diff --git a/bench/tx-generator/src/Cardano/Benchmarking/GeneratorTx/SizedMetadata.hs b/bench/tx-generator/src/Cardano/Benchmarking/GeneratorTx/SizedMetadata.hs
index c9ec3d73f57..3d5dfada91e 100644
--- a/bench/tx-generator/src/Cardano/Benchmarking/GeneratorTx/SizedMetadata.hs
+++ b/bench/tx-generator/src/Cardano/Benchmarking/GeneratorTx/SizedMetadata.hs
@@ -114,7 +114,7 @@ dummyTxSizeInEra metadata = case createAndValidateTransactionBody dummyTx of
   Left err -> error $ "metaDataSize " ++ show err
  where
   dummyTx :: TxBodyContent BuildTx era
-  dummyTx = defaultTxBodyContent
+  dummyTx = defaultTxBodyContent InBuildTx
     & setTxIns
       [ ( TxIn "dbaff4e270cfb55612d9e2ac4658a27c79da4a5271c6f90853042d1403733810" (TxIx 0)
         , BuildTxWith $ KeyWitness KeyWitnessForSpending
diff --git a/bench/tx-generator/src/Cardano/TxGenerator/Genesis.hs b/bench/tx-generator/src/Cardano/TxGenerator/Genesis.hs
index a07b0ca793a..0f34b5077f5 100644
--- a/bench/tx-generator/src/Cardano/TxGenerator/Genesis.hs
+++ b/bench/tx-generator/src/Cardano/TxGenerator/Genesis.hs
@@ -125,7 +125,7 @@ mkGenesisTransaction key ttl fee txins txouts
       (`signShelleyTransaction` [WitnessGenesisUTxOKey key])
       (createAndValidateTransactionBody txBodyContent)
  where
-  txBodyContent = defaultTxBodyContent
+  txBodyContent = defaultTxBodyContent InBuildTx
     & setTxIns (zip txins $ repeat $ BuildTxWith $ KeyWitness KeyWitnessForSpending)
     & setTxOuts txouts
     & setTxFee (mkTxFee fee)
diff --git a/bench/tx-generator/src/Cardano/TxGenerator/Tx.hs b/bench/tx-generator/src/Cardano/TxGenerator/Tx.hs
index ab7b2d952fc..7071ef64495 100644
--- a/bench/tx-generator/src/Cardano/TxGenerator/Tx.hs
+++ b/bench/tx-generator/src/Cardano/TxGenerator/Tx.hs
@@ -94,7 +94,7 @@ genTx protocolParameters (collateral, collFunds) fee metadata inFunds outputs
       (createAndValidateTransactionBody txBodyContent)
  where
   allKeys = mapMaybe getFundKey $ inFunds ++ collFunds
-  txBodyContent = defaultTxBodyContent
+  txBodyContent = defaultTxBodyContent InBuildTx
     & setTxIns (map (\f -> (getFundTxIn f, BuildTxWith $ getFundWitness f)) inFunds)
     & setTxInsCollateral collateral
     & setTxOuts outputs
diff --git a/cardano-api/src/Cardano/Api.hs b/cardano-api/src/Cardano/Api.hs
index e5a018163e3..02d58a6a108 100644
--- a/cardano-api/src/Cardano/Api.hs
+++ b/cardano-api/src/Cardano/Api.hs
@@ -163,6 +163,7 @@ module Cardano.Api (
     defaultTxBodyContent,
     defaultTxFee,
     defaultTxValidityUpperBound,
+    defaultBuildTxWith,
     setTxIns,
     setTxInsCollateral,
     setTxInsReference,
@@ -223,6 +224,7 @@ module Cardano.Api (
 
     -- ** Building vs viewing transactions
     BuildTxWith(..),
+    ModeTx(..),
     BuildTx,
     ViewTx,
 
diff --git a/cardano-api/src/Cardano/Api/TxBody.hs b/cardano-api/src/Cardano/Api/TxBody.hs
index 6f8ff8b3cf1..ad522765e98 100644
--- a/cardano-api/src/Cardano/Api/TxBody.hs
+++ b/cardano-api/src/Cardano/Api/TxBody.hs
@@ -32,6 +32,7 @@ module Cardano.Api.TxBody (
     defaultTxBodyContent,
     defaultTxFee,
     defaultTxValidityUpperBound,
+    defaultBuildTxWith,
     setTxIns,
     setTxInsCollateral,
     setTxInsReference,
@@ -106,6 +107,7 @@ module Cardano.Api.TxBody (
     BuildTxWith(..),
     BuildTx,
     ViewTx,
+    ModeTx(..),
 
     -- * Era-dependent transaction body features
     CollateralSupportedInEra(..),
@@ -1325,6 +1327,16 @@ data BuildTxWith build a where
      ViewTx      ::      BuildTxWith ViewTx  a
      BuildTxWith :: a -> BuildTxWith BuildTx a
 
+defaultBuildTxWith :: ModeTx build -> a -> BuildTxWith build a
+defaultBuildTxWith inModeTx a =
+  case inModeTx of
+    InViewTx -> ViewTx
+    InBuildTx -> BuildTxWith a
+
+data ModeTx a where
+  InBuildTx :: ModeTx BuildTx
+  InViewTx :: ModeTx ViewTx
+
 instance Functor (BuildTxWith build) where
     fmap _ ViewTx = ViewTx
     fmap f (BuildTxWith x) = BuildTxWith (f x)
@@ -1765,8 +1777,8 @@ data TxBodyContent build era =
      }
      deriving (Eq, Show)
 
-defaultTxBodyContent :: IsCardanoEra era => TxBodyContent BuildTx era
-defaultTxBodyContent = TxBodyContent
+defaultTxBodyContent :: IsCardanoEra era => ModeTx mtx -> TxBodyContent mtx era
+defaultTxBodyContent mtx = TxBodyContent
     { txIns = []
     , txInsCollateral = TxInsCollateralNone
     , txInsReference = TxInsReferenceNone
@@ -1778,7 +1790,7 @@ defaultTxBodyContent = TxBodyContent
     , txMetadata = TxMetadataNone
     , txAuxScripts = TxAuxScriptsNone
     , txExtraKeyWits = TxExtraKeyWitnessesNone
-    , txProtocolParams = BuildTxWith Nothing
+    , txProtocolParams = defaultBuildTxWith mtx Nothing
     , txWithdrawals = TxWithdrawalsNone
     , txCertificates = TxCertificatesNone
     , txUpdateProposal = TxUpdateProposalNone