diff --git a/builder/builder/utils_test.go b/builder/builder/utils_test.go
index 76e6cfdf8..f4af130da 100644
--- a/builder/builder/utils_test.go
+++ b/builder/builder/utils_test.go
@@ -57,7 +57,7 @@ func TestGenerateMerkleMultiProofs(t *testing.T) {
 
 			constraints := make(types.HashToConstraintDecoded)
 			for _, tx := range chosenConstraintTransactions {
-				constraints[tx.Hash()] = &types.ConstraintDecoded{Tx: tx}
+				constraints[tx.Hash()] = tx
 			}
 
 			inclusionProof, root, err := CalculateMerkleMultiProofs(payloadTransactions, constraints)
@@ -67,15 +67,15 @@ func TestGenerateMerkleMultiProofs(t *testing.T) {
 			leaves := make([][]byte, len(constraints))
 
 			i := 0
-			for _, constraint := range constraints {
-				if constraint == nil || constraint.Tx == nil {
-					t.Logf("nil constraint or transaction!")
+			for _, tx := range constraints {
+				if tx == nil {
+					t.Logf("nil constraint transaction!")
 				}
 
-				// Compute the hash tree root for the raw preconfirmed transaction
+				// Compute the hash tree root for the raw committed transaction
 				// and use it as "Leaf" in the proof to be verified against
 
-				withoutBlob, err := constraint.Tx.WithoutBlobTxSidecar().MarshalBinary()
+				withoutBlob, err := tx.WithoutBlobTxSidecar().MarshalBinary()
 				if err != nil {
 					t.Logf("error marshalling transaction without blob tx sidecar: %v", err)
 				}
diff --git a/builder/common/types.go b/builder/common/types.go
index b07ac1987..b74259806 100644
--- a/builder/common/types.go
+++ b/builder/common/types.go
@@ -603,35 +603,24 @@ type SignedConstraintsList = []*SignedConstraints
 
 // Reference: https://chainbound.github.io/bolt-docs/api/builder
 type SignedConstraints struct {
-	Message   ConstraintMessage   `json:"message"`
+	Message   ConstraintsMessage  `json:"message"`
 	Signature phase0.BLSSignature `json:"signature"`
 }
 
 // Reference: https://chainbound.github.io/bolt-docs/api/builder
-type ConstraintMessage struct {
-	Constraints    []*HexBytes `json:"constraints"`
-	ValidatorIndex uint64      `json:"validator_index"`
-	Slot           uint64      `json:"slot"`
-	Top            bool        `json:"top"`
+type ConstraintsMessage struct {
+	Pubkey       uint64      `json:"pubkey"`
+	Slot         uint64      `json:"slot"`
+	Top          bool        `json:"top"`
+	Transactions []*HexBytes `json:"transactions"`
 }
 
-// Reference: https://chainbound.github.io/bolt-docs/api/builder-api
-// type Constraint struct {
-// 	Index *uint64  `json:"index"`
-// 	Tx    HexBytes `json:"tx"`
-// }
-
-// ConstraintSubscriptionAuth is the struct the builder signs over to authenticate
-// when subscribing to SSE constraint events from the relay
-type ConstraintSubscriptionAuth struct {
-	PublicKey phase0.BLSPubKey `json:"publicKey"`
-	Slot      uint64           `json:"slot"`
+type SignedDelegation struct {
+	Message   Delegation          `json:"message"`
+	Signature phase0.BLSSignature `json:"signature"`
 }
 
-func (c *ConstraintSubscriptionAuth) String() string {
-	buf, err := json.Marshal(c)
-	if err != nil {
-		return fmt.Sprintf("failed to marshal ConstraintSubscriptionAuth: %v", err)
-	}
-	return string(buf)
+type Delegation struct {
+	ValidatorPubkey phase0.BLSPubKey `json:"validator_pubkey"`
+	DelegateePubkey phase0.BLSPubKey `json:"delegatee_pubkey"`
 }
diff --git a/builder/miner/worker_test.go b/builder/miner/worker_test.go
index 745a47618..bf5344876 100644
--- a/builder/miner/worker_test.go
+++ b/builder/miner/worker_test.go
@@ -122,8 +122,8 @@ func init() {
 			} else {
 				idx = nil
 			}
-			constraints := make(map[common.Hash]*types.ConstraintDecoded)
-			constraints[tx1.Hash()] = &types.ConstraintDecoded{Index: idx, Tx: tx1}
+			constraints := make(map[common.Hash]*types.Transaction)
+			constraints[tx1.Hash()] = tx1
 			// FIXME: slot 0 is probably not correct for these tests
 			testConstraintsCache.Put(0, constraints)
 		}