diff --git a/hermes_cli/moa_config.py b/hermes_cli/moa_config.py
index 389765a2d2..17ed12c6a4 100644
--- a/hermes_cli/moa_config.py
+++ b/hermes_cli/moa_config.py
@@ -29,7 +29,7 @@ def _coerce_number(value: Any, cast, default=None, *, positive: bool = False):
     """Coerce ``value`` with ``cast`` (float/int); ``default`` when unset/blank/invalid.
 
     ``int`` also accepts float-looking strings ("3.0"). With ``positive`` the result must be > 0
-    (and finite for floats) or ``default`` is returned."""
+    or ``default`` is returned. Non-finite floats always fall back to ``default``."""
     if value is None or value == "":
         return default
     try:
@@ -41,7 +41,7 @@ def _coerce_number(value: Any, cast, default=None, *, positive: bool = False):
             number = int(float(value))
         except (TypeError, ValueError, OverflowError):
             return default
-    if positive and (number <= 0 or (cast is float and not math.isfinite(number))):
+    if (cast is float and not math.isfinite(number)) or (positive and number <= 0):
         return default
     return number
 
diff --git a/tests/hermes_cli/test_moa_numeric_config.py b/tests/hermes_cli/test_moa_numeric_config.py
index a32d227307..3a71bf8a93 100644
--- a/tests/hermes_cli/test_moa_numeric_config.py
+++ b/tests/hermes_cli/test_moa_numeric_config.py
@@ -1,5 +1,6 @@
 """Malformed numeric MoA settings must degrade to defaults, not break the CLI or JSON."""
 
+import json
 import os
 from pathlib import Path
 import subprocess
@@ -33,3 +34,23 @@ def test_moa_list_tolerates_nonfinite_fanout(tmp_path, fanout):
     normalized = normalize_moa_config({"fanout": fanout})
     assert normalized["fanout"] == normalize_moa_config({})["fanout"]
 
+
+@pytest.mark.parametrize("temperature", [float("nan"), float("inf"), float("-inf"), "NaN", "inf", "-inf"])
+def test_nonfinite_temperatures_do_not_escape_into_json(temperature):
+    raw = {
+        "reference_temperature": temperature,
+        "aggregator_temperature": temperature,
+    }
+    normalized = normalize_moa_config(raw)
+    assert normalized["reference_temperature"] is None
+    assert normalized["aggregator_temperature"] is None
+    json.dumps(normalized, allow_nan=False)
+
+    finite = normalize_moa_config({
+        "reference_temperature": 0,
+        "aggregator_temperature": "0.75",
+        "fanout": {"mode": "every_n", "n": "3.0"},
+    })
+    assert finite["reference_temperature"] == 0
+    assert finite["aggregator_temperature"] == 0.75
+    assert finite["fanout"] == "every_n:3"