diff --git a/backend/csv_parser/executor.py b/backend/csv_parser/executor.py
index b80d01c..b018526 100644
--- a/backend/csv_parser/executor.py
+++ b/backend/csv_parser/executor.py
@@ -221,9 +221,13 @@ def _import_nutrition(
             validate_import_row_processing("nutrition", spec, fm)
         except ValueError as e:
             raise ValueError(str(e)) from e
-        merged_rows = aggregate_mapped_rows(mapped_rows, spec)
+        merged_rows, agg_notes = aggregate_mapped_rows(mapped_rows, spec)
+        error_details.extend(agg_notes)
     else:
         merged_rows = list(mapped_rows)
+        agg_notes = []
+
+    skipped_groups = sum(n.get("rows_in_group", 0) for n in (agg_notes or []) if n.get("error") == "mehrere_zeilen_pro_schluessel")
 
     inserted = 0
     updated = 0
@@ -285,7 +289,7 @@ def _import_nutrition(
         "rows_total": rows_total,
         "inserted": inserted,
         "updated": updated,
-        "skipped": 0,
+        "skipped": skipped_groups,
         "new_entries": new_entries,
     }
 
@@ -329,9 +333,13 @@ def _import_weight(
             validate_import_row_processing("weight", spec, fm)
         except ValueError as e:
             raise ValueError(str(e)) from e
-        merged_rows = aggregate_mapped_rows(mapped_rows, spec)
+        merged_rows, agg_notes = aggregate_mapped_rows(mapped_rows, spec)
+        error_details.extend(agg_notes)
     else:
         merged_rows = list(mapped_rows)
+        agg_notes = []
+
+    skipped_groups = sum(n.get("rows_in_group", 0) for n in (agg_notes or []) if n.get("error") == "mehrere_zeilen_pro_schluessel")
 
     inserted = 0
     updated = 0
@@ -384,7 +392,7 @@ def _import_weight(
         "rows_total": rows_total,
         "inserted": inserted,
         "updated": updated,
-        "skipped": 0,
+        "skipped": skipped_groups,
         "new_entries": new_entries,
     }
 
@@ -555,13 +563,17 @@ def _import_vitals_baseline(
             validate_import_row_processing("vitals_baseline", spec, fm)
         except ValueError as e:
             raise ValueError(str(e)) from e
-        merged_rows = aggregate_mapped_rows(mapped_rows, spec)
+        merged_rows, agg_notes = aggregate_mapped_rows(mapped_rows, spec)
+        error_details.extend(agg_notes)
     else:
         merged_rows = list(mapped_rows)
+        agg_notes = []
+
+    skipped_merge = sum(n.get("rows_in_group", 0) for n in (agg_notes or []) if n.get("error") == "mehrere_zeilen_pro_schluessel")
 
     inserted = 0
     updated = 0
-    skipped = skipped_prefilter
+    skipped = skipped_prefilter + skipped_merge
     for merged in merged_rows:
         d = coerce_date(merged.get("date"))
         if d is None:
diff --git a/backend/csv_parser/import_row_processing.py b/backend/csv_parser/import_row_processing.py
index f2bc19f..b33dbad 100644
--- a/backend/csv_parser/import_row_processing.py
+++ b/backend/csv_parser/import_row_processing.py
@@ -1,8 +1,9 @@
 """
 Zeilenaggregation nach CSV-Mapping (group_by + aggregates), vor dem DB-Upsert.
 
-Spezifikation in der Vorlage (import_row_processing JSONB) oder Modul-Default
-(import_row_processing_default in module_registry).
+Spezifikation in der Vorlage (import_row_processing JSONB). Optional: Modul-Default
+(import_row_processing_default in module_registry) nur als **Legacy-Fallback**, wenn
+die Vorlage nichts speichert — mittelfristig sollen Vorlagen explizit sein.
 """
 
 from __future__ import annotations
@@ -14,6 +15,8 @@ from typing import Any, Mapping
 from csv_parser.module_registry import get_module_definition
 
 ALLOWED_AGGREGATES = frozenset({"sum", "mean", "min", "max", "median", "first", "last"})
+# Mehr als eine CSV-Zeile pro group_by-Schlüssel
+ALLOWED_MULTI_ROW_POLICIES = frozenset({"aggregate", "reject", "first_row", "last_row"})
 
 
 def resolve_import_row_processing(module: str, mapping_row: Mapping[str, Any]) -> dict[str, Any] | None:
@@ -66,6 +69,17 @@ def validate_import_row_processing(
                 f"Erlaubt: {', '.join(sorted(ALLOWED_AGGREGATES))}"
             )
 
+    mrp = spec.get("multi_row_policy")
+    if mrp is not None and str(mrp) not in ALLOWED_MULTI_ROW_POLICIES:
+        raise ValueError(
+            f"multi_row_policy: ungültiger Wert '{mrp}'. "
+            f"Erlaubt: {', '.join(sorted(ALLOWED_MULTI_ROW_POLICIES))}"
+        )
+
+    dedupe = spec.get("dedupe_identical_rows")
+    if dedupe is not None and not isinstance(dedupe, bool):
+        raise ValueError("dedupe_identical_rows muss ein Boolean sein")
+
 
 def _sort_key_for_group(v: Any) -> Any:
     if isinstance(v, dt.datetime):
@@ -110,18 +124,46 @@ def _apply_aggregate(op: str, values: list[Any]) -> Any:
     raise ValueError(f"Unbekannte Aggregations-Operation: {op}")
 
 
+def _row_identity_signature(r: dict[str, Any]) -> tuple[Any, ...]:
+    return tuple(sorted((k, _sort_key_for_group(r.get(k))) for k in sorted(r.keys())))
+
+
+def _dedupe_identical_mapped_rows(rows: list[dict[str, Any]]) -> list[dict[str, Any]]:
+    """Exakt gleiche gemappte Zeilen (alle Keys/Werte) — erste behalten."""
+    seen: set[tuple[Any, ...]] = set()
+    out: list[dict[str, Any]] = []
+    for r in rows:
+        sig = _row_identity_signature(r)
+        if sig in seen:
+            continue
+        seen.add(sig)
+        out.append(r)
+    return out
+
+
 def aggregate_mapped_rows(
     rows: list[dict[str, Any]],
     spec: Mapping[str, Any],
-) -> list[dict[str, Any]]:
+) -> tuple[list[dict[str, Any]], list[dict[str, Any]]]:
     """
     Gruppiert gemappte Zeilen-Dicts nach group_by und wendet aggregates an.
     Felder, die weder in group_by noch in aggregates vorkommen: Wert aus der ersten Zeile der Gruppe.
+
+    Rückgabe: (merged_rows, strukturelle Fehler / Hinweise, z. B. abgelehnte Schlüsselgruppen).
     """
+    errors: list[dict[str, Any]] = []
+    rows = list(rows)
+    if spec.get("dedupe_identical_rows"):
+        rows = _dedupe_identical_mapped_rows(rows)
+
     group_by = spec.get("group_by") or []
     aggregates = spec.get("aggregates") or {}
+    policy = str(spec.get("multi_row_policy") or "aggregate")
+    if policy not in ALLOWED_MULTI_ROW_POLICIES:
+        policy = "aggregate"
+
     if not group_by:
-        return rows
+        return rows, errors
 
     buckets: dict[tuple[Any, ...], list[dict[str, Any]]] = {}
     order: list[tuple[Any, ...]] = []
@@ -132,9 +174,28 @@ def aggregate_mapped_rows(
             order.append(key)
         buckets[key].append(r)
 
+    gb_label = ", ".join(group_by)
     out: list[dict[str, Any]] = []
     for key in order:
         group_rows = buckets[key]
+        if len(group_rows) > 1:
+            if policy == "reject":
+                errors.append(
+                    {
+                        "error": "mehrere_zeilen_pro_schluessel",
+                        "message": (
+                            f"{len(group_rows)} CSV-Zeilen mit gleichem Schlüssel ({gb_label}); "
+                            "laut Vorlage abgelehnt (multi_row_policy=reject)."
+                        ),
+                        "rows_in_group": len(group_rows),
+                    }
+                )
+                continue
+            if policy == "first_row":
+                group_rows = [group_rows[0]]
+            elif policy == "last_row":
+                group_rows = [group_rows[-1]]
+
         first = group_rows[0]
         merged: dict[str, Any] = {}
         for g in group_by:
@@ -149,4 +210,4 @@ def aggregate_mapped_rows(
                     continue
                 merged[k] = v
         out.append(merged)
-    return out
+    return out, errors
diff --git a/backend/csv_parser/module_registry.py b/backend/csv_parser/module_registry.py
index 4ac8ec9..20a20e7 100644
--- a/backend/csv_parser/module_registry.py
+++ b/backend/csv_parser/module_registry.py
@@ -23,7 +23,7 @@ MODULE_DEFINITIONS: Dict[str, Dict[str, Any]] = {
         },
         "duplicate_key": ["profile_id", "date"],
         "duplicate_strategy": "update",
-        # Mehrere CSV-Zeilen pro Tag (z. B. pro Lebensmittel) → ein nutrition_log-Eintrag
+        # Legacy-Fallback wenn die Vorlage kein import_row_processing speichert — Vorlagen mittelfristig explizit.
         "import_row_processing_default": {
             "group_by": ["date"],
             "aggregates": {
@@ -69,6 +69,7 @@ MODULE_DEFINITIONS: Dict[str, Dict[str, Any]] = {
         },
         "duplicate_key": ["profile_id", "date"],
         "duplicate_strategy": "update",
+        # Legacy-Fallback — Vorlagen mittelfristig explizit setzen.
         "import_row_processing_default": {
             "group_by": ["date"],
             "aggregates": {
@@ -102,7 +103,7 @@ MODULE_DEFINITIONS: Dict[str, Dict[str, Any]] = {
         },
         "duplicate_key": ["profile_id", "date"],
         "duplicate_strategy": "update",
-        # Mehrere CSV-Zeilen pro Tag → ein Eintrag (letzte Zeile im Export zählt)
+        # Legacy-Fallback — Vorlagen mittelfristig explizit setzen.
         "import_row_processing_default": {
             "group_by": ["date"],
             "aggregates": {
diff --git a/backend/tests/test_import_row_processing.py b/backend/tests/test_import_row_processing.py
index 92684ad..54f3673 100644
--- a/backend/tests/test_import_row_processing.py
+++ b/backend/tests/test_import_row_processing.py
@@ -38,12 +38,79 @@ def test_aggregate_mapped_rows_sums_same_group():
         {"date": d, "kcal": 300.0, "protein_g": 15},
     ]
     spec = {"group_by": ["date"], "aggregates": {"kcal": "sum", "protein_g": "sum"}}
-    out = aggregate_mapped_rows(rows, spec)
+    out, err = aggregate_mapped_rows(rows, spec)
+    assert err == []
     assert len(out) == 1
     assert out[0]["kcal"] == 800.0
     assert out[0]["protein_g"] == 35
 
 
+def test_aggregate_mapped_rows_reject_second_group():
+    d = dt.date(2024, 1, 15)
+    rows = [
+        {"date": d, "kcal": 100.0},
+        {"date": d, "kcal": 200.0},
+    ]
+    spec = {
+        "group_by": ["date"],
+        "aggregates": {"kcal": "sum"},
+        "multi_row_policy": "reject",
+    }
+    out, err = aggregate_mapped_rows(rows, spec)
+    assert out == []
+    assert len(err) == 1
+    assert err[0].get("error") == "mehrere_zeilen_pro_schluessel"
+    assert err[0].get("rows_in_group") == 2
+
+
+def test_aggregate_mapped_rows_first_row_no_merge():
+    d = dt.date(2024, 1, 15)
+    rows = [
+        {"date": d, "kcal": 100.0},
+        {"date": d, "kcal": 999.0},
+    ]
+    spec = {
+        "group_by": ["date"],
+        "aggregates": {"kcal": "sum"},
+        "multi_row_policy": "first_row",
+    }
+    out, err = aggregate_mapped_rows(rows, spec)
+    assert err == []
+    assert len(out) == 1
+    assert out[0]["kcal"] == 100.0
+
+
+def test_dedupe_identical_rows_before_group():
+    d = dt.date(2024, 1, 15)
+    rows = [
+        {"date": d, "kcal": 50.0},
+        {"date": d, "kcal": 50.0},
+        {"date": d, "kcal": 50.0},
+    ]
+    spec = {
+        "group_by": ["date"],
+        "aggregates": {"kcal": "sum"},
+        "dedupe_identical_rows": True,
+    }
+    out, err = aggregate_mapped_rows(rows, spec)
+    assert err == []
+    assert len(out) == 1
+    assert out[0]["kcal"] == 50.0
+
+
+def test_validate_multi_row_policy():
+    with pytest.raises(ValueError, match="multi_row_policy"):
+        validate_import_row_processing(
+            "nutrition",
+            {
+                "group_by": ["date"],
+                "aggregates": {"kcal": "sum"},
+                "multi_row_policy": "nope",
+            },
+            {"D": "date", "K": "kcal"},
+        )
+
+
 def test_resolve_explicit_overrides_default():
     m = {
         "import_row_processing": {"group_by": ["date"], "aggregates": {"kcal": "mean"}},
diff --git a/frontend/src/pages/AdminCsvTemplateEditorPage.jsx b/frontend/src/pages/AdminCsvTemplateEditorPage.jsx
index 7f4b302..8dfdd17 100644
--- a/frontend/src/pages/AdminCsvTemplateEditorPage.jsx
+++ b/frontend/src/pages/AdminCsvTemplateEditorPage.jsx
@@ -39,38 +39,65 @@ const ROW_AGG_OPS = [
 
 const NUMERIC_ROW_AGG = new Set(['sum', 'mean', 'min', 'max', 'median'])
 
+/** Wenn mehrere CSV-Zeilen denselben group_by-Schlüssel haben */
+const MULTI_ROW_POLICY_OPTIONS = [
+  { value: 'aggregate', label: 'Zusammenführen (Funktion unten auf alle übrigen Felder)' },
+  { value: 'reject', label: 'Abweisen — Gruppe wird nicht importiert (Fehlerhinweis im Import)' },
+  { value: 'first_row', label: 'Nur erste Zeile — keine Berechnung über die Duplikat-Zeilen' },
+  { value: 'last_row', label: 'Nur letzte Zeile — keine Berechnung über die Duplikat-Zeilen' },
+]
+
 function parseStoredImportRowProcessing(irp) {
-  if (!irp || typeof irp !== 'object' || Object.keys(irp).length === 0) {
+  const safe = irp && typeof irp === 'object' ? irp : null
+  const dedupeFromStore = !!(safe && safe.dedupe_identical_rows)
+  const mrpRaw = safe && safe.multi_row_policy != null ? String(safe.multi_row_policy) : null
+  const multiRowPolicy =
+    mrpRaw && MULTI_ROW_POLICY_OPTIONS.some((o) => o.value === mrpRaw) ? mrpRaw : 'aggregate'
+
+  if (!safe || Object.keys(safe).length === 0) {
     return {
       useCustom: false,
       irregular: false,
       groupBy: [],
       mode: '',
+      multiRowPolicy: 'aggregate',
+      dedupeIdentical: false,
     }
   }
-  const gb = irp.group_by
-  const agg = irp.aggregates
+  const gb = safe.group_by
+  const agg = safe.aggregates
   if (!Array.isArray(gb) || gb.length === 0 || agg == null || typeof agg !== 'object') {
     return {
       useCustom: true,
       irregular: true,
       groupBy: Array.isArray(gb) ? [...gb] : [],
       mode: '',
+      multiRowPolicy,
+      dedupeIdentical: dedupeFromStore,
     }
   }
   const ops = [...new Set(Object.values(agg).map((x) => String(x)))]
   if (ops.length !== 1) {
-    return { useCustom: true, irregular: true, groupBy: [...gb], mode: '' }
+    return {
+      useCustom: true,
+      irregular: true,
+      groupBy: [...gb],
+      mode: '',
+      multiRowPolicy,
+      dedupeIdentical: dedupeFromStore,
+    }
   }
   return {
     useCustom: true,
     irregular: false,
     groupBy: [...gb],
     mode: ops[0],
+    multiRowPolicy,
+    dedupeIdentical: dedupeFromStore,
   }
 }
 
-function buildImportRowProcessingSimple(modFields, fm, groupBy, mode) {
+function buildImportRowProcessingSimple(modFields, fm, groupBy, mode, multiRowPolicy, dedupeIdentical) {
   const targets = new Set(
     Object.values(fm).filter((v) => v && v !== '-' && v !== '_skip'),
   )
@@ -86,7 +113,13 @@ function buildImportRowProcessingSimple(modFields, fm, groupBy, mode) {
       aggregates[t] = mode
     }
   }
-  return { group_by: groupBy, aggregates }
+  const out = {
+    group_by: groupBy,
+    aggregates,
+    multi_row_policy: multiRowPolicy || 'aggregate',
+  }
+  if (dedupeIdentical) out.dedupe_identical_rows = true
+  return out
 }
 
 /** Erlaubt Eingaben wie 1,03 oder 1.03 während des Tippens; Finale normalisiert bei Blur/Speichern. */
@@ -255,6 +288,8 @@ export default function AdminCsvTemplateEditorPage() {
   const [rowAggMode, setRowAggMode] = useState('')
   const [rowAggIrregular, setRowAggIrregular] = useState(false)
   const [rowAggJsonText, setRowAggJsonText] = useState('{}')
+  const [rowAggMultiRowPolicy, setRowAggMultiRowPolicy] = useState('aggregate')
+  const [rowAggDedupeIdentical, setRowAggDedupeIdentical] = useState(false)
 
   const modMeta = useMemo(() => modules.find((m) => m.id === module), [modules, module])
   const aggregateSleepImport = modMeta?.import_mode === 'apple_sleep_aggregate'
@@ -295,6 +330,8 @@ export default function AdminCsvTemplateEditorPage() {
     setRowAggGroupBy([])
     setRowAggMode('')
     setRowAggJsonText('{}')
+    setRowAggMultiRowPolicy('aggregate')
+    setRowAggDedupeIdentical(false)
   }, [module, isNew])
 
   useEffect(() => {
@@ -325,6 +362,8 @@ export default function AdminCsvTemplateEditorPage() {
         setRowAggIrregular(rp.irregular)
         setRowAggGroupBy(rp.groupBy)
         setRowAggMode(rp.mode)
+        setRowAggMultiRowPolicy(rp.multiRowPolicy)
+        setRowAggDedupeIdentical(rp.dedupeIdentical)
         setRowAggJsonText(JSON.stringify(t.import_row_processing || {}, null, 2))
       })
       .catch((e) => {
@@ -541,6 +580,8 @@ export default function AdminCsvTemplateEditorPage() {
       setRowAggGroupBy([])
       setRowAggMode('')
       setRowAggJsonText('{}')
+      setRowAggMultiRowPolicy('aggregate')
+      setRowAggDedupeIdentical(false)
     } catch (e) {
       setError(e.message || 'Analyse fehlgeschlagen')
     } finally {
@@ -642,6 +683,8 @@ export default function AdminCsvTemplateEditorPage() {
           fieldMappings,
           rowAggGroupBy,
           rowAggMode,
+          rowAggMultiRowPolicy,
+          rowAggDedupeIdentical,
         )
       }
     }
@@ -975,10 +1018,10 @@ export default function AdminCsvTemplateEditorPage() {
           ) : (
             <>
           <p style={{ fontSize: 13, color: 'var(--text2)', marginTop: 8, lineHeight: 1.55 }}>
-            Mehrere CSV-Zeilen mit denselben Werten in den gewählten <strong>Schlüsselfeldern</strong> werden zu einer
-            importierten Zeile zusammengefasst. Für alle übrigen zugewiesenen Zielfelder gilt{' '}
-            <strong>eine gemeinsame</strong> Funktion. Textfelder werden bei Summe/Mittelwert usw. automatisch
-            ausgelassen; mit „Erster/Letzter Wert“ sind sie enthalten.
+            <strong>Schlüsselfelder</strong> bestimmen, wann CSV-Zeilen dieselbe „Gruppe“ sind. Was bei{' '}
+            <strong>mehr als einer Zeile pro Gruppe</strong> passiert, steuern Sie unten (
+            <em>Zusammenführen / Abweisen / nur erste oder letzte Zeile</em>). Optional können{' '}
+            <strong>völlig identische</strong> gemappte Zeilen vorher entfernt werden.
           </p>
           <label
             style={{
@@ -1002,18 +1045,23 @@ export default function AdminCsvTemplateEditorPage() {
                   setRowAggGroupBy([])
                   setRowAggMode('')
                   setRowAggJsonText('{}')
+                  setRowAggMultiRowPolicy('aggregate')
+                  setRowAggDedupeIdentical(false)
                 }
               }}
               style={{ marginTop: 3 }}
             />
             <span>
-              <strong>Eigene Aggregation in dieser Vorlage speichern.</strong> Wenn deaktiviert, gilt der{' '}
-              <strong>Modul-Standard</strong> (siehe unten) bzw. kein Aggregat, wenn das Modul keinen definiert.
+              <strong>Eigene Zeilenlogik in dieser Vorlage speichern.</strong> Wenn deaktiviert, nutzt der Import den{' '}
+              <strong>Legacy-Fallback im Server-Code</strong> (nur solange die Vorlage kein JSON speichert —
+              mittelfristig sollen alle Vorlagen explizit sein).
             </span>
           </label>
           {modMeta.import_row_processing_default && (
             <details style={{ marginTop: 12, fontSize: 13, color: 'var(--text2)' }}>
-              <summary style={{ cursor: 'pointer' }}>Modul-Standard (Referenz, wenn Haken oben aus ist)</summary>
+              <summary style={{ cursor: 'pointer' }}>
+                Legacy-Fallback im Code (Referenz, wenn der Haken oben aus ist)
+              </summary>
               <pre
                 style={{
                   marginTop: 8,
@@ -1042,6 +1090,8 @@ export default function AdminCsvTemplateEditorPage() {
                     setRowAggIrregular(p.irregular)
                     setRowAggGroupBy(p.groupBy)
                     setRowAggMode(p.mode)
+                    setRowAggMultiRowPolicy(p.multiRowPolicy)
+                    setRowAggDedupeIdentical(p.dedupeIdentical)
                     setRowAggJsonText(JSON.stringify(d, null, 2))
                   }}
                 >
@@ -1052,21 +1102,10 @@ export default function AdminCsvTemplateEditorPage() {
                 <>
                   <p style={{ fontSize: 13, color: 'var(--text2)', marginTop: 14, lineHeight: 1.55 }}>
                     Diese Vorlage nutzt <strong>unterschiedliche</strong> Aggregations-Funktionen pro Feld. JSON
-                    anpassen oder vereinheitlichen (pro-Feld-Auswahl folgt in einer späteren Ausbaustufe).
+                    anpassen oder vereinheitlichen (pro-Feld-Auswahl später). Optional:{' '}
+                    <code>multi_row_policy</code> (<code>aggregate</code> | <code>reject</code> |{' '}
+                    <code>first_row</code> | <code>last_row</code>), <code>dedupe_identical_rows</code>: true.
                   </p>
-                  <textarea
-                    className="form-input"
-                    style={{
-                      width: '100%',
-                      minHeight: 160,
-                      marginTop: 8,
-                      fontFamily: 'monospace',
-                      fontSize: 12,
-                      textAlign: 'left',
-                    }}
-                    value={rowAggJsonText}
-                    onChange={(e) => setRowAggJsonText(e.target.value)}
-                  />
                 </>
               ) : (
                 <>
@@ -1141,8 +1180,114 @@ export default function AdminCsvTemplateEditorPage() {
                       </option>
                     ))}
                   </select>
+                  <label className="form-label" style={{ marginTop: 16, display: 'block' }}>
+                    Mehrere Zeilen pro Schlüssel
+                  </label>
+                  <select
+                    className="form-input"
+                    style={{
+                      width: '100%',
+                      maxWidth: 520,
+                      marginTop: 8,
+                      textAlign: 'left',
+                      minHeight: 46,
+                    }}
+                    value={rowAggMultiRowPolicy}
+                    onChange={(e) => {
+                      setRowAggIrregular(false)
+                      setRowAggMultiRowPolicy(e.target.value)
+                    }}
+                  >
+                    {MULTI_ROW_POLICY_OPTIONS.map((o) => (
+                      <option key={o.value} value={o.value}>
+                        {o.label}
+                      </option>
+                    ))}
+                  </select>
+                  <label
+                    style={{
+                      display: 'flex',
+                      alignItems: 'flex-start',
+                      gap: 10,
+                      marginTop: 14,
+                      cursor: 'pointer',
+                      fontSize: 14,
+                      color: 'var(--text1)',
+                    }}
+                  >
+                    <input
+                      type="checkbox"
+                      checked={rowAggDedupeIdentical}
+                      onChange={(e) => {
+                        setRowAggIrregular(false)
+                        setRowAggDedupeIdentical(e.target.checked)
+                      }}
+                      style={{ marginTop: 3 }}
+                    />
+                    <span>
+                      <strong>Identische Zeilen vorher entfernen</strong> (alle gemappten Felder gleich — nur die erste
+                      Zeile jeder Kopie bleibt).
+                    </span>
+                  </label>
                 </>
               )}
+              <div className="form-label" style={{ marginTop: 18 }}>
+                import_row_processing (JSON)
+              </div>
+              <p style={{ fontSize: 13, color: 'var(--text2)', marginTop: 6, lineHeight: 1.55 }}>
+                {rowAggIrregular ? (
+                  <>
+                    <strong>Bearbeitbar</strong> — wie bei <code>type_conversions</code>; beim Speichern prüft das
+                    Backend die Struktur.
+                  </>
+                ) : (
+                  <>
+                    <strong>Nur Lesen</strong> — Vorschau aus den Feldern oben; dasselbe JSON wird beim Speichern
+                    geschrieben.
+                  </>
+                )}
+              </p>
+              <textarea
+                className="form-input"
+                readOnly={!rowAggIrregular}
+                style={{
+                  width: '100%',
+                  minHeight: rowAggIrregular ? 200 : 160,
+                  marginTop: 8,
+                  fontFamily: 'monospace',
+                  fontSize: 12,
+                  textAlign: 'left',
+                  opacity: rowAggIrregular ? 1 : 0.95,
+                  background: rowAggIrregular ? undefined : 'var(--surface2)',
+                }}
+                value={
+                  rowAggIrregular
+                    ? rowAggJsonText
+                    : rowAggGroupBy.length && rowAggMode
+                      ? JSON.stringify(
+                          buildImportRowProcessingSimple(
+                            modMeta?.fields,
+                            fieldMappings,
+                            rowAggGroupBy,
+                            rowAggMode,
+                            rowAggMultiRowPolicy,
+                            rowAggDedupeIdentical,
+                          ),
+                          null,
+                          2,
+                        )
+                      : JSON.stringify(
+                          {
+                            _hinweis:
+                              'Mindestens ein Schlüsselfeld und eine gemeinsame Funktion wählen — dann erscheint hier das finale JSON.',
+                          },
+                          null,
+                          2,
+                        )
+                }
+                onChange={rowAggIrregular ? (e) => setRowAggJsonText(e.target.value) : undefined}
+                spellCheck={false}
+              />
             </>
           )}
             </>