diff --git a/app/external_reconciliation_sync.py b/app/external_reconciliation_sync.py
index ac03331..7b57ed6 100644
--- a/app/external_reconciliation_sync.py
+++ b/app/external_reconciliation_sync.py
@@ -221,7 +221,21 @@ def _looks_like_company_name(value: Any) -> bool:
 
 def _external_customer_key(record: Dict[str, Any], *, source_system: str) -> str:
     if source_system == "jasmin":
-        return _clean(_first(record, "partyKey", "customerPartyKey", "naturalKey", "key", "id"))
+        # A document naturalKey identifies the commercial document
+        # (for example ORC.ORC2026.136), not the customer. Prefer the
+        # customer party code exposed by Jasmin and never fall back to the
+        # document naturalKey when seeding/updating a fiscal customer.
+        return _clean(
+            _first(
+                record,
+                "partyKey",
+                "customerPartyKey",
+                "buyerCustomerParty",
+                "accountingParty",
+                "buyerCustomerPartyKey",
+                "accountingPartyKey",
+            )
+        )
     if source_system == "odoo":
         return _clean(_first(record, "partner_external_id", "id"))
     return _clean(_first(record, "id", "key", "externalId"))
@@ -355,7 +369,36 @@ def _jasmin_external_type(record: Dict[str, Any], default_type: str) -> str:
 
 
 def _jasmin_amount(record: Dict[str, Any]) -> Optional[str]:
-    return _decimal_or_none(_first(record, "payableAmount", "totalAmount", "total", "grossAmount", "amount"))
+    # Recent Jasmin payloads expose both flattened numeric fields and nested
+    # money objects. Prefer the payable total including tax.
+    direct = _first(
+        record,
+        "payableAmountAmount",
+        "totalAmount",
+        "grossValueAmount",
+        "taxExclusiveAmountAmount",
+        "total",
+        "grossAmount",
+        "amount",
+    )
+    if direct not in (None, ""):
+        parsed = _decimal_or_none(direct)
+        if parsed is not None:
+            return parsed
+
+    for key in ("payableAmount", "grossValue", "taxExclusiveAmount"):
+        money = record.get(key)
+        if isinstance(money, dict):
+            parsed = _decimal_or_none(
+                _first(money, "amount", "baseAmount", "reportingAmount")
+            )
+            if parsed is not None:
+                return parsed
+        elif money not in (None, ""):
+            parsed = _decimal_or_none(money)
+            if parsed is not None:
+                return parsed
+    return None
 
 
 def _jasmin_candidate_from_record(record: Dict[str, Any], *, default_type: str) -> Optional[Dict[str, Any]]:
diff --git a/scripts/repair_jasmin_reconciliation_item.py b/scripts/repair_jasmin_reconciliation_item.py
new file mode 100644
index 0000000..c553e68
--- /dev/null
+++ b/scripts/repair_jasmin_reconciliation_item.py
@@ -0,0 +1,157 @@
+#!/usr/bin/env python3
+"""Repair a Jasmin reconciliation item affected by incorrect customer mapping.
+
+Dry-run is the default. Use --apply only after reviewing the printed plan.
+This script does not create/link opportunities and does not resolve the item.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+from decimal import Decimal, InvalidOperation
+from pathlib import Path
+
+from sqlalchemy import text
+
+ROOT = Path(__file__).resolve().parents[1]
+if str(ROOT) not in sys.path:
+    sys.path.insert(0, str(ROOT))
+
+from app.db import engine
+
+
+def _clean(value: object) -> str:
+    return str(value or "").strip()
+
+
+def _money(record: dict) -> Decimal | None:
+    values = [
+        record.get("payableAmountAmount"),
+        (record.get("payableAmount") or {}).get("amount")
+        if isinstance(record.get("payableAmount"), dict)
+        else record.get("payableAmount"),
+        record.get("grossValueAmount"),
+    ]
+    for value in values:
+        if value in (None, ""):
+            continue
+        try:
+            return Decimal(str(value)).quantize(Decimal("0.01"))
+        except (InvalidOperation, ValueError):
+            continue
+    return None
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("document_number", help="Ex.: ORC.ORC2026.136")
+    parser.add_argument("--apply", action="store_true", help="Aplicar a reparação; sem esta flag faz dry-run")
+    args = parser.parse_args()
+
+    with engine.begin() as conn:
+        item = conn.execute(
+            text("""
+                SELECT ri.id::text, ri.status, ri.opportunity_id::text,
+                       ri.customer_id::text, ri.customer_tax_id,
+                       ri.document_number, ri.amount, ri.payload,
+                       c.name AS customer_name, c.tax_id,
+                       c.jasmin_customer_party_key
+                FROM reconciliation_items ri
+                LEFT JOIN customers c ON c.id = ri.customer_id
+                WHERE ri.document_number = :document_number
+                FOR UPDATE OF ri
+            """),
+            {"document_number": args.document_number},
+        ).mappings().first()
+
+        if not item:
+            raise SystemExit(f"Documento não encontrado: {args.document_number}")
+        if not item["customer_id"]:
+            raise SystemExit("O item não tem customer_id; reparação automática recusada")
+
+        payload = item["payload"] or {}
+        record = payload.get("record") if isinstance(payload, dict) else None
+        if not isinstance(record, dict):
+            raise SystemExit("payload.record não existe ou não é um objeto")
+
+        party_key = _clean(record.get("buyerCustomerParty") or record.get("accountingParty"))
+        payload_tax_id = _clean(record.get("buyerCustomerPartyTaxId") or record.get("accountingPartyTaxId"))
+        amount = _money(record)
+
+        if not party_key:
+            raise SystemExit("Não foi possível obter buyerCustomerParty/accountingParty")
+        if payload_tax_id and _clean(item["tax_id"]) and payload_tax_id != _clean(item["tax_id"]):
+            raise SystemExit(
+                f"NIF divergente: cliente={item['tax_id']} payload={payload_tax_id}; reparação recusada"
+            )
+
+        conflict = conn.execute(
+            text("""
+                SELECT id::text, name, tax_id
+                FROM customers
+                WHERE jasmin_customer_party_key = :party_key
+                  AND id <> CAST(:customer_id AS UUID)
+                LIMIT 1
+            """),
+            {"party_key": party_key, "customer_id": item["customer_id"]},
+        ).mappings().first()
+        if conflict:
+            raise SystemExit(
+                "Party key já pertence a outro cliente: "
+                + json.dumps(dict(conflict), ensure_ascii=False, default=str)
+            )
+
+        plan = {
+            "mode": "apply" if args.apply else "dry-run",
+            "document_number": item["document_number"],
+            "reconciliation_item_id": item["id"],
+            "customer_id": item["customer_id"],
+            "customer_name": item["customer_name"],
+            "tax_id": item["tax_id"],
+            "party_key_before": item["jasmin_customer_party_key"],
+            "party_key_after": party_key,
+            "amount_before": str(item["amount"]) if item["amount"] is not None else None,
+            "amount_after": str(amount) if amount is not None else None,
+            "status_unchanged": item["status"],
+            "opportunity_id_unchanged": item["opportunity_id"],
+        }
+        print(json.dumps(plan, ensure_ascii=False, indent=2, default=str))
+
+        if not args.apply:
+            conn.rollback()
+            print("DRY-RUN: nenhuma alteração aplicada.")
+            return 0
+
+        conn.execute(
+            text("""
+                UPDATE customers
+                SET jasmin_customer_party_key = :party_key,
+                    metadata = jsonb_set(
+                        COALESCE(metadata, '{}'::jsonb),
+                        '{external_customer_key}',
+                        to_jsonb(CAST(:party_key AS text)),
+                        true
+                    ),
+                    updated_at = now()
+                WHERE id = CAST(:customer_id AS UUID)
+            """),
+            {"party_key": party_key, "customer_id": item["customer_id"]},
+        )
+        if amount is not None:
+            conn.execute(
+                text("""
+                    UPDATE reconciliation_items
+                    SET amount = :amount,
+                        updated_at = now()
+                    WHERE id = CAST(:item_id AS UUID)
+                """),
+                {"amount": amount, "item_id": item["id"]},
+            )
+
+    print("Reparação aplicada. O item permanece aberto e sem opportunity_id.")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/tests/test_external_reconciliation_jasmin_mapping.py b/tests/test_external_reconciliation_jasmin_mapping.py
new file mode 100644
index 0000000..4a1eaf9
--- /dev/null
+++ b/tests/test_external_reconciliation_jasmin_mapping.py
@@ -0,0 +1,38 @@
+from app.external_reconciliation_sync import _external_customer_key, _jasmin_amount
+
+
+def test_jasmin_customer_key_prefers_party_code_over_document_natural_key():
+    record = {
+        "naturalKey": "ORC.ORC2026.136",
+        "buyerCustomerParty": "0569",
+        "accountingParty": "0569",
+    }
+
+    assert _external_customer_key(record, source_system="jasmin") == "0569"
+
+
+def test_jasmin_customer_key_does_not_use_document_natural_key():
+    record = {"naturalKey": "ORC.ORC2026.136", "id": "document-uuid"}
+
+    assert _external_customer_key(record, source_system="jasmin") == ""
+
+
+def test_jasmin_amount_reads_flattened_payable_total():
+    record = {
+        "payableAmountAmount": 441.57,
+        "grossValueAmount": 359.00,
+    }
+
+    assert _jasmin_amount(record) == "441.57"
+
+
+def test_jasmin_amount_reads_nested_money_object():
+    record = {
+        "payableAmount": {
+            "amount": 441.57,
+            "baseAmount": 441.57,
+            "reportingAmount": 441.57,
+        }
+    }
+
+    assert _jasmin_amount(record) == "441.57"