diff --git a/.github/workflows/check-outward-facing.sh b/.github/workflows/check-outward-facing.sh
new file mode 100755
index 0000000..b0b05bf
--- /dev/null
+++ b/.github/workflows/check-outward-facing.sh
@@ -0,0 +1,92 @@
+#!/bin/bash
+# check-outward-facing.sh — Scan outward-facing content for inward-facing leaks.
+#
+# Blocks internal markers from reaching public, rendered, or GitHub-rendered
+# surfaces: internal record IDs, internal decision/chapter references, German
+# structure markers on English pages, and the private source-repository name.
+#
+# Usage:
+#   bash check-outward-facing.sh --excludes "node_modules,dist,generated,..."
+#   bash check-outward-facing.sh --pattern '<custom-ere>' --excludes "..."
+#
+# Exit codes:
+#   0 = no inward-facing leak detected outside the allowlist
+#   1 = at least one leak, prints offending lines
+#   2 = bad arguments
+
+set -u
+
+# High-confidence inward markers (low false-positive rate). Bare decision codes
+# like "F3" are intentionally NOT matched standalone — they co-occur with the
+# record-ID markers below and matching them alone is too noisy to maintain.
+DEFAULT_PATTERN='(Memo [0-9]|\bM0[0-9]{2}\b|flowmcp-schemas-private|\bKap\.|\bPRD-[0-9]|Soll-|\bREV-0[0-9])'
+
+PATTERN="$DEFAULT_PATTERN"
+EXCLUDES=""
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --pattern)
+            PATTERN="$2"
+            shift 2
+            ;;
+        --excludes)
+            EXCLUDES="$2"
+            shift 2
+            ;;
+        *)
+            echo "Unknown arg: $1"
+            exit 2
+            ;;
+    esac
+done
+
+# Split excludes into basename excludes, file-pattern excludes, and full-path
+# prefix excludes (post-grep filter — grep --exclude-dir matches basename only).
+EXCLUDE_FLAGS=""
+PATH_PREFIX_FILTERS=""
+IFS=',' read -ra ITEMS <<< "$EXCLUDES"
+for item in "${ITEMS[@]}"; do
+    item_trim=$(echo "$item" | sed 's/^ *//; s/ *$//')
+    [ -z "$item_trim" ] && continue
+    case "$item_trim" in
+        *.template.md|*.template.mdx|*.template.txt|template.txt|*.lock)
+            EXCLUDE_FLAGS="$EXCLUDE_FLAGS --exclude=$item_trim"
+            ;;
+        */*)
+            PATH_PREFIX_FILTERS="$PATH_PREFIX_FILTERS|./$item_trim/"
+            ;;
+        *)
+            EXCLUDE_FLAGS="$EXCLUDE_FLAGS --exclude-dir=$item_trim --exclude=$item_trim"
+            ;;
+    esac
+done
+
+# Outward surface: rendered docs + READMEs/DISCLAIMER/CHANGELOG + Astro
+# components. Build-tooling .mjs/.js is intentionally excluded by default to
+# avoid flagging legitimate provenance comments; opt in per repo if needed.
+INCLUDE_FLAGS="--include=*.md --include=*.mdx --include=*.astro --include=*.txt"
+
+RAW_HITS=$(grep -rnE $INCLUDE_FLAGS $EXCLUDE_FLAGS "$PATTERN" . 2>/dev/null || true)
+
+if [ -n "$PATH_PREFIX_FILTERS" ]; then
+    FILTER_RE="${PATH_PREFIX_FILTERS#|}"
+    HITS=$(echo "$RAW_HITS" | grep -vE "^($FILTER_RE)" || true)
+else
+    HITS="$RAW_HITS"
+fi
+
+if [ -n "$HITS" ]; then
+    echo "::error::Inward-facing content detected on an outward-facing surface."
+    echo "$HITS"
+    echo ""
+    echo "How to fix:"
+    echo "  - Remove internal record IDs (Memo NNN, M0NN), decision/chapter refs (PRD-NN, Kap.),"
+    echo "    German structure markers (Soll-), and the private source-repository name."
+    echo "  - Use neutral, English, outward-safe phrasing (e.g. 'the schemas repository')."
+    echo "  - Add a documented allowlist entry only for genuine false positives."
+    exit 1
+fi
+
+echo "OK: no inward-facing leaks detected (pattern: $PATTERN)"
+exit 0
diff --git a/.github/workflows/check-outward-facing.yml b/.github/workflows/check-outward-facing.yml
new file mode 100644
index 0000000..9553296
--- /dev/null
+++ b/.github/workflows/check-outward-facing.yml
@@ -0,0 +1,81 @@
+name: Check Outward-Facing Content
+
+# Reusable workflow that scans a repository's outward-facing content for
+# inward-facing leaks — internal record IDs (Memo NNN, M0NN), internal
+# decision/chapter references (PRD-NN, Kap.), German structure markers on
+# English pages (Soll-), and the private source-repository name. It fails when
+# any match is found outside the allowlist paths.
+#
+# Companion local script: check-outward-facing.sh (same scan, runnable locally).
+
+on:
+  workflow_call:
+    inputs:
+      allowlist-paths:
+        type: string
+        default: "node_modules,dist,generated,archive,.git,.template.md,.template.mdx,public/spec-generated,spec/v2.0.0,spec/v3.0.0,spec/v4.0.0,spec/v4.1.0,spec/v4.2.0"
+        description: "Comma-separated path fragments to exclude (build outputs, templates, frozen historical version directories)"
+      pattern:
+        type: string
+        default: ""
+        description: "Optional ERE override for the leak pattern. Empty uses the built-in high-confidence pattern."
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Scan for inward-facing leaks
+        shell: bash
+        run: |
+          set -u
+          DEFAULT_PATTERN='(Memo [0-9]|\bM0[0-9]{2}\b|flowmcp-schemas-private|\bKap\.|\bPRD-[0-9]|Soll-|\bREV-0[0-9])'
+          PATTERN='${{ inputs.pattern }}'
+          [ -z "$PATTERN" ] && PATTERN="$DEFAULT_PATTERN"
+          EXCLUDES="${{ inputs.allowlist-paths }}"
+
+          EXCLUDE_FLAGS=""
+          PATH_PREFIX_FILTERS=""
+          IFS=',' read -ra ITEMS <<< "$EXCLUDES"
+          for item in "${ITEMS[@]}"; do
+              item_trim=$(echo "$item" | sed 's/^ *//; s/ *$//')
+              [ -z "$item_trim" ] && continue
+              case "$item_trim" in
+                  *.template.md|*.template.mdx|*.template.txt|template.txt|*.lock)
+                      EXCLUDE_FLAGS="$EXCLUDE_FLAGS --exclude=$item_trim"
+                      ;;
+                  */*)
+                      PATH_PREFIX_FILTERS="$PATH_PREFIX_FILTERS|./$item_trim/"
+                      ;;
+                  *)
+                      EXCLUDE_FLAGS="$EXCLUDE_FLAGS --exclude-dir=$item_trim --exclude=$item_trim"
+                      ;;
+              esac
+          done
+
+          INCLUDE_FLAGS="--include=*.md --include=*.mdx --include=*.astro --include=*.txt"
+
+          set +e
+          RAW_HITS=$(grep -rnE $INCLUDE_FLAGS $EXCLUDE_FLAGS "$PATTERN" . 2>/dev/null || true)
+
+          if [ -n "$PATH_PREFIX_FILTERS" ]; then
+              FILTER_RE="${PATH_PREFIX_FILTERS#|}"
+              HITS=$(echo "$RAW_HITS" | grep -vE "^($FILTER_RE)" || true)
+          else
+              HITS="$RAW_HITS"
+          fi
+
+          if [ -n "$HITS" ]; then
+              echo "::error::Inward-facing content detected on an outward-facing surface."
+              echo "$HITS"
+              echo ""
+              echo "How to fix:"
+              echo "  - Remove internal record IDs (Memo NNN, M0NN), decision/chapter refs (PRD-NN, Kap.),"
+              echo "    German structure markers (Soll-), and the private source-repository name."
+              echo "  - Use neutral, English, outward-safe phrasing (e.g. 'the schemas repository')."
+              echo "  - Add a documented allowlist entry only for genuine false positives."
+              exit 1
+          fi
+
+          echo "OK: no inward-facing leaks detected (pattern: $PATTERN)"