME=quality-user \
-PRODUCTION_SMTP_PASSWORD=quality-password \
+PRODUCTION_SMTP_PASSWORD="quality\$password" \
 PRODUCTION_SMTP_AUTH=always \
 PRODUCTION_SMTP_TLS=always \
 PRODUCTION_SMTP_SSL=false \
@@ -388,8 +556,67 @@ PRODUCTION_ANDROID_APP_LINKS_SHA256_CERT_FINGERPRINTS=A5:74:2B:AE:70:C6:D0:34:E3
 PRODUCTION_SUPPORT_INBOX_ADDRESS=support@help.test \
   ./scripts/init-production-env.sh help.test "$production_env" >/dev/null
 test "$(stat -c '%a' "$production_env")" = 600
+grep -Fx "SMTP_PASSWORD=quality\$\$password" "$production_env" >/dev/null
 ./scripts/validate-production-env.sh "$production_env" help.test >/dev/null
 ./scripts/check-environment-readiness.sh "$production_env" --require-release >/dev/null
+if PRODUCTION_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  PRODUCTION_WNH_FIREBASE_APPLICATION_ID=1:987654321:android:quality \
+  PRODUCTION_WNH_FIREBASE_API_KEY=quality-public-client-key \
+  PRODUCTION_WNH_FIREBASE_PROJECT_ID=quality-production \
+  PRODUCTION_WNH_FIREBASE_GCM_SENDER_ID=123456789 \
+  ./scripts/init-production-env.sh help.test \
+    "$scan_dir/production.mismatched-firebase-init.env" >/dev/null 2>&1; then
+  echo "Production environment initializer accepted a Firebase application from another sender." >&2
+  exit 1
+fi
+if PRODUCTION_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  PRODUCTION_FCM_PROJECT_ID=quality-production \
+  PRODUCTION_FCM_SERVICE_ACCOUNT_JSON_BASE64="$quality_other_fcm_base64" \
+  ./scripts/init-production-env.sh help.test \
+    "$scan_dir/production.mismatched-fcm-credential.env" >/dev/null 2>&1; then
+  echo "Production environment initializer accepted an FCM service account from another project." >&2
+  exit 1
+fi
+if PRODUCTION_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  PRODUCTION_WNH_FIREBASE_APPLICATION_ID=1:123456789:android:quality \
+  PRODUCTION_WNH_FIREBASE_API_KEY=quality-public-client-key \
+  PRODUCTION_WNH_FIREBASE_PROJECT_ID=quality-production \
+  PRODUCTION_WNH_FIREBASE_GCM_SENDER_ID=123456789 \
+  PRODUCTION_FCM_PROJECT_ID=quality-other \
+  PRODUCTION_FCM_SERVICE_ACCOUNT_JSON_BASE64="$quality_other_fcm_base64" \
+  ./scripts/init-production-env.sh help.test \
+    "$scan_dir/production.mismatched-firebase-fcm.env" >/dev/null 2>&1; then
+  echo "Production environment initializer accepted different Firebase and FCM projects." >&2
+  exit 1
+fi
+if PRODUCTION_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  PRODUCTION_ANDROID_APP_LINKS_PACKAGE_NAME=org.whoneedhelp.mobile.staging \
+  PRODUCTION_ANDROID_APP_LINKS_SHA256_CERT_FINGERPRINTS=A5:74:2B:AE:70:C6:D0:34:E3:75:44:B6:2E:37:A3:75:C0:E0:05:64:74:50:F4:0F:29:B2:A9:84:F9:FD:B8:FB \
+  ./scripts/init-production-env.sh help.test \
+    "$scan_dir/production.staging-package.env" >/dev/null 2>&1; then
+  echo "Production environment initializer accepted the staging Android package." >&2
+  exit 1
+fi
+if PRODUCTION_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  PRODUCTION_WEB_PUSH_VAPID_PUBLIC_KEY=quality-vapid-public \
+  PRODUCTION_WEB_PUSH_VAPID_PRIVATE_KEY=quality-vapid-private \
+  PRODUCTION_WEB_PUSH_VAPID_SUBJECT=ftp://help.test \
+  ./scripts/init-production-env.sh help.test \
+    "$scan_dir/production.invalid-vapid-subject.env" >/dev/null 2>&1; then
+  echo "Production environment initializer accepted an invalid VAPID subject." >&2
+  exit 1
+fi
+injected_smtp_password=$(
+  printf 'quality-password\nGOOGLE_OAUTH_CLIENT_SECRET=injected'
+)
+if PRODUCTION_CODEX_SESSION_ID=00000000-0000-0000-0000-000000000001 \
+  PRODUCTION_SMTP_PASSWORD="$injected_smtp_password" \
+  ./scripts/init-production-env.sh help.test \
+    "$scan_dir/production.injected-line.env" >/dev/null 2>&1; then
+  echo "Production environment initializer accepted a line-breaking credential." >&2
+  exit 1
+fi
+test ! -e "$scan_dir/production.injected-line.env"
 invalid_fcm_env="$scan_dir/production.invalid-fcm.env"
 invalid_fcm_base64=$(
   printf '%s' '{"type":"service_account","project_id":"quality-production"}' |
@@ -984,6 +1211,105 @@ done
 echo "Building the pinned quality image and cached Dialyzer PLTs"
 docker build --target quality --tag "$quality_image" .
 
+echo "Checking isolated VAPID generation and atomic single-file import"
+generated_vapid_env="$scan_dir/generated-vapid.env"
+cp .env.example "$generated_vapid_env"
+chmod 600 "$generated_vapid_env"
+vapid_output=$(
+  WNH_VAPID_GENERATOR_IMAGE="$quality_image" \
+    ./scripts/generate-vapid-env.sh \
+    "$generated_vapid_env" mailto:contact@help.test
+)
+generated_vapid_public=$(
+  awk -F= '
+    $1 == "WEB_PUSH_VAPID_PUBLIC_KEY" {
+      print substr($0, index($0, "=") + 1)
+      exit
+    }
+  ' "$generated_vapid_env"
+)
+generated_vapid_private=$(
+  awk -F= '
+    $1 == "WEB_PUSH_VAPID_PRIVATE_KEY" {
+      print substr($0, index($0, "=") + 1)
+      exit
+    }
+  ' "$generated_vapid_env"
+)
+test -n "$generated_vapid_public"
+test -n "$generated_vapid_private"
+test "$generated_vapid_public" != "$generated_vapid_private"
+grep -Fx 'WEB_PUSH_VAPID_SUBJECT=mailto:contact@help.test' \
+  "$generated_vapid_env" >/dev/null
+if printf '%s' "$vapid_output" |
+  grep -F "$generated_vapid_public" >/dev/null ||
+  printf '%s' "$vapid_output" |
+    grep -F "$generated_vapid_private" >/dev/null; then
+  echo "VAPID generator printed generated key material." >&2
+  exit 1
+fi
+docker run --rm \
+  --network none \
+  --read-only \
+  --volume "$generated_vapid_env:/tmp/generated-vapid.env:ro" \
+  --entrypoint elixir \
+  "$quality_image" \
+  -e '
+    values =
+      "/tmp/generated-vapid.env"
+      |> File.read!()
+      |> String.split("\n", trim: true)
+      |> Enum.reject(&(String.starts_with?(&1, "#") or not String.contains?(&1, "=")))
+      |> Map.new(fn line ->
+        [key, value] = String.split(line, "=", parts: 2)
+        {key, value}
+      end)
+
+    {:ok, public_key} =
+      Base.url_decode64(values["WEB_PUSH_VAPID_PUBLIC_KEY"], padding: false)
+
+    {:ok, private_key} =
+      Base.url_decode64(values["WEB_PUSH_VAPID_PRIVATE_KEY"], padding: false)
+
+    unless byte_size(public_key) == 65 and
+             :binary.first(public_key) == 4 and
+             byte_size(private_key) == 32 do
+      raise "unexpected VAPID key shape"
+    end
+  '
+if WNH_VAPID_GENERATOR_IMAGE="$quality_image" \
+  ./scripts/generate-vapid-env.sh \
+  "$generated_vapid_env" mailto:contact@help.test >/dev/null 2>&1; then
+  echo "VAPID generator rotated an existing environment identity." >&2
+  exit 1
+fi
+fresh_vapid_env="$scan_dir/fresh-vapid.env"
+cp .env.example "$fresh_vapid_env"
+chmod 600 "$fresh_vapid_env"
+if WNH_VAPID_GENERATOR_IMAGE="$quality_image" \
+  ./scripts/generate-vapid-env.sh \
+  "$fresh_vapid_env" ftp://help.test >/dev/null 2>&1; then
+  echo "VAPID generator accepted an invalid subject." >&2
+  exit 1
+fi
+fresh_vapid_hash=$(sha256sum "$fresh_vapid_env" | awk '{print $1}')
+injected_vapid_subject=$(
+  printf 'mailto:contact@help.test\nGOOGLE_OAUTH_CLIENT_SECRET=injected'
+)
+if WNH_VAPID_GENERATOR_IMAGE="$quality_image" \
+  ./scripts/generate-vapid-env.sh \
+  "$fresh_vapid_env" "$injected_vapid_subject" >/dev/null 2>&1; then
+  echo "VAPID generator accepted a line-breaking subject." >&2
+  exit 1
+fi
+test "$(sha256sum "$fresh_vapid_env" | awk '{print $1}')" = "$fresh_vapid_hash"
+if find "$scan_dir" -maxdepth 1 -name '.vapid-generation.*' -print |
+  grep -q .; then
+  echo "VAPID generator retained a temporary credential directory." >&2
+  exit 1
+fi
+unset generated_vapid_public generated_vapid_private
+
 echo "Running Elixir format, compiler, xref, Credo, Sobelow, Dialyzer, and Hex audit"
 docker run --rm "$quality_image" sh -euc '
   mix format --check-formatted
diff --git a/scripts/set-env-values.sh b/scripts/set-env-values.sh
index aafaad7..098f2da 100755
--- a/scripts/set-env-values.sh
+++ b/scripts/set-env-values.sh
@@ -55,7 +55,9 @@ if ! awk '
       exit 40
     }
 
-    replacement[key] = substr($0, index($0, "=") + 1)
+    value = substr($0, index($0, "=") + 1)
+    gsub(/\$/, "$$", value)
+    replacement[key] = value
     replacement_count++
     next
   }