diff --git a/app.py b/app.py
index 39564a8..30de69b 100644
--- a/app.py
+++ b/app.py
@@ -2560,6 +2560,7 @@ def fetch_customer_dashboard(organization_id: str):
             "hostname_konvention_aktiv": bool(hostname_praefix),
         },
         "flotten_gesundheit": _dashboard_flotten_gesundheit(geraete_rows),
+        "aktivitaeten": fetch_aktivitaeten(organization_id, DASHBOARD_LETZTE_AKTIONEN_LIMIT),
         "letzte_aktionen": [
             {
                 "occurred_at": occurred_at.isoformat(),
@@ -2572,6 +2573,88 @@ def fetch_customer_dashboard(organization_id: str):
     }
 
 
+AKTIVITAETEN_LIMIT = 50
+
+INSTALLATIONSEREIGNIS_TEXTE = {
+    "activation_confirmed": "Aktivierung bestätigt",
+    "installation_started": "Installation gestartet",
+    "installation_completed": "Installation abgeschlossen",
+    "installation_failed": "Installation fehlgeschlagen",
+}
+
+
+def fetch_aktivitaeten(organization_id: str | None = None, limit: int = AKTIVITAETEN_LIMIT):
+    """
+    Aktivitätenliste (GUI-Runde 09.10.2026, Punkt 4): Installationsereignisse
+    einzeln, Agent-Läufe zusammengefasst. Ein Lauf meldet je Merkmal ein
+    Ereignis (rund 56) mit demselben Zeitstempel - die Liste bliebe sonst
+    unlesbar. Ohne organization_id über alle Organisationen (Admin-Dashboard).
+    """
+
+    with get_database_connection() as conn:
+        with conn.cursor() as cur:
+            cur.execute(
+                """
+                WITH laeufe AS (
+                    SELECT e.device_id, e.occurred_at, count(*) AS anzahl,
+                           array_remove(array_agg(m.name ORDER BY m.name)
+                               FILTER (WHERE e.event_type LIKE '%%failed'), NULL) AS fehler
+                    FROM device_merkmal_events e
+                    JOIN merkmale m ON m.id = e.merkmal_id
+                    JOIN devices d ON d.id = e.device_id
+                    WHERE (%(org)s::uuid IS NULL OR d.organization_id = %(org)s::uuid)
+                    GROUP BY e.device_id, e.occurred_at
+                    ORDER BY e.occurred_at DESC
+                    LIMIT %(limit)s
+                ),
+                installationen AS (
+                    SELECT ie.device_id, ie.occurred_at, ie.event_type
+                    FROM device_installation_events ie
+                    JOIN devices d ON d.id = ie.device_id
+                    WHERE (%(org)s::uuid IS NULL OR d.organization_id = %(org)s::uuid)
+                    ORDER BY ie.occurred_at DESC
+                    LIMIT %(limit)s
+                )
+                SELECT x.occurred_at, x.art, x.event_type, x.anzahl, x.fehler,
+                       d.id, d.hostname, o.name
+                FROM (
+                    SELECT occurred_at, device_id, 'agent' AS art, NULL AS event_type, anzahl, fehler FROM laeufe
+                    UNION ALL
+                    SELECT occurred_at, device_id, 'installation', event_type, NULL, NULL FROM installationen
+                ) x
+                JOIN devices d ON d.id = x.device_id
+                JOIN organizations o ON o.id = d.organization_id
+                ORDER BY x.occurred_at DESC
+                LIMIT %(limit)s
+                """,
+                {"org": organization_id, "limit": limit},
+            )
+            rows = cur.fetchall()
+
+    ergebnis = []
+    for occurred_at, art, event_type, anzahl, fehler, device_id, hostname, org_name in rows:
+        fehler = fehler or []
+        if art == "agent":
+            text = f"Agent-Lauf: {anzahl} Merkmale geprüft" + (
+                f", {len(fehler)} fehlgeschlagen ({', '.join(fehler[:5])}{' …' if len(fehler) > 5 else ''})"
+                if fehler else ", ohne Fehler"
+            )
+            problem = bool(fehler)
+        else:
+            text = INSTALLATIONSEREIGNIS_TEXTE.get(event_type, event_type)
+            problem = event_type == "installation_failed"
+        ergebnis.append({
+            "zeit": occurred_at.isoformat(),
+            "art": art,
+            "text": text,
+            "problem": problem,
+            "device_id": str(device_id),
+            "hostname": hostname or "unbenannt",
+            "organization_name": org_name,
+        })
+    return ergebnis
+
+
 def fetch_admin_dashboard():
     with get_database_connection() as conn:
         with conn.cursor() as cur:
@@ -2625,6 +2708,7 @@ def fetch_admin_dashboard():
             }
             for org_id, name, geraete_anzahl, letzte_aktivitaet in organisationen
         ],
+        "aktivitaeten": fetch_aktivitaeten(None, DASHBOARD_LETZTE_AKTIONEN_LIMIT),
         "letzte_aktionen": [
             {
                 "occurred_at": occurred_at.isoformat(),
@@ -5689,6 +5773,14 @@ def set_hostname_konvention_endpoint(
     return {"success": True}
 
 
+@app.get("/api/v1/organizations/{organization_id}/aktivitaeten")
+def list_aktivitaeten(organization_id: str, limit: int = AKTIVITAETEN_LIMIT, authorization: str | None = Header(default=None)):
+    if not require_service_token(authorization):
+        return {"success": False, "error": "unauthorized", "message": "Fehlendes oder ungültiges Service-Token."}
+
+    return {"success": True, "aktivitaeten": fetch_aktivitaeten(organization_id, max(1, min(limit, 500)))}
+
+
 @app.get("/api/v1/organizations/{organization_id}/activation-codes")
 def list_activation_codes(
     organization_id: str,