diff --git a/tests/test_explanation_smoke.py b/tests/test_explanation_smoke.py
new file mode 100644
index 0000000..3c6d629
--- /dev/null
+++ b/tests/test_explanation_smoke.py
@@ -0,0 +1,67 @@
+import argparse
+import requests
+import json
+import sys
+
+def main():
+    parser = argparse.ArgumentParser(description="Testet die Explanation-Funktion des Retrievers.")
+    parser.add_argument("--url", default="http://localhost:8002/query", help="URL zum Query Endpoint")
+    parser.add_argument("--query", default="mindnet", help="Suchbegriff")
+    args = parser.parse_args()
+
+    payload = {
+        "mode": "hybrid",
+        "query": args.query,
+        "top_k": 1,
+        "explain": True,  # Das neue Flag aus WP-04b
+        "expand": {
+            "depth": 1,
+            "edge_types": ["references", "belongs_to", "depends_on", "related_to"]
+        }
+    }
+
+    print(f"--- Sende Request an {args.url} ---")
+    try:
+        r = requests.post(args.url, json=payload)
+        r.raise_for_status()
+        data = r.json()
+    except Exception as e:
+        print(f"FEHLER: {e}")
+        sys.exit(1)
+
+    hits = data.get("results", [])
+    if not hits:
+        print("Keine Treffer gefunden.")
+        return
+
+    top_hit = hits[0]
+    print(f"\nTop Treffer: {top_hit.get('node_id')}")
+    print(f"Total Score: {top_hit.get('total_score'):.4f}")
+
+    # Explanation prüfen
+    expl = top_hit.get("explanation")
+    if not expl:
+        print("\n[FAIL] Keine 'explanation' im Response erhalten!")
+        sys.exit(1)
+
+    print("\n--- EXPLANATION LAYER ---")
+    
+    bd = expl.get("breakdown", {})
+    print(f"Breakdown:")
+    print(f"  Semantic Contribution:   {bd.get('semantic_contribution', 0):.4f}")
+    print(f"  Edge Contribution:       {bd.get('edge_contribution', 0):.4f}")
+    print(f"  Centrality Contribution: {bd.get('centrality_contribution', 0):.4f}")
+    print(f"  Typ-Gewicht:             {bd.get('node_weight', 0):.2f}")
+
+    print("\nReasons:")
+    for reason in expl.get("reasons", []):
+        kind = reason.get("kind", "").upper()
+        msg = reason.get("message", "")
+        impact = reason.get("score_impact")
+        impact_str = f" ({impact:+.4f})" if impact is not None else ""
+        print(f"  [{kind}] {msg}{impact_str}")
+
+    print("\n[SUCCESS] Explanation Layer antwortet korrekt.")
+
+if __name__ == "__main__":
+    main()
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