diff --git a/lib/extract_ids.py b/lib/extract_ids.py
index f08dd2e..cf75a7c 100644
--- a/lib/extract_ids.py
+++ b/lib/extract_ids.py
@@ -7,6 +7,8 @@ Usage:
     python extract_ids.py --filename KA135776
     python extract_ids.py --filename KA135776 --tab soll
     python extract_ids.py --all
+    python extract_ids.py --all --sum2json
+    python extract_ids.py --all --sum2txt
 """
 
 import argparse
@@ -58,19 +60,23 @@ def extract_ids_from_tree(tree: dict) -> dict[str, str]:
     return ids
 
 
-def process_json(json_path: Path, tab: str, results_dir: Path) -> int:
-    """Extract IDs from one JSON file. Returns number of IDs found."""
-    with open(json_path, encoding="utf-8") as f:
-        tree = json.load(f)
-
-    ids = extract_ids_from_tree(tree)
-
-    # Derive project name: strip _ist/_soll suffix
+def get_project_name(json_path: Path) -> str:
+    """Derive project name from JSON filename by stripping _ist/_soll suffix."""
     project_name = json_path.stem
     for suffix in ("_ist", "_soll"):
         if project_name.endswith(suffix):
             project_name = project_name[: -len(suffix)]
             break
+    return project_name
+
+
+def process_json(json_path: Path, tab: str, results_dir: Path) -> tuple[dict[str, str], str, Path]:
+    """Extract IDs from one JSON file. Returns (ids dict, project_name, ids_path)."""
+    with open(json_path, encoding="utf-8") as f:
+        tree = json.load(f)
+
+    ids = extract_ids_from_tree(tree)
+    project_name = get_project_name(json_path)
 
     ids_path = results_dir / f"{project_name}_ids_{tab}.txt"
     with open(ids_path, "w", encoding="utf-8") as f:
@@ -78,7 +84,34 @@ def process_json(json_path: Path, tab: str, results_dir: Path) -> int:
             f.write(f"{nummer}: {bez}\n")
 
     print(f"  {json_path.name} -> {ids_path.name} ({len(ids)} IDs)")
-    return len(ids)
+    return ids, project_name, ids_path
+
+
+def write_sum2json(all_ids: dict[str, str], projekte: dict[str, list[str]], tab: str, results_dir: Path):
+    """Write aggregated summary as JSON file."""
+    # projekte dict: convert lists to comma-separated strings
+    projekte_str = {k: ", ".join(v) for k, v in sorted(projekte.items())}
+    data = {
+        "ids": dict(sorted(all_ids.items())),
+        "projekte": projekte_str,
+    }
+    out_path = results_dir / f"summary_ids_{tab}.json"
+    with open(out_path, "w", encoding="utf-8") as f:
+        json.dump(data, f, ensure_ascii=False, indent=2)
+    print(f"\n  Summary JSON -> {out_path.name} ({len(all_ids)} IDs, {len(projekte)} mit Projektzuordnung)")
+
+
+def write_sum2txt(all_ids: dict[str, str], projekte: dict[str, list[str]], tab: str, results_dir: Path):
+    """Write aggregated summary as TXT file with [Sivasnummern] and [Anzahl] sections."""
+    out_path = results_dir / f"summary_ids_{tab}.txt"
+    with open(out_path, "w", encoding="utf-8") as f:
+        f.write("[Sivasnummern]\n")
+        for nummer, bez in sorted(all_ids.items()):
+            f.write(f"{nummer}: {bez}\n")
+        f.write(f"\n[Anzahl]\n")
+        for nummer, prj_list in sorted(projekte.items(), key=lambda x: len(x[1]), reverse=True):
+            f.write(f"{nummer}: {len(prj_list)}\n")
+    print(f"\n  Summary TXT -> {out_path.name} ({len(all_ids)} IDs)")
 
 
 def main():
@@ -102,6 +135,16 @@ def main():
         dest="process_all",
         help="Alle *_<tab>.json Dateien im results/-Ordner verarbeiten",
     )
+    parser.add_argument(
+        "--sum2json",
+        action="store_true",
+        help="Alle IDs in eine summary_ids_<tab>.json zusammenfassen (ids + projekte)",
+    )
+    parser.add_argument(
+        "--sum2txt",
+        action="store_true",
+        help="Alle IDs in eine summary_ids_<tab>.txt zusammenfassen ([Sivasnummern] + [Anzahl])",
+    )
     args = parser.parse_args()
 
     if not args.process_all and not args.filename:
@@ -127,11 +170,32 @@ def main():
 
     print(f"Verarbeite {len(json_files)} JSON-Dateien aus {results_dir}\n")
     total_ids = 0
+    # Aggregation dicts for --sum2json / --sum2txt
+    all_ids: dict[str, str] = {}
+    projekte: dict[str, list[str]] = {}
+    individual_txt_files: list[Path] = []
+
     for json_path in json_files:
-        total_ids += process_json(json_path, args.tab, results_dir)
+        ids, project_name, ids_path = process_json(json_path, args.tab, results_dir)
+        total_ids += len(ids)
+        individual_txt_files.append(ids_path)
+        for nummer, bez in ids.items():
+            all_ids[nummer] = bez
+            projekte.setdefault(nummer, []).append(project_name)
 
     print(f"\nFertig: {total_ids} IDs aus {len(json_files)} Dateien extrahiert.")
 
+    if args.sum2json:
+        write_sum2json(all_ids, projekte, args.tab, results_dir)
+    if args.sum2txt:
+        write_sum2txt(all_ids, projekte, args.tab, results_dir)
+
+    # Einzelne _ids_ txt-Dateien loeschen wenn Summary erzeugt wurde
+    if args.sum2json or args.sum2txt:
+        for txt_path in individual_txt_files:
+            txt_path.unlink(missing_ok=True)
+        print(f"  {len(individual_txt_files)} einzelne _ids_ Dateien geloescht.")
+
 
 if __name__ == "__main__":
     main()