diff --git a/cabal.project b/cabal.project
index 7d699e8d362..11d36b00248 100644
--- a/cabal.project
+++ b/cabal.project
@@ -34,6 +34,52 @@ constraints:
 package acts
   flags: -finitary
 
+-- BEGIN SRP STANZAS MANAGED BY STANZAMAN --
+
+source-repository-package
+  type: git
+  location: https://github.com/IntersectMBO/cardano-api.git
+  tag: 13b452f32cf053a803988f455551a697726c65cc
+  subdir: cardano-api
+  --sha256: 1fq901pjq1k3hiqygnmifw6w9pydqb4xr4i987n69r2jp1k3025m
+
+source-repository-package
+  type: git
+  location: https://github.com/IntersectMBO/ouroboros-network.git
+  tag: 65da1ad619473f9467d3336a6d6e9a2a8714913d
+  subdir: network-mux
+  --sha256: 1r5y5px0kj4nhb65s9i7pr0sikxghfqwfkzmsgiql2maic4nglwi
+
+source-repository-package
+  type: git
+  location: https://github.com/IntersectMBO/ouroboros-network.git
+  tag: 65da1ad619473f9467d3336a6d6e9a2a8714913d
+  subdir: cardano-diffusion
+  --sha256: 1r5y5px0kj4nhb65s9i7pr0sikxghfqwfkzmsgiql2maic4nglwi
+
+source-repository-package
+  type: git
+  location: https://github.com/IntersectMBO/ouroboros-network.git
+  tag: 65da1ad619473f9467d3336a6d6e9a2a8714913d
+  subdir: ouroboros-network
+  --sha256: 1r5y5px0kj4nhb65s9i7pr0sikxghfqwfkzmsgiql2maic4nglwi
+
+source-repository-package
+  type: git
+  location: https://github.com/IntersectMBO/cardano-cli.git
+  tag: c632e6e114b1f2d7715afd34ec44750a0595efc1
+  subdir: cardano-cli
+  --sha256: 0d4vs59z3wlhnl2ns8g8lqrc7xgm2nfid5cfyq0kms2jgmi89wiz
+
+source-repository-package
+  type: git
+  location: https://github.com/IntersectMBO/ouroboros-consensus.git
+  tag: bca18fd361d8342bdbfb8a08366e86479677ce30
+  subdir: .
+  --sha256: 11znnl9zk59bxr6dn76zrni6i0q32bqnlxqf4wprvxikg4r666pa
+
+-- END SRP STANZAS MANAGED BY STANZAMAN --
+
 packages:
   cardano-node
   cardano-node-capi
@@ -81,12 +127,22 @@ package plutus-scripts-bench
 allow-newer:
   , katip:Win32
 
+-- The SRP stanza for cardano-api pins it to a version with plutus-{core,ledger-api} ^>=1.61,
+-- while plutus-scripts-bench requires ^>=1.63. Allow the relaxation.
+allow-newer:
+  , cardano-api:plutus-core
+  , cardano-api:plutus-ledger-api
+
 -- There is a suspected bug in `cabal` (https://github.com/haskell/cabal/issues/11663)
 -- that can be worked around with the following allow-newer stanzas
 allow-newer:
   , io-sim:time
   , io-classes:time
 
+allow-newer:
+  , cardano-diffusion:trace-dispatcher
+  , ouroboros-network:trace-dispatcher
+
 -- IMPORTANT
 -- Do NOT add more source-repository-package stanzas here unless they are strictly
 -- temporary! Please read the section in CONTRIBUTING about updating dependencies.
diff --git a/cardano-node/src/Cardano/Node/Tracing/Tracers/Startup.hs b/cardano-node/src/Cardano/Node/Tracing/Tracers/Startup.hs
index 3577fe2ed2b..63db18778a1 100644
--- a/cardano-node/src/Cardano/Node/Tracing/Tracers/Startup.hs
+++ b/cardano-node/src/Cardano/Node/Tracing/Tracers/Startup.hs
@@ -508,6 +508,7 @@ nodeToClientVersionToInt = \case
   NodeToClientV_21 -> 21
   NodeToClientV_22 -> 22
   NodeToClientV_23 -> 23
+  NodeToClientV_24 -> 24
 
 nodeToNodeVersionToInt :: NodeToNodeVersion -> Int
 nodeToNodeVersionToInt = \case
diff --git a/cardano-node/src/Cardano/Tracing/OrphanInstances/Shelley.hs b/cardano-node/src/Cardano/Tracing/OrphanInstances/Shelley.hs
index d067a4a2e4b..08e1aff82bc 100644
--- a/cardano-node/src/Cardano/Tracing/OrphanInstances/Shelley.hs
+++ b/cardano-node/src/Cardano/Tracing/OrphanInstances/Shelley.hs
@@ -1368,6 +1368,7 @@ instance ToJSON ShelleyNodeToClientVersion where
   toJSON ShelleyNodeToClientVersion13 = String "ShelleyNodeToClientVersion13"
   toJSON ShelleyNodeToClientVersion14 = String "ShelleyNodeToClientVersion14"
   toJSON ShelleyNodeToClientVersion15 = String "ShelleyNodeToClientVersion15"
+  toJSON ShelleyNodeToClientVersion16 = String "ShelleyNodeToClientVersion16"
 
 --------------------------------------------------------------------------------
 -- Conway related
diff --git a/cardano-testnet/cardano-testnet.cabal b/cardano-testnet/cardano-testnet.cabal
index 3d24101a0ad..31ed2d5790a 100644
--- a/cardano-testnet/cardano-testnet.cabal
+++ b/cardano-testnet/cardano-testnet.cabal
@@ -220,6 +220,8 @@ test-suite cardano-testnet-test
                         Cardano.Testnet.Test.Cli.Transaction
                         Cardano.Testnet.Test.Cli.Transaction.BuildEstimate
                         Cardano.Testnet.Test.Cli.Transaction.RegisterDeregisterStakeAddress
+                        Cardano.Testnet.Test.Cli.Transaction.Validate
+                        Cardano.Testnet.Test.Cli.Transaction.ValidateErrors
                         Cardano.Testnet.Test.Cli.Transaction.WithdrawalReward
                         Cardano.Testnet.Test.DumpConfig
                         Cardano.Testnet.Test.FoldEpochState
diff --git a/cardano-testnet/test/cardano-testnet-test/Cardano/Testnet/Test/Cli/Transaction/Validate.hs b/cardano-testnet/test/cardano-testnet-test/Cardano/Testnet/Test/Cli/Transaction/Validate.hs
new file mode 100644
index 00000000000..4cbb1364289
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/Cardano/Testnet/Test/Cli/Transaction/Validate.hs
@@ -0,0 +1,525 @@
+{-# LANGUAGE DisambiguateRecordFields #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE NumericUnderscores #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeApplications #-}
+
+module Cardano.Testnet.Test.Cli.Transaction.Validate
+  ( hprop_transaction_validate
+  ) where
+
+import           Cardano.Api
+
+import           Cardano.Testnet
+
+import           Prelude
+
+import           Control.Monad (void)
+import           Data.Default.Class
+import qualified Data.Text as Text
+import           GHC.IO.Exception (ExitCode (..))
+import           System.FilePath ((</>))
+
+import           Testnet.Components.Configuration
+import           Testnet.Components.Query (findLargestUtxoForPaymentKey,
+                   findLargestUtxoWithAddress, getEpochStateView, retryUntilJustM,
+                   TestnetWaitPeriod (..), waitForBlocks)
+import           Testnet.Defaults (plutusV3Script, plutusV3SupplementalDatumScript)
+import           Testnet.Process.Run (execCli', execCliAny, mkExecConfig)
+import           Testnet.Property.Util (integrationRetryWorkspace)
+import           Testnet.Types
+
+import           Hedgehog (Property)
+import qualified Hedgehog as H
+import qualified Hedgehog.Extras as H
+
+-- Deterministic signing key for reproducible golden tests.
+-- Key hash: fe8c2213ed33ae44e3629706a3c7d34f0dce29753646602177756a5f
+-- Address (testnet-magic 42): addr_test1vrlgcgsna5e6u38rv2tsdg786d8smn3fw5myvcppwa6k5hc4u8utx
+testSigningKey :: String
+testSigningKey =
+  "{\"type\":\"PaymentSigningKeyShelley_ed25519\",\"description\":\"Payment Signing Key\",\"cborHex\":\"5820aabbccddee0011223344556677889900aabbccddee00112233445566778899aa\"}"
+
+-- | Integration test for @cardano-cli latest transaction validate@.
+--
+-- Spins up a testnet then validates several transactions (both valid and
+-- invalid) using the new validate command, comparing output against golden
+-- files.
+--
+-- Execute me with:
+-- @DISABLE_RETRIES=1 cabal test cardano-testnet-test --test-options '-p "/transaction validate/"'@
+-- If you want to recreate golden files, set RECREATE_GOLDEN_FILES=1
+hprop_transaction_validate :: Property
+hprop_transaction_validate = integrationRetryWorkspace 2 "transaction validate" $ \tempAbsBasePath' -> H.runWithDefaultWatchdog_ $ do
+  conf@Conf{tempAbsPath} <- mkConf tempAbsBasePath'
+  let tempAbsPath' = unTmpAbsPath tempAbsPath
+  work <- H.createDirectoryIfMissing $ tempAbsPath' </> "work"
+
+  let sbe = ShelleyBasedEraConway
+      era = toCardanoEra sbe
+      cEra = AnyCardanoEra era
+      tempBaseAbsPath = makeTmpBaseAbsPath $ TmpAbsolutePath tempAbsPath'
+      creationOptions = def{creationEra = AnyShelleyBasedEra sbe}
+
+  TestnetRuntime
+    { configurationFile
+    , testnetMagic
+    , testnetNodes
+    , wallets = wallet0 : wallet1 : _
+    } <-
+    createAndRunTestnet creationOptions def conf
+
+  node <- H.headM testnetNodes
+  poolSprocket1 <- H.noteShow $ nodeSprocket node
+  execConfig <- mkExecConfig tempBaseAbsPath poolSprocket1 testnetMagic
+  epochStateView <- getEpochStateView configurationFile (nodeSocketPath node)
+
+  -- Write deterministic key to file and derive address
+  let testSKeyFile = work </> "test-skey.json"
+      testVKeyFile = work </> "test-vkey.json"
+  H.writeFile testSKeyFile testSigningKey
+  void $ execCli' execConfig
+    [ "latest", "key", "verification-key"
+    , "--signing-key-file", testSKeyFile
+    , "--verification-key-file", testVKeyFile
+    ]
+  testAddr <- filter (/= '\n') <$>
+    execCli' execConfig
+      [ "latest", "address", "build"
+      , "--payment-verification-key-file", testVKeyFile
+      ]
+  H.note_ $ "Deterministic test address: " <> testAddr
+
+  -- ====================================================================
+  -- Setup: Fund the deterministic address with known amounts
+  -- ====================================================================
+  H.note_ "=== Setup: funding deterministic address ==="
+  let fundingAmount = 10_000_000 :: Int
+      wallet0SKeyFile = signingKeyFp $ paymentKeyInfoPair wallet0
+      wallet0Addr = Text.unpack $ paymentKeyInfoAddr wallet0
+
+  txinFund <- findLargestUtxoForPaymentKey epochStateView sbe wallet0
+  let fundTxBody = work </> "fund-tx.body"
+      fundTxSigned = work </> "fund-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build"
+    , "--change-address", wallet0Addr
+    , "--tx-in", Text.unpack $ renderTxIn txinFund
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--out-file", fundTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", fundTxBody
+    , "--signing-key-file", wallet0SKeyFile
+    , "--out-file", fundTxSigned
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "submit"
+    , "--tx-file", fundTxSigned
+    ]
+
+  H.noteShowM_ $ waitForBlocks epochStateView 1
+
+  -- Find the funded UTxOs at our deterministic address
+  testUtxos <- retryUntilJustM epochStateView (WaitForBlocks 3) $ do
+    utxos <- findLargestUtxoWithAddress epochStateView sbe $ Text.pack testAddr
+    case utxos of
+      Just _ -> return $ Just ()
+      Nothing -> return Nothing
+
+  _ <- H.note $ "Test UTxOs funded: " <> show testUtxos
+
+  -- ====================================================================
+  -- Test 1: Valid simple ADA transfer
+  -- ====================================================================
+  H.note_ "=== Test 1: Valid simple transaction ==="
+
+  txin1 <- findLargestUtxoForPaymentKey epochStateView sbe wallet0
+  let validTxBody = work </> "valid-tx.body"
+      validTxSigned = work </> "valid-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build"
+    , "--change-address", wallet0Addr
+    , "--tx-in", Text.unpack $ renderTxIn txin1
+    , "--tx-out", Text.unpack (paymentKeyInfoAddr wallet1) <> "+" <> show @Int 5_000_000
+    , "--out-file", validTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", validTxBody
+    , "--signing-key-file", wallet0SKeyFile
+    , "--out-file", validTxSigned
+    ]
+
+  (exitCode1, stdout1, stderr1) <- execCliAny execConfig
+    [ anyEraToString cEra, "transaction", "validate"
+    , "--tx-file", validTxSigned
+    ]
+
+  H.note_ $ "Exit code: " <> show exitCode1
+  H.note_ $ "Stdout: " <> stdout1
+  H.note_ $ "Stderr: " <> stderr1
+
+  exitCode1 H.=== ExitSuccess
+  H.diffVsGoldenFile
+    stdout1
+    "test/cardano-testnet-test/files/golden/tx_validate/valid_simple.out"
+
+  -- ====================================================================
+  -- Test 2: Fee too low (build-raw with deterministic UTxO)
+  -- The deterministic UTxO has exactly 10,000,000 lovelace.
+  -- output = 10,000,000 - 100 = 9,999,900 so value IS conserved,
+  -- but fee=100 < min_fee=194.
+  -- ====================================================================
+  H.note_ "=== Test 2: Fee too low ==="
+
+  testTxin2 <- fmap fst . H.nothingFailM $
+    findLargestUtxoWithAddress epochStateView sbe $ Text.pack testAddr
+  let feeTooLowTxBody = work </> "fee-too-low-tx.body"
+      feeTooLowTxSigned = work </> "fee-too-low-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn testTxin2
+    , "--tx-out", testAddr <> "+9999900"
+    , "--fee", "100"
+    , "--out-file", feeTooLowTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", feeTooLowTxBody
+    , "--signing-key-file", testSKeyFile
+    , "--out-file", feeTooLowTxSigned
+    ]
+
+  (exitCode2, stdout2, stderr2) <- execCliAny execConfig
+    [ anyEraToString cEra, "transaction", "validate"
+    , "--tx-file", feeTooLowTxSigned
+    ]
+
+  H.note_ $ "Exit code: " <> show exitCode2
+  H.note_ $ "Stdout: " <> stdout2
+  H.note_ $ "Stderr: " <> stderr2
+
+  exitCode2 H.=== ExitFailure 1
+  H.diffVsGoldenFile
+    stdout2
+    "test/cardano-testnet-test/files/golden/tx_validate/fee_too_low.out"
+
+  -- ====================================================================
+  -- Test 3: Value not conserved
+  -- Deterministic UTxO has 10,000,000 lovelace.
+  -- output = 999,999,000,000, fee = 200,000
+  -- consumed = 10,000,000, produced = 999,999,200,000
+  -- ====================================================================
+  H.note_ "=== Test 3: Value not conserved ==="
+
+  let valueNotConservedTxBody = work </> "value-not-conserved-tx.body"
+      valueNotConservedTxSigned = work </> "value-not-conserved-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn testTxin2
+    , "--tx-out", testAddr <> "+999999000000"
+    , "--fee", "200000"
+    , "--out-file", valueNotConservedTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", valueNotConservedTxBody
+    , "--signing-key-file", testSKeyFile
+    , "--out-file", valueNotConservedTxSigned
+    ]
+
+  (exitCode3, stdout3, stderr3) <- execCliAny execConfig
+    [ anyEraToString cEra, "transaction", "validate"
+    , "--tx-file", valueNotConservedTxSigned
+    ]
+
+  H.note_ $ "Exit code: " <> show exitCode3
+  H.note_ $ "Stdout: " <> stdout3
+  H.note_ $ "Stderr: " <> stderr3
+
+  exitCode3 H.=== ExitFailure 1
+  H.diffVsGoldenFile
+    stdout3
+    "test/cardano-testnet-test/files/golden/tx_validate/value_not_conserved.out"
+
+  -- ====================================================================
+  -- Test 4: Missing witness
+  -- Build a tx spending from the deterministic key's UTxO,
+  -- but sign with wallet1's key instead.
+  -- Expected missing key hash: fe8c2213ed33ae44e3629706a3c7d34f0dce29753646602177756a5f
+  -- ====================================================================
+  H.note_ "=== Test 4: Missing witness ==="
+
+  let missingWitnessTxBody = work </> "missing-witness-tx.body"
+      missingWitnessTxSigned = work </> "missing-witness-tx.signed"
+      wallet1SKeyFile = signingKeyFp $ paymentKeyInfoPair wallet1
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn testTxin2
+    , "--tx-out", testAddr <> "+9999600"
+    , "--fee", "400"
+    , "--out-file", missingWitnessTxBody
+    ]
+
+  -- Sign with wallet1's key instead of the deterministic test key
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", missingWitnessTxBody
+    , "--signing-key-file", wallet1SKeyFile
+    , "--out-file", missingWitnessTxSigned
+    ]
+
+  (exitCode4, stdout4, stderr4) <- execCliAny execConfig
+    [ anyEraToString cEra, "transaction", "validate"
+    , "--tx-file", missingWitnessTxSigned
+    ]
+
+  H.note_ $ "Exit code: " <> show exitCode4
+  H.note_ $ "Stdout: " <> stdout4
+  H.note_ $ "Stderr: " <> stderr4
+
+  exitCode4 H.=== ExitFailure 1
+  H.diffVsGoldenFile
+    stdout4
+    "test/cardano-testnet-test/files/golden/tx_validate/missing_witness.out"
+
+  -- ====================================================================
+  -- Test 5: Valid Plutus script transaction (always-succeeds)
+  -- Uses plutusV3Script which is a trivial always-succeeds PlutusV3 script.
+  -- ====================================================================
+  H.note_ "=== Test 5: Valid Plutus script ==="
+  let alwaysSucceedsScript = work </> "always-succeeds.plutusV3"
+  H.writeFile alwaysSucceedsScript $ Text.unpack plutusV3Script
+
+  alwaysSucceedsAddr <- filter (/= '\n') <$>
+    execCli' execConfig
+      [ "latest", "address", "build"
+      , "--payment-script-file", alwaysSucceedsScript
+      ]
+
+  scriptDatumHash <- filter (/= '\n') <$>
+    execCli' execConfig
+      [ "latest", "transaction", "hash-script-data"
+      , "--script-data-value", "0"
+      ]
+
+  -- Send ADA to the always-succeeds script address
+  txinForScript <- findLargestUtxoForPaymentKey epochStateView sbe wallet0
+  let sendToScriptTxBody = work </> "send-to-script-tx.body"
+      sendToScriptTxSigned = work </> "send-to-script-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build"
+    , "--change-address", wallet0Addr
+    , "--tx-in", Text.unpack $ renderTxIn txinForScript
+    , "--tx-out", alwaysSucceedsAddr <> "+" <> show @Int 5_000_000
+    , "--tx-out-datum-hash", scriptDatumHash
+    , "--out-file", sendToScriptTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", sendToScriptTxBody
+    , "--signing-key-file", wallet0SKeyFile
+    , "--out-file", sendToScriptTxSigned
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "submit"
+    , "--tx-file", sendToScriptTxSigned
+    ]
+
+  -- Wait for the UTxO to appear at the script address
+  txinCollateral <- findLargestUtxoForPaymentKey epochStateView sbe wallet1
+  alwaysSucceedsTxIn <- fmap fst . retryUntilJustM epochStateView (WaitForBlocks 3) $
+    findLargestUtxoWithAddress epochStateView sbe $ Text.pack alwaysSucceedsAddr
+
+  -- Spend from the always-succeeds script address
+  let spendScriptTxBody = work </> "spend-script-tx.body"
+      spendScriptTxSigned = work </> "spend-script-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build"
+    , "--change-address", Text.unpack $ paymentKeyInfoAddr wallet1
+    , "--tx-in-collateral", Text.unpack $ renderTxIn txinCollateral
+    , "--tx-in", Text.unpack $ renderTxIn alwaysSucceedsTxIn
+    , "--tx-in-script-file", alwaysSucceedsScript
+    , "--tx-in-datum-value", "0"
+    , "--tx-in-redeemer-value", "0"
+    , "--tx-out", Text.unpack (paymentKeyInfoAddr wallet1) <> "+" <> show @Int 2_000_000
+    , "--out-file", spendScriptTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", spendScriptTxBody
+    , "--signing-key-file", wallet1SKeyFile
+    , "--out-file", spendScriptTxSigned
+    ]
+
+  (exitCode5, stdout5, stderr5) <- execCliAny execConfig
+    [ anyEraToString cEra, "transaction", "validate"
+    , "--tx-file", spendScriptTxSigned
+    ]
+
+  H.note_ $ "Exit code: " <> show exitCode5
+  H.note_ $ "Stdout: " <> stdout5
+  H.note_ $ "Stderr: " <> stderr5
+
+  exitCode5 H.=== ExitSuccess
+  H.diffVsGoldenFile
+    stdout5
+    "test/cardano-testnet-test/files/golden/tx_validate/valid_plutus.out"
+
+  -- ====================================================================
+  -- Test 6: Failing Plutus script (supplemental datum not found)
+  -- Uses plutusV3SupplementalDatumScript which requires a supplemental
+  -- datum with hash of integer 1 to be present in the transaction.
+  -- We intentionally omit it so the script fails during evaluation.
+  -- ====================================================================
+  H.note_ "=== Test 6: Failing Plutus script ==="
+  let supplementalDatumScript = work </> "supplemental-datum.plutusV3"
+  H.writeFile supplementalDatumScript $ Text.unpack plutusV3SupplementalDatumScript
+
+  supplementalDatumScriptAddr <- filter (/= '\n') <$>
+    execCli' execConfig
+      [ "latest", "address", "build"
+      , "--payment-script-file", supplementalDatumScript
+      ]
+
+  -- Send ADA to the supplemental datum script address
+  txinForScript2 <- findLargestUtxoForPaymentKey epochStateView sbe wallet1
+  let sendToScript2TxBody = work </> "send-to-script-2-tx.body"
+      sendToScript2TxSigned = work </> "send-to-script-2-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build"
+    , "--change-address", Text.unpack $ paymentKeyInfoAddr wallet1
+    , "--tx-in", Text.unpack $ renderTxIn txinForScript2
+    , "--tx-out", supplementalDatumScriptAddr <> "+" <> show @Int 5_000_000
+    , "--tx-out-datum-hash", scriptDatumHash
+    , "--out-file", sendToScript2TxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", sendToScript2TxBody
+    , "--signing-key-file", wallet1SKeyFile
+    , "--out-file", sendToScript2TxSigned
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "submit"
+    , "--tx-file", sendToScript2TxSigned
+    ]
+
+  -- Wait for the UTxO to appear at the script address
+  txinCollateral2 <- findLargestUtxoForPaymentKey epochStateView sbe wallet0
+  supplementalDatumTxIn <- fmap fst . retryUntilJustM epochStateView (WaitForBlocks 3) $
+    findLargestUtxoWithAddress epochStateView sbe $ Text.pack supplementalDatumScriptAddr
+
+  -- Build spending tx WITHOUT the supplemental datum → script will fail
+  let failScriptTxBody = work </> "fail-script-tx.body"
+      failScriptTxSigned = work </> "fail-script-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "query", "protocol-parameters"
+    , "--out-file", work </> "pparams.json"
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in-collateral", Text.unpack $ renderTxIn txinCollateral2
+    , "--tx-in", Text.unpack $ renderTxIn supplementalDatumTxIn
+    , "--tx-in-script-file", supplementalDatumScript
+    , "--tx-in-datum-value", "0"
+    , "--tx-in-redeemer-value", "0"
+    , "--tx-in-execution-units", "(5000000000, 10000000)"
+    , "--tx-out", wallet0Addr <> "+" <> show @Int 2_000_000
+    , "--fee", "3000000"
+    , "--protocol-params-file", work </> "pparams.json"
+    , "--out-file", failScriptTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", failScriptTxBody
+    , "--signing-key-file", wallet0SKeyFile
+    , "--out-file", failScriptTxSigned
+    ]
+
+  (exitCode6, stdout6, stderr6) <- execCliAny execConfig
+    [ anyEraToString cEra, "transaction", "validate"
+    , "--tx-file", failScriptTxSigned
+    ]
+
+  H.note_ $ "Exit code: " <> show exitCode6
+  H.note_ $ "Stdout: " <> stdout6
+  H.note_ $ "Stderr: " <> stderr6
+
+  exitCode6 H.=== ExitFailure 1
+  H.diffVsGoldenFile
+    stdout6
+    "test/cardano-testnet-test/files/golden/tx_validate/failing_plutus.out"
+
+  -- ====================================================================
+  -- Test 7: Multiple errors (fee too low + value not conserved)
+  -- Deterministic UTxO has 10,000,000 lovelace.
+  -- output = 999,999,000,000, fee = 100
+  -- consumed = 10,000,000, produced = 999,999,000,100
+  -- min_fee = 198, fee = 100
+  -- ====================================================================
+  H.note_ "=== Test 7: Multiple errors ==="
+
+  -- Use a different deterministic UTxO
+  testTxin7 <- fmap fst . H.nothingFailM $
+    findLargestUtxoWithAddress epochStateView sbe $ Text.pack testAddr
+  let multiErrorTxBody = work </> "multi-error-tx.body"
+      multiErrorTxSigned = work </> "multi-error-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn testTxin7
+    , "--tx-out", testAddr <> "+999999000000"
+    , "--fee", "100"
+    , "--out-file", multiErrorTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", multiErrorTxBody
+    , "--signing-key-file", testSKeyFile
+    , "--out-file", multiErrorTxSigned
+    ]
+
+  (exitCode7, stdout7, stderr7) <- execCliAny execConfig
+    [ anyEraToString cEra, "transaction", "validate"
+    , "--tx-file", multiErrorTxSigned
+    ]
+
+  H.note_ $ "Exit code: " <> show exitCode7
+  H.note_ $ "Stdout: " <> stdout7
+  H.note_ $ "Stderr: " <> stderr7
+
+  exitCode7 H.=== ExitFailure 1
+  H.diffVsGoldenFile
+    stdout7
+    "test/cardano-testnet-test/files/golden/tx_validate/multi_error.out"
+
+  H.success
diff --git a/cardano-testnet/test/cardano-testnet-test/Cardano/Testnet/Test/Cli/Transaction/ValidateErrors.hs b/cardano-testnet/test/cardano-testnet-test/Cardano/Testnet/Test/Cli/Transaction/ValidateErrors.hs
new file mode 100644
index 00000000000..462cbdc512a
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/Cardano/Testnet/Test/Cli/Transaction/ValidateErrors.hs
@@ -0,0 +1,543 @@
+{-# LANGUAGE DisambiguateRecordFields #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE NumericUnderscores #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeApplications #-}
+
+module Cardano.Testnet.Test.Cli.Transaction.ValidateErrors
+  ( hprop_transaction_validate_all_errors
+  ) where
+
+import           Cardano.Api
+
+import           Cardano.Testnet
+
+import           Prelude
+
+import           Control.Monad (void)
+import           Data.Default.Class
+import           Data.List (intercalate, isInfixOf)
+import qualified Cardano.Api.UTxO as Utxo
+import qualified Data.Text as Text
+import           GHC.IO.Exception (ExitCode (..))
+import           System.FilePath ((</>))
+
+import           Testnet.Components.Configuration
+import           Testnet.Components.Query (findLargestUtxoForPaymentKey,
+                   findLargestUtxoWithAddress, findUtxosWithAddress,
+                   getEpochStateView, retryUntilJustM,
+                   TestnetWaitPeriod (..), waitForBlocks)
+import           Testnet.Defaults (plutusV3Script, plutusV3SupplementalDatumScript)
+import           Testnet.Process.Run (execCli', execCliAny, mkExecConfig)
+import           Testnet.Property.Util (integrationRetryWorkspace)
+import           Testnet.Types
+
+import           Hedgehog (Property)
+import qualified Hedgehog as H
+import qualified Hedgehog.Extras as H
+
+-- Same deterministic signing key as in the Validate test.
+-- Key hash: fe8c2213ed33ae44e3629706a3c7d34f0dce29753646602177756a5f
+testSigningKey :: String
+testSigningKey =
+  "{\"type\":\"PaymentSigningKeyShelley_ed25519\",\"description\":\"Payment Signing Key\",\"cborHex\":\"5820aabbccddee0011223344556677889900aabbccddee00112233445566778899aa\"}"
+
+-- | Comprehensive integration test for @cardano-cli latest transaction validate@.
+--
+-- Exercises every category of validation error:
+--
+-- Phase 1 (ledger rules):
+--   ConwayMempoolFailure, OutputTooSmallUTxO, FeeTooSmallUTxO, ValueNotConservedUTxO,
+--   OutsideValidityIntervalUTxO, MissingVKeyWitnessesUTXOW, MaxTxSizeUTxO,
+--   ExUnitsTooBigUTxO, TooManyCollateralInputs, NoCollateralInputs,
+--   InsufficientCollateral, IncorrectTotalCollateralField,
+--   MissingScriptWitnessesUTXOW
+--
+-- Phase 2 (Plutus script evaluation):
+--   Script evaluation failure (CekError)
+--
+-- Execute me with:
+-- @DISABLE_RETRIES=1 cabal test cardano-testnet-test --test-options '-p "/transaction validate all errors/"'@
+hprop_transaction_validate_all_errors :: Property
+hprop_transaction_validate_all_errors = integrationRetryWorkspace 2 "validate-errors" $ \tempAbsBasePath' -> H.runWithDefaultWatchdog_ $ do
+  conf@Conf{tempAbsPath} <- mkConf tempAbsBasePath'
+  let tempAbsPath' = unTmpAbsPath tempAbsPath
+  work <- H.createDirectoryIfMissing $ tempAbsPath' </> "work"
+
+  let sbe = ShelleyBasedEraConway
+      era = toCardanoEra sbe
+      cEra = AnyCardanoEra era
+      tempBaseAbsPath = makeTmpBaseAbsPath $ TmpAbsolutePath tempAbsPath'
+      creationOptions = def{creationEra = AnyShelleyBasedEra sbe}
+
+  TestnetRuntime
+    { configurationFile
+    , testnetMagic
+    , testnetNodes
+    , wallets = wallet0 : wallet1 : _
+    } <-
+    createAndRunTestnet creationOptions def conf
+
+  node <- H.headM testnetNodes
+  poolSprocket1 <- H.noteShow $ nodeSprocket node
+  execConfig <- mkExecConfig tempBaseAbsPath poolSprocket1 testnetMagic
+  epochStateView <- getEpochStateView configurationFile (nodeSocketPath node)
+
+  -- ====================================================================
+  -- Setup: deterministic key + fund address with 6 UTxOs
+  -- ====================================================================
+  let testSKeyFile = work </> "test-skey.json"
+      testVKeyFile = work </> "test-vkey.json"
+  H.writeFile testSKeyFile testSigningKey
+  void $ execCli' execConfig
+    [ "latest", "key", "verification-key"
+    , "--signing-key-file", testSKeyFile
+    , "--verification-key-file", testVKeyFile
+    ]
+  testAddr <- filter (/= '\n') <$>
+    execCli' execConfig
+      [ "latest", "address", "build"
+      , "--payment-verification-key-file", testVKeyFile
+      ]
+  H.note_ $ "Deterministic test address: " <> testAddr
+
+  let fundingAmount = 10_000_000 :: Int
+      wallet0SKeyFile = signingKeyFp $ paymentKeyInfoPair wallet0
+      wallet0Addr = Text.unpack $ paymentKeyInfoAddr wallet0
+      wallet1SKeyFile = signingKeyFp $ paymentKeyInfoPair wallet1
+
+  txinFund <- findLargestUtxoForPaymentKey epochStateView sbe wallet0
+  let fundTxBody = work </> "fund-tx.body"
+      fundTxSigned = work </> "fund-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build"
+    , "--change-address", wallet0Addr
+    , "--tx-in", Text.unpack $ renderTxIn txinFund
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--tx-out", testAddr <> "+" <> show fundingAmount
+    , "--out-file", fundTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", fundTxBody
+    , "--signing-key-file", wallet0SKeyFile
+    , "--out-file", fundTxSigned
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "submit"
+    , "--tx-file", fundTxSigned
+    ]
+
+  H.noteShowM_ $ waitForBlocks epochStateView 1
+
+  _ <- retryUntilJustM epochStateView (WaitForBlocks 3) $
+    findLargestUtxoWithAddress epochStateView sbe $ Text.pack testAddr
+
+  testUtxosList <- Utxo.toList <$> findUtxosWithAddress epochStateView sbe (Text.pack testAddr)
+  let testTxIns = map fst testUtxosList
+  H.note_ $ "Found " <> show (length testTxIns) <> " UTxOs at test address"
+  H.assert $ length testTxIns >= 6
+
+  -- ====================================================================
+  -- Setup: always-succeeds Plutus V3 script address + fund it
+  -- ====================================================================
+  let alwaysSucceedsScript = work </> "always-succeeds.plutusV3"
+  H.writeFile alwaysSucceedsScript $ Text.unpack plutusV3Script
+
+  alwaysSucceedsAddr <- filter (/= '\n') <$>
+    execCli' execConfig
+      [ "latest", "address", "build"
+      , "--payment-script-file", alwaysSucceedsScript
+      ]
+
+  scriptDatumHash <- filter (/= '\n') <$>
+    execCli' execConfig
+      [ "latest", "transaction", "hash-script-data"
+      , "--script-data-value", "0"
+      ]
+
+  txinForScript <- findLargestUtxoForPaymentKey epochStateView sbe wallet0
+  let sendToScriptTxBody = work </> "send-to-script-tx.body"
+      sendToScriptTxSigned = work </> "send-to-script-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build"
+    , "--change-address", wallet0Addr
+    , "--tx-in", Text.unpack $ renderTxIn txinForScript
+    , "--tx-out", alwaysSucceedsAddr <> "+5000000"
+    , "--tx-out-datum-hash", scriptDatumHash
+    , "--out-file", sendToScriptTxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", sendToScriptTxBody
+    , "--signing-key-file", wallet0SKeyFile
+    , "--out-file", sendToScriptTxSigned
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "submit"
+    , "--tx-file", sendToScriptTxSigned
+    ]
+
+  scriptTxIn <- fmap fst . retryUntilJustM epochStateView (WaitForBlocks 3) $
+    findLargestUtxoWithAddress epochStateView sbe $ Text.pack alwaysSucceedsAddr
+
+  -- ====================================================================
+  -- Setup: supplemental-datum Plutus V3 script address + fund it
+  -- ====================================================================
+  let supplementalDatumScript = work </> "supplemental-datum.plutusV3"
+  H.writeFile supplementalDatumScript $ Text.unpack plutusV3SupplementalDatumScript
+
+  supplementalDatumScriptAddr <- filter (/= '\n') <$>
+    execCli' execConfig
+      [ "latest", "address", "build"
+      , "--payment-script-file", supplementalDatumScript
+      ]
+
+  txinForScript2 <- findLargestUtxoForPaymentKey epochStateView sbe wallet1
+  let sendToScript2TxBody = work </> "send-to-script-2-tx.body"
+      sendToScript2TxSigned = work </> "send-to-script-2-tx.signed"
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build"
+    , "--change-address", Text.unpack $ paymentKeyInfoAddr wallet1
+    , "--tx-in", Text.unpack $ renderTxIn txinForScript2
+    , "--tx-out", supplementalDatumScriptAddr <> "+5000000"
+    , "--tx-out-datum-hash", scriptDatumHash
+    , "--out-file", sendToScript2TxBody
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "sign"
+    , "--tx-body-file", sendToScript2TxBody
+    , "--signing-key-file", wallet1SKeyFile
+    , "--out-file", sendToScript2TxSigned
+    ]
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "submit"
+    , "--tx-file", sendToScript2TxSigned
+    ]
+
+  supplementalDatumTxIn <- fmap fst . retryUntilJustM epochStateView (WaitForBlocks 3) $
+    findLargestUtxoWithAddress epochStateView sbe $ Text.pack supplementalDatumScriptAddr
+
+  -- Fetch protocol parameters for build-raw with scripts
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "query", "protocol-parameters"
+    , "--out-file", work </> "pparams.json"
+    ]
+
+  -- Helper: assert that stdout contains an expected substring
+  let assertContains :: String -> String -> H.Integration ()
+      assertContains output expected = do
+        H.note_ $ "  Checking for: " <> expected
+        H.assert $ expected `isInfixOf` output
+
+  -- Helper: sign tx body and run validate, returning (exitCode, stdout, stderr)
+  let signAndValidate skey txBody txSigned = do
+        void $ execCli' execConfig
+          [ anyEraToString cEra, "transaction", "sign"
+          , "--tx-body-file", txBody
+          , "--signing-key-file", skey
+          , "--out-file", txSigned
+          ]
+        execCliAny execConfig
+          [ anyEraToString cEra, "transaction", "validate"
+          , "--tx-file", txSigned
+          ]
+
+  -- ====================================================================
+  -- Test 1: ConwayMempoolFailure (non-existent input)
+  -- The all-zeros TxIn is caught by the mempool shortcircuit check
+  -- before the UTxO rules can fire BadInputsUTxO.
+  -- ====================================================================
+  H.note_ "=== Test 1: ConwayMempoolFailure (non-existent input) ==="
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", "0000000000000000000000000000000000000000000000000000000000000000#0"
+    , "--tx-out", testAddr <> "+9800000"
+    , "--fee", "200000"
+    , "--out-file", work </> "bad-input-tx.body"
+    ]
+
+  (ec1, out1, _stderr1) <- signAndValidate testSKeyFile
+    (work </> "bad-input-tx.body") (work </> "bad-input-tx.signed")
+
+  H.note_ $ "Output:\n" <> out1
+  ec1 H.=== ExitFailure 1
+  assertContains out1 "Phase 1: FAILED"
+  assertContains out1 "ConwayMempoolFailure:"
+
+  -- ====================================================================
+  -- Test 2: Mega combo — 5 Phase 1 errors in one transaction
+  --   OutputTooSmallUTxO + FeeTooSmallUTxO + ValueNotConservedUTxO
+  --   + OutsideValidityIntervalUTxO + MissingVKeyWitnessesUTXOW
+  --
+  -- Uses a real input (10M lovelace):
+  --   output₁ = 1 lovelace (too small)
+  --   output₂ = 999,999,000,000 lovelace (blows up value conservation)
+  --   fee = 100 (too small)
+  --   --invalid-hereafter 1 (expired)
+  --   signed with wallet1's key (wrong key for testAddr)
+  -- ====================================================================
+  H.note_ "=== Test 2: Mega combo (5 Phase 1 errors) ==="
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn (head testTxIns)
+    , "--tx-out", testAddr <> "+1"
+    , "--tx-out", testAddr <> "+999999000000"
+    , "--fee", "100"
+    , "--invalid-hereafter", "1"
+    , "--out-file", work </> "mega-combo-tx.body"
+    ]
+
+  (ec2, out2, _stderr2) <- signAndValidate wallet1SKeyFile
+    (work </> "mega-combo-tx.body") (work </> "mega-combo-tx.signed")
+
+  H.note_ $ "Output:\n" <> out2
+  ec2 H.=== ExitFailure 1
+  assertContains out2 "Phase 1: FAILED"
+  -- Values are deterministic: input = 10M, outputs = 1 + 999,999,000,000, fee = 100
+  -- Missing key hash = fe8c22... (the deterministic test key)
+  -- Slot 1 is the expired validity upper bound (current slot is dynamic)
+  assertContains out2 "BabbageOutputTooSmallUTxO:"
+  assertContains out2 "FeeTooSmallUTxO: minimum fee is"
+  assertContains out2 "ValueNotConservedUTxO: supplied 10000000 lovelace, expected = 999999000101 lovelace"
+  assertContains out2 "OutsideValidityIntervalUTxO:"
+  assertContains out2 "MissingVKeyWitnessesUTXOW: fe8c2213ed33ae44e3629706a3c7d34f0dce29753646602177756a5f"
+
+  -- ====================================================================
+  -- Test 3: MaxTxSizeUTxO
+  -- Attach enormous metadata (300 × 64-byte strings ≈ 21 KB > 16 KB limit).
+  -- ====================================================================
+  H.note_ "=== Test 3: MaxTxSizeUTxO ==="
+
+  let metadataEntry i = "  \"" <> show @Int i <> "\": \"" <> replicate 64 'A' <> "\""
+      largeMetadata = "{\n" <> intercalate ",\n" (map metadataEntry [0..299]) <> "\n}"
+  H.writeFile (work </> "large-metadata.json") largeMetadata
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn (head testTxIns)
+    , "--tx-out", testAddr <> "+9800000"
+    , "--fee", "200000"
+    , "--json-metadata-no-schema"
+    , "--metadata-json-file", work </> "large-metadata.json"
+    , "--out-file", work </> "max-tx-size-tx.body"
+    ]
+
+  (ec3, out3, _stderr3) <- signAndValidate testSKeyFile
+    (work </> "max-tx-size-tx.body") (work </> "max-tx-size-tx.signed")
+
+  H.note_ $ "Output:\n" <> out3
+  ec3 H.=== ExitFailure 1
+  assertContains out3 "Phase 1: FAILED"
+  -- 300 entries × ~68 CBOR bytes = ~20 KB > 16384 byte limit
+  assertContains out3 "MaxTxSizeUTxO: supplied 20657 bytes, expected ≤ 16384 bytes"
+  H.diffVsGoldenFile out3
+    "test/cardano-testnet-test/files/golden/tx_validate/errors_max_tx_size.out"
+
+  -- ====================================================================
+  -- Test 4: ExUnitsTooBigUTxO + TooManyCollateralInputs
+  -- Script input with execution units far above max (140M mem, 10B steps).
+  -- 4 collateral inputs (max allowed is 3).
+  -- ====================================================================
+  H.note_ "=== Test 4: ExUnitsTooBigUTxO + TooManyCollateralInputs ==="
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn scriptTxIn
+    , "--tx-in-script-file", alwaysSucceedsScript
+    , "--tx-in-datum-value", "0"
+    , "--tx-in-redeemer-value", "0"
+    , "--tx-in-execution-units", "(999999999999, 999999999999)"
+    , "--tx-in", Text.unpack $ renderTxIn (head testTxIns)
+    , "--tx-in-collateral", Text.unpack $ renderTxIn (testTxIns !! 1)
+    , "--tx-in-collateral", Text.unpack $ renderTxIn (testTxIns !! 2)
+    , "--tx-in-collateral", Text.unpack $ renderTxIn (testTxIns !! 3)
+    , "--tx-in-collateral", Text.unpack $ renderTxIn (testTxIns !! 4)
+    , "--tx-out", testAddr <> "+12000000"
+    , "--fee", "3000000"
+    , "--protocol-params-file", work </> "pparams.json"
+    , "--out-file", work </> "exunits-collateral-tx.body"
+    ]
+
+  (ec4, out4, _stderr4) <- signAndValidate testSKeyFile
+    (work </> "exunits-collateral-tx.body") (work </> "exunits-collateral-tx.signed")
+
+  H.note_ $ "Output:\n" <> out4
+  ec4 H.=== ExitFailure 1
+  assertContains out4 "Phase 1: FAILED"
+  -- ExUnits (999999999999, 999999999999) far exceed max (140000000, 10000000000)
+  assertContains out4 "ExUnitsTooBigUTxO:"
+  -- 4 collateral inputs > maxCollateralInputs (3)
+  assertContains out4 "TooManyCollateralInputs: supplied 4, expected ≤ 3"
+
+  -- ====================================================================
+  -- Test 5: NoCollateralInputs
+  -- Script transaction with no --tx-in-collateral at all.
+  -- ====================================================================
+  H.note_ "=== Test 5: NoCollateralInputs ==="
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn scriptTxIn
+    , "--tx-in-script-file", alwaysSucceedsScript
+    , "--tx-in-datum-value", "0"
+    , "--tx-in-redeemer-value", "0"
+    , "--tx-in-execution-units", "(1000000, 2000000)"
+    , "--tx-out", testAddr <> "+2000000"
+    , "--fee", "3000000"
+    , "--protocol-params-file", work </> "pparams.json"
+    , "--out-file", work </> "no-collateral-tx.body"
+    ]
+
+  (ec5, out5, _stderr5) <- signAndValidate testSKeyFile
+    (work </> "no-collateral-tx.body") (work </> "no-collateral-tx.signed")
+
+  H.note_ $ "Output:\n" <> out5
+  ec5 H.=== ExitFailure 1
+  assertContains out5 "Phase 1: FAILED"
+  assertContains out5 "NoCollateralInputs"
+  -- 0 collateral, required = fee 3M × 150% = 4.5M
+  assertContains out5 "InsufficientCollateral: actual collateral is 0 lovelace, required collateral is 4500000 lovelace"
+  H.diffVsGoldenFile out5
+    "test/cardano-testnet-test/files/golden/tx_validate/errors_no_collateral.out"
+
+  -- ====================================================================
+  -- Test 6: InsufficientCollateral
+  -- Script tx with fee = 10M → required collateral = 15M (150%).
+  -- Collateral UTxO has only 10M → insufficient.
+  -- Uses a second regular input (10M) so that value is conserved:
+  --   consumed = 5M (script) + 10M (regular) = 15M
+  --   produced = 5M (output) + 10M (fee) = 15M
+  -- ====================================================================
+  H.note_ "=== Test 6: InsufficientCollateral ==="
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn scriptTxIn
+    , "--tx-in-script-file", alwaysSucceedsScript
+    , "--tx-in-datum-value", "0"
+    , "--tx-in-redeemer-value", "0"
+    , "--tx-in-execution-units", "(1000000, 2000000)"
+    , "--tx-in", Text.unpack $ renderTxIn (head testTxIns)
+    , "--tx-in-collateral", Text.unpack $ renderTxIn (testTxIns !! 1)
+    , "--tx-out", testAddr <> "+5000000"
+    , "--fee", "10000000"
+    , "--protocol-params-file", work </> "pparams.json"
+    , "--out-file", work </> "insufficient-collateral-tx.body"
+    ]
+
+  (ec6, out6, _stderr6) <- signAndValidate testSKeyFile
+    (work </> "insufficient-collateral-tx.body") (work </> "insufficient-collateral-tx.signed")
+
+  H.note_ $ "Output:\n" <> out6
+  ec6 H.=== ExitFailure 1
+  assertContains out6 "Phase 1: FAILED"
+  -- 10M collateral < 10M fee × 150% = 15M required
+  assertContains out6 "InsufficientCollateral: actual collateral is 10000000 lovelace, required collateral is 15000000 lovelace"
+
+  -- ====================================================================
+  -- Test 7: IncorrectTotalCollateralField
+  -- Declares --tx-total-collateral 1 but the actual collateral is 10M.
+  -- Value-balanced, fee reasonable, so only the total-collateral mismatch fires.
+  -- ====================================================================
+  H.note_ "=== Test 7: IncorrectTotalCollateralField ==="
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn scriptTxIn
+    , "--tx-in-script-file", alwaysSucceedsScript
+    , "--tx-in-datum-value", "0"
+    , "--tx-in-redeemer-value", "0"
+    , "--tx-in-execution-units", "(1000000, 2000000)"
+    , "--tx-in", Text.unpack $ renderTxIn (head testTxIns)
+    , "--tx-in-collateral", Text.unpack $ renderTxIn (testTxIns !! 1)
+    , "--tx-total-collateral", "1"
+    , "--tx-out", testAddr <> "+12000000"
+    , "--fee", "3000000"
+    , "--protocol-params-file", work </> "pparams.json"
+    , "--out-file", work </> "incorrect-total-collateral-tx.body"
+    ]
+
+  (ec7, out7, _stderr7) <- signAndValidate testSKeyFile
+    (work </> "incorrect-total-collateral-tx.body") (work </> "incorrect-total-collateral-tx.signed")
+
+  H.note_ $ "Output:\n" <> out7
+  ec7 H.=== ExitFailure 1
+  assertContains out7 "Phase 1: FAILED"
+  -- Declared --tx-total-collateral 1, but actual sum of collateral inputs is 10M
+  assertContains out7 "IncorrectTotalCollateralField: declared total collateral is 1 lovelace, actual total collateral is 10000000 lovelace"
+
+  -- ====================================================================
+  -- Test 8: MissingScriptWitnessesUTXOW
+  -- Spend a UTxO at the script address without providing the script.
+  -- ====================================================================
+  H.note_ "=== Test 8: MissingScriptWitnessesUTXOW ==="
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in", Text.unpack $ renderTxIn scriptTxIn
+    , "--tx-out", testAddr <> "+2000000"
+    , "--fee", "3000000"
+    , "--out-file", work </> "missing-script-witness-tx.body"
+    ]
+
+  (ec8, out8, _stderr8) <- signAndValidate testSKeyFile
+    (work </> "missing-script-witness-tx.body") (work </> "missing-script-witness-tx.signed")
+
+  H.note_ $ "Output:\n" <> out8
+  ec8 H.=== ExitFailure 1
+  assertContains out8 "Phase 1: FAILED"
+  -- The always-succeeds script hash
+  assertContains out8 "MissingScriptWitnessesUTXOW: 186e32faa80a26810392fda6d559c7ed4721a65ce1c9d4ef3e1c87b4"
+  H.diffVsGoldenFile out8
+    "test/cardano-testnet-test/files/golden/tx_validate/errors_missing_script_witness.out"
+
+  -- ====================================================================
+  -- Test 9: Phase 2 script evaluation failure
+  -- The supplemental-datum script requires datum with hash of integer 1
+  -- in the transaction.  We omit it → script fails at evaluation.
+  -- ====================================================================
+  H.note_ "=== Test 9: Phase 2 script failure ==="
+
+  txinCollateral9 <- findLargestUtxoForPaymentKey epochStateView sbe wallet0
+
+  void $ execCli' execConfig
+    [ anyEraToString cEra, "transaction", "build-raw"
+    , "--tx-in-collateral", Text.unpack $ renderTxIn txinCollateral9
+    , "--tx-in", Text.unpack $ renderTxIn supplementalDatumTxIn
+    , "--tx-in-script-file", supplementalDatumScript
+    , "--tx-in-datum-value", "0"
+    , "--tx-in-redeemer-value", "0"
+    , "--tx-in-execution-units", "(5000000000, 10000000)"
+    , "--tx-out", wallet0Addr <> "+2000000"
+    , "--fee", "3000000"
+    , "--protocol-params-file", work </> "pparams.json"
+    , "--out-file", work </> "phase2-fail-tx.body"
+    ]
+
+  (ec9, out9, _stderr9) <- signAndValidate wallet0SKeyFile
+    (work </> "phase2-fail-tx.body") (work </> "phase2-fail-tx.signed")
+
+  H.note_ $ "Output:\n" <> out9
+  ec9 H.=== ExitFailure 1
+  assertContains out9 "Phase 2: FAILED"
+  H.diffVsGoldenFile out9
+    "test/cardano-testnet-test/files/golden/tx_validate/errors_phase2_failure.out"
+
+  H.success
diff --git a/cardano-testnet/test/cardano-testnet-test/cardano-testnet-test.hs b/cardano-testnet/test/cardano-testnet-test/cardano-testnet-test.hs
index 49fe74b79a4..44fb2253c31 100644
--- a/cardano-testnet/test/cardano-testnet-test/cardano-testnet-test.hs
+++ b/cardano-testnet/test/cardano-testnet-test/cardano-testnet-test.hs
@@ -19,6 +19,8 @@ import qualified Cardano.Testnet.Test.Cli.StakeSnapshot
 import qualified Cardano.Testnet.Test.Cli.Transaction
 import qualified Cardano.Testnet.Test.Cli.Transaction.BuildEstimate
 import qualified Cardano.Testnet.Test.Cli.Transaction.RegisterDeregisterStakeAddress
+import qualified Cardano.Testnet.Test.Cli.Transaction.Validate
+import qualified Cardano.Testnet.Test.Cli.Transaction.ValidateErrors
 import qualified Cardano.Testnet.Test.Cli.Transaction.WithdrawalReward
 import qualified Cardano.Testnet.Test.DumpConfig
 import qualified Cardano.Testnet.Test.FoldEpochState
@@ -119,6 +121,8 @@ tests = do
           , ignoreOnWindows "simple transaction build" Cardano.Testnet.Test.Cli.Transaction.hprop_transaction
           , ignoreOnWindows "Transaction Build Estimate" Cardano.Testnet.Test.Cli.Transaction.BuildEstimate.hprop_tx_build_estimate
           , ignoreOnWindows "register deregister stake address in transaction build"  Cardano.Testnet.Test.Cli.Transaction.RegisterDeregisterStakeAddress.hprop_tx_register_deregister_stake_address
+          , ignoreOnWindows "transaction validate" Cardano.Testnet.Test.Cli.Transaction.Validate.hprop_transaction_validate
+          , ignoreOnWindows "transaction validate all errors" Cardano.Testnet.Test.Cli.Transaction.ValidateErrors.hprop_transaction_validate_all_errors
           , ignoreOnWindows "transaction build with withdrawal" Cardano.Testnet.Test.Cli.Transaction.WithdrawalReward.hprop_tx_withdrawal_reward
           , ignoreOnWindows "transaction build with plutus withdrawal" Cardano.Testnet.Test.Cli.Transaction.WithdrawalReward.hprop_tx_withdrawal_reward_plutus_v3
           -- FIXME
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_max_tx_size.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_max_tx_size.out
new file mode 100644
index 00000000000..d45c7f31178
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_max_tx_size.out
@@ -0,0 +1,4 @@
+Transaction validation failed.
+Phase 1: FAILED
+  MaxTxSizeUTxO: supplied 20657 bytes, expected ≤ 16384 bytes
+Phase 2: passed (0 scripts evaluated)
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_missing_script_witness.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_missing_script_witness.out
new file mode 100644
index 00000000000..f1397405b72
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_missing_script_witness.out
@@ -0,0 +1,4 @@
+Transaction validation failed.
+Phase 1: FAILED
+  MissingScriptWitnessesUTXOW: 186e32faa80a26810392fda6d559c7ed4721a65ce1c9d4ef3e1c87b4
+Phase 2: passed (0 scripts evaluated)
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_no_collateral.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_no_collateral.out
new file mode 100644
index 00000000000..5165a0ab58f
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_no_collateral.out
@@ -0,0 +1,6 @@
+Transaction validation failed.
+Phase 1: FAILED
+  InsufficientCollateral: actual collateral is 0 lovelace, required collateral is 4500000 lovelace
+  NoCollateralInputs
+Phase 2: passed (1 script evaluated)
+  Spend:0 passed (mem: 500, steps: 64100)
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_phase2_failure.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_phase2_failure.out
new file mode 100644
index 00000000000..b8711d6d07c
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/errors_phase2_failure.out
@@ -0,0 +1,8 @@
+Transaction validation failed.
+Phase 1: passed
+Phase 2: FAILED
+  Spend:0 FAILED
+    CekError An error has occurred:
+    The machine terminated because of an error, either from a built-in function or from an explicit use of 'error'.
+    Caused by: error
+    Logs: PT5
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/failing_plutus.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/failing_plutus.out
new file mode 100644
index 00000000000..b8711d6d07c
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/failing_plutus.out
@@ -0,0 +1,8 @@
+Transaction validation failed.
+Phase 1: passed
+Phase 2: FAILED
+  Spend:0 FAILED
+    CekError An error has occurred:
+    The machine terminated because of an error, either from a built-in function or from an explicit use of 'error'.
+    Caused by: error
+    Logs: PT5
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/fee_too_low.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/fee_too_low.out
new file mode 100644
index 00000000000..fe431f228ad
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/fee_too_low.out
@@ -0,0 +1,4 @@
+Transaction validation failed.
+Phase 1: FAILED
+  FeeTooSmallUTxO: minimum fee is 193 lovelace, transaction specifies 100 lovelace
+Phase 2: passed (0 scripts evaluated)
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/missing_witness.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/missing_witness.out
new file mode 100644
index 00000000000..e25bc9eea69
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/missing_witness.out
@@ -0,0 +1,4 @@
+Transaction validation failed.
+Phase 1: FAILED
+  MissingVKeyWitnessesUTXOW: fe8c2213ed33ae44e3629706a3c7d34f0dce29753646602177756a5f
+Phase 2: passed (0 scripts evaluated)
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/multi_error.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/multi_error.out
new file mode 100644
index 00000000000..2efa6be2b57
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/multi_error.out
@@ -0,0 +1,5 @@
+Transaction validation failed.
+Phase 1: FAILED
+  FeeTooSmallUTxO: minimum fee is 197 lovelace, transaction specifies 100 lovelace
+  ValueNotConservedUTxO: supplied 10000000 lovelace, expected = 999999000100 lovelace
+Phase 2: passed (0 scripts evaluated)
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/valid_plutus.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/valid_plutus.out
new file mode 100644
index 00000000000..7075c6ad8a7
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/valid_plutus.out
@@ -0,0 +1,4 @@
+Transaction is valid.
+Phase 1: passed
+Phase 2: passed (1 script evaluated)
+  Spend:0 passed (mem: 500, steps: 64100)
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/valid_simple.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/valid_simple.out
new file mode 100644
index 00000000000..c4a2600d75e
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/valid_simple.out
@@ -0,0 +1,3 @@
+Transaction is valid.
+Phase 1: passed
+Phase 2: passed (0 scripts evaluated)
diff --git a/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/value_not_conserved.out b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/value_not_conserved.out
new file mode 100644
index 00000000000..6d1efc8819d
--- /dev/null
+++ b/cardano-testnet/test/cardano-testnet-test/files/golden/tx_validate/value_not_conserved.out
@@ -0,0 +1,4 @@
+Transaction validation failed.
+Phase 1: FAILED
+  ValueNotConservedUTxO: supplied 10000000 lovelace, expected = 999999200000 lovelace
+Phase 2: passed (0 scripts evaluated)