diff --git a/api/cosmos/autocli/v1/options.pulsar.go b/api/cosmos/autocli/v1/options.pulsar.go
index a97a51701f..1742c5fcae 100644
--- a/api/cosmos/autocli/v1/options.pulsar.go
+++ b/api/cosmos/autocli/v1/options.pulsar.go
@@ -3779,6 +3779,7 @@ var (
 	md_PositionalArgDescriptor             protoreflect.MessageDescriptor
 	fd_PositionalArgDescriptor_proto_field protoreflect.FieldDescriptor
 	fd_PositionalArgDescriptor_varargs     protoreflect.FieldDescriptor
+	fd_PositionalArgDescriptor_optional    protoreflect.FieldDescriptor
 )
 
 func init() {
@@ -3786,6 +3787,7 @@ func init() {
 	md_PositionalArgDescriptor = File_cosmos_autocli_v1_options_proto.Messages().ByName("PositionalArgDescriptor")
 	fd_PositionalArgDescriptor_proto_field = md_PositionalArgDescriptor.Fields().ByName("proto_field")
 	fd_PositionalArgDescriptor_varargs = md_PositionalArgDescriptor.Fields().ByName("varargs")
+	fd_PositionalArgDescriptor_optional = md_PositionalArgDescriptor.Fields().ByName("optional")
 }
 
 var _ protoreflect.Message = (*fastReflection_PositionalArgDescriptor)(nil)
@@ -3865,6 +3867,12 @@ func (x *fastReflection_PositionalArgDescriptor) Range(f func(protoreflect.Field
 			return
 		}
 	}
+	if x.Optional != false {
+		value := protoreflect.ValueOfBool(x.Optional)
+		if !f(fd_PositionalArgDescriptor_optional, value) {
+			return
+		}
+	}
 }
 
 // Has reports whether a field is populated.
@@ -3884,6 +3892,8 @@ func (x *fastReflection_PositionalArgDescriptor) Has(fd protoreflect.FieldDescri
 		return x.ProtoField != ""
 	case "cosmos.autocli.v1.PositionalArgDescriptor.varargs":
 		return x.Varargs != false
+	case "cosmos.autocli.v1.PositionalArgDescriptor.optional":
+		return x.Optional != false
 	default:
 		if fd.IsExtension() {
 			panic(fmt.Errorf("proto3 declared messages do not support extensions: cosmos.autocli.v1.PositionalArgDescriptor"))
@@ -3904,6 +3914,8 @@ func (x *fastReflection_PositionalArgDescriptor) Clear(fd protoreflect.FieldDesc
 		x.ProtoField = ""
 	case "cosmos.autocli.v1.PositionalArgDescriptor.varargs":
 		x.Varargs = false
+	case "cosmos.autocli.v1.PositionalArgDescriptor.optional":
+		x.Optional = false
 	default:
 		if fd.IsExtension() {
 			panic(fmt.Errorf("proto3 declared messages do not support extensions: cosmos.autocli.v1.PositionalArgDescriptor"))
@@ -3926,6 +3938,9 @@ func (x *fastReflection_PositionalArgDescriptor) Get(descriptor protoreflect.Fie
 	case "cosmos.autocli.v1.PositionalArgDescriptor.varargs":
 		value := x.Varargs
 		return protoreflect.ValueOfBool(value)
+	case "cosmos.autocli.v1.PositionalArgDescriptor.optional":
+		value := x.Optional
+		return protoreflect.ValueOfBool(value)
 	default:
 		if descriptor.IsExtension() {
 			panic(fmt.Errorf("proto3 declared messages do not support extensions: cosmos.autocli.v1.PositionalArgDescriptor"))
@@ -3950,6 +3965,8 @@ func (x *fastReflection_PositionalArgDescriptor) Set(fd protoreflect.FieldDescri
 		x.ProtoField = value.Interface().(string)
 	case "cosmos.autocli.v1.PositionalArgDescriptor.varargs":
 		x.Varargs = value.Bool()
+	case "cosmos.autocli.v1.PositionalArgDescriptor.optional":
+		x.Optional = value.Bool()
 	default:
 		if fd.IsExtension() {
 			panic(fmt.Errorf("proto3 declared messages do not support extensions: cosmos.autocli.v1.PositionalArgDescriptor"))
@@ -3974,6 +3991,8 @@ func (x *fastReflection_PositionalArgDescriptor) Mutable(fd protoreflect.FieldDe
 		panic(fmt.Errorf("field proto_field of message cosmos.autocli.v1.PositionalArgDescriptor is not mutable"))
 	case "cosmos.autocli.v1.PositionalArgDescriptor.varargs":
 		panic(fmt.Errorf("field varargs of message cosmos.autocli.v1.PositionalArgDescriptor is not mutable"))
+	case "cosmos.autocli.v1.PositionalArgDescriptor.optional":
+		panic(fmt.Errorf("field optional of message cosmos.autocli.v1.PositionalArgDescriptor is not mutable"))
 	default:
 		if fd.IsExtension() {
 			panic(fmt.Errorf("proto3 declared messages do not support extensions: cosmos.autocli.v1.PositionalArgDescriptor"))
@@ -3991,6 +4010,8 @@ func (x *fastReflection_PositionalArgDescriptor) NewField(fd protoreflect.FieldD
 		return protoreflect.ValueOfString("")
 	case "cosmos.autocli.v1.PositionalArgDescriptor.varargs":
 		return protoreflect.ValueOfBool(false)
+	case "cosmos.autocli.v1.PositionalArgDescriptor.optional":
+		return protoreflect.ValueOfBool(false)
 	default:
 		if fd.IsExtension() {
 			panic(fmt.Errorf("proto3 declared messages do not support extensions: cosmos.autocli.v1.PositionalArgDescriptor"))
@@ -4067,6 +4088,9 @@ func (x *fastReflection_PositionalArgDescriptor) ProtoMethods() *protoiface.Meth
 		if x.Varargs {
 			n += 2
 		}
+		if x.Optional {
+			n += 2
+		}
 		if x.unknownFields != nil {
 			n += len(x.unknownFields)
 		}
@@ -4096,6 +4120,16 @@ func (x *fastReflection_PositionalArgDescriptor) ProtoMethods() *protoiface.Meth
 			i -= len(x.unknownFields)
 			copy(dAtA[i:], x.unknownFields)
 		}
+		if x.Optional {
+			i--
+			if x.Optional {
+				dAtA[i] = 1
+			} else {
+				dAtA[i] = 0
+			}
+			i--
+			dAtA[i] = 0x18
+		}
 		if x.Varargs {
 			i--
 			if x.Varargs {
@@ -4214,6 +4248,26 @@ func (x *fastReflection_PositionalArgDescriptor) ProtoMethods() *protoiface.Meth
 					}
 				}
 				x.Varargs = bool(v != 0)
+			case 3:
+				if wireType != 0 {
+					return protoiface.UnmarshalOutput{NoUnkeyedLiterals: input.NoUnkeyedLiterals, Flags: input.Flags}, fmt.Errorf("proto: wrong wireType = %d for field Optional", wireType)
+				}
+				var v int
+				for shift := uint(0); ; shift += 7 {
+					if shift >= 64 {
+						return protoiface.UnmarshalOutput{NoUnkeyedLiterals: input.NoUnkeyedLiterals, Flags: input.Flags}, runtime.ErrIntOverflow
+					}
+					if iNdEx >= l {
+						return protoiface.UnmarshalOutput{NoUnkeyedLiterals: input.NoUnkeyedLiterals, Flags: input.Flags}, io.ErrUnexpectedEOF
+					}
+					b := dAtA[iNdEx]
+					iNdEx++
+					v |= int(b&0x7F) << shift
+					if b < 0x80 {
+						break
+					}
+				}
+				x.Optional = bool(v != 0)
 			default:
 				iNdEx = preIndex
 				skippy, err := runtime.Skip(dAtA[iNdEx:])
@@ -4622,8 +4676,11 @@ type PositionalArgDescriptor struct {
 	ProtoField string `protobuf:"bytes,1,opt,name=proto_field,json=protoField,proto3" json:"proto_field,omitempty"`
 	// varargs makes a positional parameter a varargs parameter. This can only be
 	// applied to last positional parameter and the proto_field must a repeated
-	// field.
+	// field. Note: It is mutually exclusive with optional.
 	Varargs bool `protobuf:"varint,2,opt,name=varargs,proto3" json:"varargs,omitempty"`
+	// optional makes a positional parameter optional. This can only be applied
+	// to the last positional parameter. Note: It is mutually exclusive with varargs.
+	Optional bool `protobuf:"varint,3,opt,name=optional,proto3" json:"optional,omitempty"`
 }
 
 func (x *PositionalArgDescriptor) Reset() {
@@ -4660,6 +4717,13 @@ func (x *PositionalArgDescriptor) GetVarargs() bool {
 	return false
 }
 
+func (x *PositionalArgDescriptor) GetOptional() bool {
+	if x != nil {
+		return x.Optional
+	}
+	return false
+}
+
 var File_cosmos_autocli_v1_options_proto protoreflect.FileDescriptor
 
 var file_cosmos_autocli_v1_options_proto_rawDesc = []byte{
@@ -4745,25 +4809,26 @@ var file_cosmos_autocli_v1_options_proto_rawDesc = []byte{
 	0x63, 0x61, 0x74, 0x65, 0x64, 0x18, 0x07, 0x20, 0x01, 0x28, 0x09, 0x52, 0x13, 0x73, 0x68, 0x6f,
 	0x72, 0x74, 0x68, 0x61, 0x6e, 0x64, 0x44, 0x65, 0x70, 0x72, 0x65, 0x63, 0x61, 0x74, 0x65, 0x64,
 	0x12, 0x16, 0x0a, 0x06, 0x68, 0x69, 0x64, 0x64, 0x65, 0x6e, 0x18, 0x08, 0x20, 0x01, 0x28, 0x08,
-	0x52, 0x06, 0x68, 0x69, 0x64, 0x64, 0x65, 0x6e, 0x22, 0x54, 0x0a, 0x17, 0x50, 0x6f, 0x73, 0x69,
+	0x52, 0x06, 0x68, 0x69, 0x64, 0x64, 0x65, 0x6e, 0x22, 0x70, 0x0a, 0x17, 0x50, 0x6f, 0x73, 0x69,
 	0x74, 0x69, 0x6f, 0x6e, 0x61, 0x6c, 0x41, 0x72, 0x67, 0x44, 0x65, 0x73, 0x63, 0x72, 0x69, 0x70,
 	0x74, 0x6f, 0x72, 0x12, 0x1f, 0x0a, 0x0b, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x5f, 0x66, 0x69, 0x65,
 	0x6c, 0x64, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x0a, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x46,
 	0x69, 0x65, 0x6c, 0x64, 0x12, 0x18, 0x0a, 0x07, 0x76, 0x61, 0x72, 0x61, 0x72, 0x67, 0x73, 0x18,
-	0x02, 0x20, 0x01, 0x28, 0x08, 0x52, 0x07, 0x76, 0x61, 0x72, 0x61, 0x72, 0x67, 0x73, 0x42, 0xb9,
-	0x01, 0x0a, 0x15, 0x63, 0x6f, 0x6d, 0x2e, 0x63, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x2e, 0x61, 0x75,
-	0x74, 0x6f, 0x63, 0x6c, 0x69, 0x2e, 0x76, 0x31, 0x42, 0x0c, 0x4f, 0x70, 0x74, 0x69, 0x6f, 0x6e,
-	0x73, 0x50, 0x72, 0x6f, 0x74, 0x6f, 0x50, 0x01, 0x5a, 0x2c, 0x63, 0x6f, 0x73, 0x6d, 0x6f, 0x73,
-	0x73, 0x64, 0x6b, 0x2e, 0x69, 0x6f, 0x2f, 0x61, 0x70, 0x69, 0x2f, 0x63, 0x6f, 0x73, 0x6d, 0x6f,
-	0x73, 0x2f, 0x61, 0x75, 0x74, 0x6f, 0x63, 0x6c, 0x69, 0x2f, 0x76, 0x31, 0x3b, 0x61, 0x75, 0x74,
-	0x6f, 0x63, 0x6c, 0x69, 0x76, 0x31, 0xa2, 0x02, 0x03, 0x43, 0x41, 0x58, 0xaa, 0x02, 0x11, 0x43,
-	0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x2e, 0x41, 0x75, 0x74, 0x6f, 0x63, 0x6c, 0x69, 0x2e, 0x56, 0x31,
-	0xca, 0x02, 0x11, 0x43, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x5c, 0x41, 0x75, 0x74, 0x6f, 0x63, 0x6c,
-	0x69, 0x5c, 0x56, 0x31, 0xe2, 0x02, 0x1d, 0x43, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x5c, 0x41, 0x75,
-	0x74, 0x6f, 0x63, 0x6c, 0x69, 0x5c, 0x56, 0x31, 0x5c, 0x47, 0x50, 0x42, 0x4d, 0x65, 0x74, 0x61,
-	0x64, 0x61, 0x74, 0x61, 0xea, 0x02, 0x13, 0x43, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x3a, 0x3a, 0x41,
-	0x75, 0x74, 0x6f, 0x63, 0x6c, 0x69, 0x3a, 0x3a, 0x56, 0x31, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74,
-	0x6f, 0x33,
+	0x02, 0x20, 0x01, 0x28, 0x08, 0x52, 0x07, 0x76, 0x61, 0x72, 0x61, 0x72, 0x67, 0x73, 0x12, 0x1a,
+	0x0a, 0x08, 0x6f, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x61, 0x6c, 0x18, 0x03, 0x20, 0x01, 0x28, 0x08,
+	0x52, 0x08, 0x6f, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x61, 0x6c, 0x42, 0xb9, 0x01, 0x0a, 0x15, 0x63,
+	0x6f, 0x6d, 0x2e, 0x63, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x2e, 0x61, 0x75, 0x74, 0x6f, 0x63, 0x6c,
+	0x69, 0x2e, 0x76, 0x31, 0x42, 0x0c, 0x4f, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x50, 0x72, 0x6f,
+	0x74, 0x6f, 0x50, 0x01, 0x5a, 0x2c, 0x63, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x73, 0x64, 0x6b, 0x2e,
+	0x69, 0x6f, 0x2f, 0x61, 0x70, 0x69, 0x2f, 0x63, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x2f, 0x61, 0x75,
+	0x74, 0x6f, 0x63, 0x6c, 0x69, 0x2f, 0x76, 0x31, 0x3b, 0x61, 0x75, 0x74, 0x6f, 0x63, 0x6c, 0x69,
+	0x76, 0x31, 0xa2, 0x02, 0x03, 0x43, 0x41, 0x58, 0xaa, 0x02, 0x11, 0x43, 0x6f, 0x73, 0x6d, 0x6f,
+	0x73, 0x2e, 0x41, 0x75, 0x74, 0x6f, 0x63, 0x6c, 0x69, 0x2e, 0x56, 0x31, 0xca, 0x02, 0x11, 0x43,
+	0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x5c, 0x41, 0x75, 0x74, 0x6f, 0x63, 0x6c, 0x69, 0x5c, 0x56, 0x31,
+	0xe2, 0x02, 0x1d, 0x43, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x5c, 0x41, 0x75, 0x74, 0x6f, 0x63, 0x6c,
+	0x69, 0x5c, 0x56, 0x31, 0x5c, 0x47, 0x50, 0x42, 0x4d, 0x65, 0x74, 0x61, 0x64, 0x61, 0x74, 0x61,
+	0xea, 0x02, 0x13, 0x43, 0x6f, 0x73, 0x6d, 0x6f, 0x73, 0x3a, 0x3a, 0x41, 0x75, 0x74, 0x6f, 0x63,
+	0x6c, 0x69, 0x3a, 0x3a, 0x56, 0x31, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
 }
 
 var (
diff --git a/client/v2/CHANGELOG.md b/client/v2/CHANGELOG.md
index 0c3c9d0385..798cde4380 100644
--- a/client/v2/CHANGELOG.md
+++ b/client/v2/CHANGELOG.md
@@ -34,4 +34,4 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 # Changelog
 
-## [Unreleased]
+## [Unreleased]
\ No newline at end of file
diff --git a/client/v2/autocli/app.go b/client/v2/autocli/app.go
index 0172b4c3e8..a365af904d 100644
--- a/client/v2/autocli/app.go
+++ b/client/v2/autocli/app.go
@@ -4,11 +4,12 @@ import (
 	"errors"
 
 	autocliv1 "cosmossdk.io/api/cosmos/autocli/v1"
-	"cosmossdk.io/client/v2/autocli/flag"
 	"cosmossdk.io/core/address"
 	"cosmossdk.io/core/appmodule"
 	"cosmossdk.io/depinject"
 
+	"cosmossdk.io/client/v2/autocli/flag"
+
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/client/flags"
 	"github.com/spf13/cobra"
diff --git a/client/v2/autocli/common_test.go b/client/v2/autocli/common_test.go
index 4f605a4f48..9cfb9582fe 100644
--- a/client/v2/autocli/common_test.go
+++ b/client/v2/autocli/common_test.go
@@ -68,6 +68,49 @@ func testExecCommon(t *testing.T, buildModuleCommand func(string, *Builder) (*co
 	return conn
 }
 
+func testExecCommonWithErr(t *testing.T, expectedErr string, buildModuleCommand func(string, *Builder) (*cobra.Command, error), args ...string) {
+	server := grpc.NewServer()
+	testpb.RegisterQueryServer(server, &testEchoServer{})
+	reflectionv2alpha1.RegisterReflectionServiceServer(server, &testReflectionServer{})
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	assert.NilError(t, err)
+	go func() {
+		err := server.Serve(listener)
+		if err != nil {
+			panic(err)
+		}
+	}()
+
+	clientConn, err := grpc.Dial(listener.Addr().String(), grpc.WithTransportCredentials(insecure.NewCredentials()))
+	assert.NilError(t, err)
+	defer func() {
+		err := clientConn.Close()
+		if err != nil {
+			panic(err)
+		}
+	}()
+
+	conn := &testClientConn{
+		ClientConn: clientConn,
+		t:          t,
+		out:        &bytes.Buffer{},
+		errorOut:   &bytes.Buffer{},
+	}
+	b := &Builder{
+		Builder: flag.Builder{
+			AddressCodec: addresscodec.NewBech32Codec("cosmos"),
+		},
+		GetClientConn: func(*cobra.Command) (grpc.ClientConnInterface, error) {
+			return conn, nil
+		},
+		AddQueryConnFlags: flags.AddQueryFlagsToCmd,
+		AddTxConnFlags:    flags.AddTxFlagsToCmd,
+	}
+
+	_, err = buildModuleCommand("test", b)
+	assert.Equal(t, expectedErr, err.Error())
+}
+
 type testReflectionServer struct {
 	reflectionv2alpha1.UnimplementedReflectionServiceServer
 }
diff --git a/client/v2/autocli/flag/message.go b/client/v2/autocli/flag/message.go
index 6d07e3564a..5ea1943cd4 100644
--- a/client/v2/autocli/flag/message.go
+++ b/client/v2/autocli/flag/message.go
@@ -15,6 +15,7 @@ type MessageBinder struct {
 	positionalFlagSet *pflag.FlagSet
 	positionalArgs    []fieldBinding
 	hasVarargs        bool
+	hasOptional       bool
 
 	flagBindings []fieldBinding
 	messageType  protoreflect.MessageType
@@ -32,8 +33,8 @@ func (m MessageBinder) Bind(msg protoreflect.Message, positionalArgs []string) e
 	// first set positional args in the positional arg flag set
 	n := len(positionalArgs)
 	for i := range m.positionalArgs {
-		if i >= n {
-			panic("unexpected: validate args should have caught this")
+		if i == n {
+			break
 		}
 
 		name := fmt.Sprintf("%d", i)
diff --git a/client/v2/autocli/flag/register.go b/client/v2/autocli/flag/register.go
index a3a525b343..a65b1e0481 100644
--- a/client/v2/autocli/flag/register.go
+++ b/client/v2/autocli/flag/register.go
@@ -24,6 +24,7 @@ func (b *Builder) addMessageFlags(ctx context.Context, flagSet *pflag.FlagSet, m
 
 	isPositional := map[string]bool{}
 	hasVarargs := false
+	hasOptional := false
 	n := len(commandOptions.PositionalArgs)
 	// positional args are also parsed using a FlagSet so that we can reuse all the same parsers
 	handler.positionalFlagSet = pflag.NewFlagSet("positional", pflag.ContinueOnError)
@@ -43,6 +44,14 @@ func (b *Builder) addMessageFlags(ctx context.Context, flagSet *pflag.FlagSet, m
 			hasVarargs = true
 		}
 
+		if arg.Optional {
+			if i != n-1 {
+				return nil, fmt.Errorf("optional positional argument %s must be the last argument", arg.ProtoField)
+			}
+
+			hasOptional = true
+		}
+
 		_, hasValue, err := b.addFieldFlag(
 			ctx,
 			handler.positionalFlagSet,
@@ -63,6 +72,9 @@ func (b *Builder) addMessageFlags(ctx context.Context, flagSet *pflag.FlagSet, m
 	if hasVarargs {
 		handler.CobraArgs = cobra.MinimumNArgs(n)
 		handler.hasVarargs = true
+	} else if hasOptional {
+		handler.CobraArgs = cobra.RangeArgs(n-1, n)
+		handler.hasOptional = true
 	} else {
 		handler.CobraArgs = cobra.ExactArgs(n)
 	}
diff --git a/client/v2/autocli/query_test.go b/client/v2/autocli/query_test.go
index 635060b3f9..64386aa30e 100644
--- a/client/v2/autocli/query_test.go
+++ b/client/v2/autocli/query_test.go
@@ -25,6 +25,20 @@ var buildModuleQueryCommand = func(moduleName string, b *Builder) (*cobra.Comman
 	return cmd, err
 }
 
+var buildModuleQueryCommandOptional = func(moduleName string, b *Builder) (*cobra.Command, error) {
+	cmd := topLevelCmd(moduleName, fmt.Sprintf("Querying commands for the %s module", moduleName))
+
+	err := b.AddQueryServiceCommands(cmd, testCmdDescOptional)
+	return cmd, err
+}
+
+var buildModuleVargasOptional = func(moduleName string, b *Builder) (*cobra.Command, error) {
+	cmd := topLevelCmd(moduleName, fmt.Sprintf("Querying commands for the %s module", moduleName))
+
+	err := b.AddQueryServiceCommands(cmd, testCmdDescInvalidOptAndVargas)
+	return cmd, err
+}
+
 var testCmdDesc = &autocliv1.ServiceCommandDescriptor{
 	Service: testpb.Query_ServiceDesc.ServiceName,
 	RpcCommandOptions: []*autocliv1.RpcCommandOptions{
@@ -117,6 +131,60 @@ var testCmdDesc = &autocliv1.ServiceCommandDescriptor{
 	},
 }
 
+var testCmdDescOptional = &autocliv1.ServiceCommandDescriptor{
+	Service: testpb.Query_ServiceDesc.ServiceName,
+	RpcCommandOptions: []*autocliv1.RpcCommandOptions{
+		{
+			RpcMethod:  "Echo",
+			Use:        "echo [pos1] [pos2] [pos3...]",
+			Version:    "1.0",
+			Alias:      []string{"e"},
+			SuggestFor: []string{"eco"},
+			Example:    "echo 1 abc {}",
+			Short:      "echo echos the value provided by the user",
+			Long:       "echo echos the value provided by the user as a proto JSON object with populated with the provided fields and positional arguments",
+			PositionalArgs: []*autocliv1.PositionalArgDescriptor{
+				{
+					ProtoField: "positional1",
+				},
+				{
+					ProtoField: "positional2",
+					Optional:   true,
+				},
+			},
+		},
+	},
+}
+
+var testCmdDescInvalidOptAndVargas = &autocliv1.ServiceCommandDescriptor{
+	Service: testpb.Query_ServiceDesc.ServiceName,
+	RpcCommandOptions: []*autocliv1.RpcCommandOptions{
+		{
+			RpcMethod:  "Echo",
+			Use:        "echo [pos1] [pos2] [pos3...]",
+			Version:    "1.0",
+			Alias:      []string{"e"},
+			SuggestFor: []string{"eco"},
+			Example:    "echo 1 abc {}",
+			Short:      "echo echos the value provided by the user",
+			Long:       "echo echos the value provided by the user as a proto JSON object with populated with the provided fields and positional arguments",
+			PositionalArgs: []*autocliv1.PositionalArgDescriptor{
+				{
+					ProtoField: "positional1",
+				},
+				{
+					ProtoField: "positional2",
+					Optional:   true,
+				},
+				{
+					ProtoField: "positional3_varargs",
+					Varargs:    true,
+				},
+			},
+		},
+	},
+}
+
 func TestCoin(t *testing.T) {
 	conn := testExecCommon(t, buildModuleQueryCommand,
 		"echo",
@@ -130,6 +198,40 @@ func TestCoin(t *testing.T) {
 	assert.DeepEqual(t, conn.lastRequest, conn.lastResponse.(*testpb.EchoResponse).Request, protocmp.Transform())
 }
 
+func TestOptional(t *testing.T) {
+	conn := testExecCommon(t, buildModuleQueryCommandOptional,
+		"echo",
+		"1",
+		"abc",
+	)
+	request := conn.lastRequest.(*testpb.EchoRequest)
+	assert.Equal(t, request.Positional2, "abc")
+	assert.DeepEqual(t, conn.lastRequest, conn.lastResponse.(*testpb.EchoResponse).Request, protocmp.Transform())
+
+	conn = testExecCommon(t, buildModuleQueryCommandOptional,
+		"echo",
+		"1",
+	)
+	request = conn.lastRequest.(*testpb.EchoRequest)
+	assert.Equal(t, request.Positional2, "")
+	assert.DeepEqual(t, conn.lastRequest, conn.lastResponse.(*testpb.EchoResponse).Request, protocmp.Transform())
+
+	conn = testExecCommon(t, buildModuleQueryCommandOptional,
+		"echo",
+		"1",
+		"abc",
+		"extra-arg",
+	)
+	assert.Equal(t, conn.errorOut.String(), "Error: accepts between 1 and 2 arg(s), received 3\n")
+
+	testExecCommonWithErr(t, "optional positional argument positional2 must be the last argument", buildModuleVargasOptional,
+		"echo",
+		"1",
+		"abc",
+		"extra-arg",
+	)
+}
+
 func TestMap(t *testing.T) {
 	conn := testExecCommon(t, buildModuleQueryCommand,
 		"echo",
diff --git a/client/v2/go.mod b/client/v2/go.mod
index 21c58fa31c..e89b893a2a 100644
--- a/client/v2/go.mod
+++ b/client/v2/go.mod
@@ -3,7 +3,7 @@ module cosmossdk.io/client/v2
 go 1.20
 
 require (
-	cosmossdk.io/api v0.4.2
+	cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495
 	cosmossdk.io/core v0.8.0
 	cosmossdk.io/depinject v1.0.0-alpha.3
 	github.com/cockroachdb/errors v1.10.0
diff --git a/client/v2/go.sum b/client/v2/go.sum
index 963f11f4f7..b3e7b29e16 100644
--- a/client/v2/go.sum
+++ b/client/v2/go.sum
@@ -35,8 +35,8 @@ cloud.google.com/go/storage v1.6.0/go.mod h1:N7U0C8pVQ/+NIKOBQyamJIeKQKkZ+mxpohl
 cloud.google.com/go/storage v1.8.0/go.mod h1:Wv1Oy7z6Yz3DshWRJFhqM/UCfaWIRTdp0RXyy7KQOVs=
 cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9ullr3+Kg0=
 cloud.google.com/go/storage v1.14.0/go.mod h1:GrKmX003DSIwi9o29oFT7YDnHYwZoctc3fOKtUw0Xmo=
-cosmossdk.io/api v0.4.2 h1:lQBMl4xINnMnBOR/tQLtjlDnR4exr4e6/SfHR8PILE0=
-cosmossdk.io/api v0.4.2/go.mod h1:qrVgOp7DIeAXa+Tt5dDjOC47bZCDrwx8ZHxrmy7STNE=
+cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495 h1:wreIRQKuKccFCOI4TWoVy/6tQNiDX4ms7VKNrXP4DEM=
+cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495/go.mod h1:qrVgOp7DIeAXa+Tt5dDjOC47bZCDrwx8ZHxrmy7STNE=
 cosmossdk.io/collections v0.2.0 h1:CgMfLtE16+qox3zBYrGh60i4yKV8SeExLnIdOS2sbQs=
 cosmossdk.io/collections v0.2.0/go.mod h1:Oc1FK0vlmxJZsgUn9/o3ldE6zNyWKvobVzaLhWknZJE=
 cosmossdk.io/core v0.8.0 h1:LcJnu52E1a8f8E317VfQ1xK/RZe+IuhMNQAjnDLh25M=
diff --git a/proto/cosmos/autocli/v1/options.proto b/proto/cosmos/autocli/v1/options.proto
index b023490c97..4aecf1915a 100644
--- a/proto/cosmos/autocli/v1/options.proto
+++ b/proto/cosmos/autocli/v1/options.proto
@@ -81,6 +81,7 @@ message RpcCommandOptions {
 
   // skip specifies whether to skip this rpc method when generating commands.
   bool skip = 12;
+
 }
 
 // FlagOptions are options for flags generated from rpc request fields.
@@ -119,6 +120,10 @@ message PositionalArgDescriptor {
 
   // varargs makes a positional parameter a varargs parameter. This can only be
   // applied to last positional parameter and the proto_field must a repeated
-  // field.
+  // field. Note: It is mutually exclusive with optional.
   bool varargs = 2;
+
+  // optional makes the last positional parameter optional. 
+  // Note: It is mutually exclusive with varargs.
+  bool optional = 3;
 }
diff --git a/simapp/go.mod b/simapp/go.mod
index dc592b5ae4..3559a5f3ca 100644
--- a/simapp/go.mod
+++ b/simapp/go.mod
@@ -3,7 +3,7 @@ module cosmossdk.io/simapp
 go 1.20
 
 require (
-	cosmossdk.io/api v0.4.2
+	cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495
 	cosmossdk.io/client/v2 v2.0.0-20230614103911-b3da8bb4e801
 	cosmossdk.io/core v0.8.0
 	cosmossdk.io/depinject v1.0.0-alpha.3
diff --git a/simapp/go.sum b/simapp/go.sum
index 0a5e4ed29b..bd6c8040d7 100644
--- a/simapp/go.sum
+++ b/simapp/go.sum
@@ -188,8 +188,8 @@ cloud.google.com/go/webrisk v1.4.0/go.mod h1:Hn8X6Zr+ziE2aNd8SliSDWpEnSS1u4R9+xX
 cloud.google.com/go/webrisk v1.5.0/go.mod h1:iPG6fr52Tv7sGk0H6qUFzmL3HHZev1htXuWDEEsqMTg=
 cloud.google.com/go/workflows v1.6.0/go.mod h1:6t9F5h/unJz41YqfBmqSASJSXccBLtD1Vwf+KmJENM0=
 cloud.google.com/go/workflows v1.7.0/go.mod h1:JhSrZuVZWuiDfKEFxU0/F1PQjmpnpcoISEXH2bcHC3M=
-cosmossdk.io/api v0.4.2 h1:lQBMl4xINnMnBOR/tQLtjlDnR4exr4e6/SfHR8PILE0=
-cosmossdk.io/api v0.4.2/go.mod h1:qrVgOp7DIeAXa+Tt5dDjOC47bZCDrwx8ZHxrmy7STNE=
+cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495 h1:wreIRQKuKccFCOI4TWoVy/6tQNiDX4ms7VKNrXP4DEM=
+cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495/go.mod h1:qrVgOp7DIeAXa+Tt5dDjOC47bZCDrwx8ZHxrmy7STNE=
 cosmossdk.io/collections v0.2.0 h1:CgMfLtE16+qox3zBYrGh60i4yKV8SeExLnIdOS2sbQs=
 cosmossdk.io/collections v0.2.0/go.mod h1:Oc1FK0vlmxJZsgUn9/o3ldE6zNyWKvobVzaLhWknZJE=
 cosmossdk.io/core v0.8.0 h1:LcJnu52E1a8f8E317VfQ1xK/RZe+IuhMNQAjnDLh25M=
diff --git a/tests/go.mod b/tests/go.mod
index a556d485d6..0060550cfe 100644
--- a/tests/go.mod
+++ b/tests/go.mod
@@ -3,7 +3,7 @@ module github.com/cosmos/cosmos-sdk/tests
 go 1.20
 
 require (
-	cosmossdk.io/api v0.4.2
+	cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495
 	cosmossdk.io/collections v0.2.0
 	cosmossdk.io/core v0.8.0
 	cosmossdk.io/depinject v1.0.0-alpha.3
diff --git a/tests/go.sum b/tests/go.sum
index 25dc4a6f27..9f5380d3f2 100644
--- a/tests/go.sum
+++ b/tests/go.sum
@@ -188,8 +188,8 @@ cloud.google.com/go/webrisk v1.4.0/go.mod h1:Hn8X6Zr+ziE2aNd8SliSDWpEnSS1u4R9+xX
 cloud.google.com/go/webrisk v1.5.0/go.mod h1:iPG6fr52Tv7sGk0H6qUFzmL3HHZev1htXuWDEEsqMTg=
 cloud.google.com/go/workflows v1.6.0/go.mod h1:6t9F5h/unJz41YqfBmqSASJSXccBLtD1Vwf+KmJENM0=
 cloud.google.com/go/workflows v1.7.0/go.mod h1:JhSrZuVZWuiDfKEFxU0/F1PQjmpnpcoISEXH2bcHC3M=
-cosmossdk.io/api v0.4.2 h1:lQBMl4xINnMnBOR/tQLtjlDnR4exr4e6/SfHR8PILE0=
-cosmossdk.io/api v0.4.2/go.mod h1:qrVgOp7DIeAXa+Tt5dDjOC47bZCDrwx8ZHxrmy7STNE=
+cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495 h1:wreIRQKuKccFCOI4TWoVy/6tQNiDX4ms7VKNrXP4DEM=
+cosmossdk.io/api v0.4.3-0.20230615032830-feb87fce5495/go.mod h1:qrVgOp7DIeAXa+Tt5dDjOC47bZCDrwx8ZHxrmy7STNE=
 cosmossdk.io/collections v0.2.0 h1:CgMfLtE16+qox3zBYrGh60i4yKV8SeExLnIdOS2sbQs=
 cosmossdk.io/collections v0.2.0/go.mod h1:Oc1FK0vlmxJZsgUn9/o3ldE6zNyWKvobVzaLhWknZJE=
 cosmossdk.io/core v0.8.0 h1:LcJnu52E1a8f8E317VfQ1xK/RZe+IuhMNQAjnDLh25M=