diff --git a/agora/Agora/Governor/Scripts.hs b/agora/Agora/Governor/Scripts.hs
index 1525f90..3957821 100644
--- a/agora/Agora/Governor/Scripts.hs
+++ b/agora/Agora/Governor/Scripts.hs
@@ -28,6 +28,7 @@ import Agora.Governor (
  )
 import Agora.Proposal (
   PProposalDatum (..),
+  PProposalEffectGroup,
   ProposalStatus (Draft, Locked),
   phasNeutralEffect,
   pisEffectsVotesCompatible,
@@ -36,7 +37,14 @@ import Agora.Proposal (
   pwinner,
  )
 import Agora.Proposal.Time (createProposalStartingTime)
-import Agora.Scripts (AgoraScripts, authorityTokenSymbol, governorSTSymbol, proposalSTSymbol, proposalValidatoHash, stakeSTSymbol)
+import Agora.Scripts (
+  AgoraScripts,
+  authorityTokenSymbol,
+  governorSTSymbol,
+  proposalSTSymbol,
+  proposalValidatoHash,
+  stakeSTSymbol,
+ )
 import Agora.Stake (
   PProposalLock (..),
   PStakeDatum (..),
@@ -45,17 +53,17 @@ import Agora.Stake (
 import Agora.Utils (
   pfindDatum,
   pfromDatumHash,
+  pfstTuple,
   pmustFindDatum,
+  psndTuple,
   validatorHashToAddress,
  )
 import Plutarch.Api.V1 (
   PCurrencySymbol,
-  PMap,
-  PValidatorHash,
  )
+import Plutarch.Api.V1.AssocMap qualified as AssocMap
 import Plutarch.Api.V2 (
   PAddress,
-  PDatumHash,
   PMintingPolicy,
   PScriptPurpose (PMinting, PSpending),
   PTxOut,
@@ -66,10 +74,9 @@ import Plutarch.Extra.Field (pletAllC)
 import Plutarch.Extra.IsData (pmatchEnumFromData)
 import Plutarch.Extra.List (pfirstJust)
 import Plutarch.Extra.Map (
-  plookup,
   plookup',
  )
-import Plutarch.Extra.Maybe (passertPJust, pfromJust, pnothing)
+import Plutarch.Extra.Maybe (passertPDJust, passertPJust, pfromJust, pmaybeData, pnothing)
 import Plutarch.Extra.Record (mkRecordConstr, (.&), (.=))
 import Plutarch.Extra.ScriptContext (
   pfindOutputsToAddress,
@@ -489,35 +496,44 @@ governorValidator as =
           pguardC "Output GATs is more than minted GATs" $
             plength # outputsWithGAT #== gatCount
 
-          let gatOutputValidator' :: Term s (PMap _ PValidatorHash PDatumHash :--> PTxOut :--> PBool)
-              gatOutputValidator' =
+          let validateGATOutput' :: Term s (PProposalEffectGroup :--> PTxOut :--> PBool)
+              validateGATOutput' =
                 phoistAcyclic $
                   plam
-                    ( \effects output' -> unTermCont $ do
-                        output <- pletFieldsC @'["address", "datum"] output'
+                    ( \effects output -> unTermCont $ do
+                        outputF <- pletFieldsC @'["address", "datum", "referenceScript"] output
 
-                        let scriptHash =
-                              passertPJust # "GAT receiver is not a script"
-                                #$ pscriptHashFromAddress # output.address
-                            datumHash =
-                              ptrace
-                                "Output to effect should have datum"
-                                pfromDatumHash
-                                # output.datum
-
-                            expectedDatumHash =
-                              passertPJust # "Receiver is not in the effect list"
-                                #$ plookup # scriptHash # effects
+                        let receiverScriptHash =
+                              passertPJust # "GAT receiver should be a script"
+                                #$ pscriptHashFromAddress # outputF.address
+                            effect =
+                              passertPJust # "Receiver should be in the effect group"
+                                #$ AssocMap.plookup # receiverScriptHash # effects
+                            hasCorrectReferenceScript =
+                              pmaybeData
+                                # pconstant True
+                                # plam
+                                  ( ( passertPDJust
+                                        # "Output UTXO should have a reference script"
+                                        # outputF.referenceScript
+                                        #==
+                                    )
+                                      . pfromData
+                                  )
+                                # (psndTuple # effect)
+                            hasCorrectDatum =
+                              pfstTuple # effect #== pfromDatumHash # outputF.datum
 
                         pure $
                           foldr1
                             (#&&)
-                            [ ptraceIfFalse "GAT must be tagged by the effect hash" $ authorityTokensValidIn # patSymbol # output'
-                            , ptraceIfFalse "Unexpected datum" $ datumHash #== expectedDatumHash
+                            [ ptraceIfFalse "GAT valid" $ authorityTokensValidIn # patSymbol # output
+                            , ptraceIfFalse "Correct datum" hasCorrectDatum
+                            , ptraceIfFalse "Reference script correct" hasCorrectReferenceScript
                             ]
                     )
 
-              gatOutputValidator = gatOutputValidator' # effectGroup
+              validateGATOutput = validateGATOutput' # effectGroup
 
           pguardC "GATs valid" $
             pfoldr
@@ -526,7 +542,7 @@ governorValidator as =
                     let value = pfield @"value" # txOut
                         atValue = psymbolValueOf # patSymbol # value
                      in pif (atValue #== 0) r $
-                          pif (atValue #== 1) (r #&& gatOutputValidator # txOut) $ pconstant False
+                          pif (atValue #== 1) (r #&& validateGATOutput # txOut) $ pconstant False
                 )
               # pconstant True
               # pfromData txInfoF.outputs
diff --git a/agora/Agora/Plutarch/Orphans.hs b/agora/Agora/Plutarch/Orphans.hs
index 57778e6..1f22824 100644
--- a/agora/Agora/Plutarch/Orphans.hs
+++ b/agora/Agora/Plutarch/Orphans.hs
@@ -7,7 +7,7 @@
 
 module Agora.Plutarch.Orphans () where
 
-import Plutarch.Api.V1 (PDatumHash (..))
+import Plutarch.Api.V2 (PDatumHash (..), PScriptHash (..))
 import Plutarch.Builtin (PIsData (..))
 import Plutarch.Extra.TermCont (ptryFromC)
 import Plutarch.TryFrom (PTryFrom (..))
@@ -37,3 +37,18 @@ instance PTryFrom PData (PAsData PUnit)
 instance (PIsData a) => PIsData (PAsData a) where
   pfromDataImpl = punsafeCoerce
   pdataImpl = pdataImpl . pfromData
+
+-- | @since 1.0.0
+instance PTryFrom PData (PAsData PScriptHash) where
+  type PTryFromExcess PData (PAsData PScriptHash) = Flip Term PScriptHash
+  ptryFrom' opq = runTermCont $ do
+    (pfromData -> unwrapped, _) <- ptryFromC @(PAsData PByteString) opq
+
+    tcont $ \f ->
+      pif
+        -- Blake2b_224 hash: 224 bits/28 bytes.
+        (plengthBS # unwrapped #== 28)
+        (f ())
+        (ptraceError "ptryFrom(PScriptHash): must be 32 bytes long")
+
+    pure (punsafeCoerce opq, pcon $ PScriptHash unwrapped)
diff --git a/agora/Agora/Proposal.hs b/agora/Agora/Proposal.hs
index 2cccdb3..9b124c6 100644
--- a/agora/Agora/Proposal.hs
+++ b/agora/Agora/Proposal.hs
@@ -11,6 +11,7 @@ module Agora.Proposal (
   -- * Haskell-land
 
   -- Proposal (..),
+  ProposalEffectGroup,
   ProposalDatum (..),
   ProposalRedeemer (..),
   ProposalStatus (..),
@@ -21,6 +22,7 @@ module Agora.Proposal (
   emptyVotesFor,
 
   -- * Plutarch-land
+  PProposalEffectGroup,
   PProposalDatum (..),
   PProposalRedeemer (..),
   PProposalStatus (..),
@@ -41,7 +43,12 @@ module Agora.Proposal (
 ) where
 
 import Agora.Plutarch.Orphans ()
-import Agora.Proposal.Time (PProposalStartingTime, PProposalTimingConfig, ProposalStartingTime, ProposalTimingConfig)
+import Agora.Proposal.Time (
+  PProposalStartingTime,
+  PProposalTimingConfig,
+  ProposalStartingTime,
+  ProposalTimingConfig,
+ )
 import Agora.SafeMoney (GTTag)
 import Data.Tagged (Tagged)
 import Generics.SOP qualified as SOP
@@ -50,7 +57,10 @@ import Plutarch.Api.V1.AssocMap qualified as PAssocMap
 import Plutarch.Api.V2 (
   KeyGuarantees (Unsorted),
   PDatumHash,
+  PMaybeData,
   PPubKeyHash,
+  PScriptHash,
+  PTuple,
  )
 import Plutarch.DataRepr (DerivePConstantViaData (..), PDataFields)
 import Plutarch.Extra.Comonad (pextract)
@@ -75,7 +85,7 @@ import Plutarch.Lift (
  )
 import Plutarch.SafeMoney (PDiscrete (..))
 import Plutarch.Show (PShow (..))
-import PlutusLedgerApi.V1 (DatumHash, PubKeyHash, ValidatorHash)
+import PlutusLedgerApi.V2 (DatumHash, PubKeyHash, ScriptHash, ValidatorHash)
 import PlutusTx qualified
 import PlutusTx.AssocMap qualified as AssocMap
 
@@ -272,6 +282,9 @@ newtype ProposalVotes = ProposalVotes
 emptyVotesFor :: forall a. AssocMap.Map ResultTag a -> ProposalVotes
 emptyVotesFor = ProposalVotes . AssocMap.mapWithKey (const . const 0)
 
+-- | @since 0.3.0
+type ProposalEffectGroup = AssocMap.Map ValidatorHash (DatumHash, Maybe ScriptHash)
+
 {- | Haskell-level datum for Proposal scripts.
 
      @since 0.1.0
@@ -282,7 +295,7 @@ data ProposalDatum = ProposalDatum
   -- TODO: could we encode this more efficiently?
   -- This is shaped this way for future proofing.
   -- See https://github.com/Liqwid-Labs/agora/issues/39
-  , effects :: AssocMap.Map ResultTag (AssocMap.Map ValidatorHash DatumHash)
+  , effects :: AssocMap.Map ResultTag ProposalEffectGroup
   -- ^ Effect lookup table. First by result, then by effect hash.
   , status :: ProposalStatus
   -- ^ The status the proposal is in.
@@ -583,6 +596,15 @@ deriving via
   instance
     (PConstantDecl ProposalVotes)
 
+type PProposalEffectGroup =
+  PMap
+    'Unsorted
+    PValidatorHash
+    ( PTuple
+        PDatumHash
+        (PMaybeData (PAsData PScriptHash))
+    )
+
 {- | Plutarch-level version of 'ProposalDatum'.
 
      @since 0.1.0
@@ -593,7 +615,7 @@ newtype PProposalDatum (s :: S) = PProposalDatum
         s
         ( PDataRecord
             '[ "proposalId" ':= PProposalId
-             , "effects" ':= PMap 'Unsorted PResultTag (PMap 'Unsorted PValidatorHash PDatumHash)
+             , "effects" ':= PMap 'Unsorted PResultTag PProposalEffectGroup
              , "status" ':= PProposalStatus
              , "cosigners" ':= PBuiltinList (PAsData PPubKeyHash)
              , "thresholds" ':= PProposalThresholds
@@ -678,7 +700,7 @@ phasNeutralEffect ::
   forall (s :: S).
   Term
     s
-    ( PMap 'Unsorted PResultTag (PMap 'Unsorted PValidatorHash PDatumHash)
+    ( PMap 'Unsorted PResultTag PProposalEffectGroup
         :--> PBool
     )
 phasNeutralEffect = phoistAcyclic $ PAssocMap.pany # PAssocMap.pnull
@@ -691,7 +713,7 @@ pisEffectsVotesCompatible ::
   forall (s :: S).
   Term
     s
-    ( PMap 'Unsorted PResultTag (PMap 'Unsorted PValidatorHash PDatumHash)
+    ( PMap 'Unsorted PResultTag PProposalEffectGroup
         :--> PProposalVotes
         :--> PBool
     )
@@ -811,7 +833,7 @@ phighestVotes = phoistAcyclic $
 pneutralOption ::
   Term
     s
-    ( PMap 'Unsorted PResultTag (PMap 'Unsorted PValidatorHash PDatumHash)
+    ( PMap 'Unsorted PResultTag PProposalEffectGroup
         :--> PResultTag
     )
 pneutralOption = phoistAcyclic $
diff --git a/agora/Agora/Proposal/Time.hs b/agora/Agora/Proposal/Time.hs
index 4929370..9a9ca82 100644
--- a/agora/Agora/Proposal/Time.hs
+++ b/agora/Agora/Proposal/Time.hs
@@ -44,8 +44,9 @@ import Plutarch.DataRepr (
   PDataFields,
  )
 import Plutarch.Extra.Applicative (PApply (pliftA2))
+import Plutarch.Extra.Bind ((#>>=))
 import Plutarch.Extra.Field (pletAll, pletAllC)
-import Plutarch.Extra.Maybe (pjust, pmaybe, pnothing)
+import Plutarch.Extra.Maybe (pjust, pnothing)
 import Plutarch.Extra.TermCont (pmatchC)
 import Plutarch.Lift (
   DerivePConstantViaNewtype (..),
@@ -357,8 +358,7 @@ createProposalStartingTime = phoistAcyclic $
                       "createProposalStartingTime: given time range should be tight enough"
                       pnothing
                   )
-     in -- TODO: PMonad when?
-        pmaybe # pnothing # f # ct
+     in ct #>>= f
 
 {- | Get the current proposal time, from the 'PlutusLedgerApi.V1.txInfoValidPeriod' field.
 
diff --git a/agora/Agora/Utils.hs b/agora/Agora/Utils.hs
index 9352fd4..a7c8116 100644
--- a/agora/Agora/Utils.hs
+++ b/agora/Agora/Utils.hs
@@ -24,6 +24,8 @@ module Agora.Utils (
   pfromDatumHash,
   pfromInlineDatum,
   ptryFindDatum,
+  pfstTuple,
+  psndTuple,
 ) where
 
 import Plutarch.Api.V1.AssocMap (KeyGuarantees (Unsorted), PMap)
@@ -32,6 +34,7 @@ import Plutarch.Api.V2 (
   PDatum,
   PDatumHash,
   POutputDatum (..),
+  PTuple,
  )
 import Plutarch.Extra.Functor (pfmap)
 import Plutarch.Extra.Maybe (passertPJust, pjust, pnothing)
@@ -235,3 +238,17 @@ infixr 8 #.**
   Term s c ->
   Term s e
 (#.**) f g x y z = f #$ g # x # y # z
+
+{- | Extract the first component of a 'PTuple'.
+
+     @since 1.0.0
+-}
+pfstTuple :: forall a b s. (PIsData a) => Term s (PTuple a b :--> a)
+pfstTuple = phoistAcyclic $ plam $ pfromData . (pfield @"_0" #)
+
+{- | Extract the second component of a 'PTuple'.
+
+     @since 1.0.0
+-}
+psndTuple :: forall b a s. (PIsData b) => Term s (PTuple a b :--> b)
+psndTuple = phoistAcyclic $ plam $ pfromData . (pfield @"_1" #)