diff --git a/pkg/tbtc/marshaling_test.go b/pkg/tbtc/marshaling_test.go
index 32b6977f0a..5fa3692918 100644
--- a/pkg/tbtc/marshaling_test.go
+++ b/pkg/tbtc/marshaling_test.go
@@ -231,6 +231,22 @@ func TestCoordinationMessage_MarshalingRoundtrip(t *testing.T) {
 				SweepTxFee:               big.NewInt(8000),
 			},
 		},
+		"with reservation anchor proposal": {
+			proposal: &ReservationAnchorProposal{
+				DepositFundingTxHash:      parseHash("709b55bd3da0f5a838125bd0ee20c5bfdd7caba173912d4281cae816b79a201b"),
+				DepositFundingOutputIndex: 2,
+				RequestNonce:              7,
+				AnchorTxFee:               big.NewInt(1500),
+			},
+		},
+		"with reservation reanchor proposal": {
+			proposal: &ReservationReanchorProposal{
+				ReservationKey:            big.NewInt(424242),
+				RequestNonce:              4,
+				TargetWalletPublicKeyHash: toByte20("f87eb7ec3b15a3fdd7b57754d765694b3e0b4bf4"),
+				ReanchorTxFee:             big.NewInt(1200),
+			},
+		},
 	}
 
 	walletPublicKeyHash := toByte20("aa768412ceed10bd423c025542ca90071f9fb62d")
@@ -402,6 +418,64 @@ func TestFuzzCoordinationMessage_MarshalingRoundtrip_WithMovedFundsSweepProposal
 	}
 }
 
+func TestFuzzCoordinationMessage_MarshalingRoundtrip_WithReservationAnchorProposal(t *testing.T) {
+	for i := 0; i < 10; i++ {
+		var (
+			senderID            group.MemberIndex
+			coordinationBlock   uint64
+			walletPublicKeyHash [20]byte
+			proposal            ReservationAnchorProposal
+		)
+
+		f := fuzz.New().NilChance(0.1).
+			NumElements(0, 512).
+			Funcs(pbutils.FuzzFuncs()...)
+
+		f.Fuzz(&senderID)
+		f.Fuzz(&coordinationBlock)
+		f.Fuzz(&walletPublicKeyHash)
+		f.Fuzz(&proposal)
+
+		coordinationMsg := &coordinationMessage{
+			senderID:            senderID,
+			coordinationBlock:   coordinationBlock,
+			walletPublicKeyHash: walletPublicKeyHash,
+			proposal:            &proposal,
+		}
+
+		_ = pbutils.RoundTrip(coordinationMsg, &coordinationMessage{})
+	}
+}
+
+func TestFuzzCoordinationMessage_MarshalingRoundtrip_WithReservationReanchorProposal(t *testing.T) {
+	for i := 0; i < 10; i++ {
+		var (
+			senderID            group.MemberIndex
+			coordinationBlock   uint64
+			walletPublicKeyHash [20]byte
+			proposal            ReservationReanchorProposal
+		)
+
+		f := fuzz.New().NilChance(0.1).
+			NumElements(0, 512).
+			Funcs(pbutils.FuzzFuncs()...)
+
+		f.Fuzz(&senderID)
+		f.Fuzz(&coordinationBlock)
+		f.Fuzz(&walletPublicKeyHash)
+		f.Fuzz(&proposal)
+
+		coordinationMsg := &coordinationMessage{
+			senderID:            senderID,
+			coordinationBlock:   coordinationBlock,
+			walletPublicKeyHash: walletPublicKeyHash,
+			proposal:            &proposal,
+		}
+
+		_ = pbutils.RoundTrip(coordinationMsg, &coordinationMessage{})
+	}
+}
+
 func TestFuzzCoordinationMessage_MarshalingRoundtrip_WithNoopProposal(t *testing.T) {
 	for i := 0; i < 10; i++ {
 		var (
diff --git a/pkg/tbtc/reservation_test.go b/pkg/tbtc/reservation_test.go
index 899d9a144c..d0649d9329 100644
--- a/pkg/tbtc/reservation_test.go
+++ b/pkg/tbtc/reservation_test.go
@@ -137,7 +137,7 @@ func TestReservationProposals_MarshalingRoundtrip(t *testing.T) {
 	roundtrip(reanchorProposal, &ReservationReanchorProposal{})
 }
 
-func TestReservationProposals_UnmarshalRejectsMissingIntegers(t *testing.T) {
+func TestReservationProposals_UnmarshalRejectsInvalidFields(t *testing.T) {
 	tests := map[string]struct {
 		actionType    WalletActionType
 		payload       []byte
@@ -201,6 +201,36 @@ func TestReservationProposals_UnmarshalRejectsMissingIntegers(t *testing.T) {
 			}),
 			expectedError: "cannot unmarshal proposal payload: [invalid re-anchor transaction fee byte length: [9]]",
 		},
+		"anchor zero fee marshaled through Marshal is rejected as missing": {
+			actionType: ActionReservationAnchor,
+			payload: marshalThroughProposal(t, &ReservationAnchorProposal{
+				DepositFundingTxHash:      bitcoin.Hash{0x01, 0x02},
+				DepositFundingOutputIndex: 3,
+				RequestNonce:              1,
+				AnchorTxFee:               big.NewInt(0),
+			}),
+			expectedError: "cannot unmarshal proposal payload: [anchor transaction fee is required]",
+		},
+		"re-anchor zero reservation key marshaled through Marshal is rejected as missing": {
+			actionType: ActionReservationReanchor,
+			payload: marshalThroughProposal(t, &ReservationReanchorProposal{
+				ReservationKey:            big.NewInt(0),
+				RequestNonce:              3,
+				TargetWalletPublicKeyHash: [20]byte{0xaa, 0xbb},
+				ReanchorTxFee:             big.NewInt(1700),
+			}),
+			expectedError: "cannot unmarshal proposal payload: [reservation key is required]",
+		},
+		"re-anchor zero fee marshaled through Marshal is rejected as missing": {
+			actionType: ActionReservationReanchor,
+			payload: marshalThroughProposal(t, &ReservationReanchorProposal{
+				ReservationKey:            big.NewInt(54321),
+				RequestNonce:              3,
+				TargetWalletPublicKeyHash: [20]byte{0xaa, 0xbb},
+				ReanchorTxFee:             big.NewInt(0),
+			}),
+			expectedError: "cannot unmarshal proposal payload: [re-anchor transaction fee is required]",
+		},
 	}
 
 	for testName, test := range tests {
@@ -230,6 +260,19 @@ func marshalPb(t *testing.T, msg proto.Message) []byte {
 	return data
 }
 
+// marshalThroughProposal marshals a CoordinationProposal via its own Marshal
+// method, for use as a test fixture payload. Unlike marshalPb, this exercises
+// the proposal's real wire-encoding path (e.g. *big.Int.Bytes()) rather than
+// hand-constructing the protobuf message directly.
+func marshalThroughProposal(t *testing.T, proposal CoordinationProposal) []byte {
+	t.Helper()
+	data, err := proposal.Marshal()
+	if err != nil {
+		t.Fatal(err)
+	}
+	return data
+}
+
 func signReservationTransaction(
 	t *testing.T,
 	builder *bitcoin.TransactionBuilder,