diff --git a/cardano-cli/src/Cardano/CLI/EraBased/Options/Governance/Actions.hs b/cardano-cli/src/Cardano/CLI/EraBased/Options/Governance/Actions.hs
index 11b4fc71e6..46501e1aea 100644
--- a/cardano-cli/src/Cardano/CLI/EraBased/Options/Governance/Actions.hs
+++ b/cardano-cli/src/Cardano/CLI/EraBased/Options/Governance/Actions.hs
@@ -210,10 +210,10 @@ pUpdateProtocolParametersCmd =
 -- | Cost models only makes sense in eras from Alonzo onwards. For earlier
 -- eras, this parser doesn't show up in the command line and returns 'Nothing'.
 pCostModelsFile :: ShelleyBasedEra era -> Parser (Maybe (Cmd.CostModelsFile era))
-pCostModelsFile =
-  caseShelleyToMaryOrAlonzoEraOnwards
-    (const $ pure Nothing)
-    (\alonzoOnwards -> fmap (fmap $ Cmd.CostModelsFile alonzoOnwards . File) . optional $ pCostModels (Just "new"))
+pCostModelsFile sbe =
+  forEraInEon sbe (pure Nothing) $ \alonzoOnwards -> do
+    file <- optional $ pCostModels (Just "new")
+    pure $ Cmd.CostModelsFile alonzoOnwards . File <$> file
 
 pGovernanceActionProtocolParametersUpdateCmd :: ()
   => CardanoEra era