diff --git a/retry_tail_analysis/src/retry_tail_analysis/cli.py b/retry_tail_analysis/src/retry_tail_analysis/cli.py
new file mode 100644
index 0000000..5bd18e8
--- /dev/null
+++ b/retry_tail_analysis/src/retry_tail_analysis/cli.py
@@ -0,0 +1,60 @@
+import argparse
+import json
+import sys
+from pathlib import Path
+from typing import List
+
+from retry_tail_analysis.core import analyze_retry_tail, ExperimentData
+
+
+def _load_experiment_data(file_path: Path) -> List[ExperimentData]:
+    """Lädt und validiert Experimentdaten aus einer JSON-Datei."""
+    if not file_path.exists() or not file_path.is_file():
+        raise FileNotFoundError(f"Eingabedatei nicht gefunden: {file_path}")
+
+    with file_path.open(encoding="utf-8") as f:
+        try:
+            raw_data = json.load(f)
+        except json.JSONDecodeError as e:
+            raise ValueError(f"Fehler beim Lesen der JSON-Datei: {e}") from e
+
+    if not isinstance(raw_data, list):
+        raise ValueError("Erwartet eine Liste von Experimentobjekten im JSON.")
+
+    data_objects = []
+    for idx, entry in enumerate(raw_data, start=1):
+        if not isinstance(entry, dict):
+            raise TypeError(f"Eintrag {idx} ist kein Objekt: {entry}")
+        required_fields = {"run_id", "retry_tailp99", "threshold"}
+        if not required_fields.issubset(entry.keys()):
+            missing = required_fields - set(entry.keys())
+            raise ValueError(f"Fehlende Felder in Eintrag {idx}: {missing}")
+        try:
+            run_id = str(entry["run_id"])
+            retry_tailp99 = float(entry["retry_tailp99"])
+            threshold = float(entry["threshold"])
+        except (ValueError, TypeError) as e:
+            raise ValueError(f"Ungültige Typen in Eintrag {idx}: {e}") from e
+        data_objects.append(ExperimentData(run_id, retry_tailp99, threshold))
+    assert data_objects, "Keine gültigen Experimentdaten gefunden."
+    return data_objects
+
+
+def main() -> None:
+    """CLI-Einstiegspunkt: führt die Analyse basierend auf JSON-Input aus."""
+    parser = argparse.ArgumentParser(description="Analyse der retry_tailp99-Werte aus JSON-Experimentdaten.")
+    parser.add_argument("--input", required=True, help="Pfad zur JSON-Datei mit Experimentdaten.")
+    args = parser.parse_args()
+
+    input_path = Path(args.input)
+    try:
+        data = _load_experiment_data(input_path)
+        result = analyze_retry_tail(data)
+        print(f"Aggregierter retry_tailp99-Wert: {result:.4f}")
+    except Exception as exc:  # noqa: BLE001
+        print(f"Fehler: {exc}", file=sys.stderr)
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()