diff --git a/x/coredaos/types/msgs.go b/x/coredaos/types/msgs.go
index c0f226e7..7e8d71a9 100644
--- a/x/coredaos/types/msgs.go
+++ b/x/coredaos/types/msgs.go
@@ -7,6 +7,10 @@ import (
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 )
 
+const (
+	MaxAnnotationLength = 1000
+)
+
 var _, _, _, _, _ sdk.Msg = &MsgAnnotateProposal{}, &MsgEndorseProposal{}, &MsgExtendVotingPeriod{}, &MsgVetoProposal{}, &MsgUpdateParams{}
 
 // NewMsgAnnotateProposal creates a new MsgAnnotateProposal instance
@@ -36,6 +40,11 @@ func (msg *MsgAnnotateProposal) ValidateBasic() error {
 	if len(msg.Annotation) == 0 {
 		return errorsmod.Wrap(sdkerrors.ErrInvalidRequest, "annotation cannot be empty")
 	}
+	if len(msg.Annotation) > MaxAnnotationLength {
+		return errorsmod.Wrapf(sdkerrors.ErrInvalidRequest,
+			"invalid annotation length; got: %d, max: %d", len(msg.Annotation), MaxAnnotationLength,
+		)
+	}
 	return nil
 }
 
diff --git a/x/coredaos/types/msgs_test.go b/x/coredaos/types/msgs_test.go
index 7e253e0d..83ef1c5c 100644
--- a/x/coredaos/types/msgs_test.go
+++ b/x/coredaos/types/msgs_test.go
@@ -1,11 +1,13 @@
 package types_test
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/atomone-hub/atomone/x/coredaos/types"
-	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/stretchr/testify/require"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
 var addrs = []sdk.AccAddress{
@@ -22,6 +24,7 @@ func TestMsgAnnotateProposal_ValidateBasic(t *testing.T) {
 	}{
 		{sdk.AccAddress{}, 0, "annotation", false},
 		{addrs[0], 0, "", false},
+		{addrs[0], 0, strings.Repeat("x", 3001), false},
 		{addrs[0], 0, "annotation", true},
 	}
 	for i, tc := range tests {