diff --git a/.gitea/workflows/class-txt-check.yml b/.gitea/workflows/class-txt-check.yml
new file mode 100644
index 000000000..eda9f6e45
--- /dev/null
+++ b/.gitea/workflows/class-txt-check.yml
@@ -0,0 +1,81 @@
+# .gitea/workflows/class-txt-check.yml
+name: CLASS.TXT.json Check
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize, edited]
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  class-txt-check:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - name: Get changed CLASS.TXT.json files
+        id: changed-files
+        run: |
+          BASE_SHA="${{ gitea.event.pull_request.base.sha }}"
+          changed=$(git diff --name-only ${BASE_SHA}...HEAD | grep -E 'CLASS\.TXT\.json$' | tr '\n' ' ' || true)
+          echo "files=$changed" >> $GITHUB_OUTPUT
+          echo "CHANGED_FILES=$changed" >> $GITHUB_ENV
+          echo "Changed CLASS.TXT.json files: $changed"
+
+      - name: Run duplicate title check
+        id: class-check
+        run: |
+          python3 .gitea/workflows/helpers/class-txt-check.py
+
+      - name: Comment on PR with violations
+        if: failure() && steps.class-check.outcome == 'failure'
+        env:
+          GITEA_SERVER_URL: ${{ gitea.server_url }}
+          REPO: ${{ gitea.repository }}
+          PR_NUMBER: ${{ gitea.event.pull_request.number }}
+          TOKEN: ${{ gitea.token }}
+        run: |
+          set -euo pipefail
+
+          # Ensure URL starts with http
+          if [[ ! "${GITEA_SERVER_URL}" =~ ^https?:// ]]; then
+            GITEA_SERVER_URL="http://${GITEA_SERVER_URL}"
+            echo "Added http:// prefix to URL"
+          fi
+
+          # Generate comment message
+          MSG=$(python3 .gitea/workflows/helpers/class-comment.py)
+          echo "$MSG"
+
+          # Extract body from JSON
+          BODY=$(echo "$MSG" | python3 -c "import sys, json; print(json.load(sys.stdin)['body'])")
+
+          # Build the full URL
+          FULL_URL="${GITEA_SERVER_URL}/api/v1/repos/${REPO}/issues/${PR_NUMBER}/comments"
+          echo "Posting comment to: ${FULL_URL}"
+
+          # Comment on PR
+          curl -sS -X POST \
+            -H "Authorization: token ${TOKEN}" \
+            -H "Content-Type: application/json" \
+            "${FULL_URL}" \
+            -d "$(echo "$BODY" | python3 -c "import sys, json; print(json.dumps({'body': sys.stdin.read()}))")"
+
+      - name: Final status
+        if: always()
+        run: |
+          if [ -f violations.json ]; then
+            echo "::error::CLASS.TXT.json check failed. See previous step for details."
+            exit 1
+          fi
diff --git a/.gitea/workflows/docs-precheck.yml b/.gitea/workflows/docs-precheck.yml
index e031ae391..16a001241 100644
--- a/.gitea/workflows/docs-precheck.yml
+++ b/.gitea/workflows/docs-precheck.yml
@@ -39,7 +39,7 @@ jobs:
       - name: Run underscore check
         id: underscore-check
         run: |
-          python3 .gitea/workflows/underscore-check.py
+          python3 .gitea/workflows/helpers/underscore-check.py
 
       - name: Comment on PR with violations
         if: failure() && steps.underscore-check.outcome == 'failure'
@@ -58,7 +58,7 @@ jobs:
           fi
 
           # Generate comment message
-          MSG=$(python3 .gitea/workflows/generate-comment.py)
+          MSG=$(python3 .gitea/workflows/helpers/underscore-comment.py)
           echo "$MSG"
 
           # Extract body from JSON
diff --git a/.gitea/workflows/helpers/class-comment.py b/.gitea/workflows/helpers/class-comment.py
new file mode 100755
index 000000000..a4bfbb4de
--- /dev/null
+++ b/.gitea/workflows/helpers/class-comment.py
@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+"""Generate PR comment from CLASS.TXT.json violations."""
+
+import json
+import sys
+
+
+def main():
+    try:
+        with open("violations.json", "r") as f:
+            violations = json.load(f)
+    except Exception:
+        violations = []
+
+    if not violations:
+        print(json.dumps({"body": "No violations to report"}))
+        sys.exit(0)
+
+    # Group violations by file
+    by_file = {}
+    for v in violations:
+        key = v["file"]
+        if key not in by_file:
+            by_file[key] = []
+        by_file[key].append(v)
+
+    # Build message
+    lines = [
+        "❌ **Duplicate title detected in CLASS.TXT.json**",
+        "",
+        "Found child documents with duplicate titles under the same parent:",
+        "",
+    ]
+
+    for filepath, file_violations in by_file.items():
+        lines.append(f"**{filepath}:**")
+        for v in file_violations:
+            parent_code = v["parent_code"]
+            parent_title = v["parent_title"]
+            duplicate_title = v["duplicate_title"]
+            codes = v["codes"]
+
+            lines.append(f"   - Parent: `{parent_title}` (code: `{parent_code}`)")
+            lines.append(f"     Duplicate title: `{duplicate_title}`")
+            for code in codes:
+                lines.append(f"       - Document code: `{code}`")
+        lines.append("")
+
+    lines.append(
+        "**Please ensure all child documents under the same parent have unique titles.**"
+    )
+
+    message = "\n".join(lines)
+    print(json.dumps({"body": message}))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/.gitea/workflows/helpers/class-txt-check.py b/.gitea/workflows/helpers/class-txt-check.py
new file mode 100755
index 000000000..592c0432b
--- /dev/null
+++ b/.gitea/workflows/helpers/class-txt-check.py
@@ -0,0 +1,140 @@
+#!/usr/bin/env python3
+"""Check CLASS.TXT.json files for duplicate titles under the same parent."""
+
+import sys
+import os
+import json
+
+
+def check_duplicate_titles(json_path):
+    """
+    Check for duplicate titles under the same parent.
+
+    Returns list of violations:
+    [
+      {
+        'file': 'path/to/CLASS.TXT.json',
+        'parent_code': '3',
+        'parent_title': 'Virtual Private Cloud',
+        'duplicate_title': 'Creating a VPC',
+        'codes': ['4', '6']
+      }
+    ]
+    """
+    violations = []
+
+    # Load the JSON file
+    try:
+        with open(json_path, "r", encoding="utf-8") as f:
+            data = json.load(f)
+    except json.JSONDecodeError as e:
+        print(f"Error parsing JSON in {json_path}: {e}")
+        return []
+    except Exception as e:
+        print(f"Error reading {json_path}: {e}")
+        return []
+
+    # Build a code-to-title map for looking up parent titles
+    code_to_title = {}
+    for entry in data:
+        code = entry.get("code", "")
+        title = entry.get("title", "")
+        if code and title:
+            code_to_title[code] = title
+
+    # Group documents by p_code (parent code)
+    parent_groups = {}
+    for entry in data:
+        p_code = entry.get("p_code", "")
+        code = entry.get("code", "")
+        title = entry.get("title", "")
+
+        # Skip if missing required fields
+        if not code or not title:
+            continue
+
+        # Group by parent code
+        if p_code not in parent_groups:
+            parent_groups[p_code] = []
+
+        parent_groups[p_code].append({"code": code, "title": title})
+
+    # Check each parent group for duplicate titles
+    for p_code, children in parent_groups.items():
+        # Group children by title (case-insensitive)
+        title_groups = {}
+        for child in children:
+            title_lower = child["title"].lower().strip()
+            if title_lower not in title_groups:
+                title_groups[title_lower] = []
+            title_groups[title_lower].append(child)
+
+        # Find duplicates (titles that appear more than once)
+        for title_lower, docs in title_groups.items():
+            if len(docs) > 1:
+                # Get the original title (from first occurrence)
+                original_title = docs[0]["title"]
+
+                # Get parent title
+                parent_title = code_to_title.get(
+                    p_code, "(root)" if p_code == "" else f"(unknown parent: {p_code})"
+                )
+
+                # Collect document codes
+                codes = [doc["code"] for doc in docs]
+
+                violations.append(
+                    {
+                        "file": json_path,
+                        "parent_code": p_code if p_code else "(root)",
+                        "parent_title": parent_title,
+                        "duplicate_title": original_title,
+                        "codes": codes,
+                    }
+                )
+
+    return violations
+
+
+def main():
+    # Get changed files from environment
+    changed_files_str = os.environ.get("CHANGED_FILES", "")
+    changed_files = [f.strip() for f in changed_files_str.split() if f.strip()]
+
+    if not changed_files:
+        print("No CLASS.TXT.json files changed in this PR")
+        sys.exit(0)
+
+    print(f"Checking {len(changed_files)} CLASS.TXT.json file(s): {changed_files}")
+
+    all_violations = []
+
+    for filepath in changed_files:
+        if not os.path.exists(filepath):
+            print(f"Warning: File not found: {filepath}")
+            continue
+
+        violations = check_duplicate_titles(filepath)
+        all_violations.extend(violations)
+
+    # Output results
+    if all_violations:
+        # Write violations to JSON file for later use
+        with open("violations.json", "w") as f:
+            json.dump(all_violations, f, indent=2)
+
+        print(f"\nFound {len(all_violations)} violation(s):")
+        for v in all_violations:
+            print(f"   {v['file']}")
+            print(f"      Parent: {v['parent_title']} (code: {v['parent_code']})")
+            print(f'      Duplicate title: "{v["duplicate_title"]}"')
+            print(f"      Document codes: {', '.join(v['codes'])}")
+
+        sys.exit(1)
+    else:
+        print("\nNo violations found")
+        sys.exit(0)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/.gitea/workflows/underscore-check.py b/.gitea/workflows/helpers/underscore-check.py
similarity index 100%
rename from .gitea/workflows/underscore-check.py
rename to .gitea/workflows/helpers/underscore-check.py
diff --git a/.gitea/workflows/generate-comment.py b/.gitea/workflows/helpers/underscore-comment.py
similarity index 100%
rename from .gitea/workflows/generate-comment.py
rename to .gitea/workflows/helpers/underscore-comment.py
diff --git a/docs/apig/umn/CLASS.TXT.json b/docs/apig/umn/CLASS.TXT.json
index 0fcfe8334..d566ff3cf 100644
--- a/docs/apig/umn/CLASS.TXT.json
+++ b/docs/apig/umn/CLASS.TXT.json
@@ -515,7 +515,7 @@
 	{
 		"desc":"Meaning: Request throttling policy.Scope of effect: Operation Object (2.0)/Operation Object (3.0)Example:",
 		"product_code":"apig",
-		"title":"x-apigateway-ratelimit",
+		"title":"x-apigateway-ratelimits",
 		"uri":"apig_03_0098.html",
 		"doc_type":"usermanual",
 		"p_code":"43",