diff --git a/application/account_facts.py b/application/account_facts.py
index 2b1d3005..4c61b9ff 100644
--- a/application/account_facts.py
+++ b/application/account_facts.py
@@ -167,7 +167,7 @@ def collect_account_facts(
     except Exception:
         raise _fail("spot_read_failed") from None
     if not isinstance(account, Mapping):
-        raise _fail("spot_response_invalid")
+        raise _fail("spot_response_not_object")
     uid = account.get("uid")
     if isinstance(uid, bool) or not isinstance(uid, (str, int)) or not str(uid):
         raise _fail("account_identity_missing")
@@ -178,19 +178,23 @@ def collect_account_facts(
         raise _fail("account_identity_mismatch")
 
     balances = account.get("balances")
-    if not isinstance(balances, list) or len(balances) > 5000:
-        raise _fail("spot_response_invalid")
+    if not isinstance(balances, list):
+        raise _fail("spot_balances_invalid")
+    if len(balances) > 5000:
+        raise _fail("spot_balances_limit_exceeded")
     assets: dict[str, dict[str, Decimal]] = {}
     for row in balances:
         if not isinstance(row, Mapping):
-            raise _fail("spot_response_invalid")
+            raise _fail("spot_balance_row_invalid")
         asset = row.get("asset")
-        if (
-            not isinstance(asset, str)
-            or not _ASSET.fullmatch(asset)
-            or asset in assets
-        ):
-            raise _fail("spot_response_invalid")
+        if not isinstance(asset, str):
+            raise _fail("spot_asset_type_invalid")
+        if not asset.isascii():
+            raise _fail("spot_asset_non_ascii")
+        if not _ASSET.fullmatch(asset):
+            raise _fail("spot_asset_format_invalid")
+        if asset in assets:
+            raise _fail("spot_asset_duplicate")
         assets[asset] = {
             "spot_free": _decimal(row.get("free")),
             "spot_locked": _decimal(row.get("locked")),
diff --git a/tests/test_binance_account_facts.py b/tests/test_binance_account_facts.py
index 1db1f097..4680bdfa 100644
--- a/tests/test_binance_account_facts.py
+++ b/tests/test_binance_account_facts.py
@@ -439,6 +439,32 @@ def get_account(self):
     assert client.calls == [("spot",)]
 
 
+@pytest.mark.parametrize(("account", "reason"), [
+    (None, "spot_response_not_object"),
+    ({"uid": "123456", "balances": None}, "spot_balances_invalid"),
+    ({"uid": "123456", "balances": [{}] * 5001}, "spot_balances_limit_exceeded"),
+    ({"uid": "123456", "balances": ["synthetic-private-row"]}, "spot_balance_row_invalid"),
+    ({"uid": "123456", "balances": [{"asset": 17}]}, "spot_asset_type_invalid"),
+    ({"uid": "123456", "balances": [{"asset": "synthetic-bad-symbol"}]}, "spot_asset_format_invalid"),
+    ({"uid": "123456", "balances": [{"asset": "币"}]}, "spot_asset_non_ascii"),
+    ({"uid": "123456", "balances": [
+        {"asset": "SYNTHETIC", "free": "0", "locked": "0"},
+        {"asset": "SYNTHETIC", "free": "0", "locked": "0"},
+    ]}, "spot_asset_duplicate"),
+])
+def test_spot_validation_uses_fixed_reason_without_echoing_response_values(account, reason):
+    class InvalidSpot(FakeBinance):
+        def get_account(self):
+            self.calls.append(("spot",))
+            return account
+
+    client = InvalidSpot()
+    with pytest.raises(AccountFactsUnavailable) as raised:
+        _collect(client)
+    assert str(raised.value) == f"binance_account_facts_{reason}"
+    assert client.calls == [("spot",)]
+
+
 def test_rejects_earn_asset_without_an_explicit_spot_balance_row():
     class SpotWithoutEarnAsset(FakeBinance):
         def get_account(self):