diff --git a/python/lsst/analysis/tools/atools/calexpMetrics.py b/python/lsst/analysis/tools/atools/calexpMetrics.py
index 4ab00cb0f..b14197b04 100644
--- a/python/lsst/analysis/tools/atools/calexpMetrics.py
+++ b/python/lsst/analysis/tools/atools/calexpMetrics.py
@@ -77,6 +77,7 @@ class CalexpSummaryMetrics(AnalysisTool):
         "effTimePsfSigmaScale": "",
         "effTimeSkyBgScale": "",
         "effTimeZeroPointScale": "",
+        "magLim": "mag",
     }
 
     def setDefaults(self):