diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..2906418
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,27 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+tab_width = 4
+indent_style = space
+insert_final_newline = false
+max_line_length = 120
+trim_trailing_whitespace = true
+
+[*.go]
+indent_style = tab
+ij_smart_tabs = true
+ij_go_GROUP_CURRENT_PROJECT_IMPORTS = true
+ij_go_group_stdlib_imports = true
+ij_go_import_sorting = goimports
+ij_go_local_group_mode = project
+ij_go_move_all_imports_in_one_declaration = true
+ij_go_move_all_stdlib_imports_in_one_group = true
+ij_go_remove_redundant_import_aliases = true
+
+[*.{yml,yaml}]
+indent_size = 2
+tab_width = 2
+insert_final_newline = true
\ No newline at end of file
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..db9b789
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,17 @@
+module code.icb4dc0.de/buildr/common
+
+go 1.21
+
+toolchain go1.21.0
+
+require code.icb4dc0.de/buildr/api v0.0.0-20230817151157-dbc0adad8f8b
+
+require (
+	github.com/golang/protobuf v1.5.3 // indirect
+	golang.org/x/net v0.14.0 // indirect
+	golang.org/x/sys v0.11.0 // indirect
+	golang.org/x/text v0.12.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20230815205213-6bfd019c3878 // indirect
+	google.golang.org/grpc v1.57.0 // indirect
+	google.golang.org/protobuf v1.31.0 // indirect
+)
diff --git a/protocol/api.go b/protocol/api.go
new file mode 100644
index 0000000..8275dbf
--- /dev/null
+++ b/protocol/api.go
@@ -0,0 +1,11 @@
+package protocol
+
+import rpcv1 "code.icb4dc0.de/buildr/api/generated/rpc/v1"
+
+type SpecUnmarshaler interface {
+	UnmarshalModuleSpec(val *rpcv1.ModuleSpec) error
+}
+
+type SpecValueUnmarshaler interface {
+	UnmarshalSpecValue(val *rpcv1.ModuleSpec_Value) error
+}
diff --git a/protocol/constraints.go b/protocol/constraints.go
new file mode 100644
index 0000000..b715a7c
--- /dev/null
+++ b/protocol/constraints.go
@@ -0,0 +1,21 @@
+package protocol
+
+type Signed interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64
+}
+
+type Unsigned interface {
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr
+}
+
+type Integer interface {
+	Signed | Unsigned
+}
+
+type Float interface {
+	~float32 | ~float64
+}
+
+type Numeric interface {
+	Integer | Float
+}
diff --git a/protocol/marshal.go b/protocol/marshal.go
new file mode 100644
index 0000000..cb94401
--- /dev/null
+++ b/protocol/marshal.go
@@ -0,0 +1,236 @@
+package protocol
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strings"
+
+	rpcv1 "code.icb4dc0.de/buildr/api/generated/rpc/v1"
+)
+
+var ErrExpectedStruct = errors.New("expected struct")
+
+func Marshal(in any) (*rpcv1.ModuleSpec, error) {
+	cfg := marshalConfig{
+		TagName: "hcl",
+	}
+
+	val := reflect.ValueOf(in)
+	if val.Kind() == reflect.Ptr {
+		val = val.Elem()
+	}
+
+	if val.Kind() != reflect.Struct {
+		return nil, fmt.Errorf("%w: got %T", ErrExpectedStruct, in)
+	}
+
+	return cfg.marshal(val)
+}
+
+type marshalConfig struct {
+	TagName string
+}
+
+func (cfg marshalConfig) marshal(in reflect.Value) (*rpcv1.ModuleSpec, error) {
+	numField := in.NumField()
+
+	out := &rpcv1.ModuleSpec{
+		Values: make(map[string]*rpcv1.ModuleSpec_Value, numField),
+	}
+
+	// TODO consider tag for field name
+
+	inputType := in.Type()
+
+	for i := 0; i < numField; i++ {
+		structField := inputType.Field(i)
+		if !structField.IsExported() {
+			continue
+		}
+
+		fieldName := cfg.fieldName(structField)
+
+		out.Values[fieldName] = cfg.mapReflectValueToSpecValue(in.Field(i))
+	}
+
+	return out, nil
+}
+
+func (cfg marshalConfig) mapReflectValueToSpecValue(in reflect.Value) *rpcv1.ModuleSpec_Value {
+	switch in.Kind() {
+	case reflect.Map:
+		return cfg.mapValue(in)
+	case reflect.Bool:
+		return boolValue(in.Bool())
+	case reflect.String:
+		return stringValue(in.String())
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return intValue(in.Int())
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return intValue(in.Uint())
+	case reflect.Float32, reflect.Float64:
+		return floatValue(in.Float())
+	case reflect.Struct:
+		return cfg.structValue(in)
+	case reflect.Slice, reflect.Array:
+		switch in.Type().Elem().Kind() {
+		case reflect.Bool:
+			return boolSliceValue(in)
+		case reflect.String:
+			return stringSliceValue(in)
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			return intSliceValue(in, reflect.Value.Int)
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			return intSliceValue(in, func(v reflect.Value) int64 {
+				return int64(v.Uint())
+			})
+		case reflect.Float32, reflect.Float64:
+			return floatSliceValue(in)
+		default:
+			return nil
+		}
+	default:
+		return nil
+	}
+}
+
+func (cfg marshalConfig) fieldName(field reflect.StructField) string {
+	tagVal, ok := field.Tag.Lookup(cfg.TagName)
+	if !ok {
+		return field.Name
+	}
+
+	split := strings.Split(tagVal, ",")
+
+	switch {
+	case len(split) == 0:
+		fallthrough
+	case split[0] == "":
+		return strings.ToLower(field.Name)
+	default:
+		return strings.ToLower(split[0])
+	}
+}
+
+func (cfg marshalConfig) mapValue(in reflect.Value) *rpcv1.ModuleSpec_Value {
+	result := &rpcv1.ModuleSpec_Value{
+		Type:         rpcv1.ModuleSpec_ValueTypeMap,
+		ComplexValue: make(map[string]*rpcv1.ModuleSpec_Value, in.Len()),
+	}
+
+	iter := in.MapRange()
+	for iter.Next() {
+		result.ComplexValue[iter.Key().String()] = cfg.mapReflectValueToSpecValue(iter.Value())
+	}
+
+	return result
+}
+
+func (cfg marshalConfig) structValue(in reflect.Value) *rpcv1.ModuleSpec_Value {
+	inputType := in.Type()
+	numFields := inputType.NumField()
+	result := &rpcv1.ModuleSpec_Value{
+		Type:         rpcv1.ModuleSpec_ValueTypeObject,
+		ComplexValue: make(map[string]*rpcv1.ModuleSpec_Value, numFields),
+	}
+
+	for i := 0; i < numFields; i++ {
+		structField := inputType.Field(i)
+		if !structField.IsExported() {
+			continue
+		}
+
+		result.ComplexValue[structField.Name] = cfg.mapReflectValueToSpecValue(in.Field(i))
+	}
+
+	return result
+}
+
+func boolValue(in bool) *rpcv1.ModuleSpec_Value {
+	return &rpcv1.ModuleSpec_Value{
+		Type: rpcv1.ModuleSpec_ValueTypeSingle,
+		SingleValue: &rpcv1.ModuleSpec_Value_BoolValue{
+			BoolValue: in,
+		},
+	}
+}
+
+func boolSliceValue(val reflect.Value) *rpcv1.ModuleSpec_Value {
+	result := &rpcv1.ModuleSpec_Value{
+		Type:       rpcv1.ModuleSpec_ValueTypeBoolSlice,
+		BoolValues: make([]bool, 0, val.Len()),
+	}
+
+	for i := 0; i < val.Len(); i++ {
+		result.BoolValues = append(result.BoolValues, val.Index(i).Bool())
+	}
+
+	return result
+}
+
+func intValue[T Integer](in T) *rpcv1.ModuleSpec_Value {
+	return &rpcv1.ModuleSpec_Value{
+		Type: rpcv1.ModuleSpec_ValueTypeSingle,
+		SingleValue: &rpcv1.ModuleSpec_Value_IntValue{
+			IntValue: int64(in),
+		},
+	}
+}
+
+func intSliceValue(val reflect.Value, selector func(v reflect.Value) int64) *rpcv1.ModuleSpec_Value {
+	result := &rpcv1.ModuleSpec_Value{
+		Type:      rpcv1.ModuleSpec_ValueTypeIntSlice,
+		IntValues: make([]int64, 0, val.Len()),
+	}
+
+	for i := 0; i < val.Len(); i++ {
+		result.IntValues = append(result.IntValues, selector(val.Index(i)))
+	}
+
+	return result
+}
+
+func floatValue[T Float](in T) *rpcv1.ModuleSpec_Value {
+	return &rpcv1.ModuleSpec_Value{
+		Type: rpcv1.ModuleSpec_ValueTypeSingle,
+		SingleValue: &rpcv1.ModuleSpec_Value_DoubleValue{
+			DoubleValue: float64(in),
+		},
+	}
+}
+
+func floatSliceValue(val reflect.Value) *rpcv1.ModuleSpec_Value {
+	result := &rpcv1.ModuleSpec_Value{
+		Type:         rpcv1.ModuleSpec_ValueTypeDoubleSlice,
+		DoubleValues: make([]float64, 0, val.Len()),
+	}
+
+	for i := 0; i < val.Len(); i++ {
+		result.DoubleValues = append(result.DoubleValues, val.Index(i).Float())
+	}
+
+	return result
+}
+
+func stringValue(in string) *rpcv1.ModuleSpec_Value {
+	return &rpcv1.ModuleSpec_Value{
+		Type: rpcv1.ModuleSpec_ValueTypeSingle,
+		SingleValue: &rpcv1.ModuleSpec_Value_StringValue{
+			StringValue: in,
+		},
+	}
+}
+
+func stringSliceValue(val reflect.Value) *rpcv1.ModuleSpec_Value {
+	result := &rpcv1.ModuleSpec_Value{
+		Type:         rpcv1.ModuleSpec_ValueTypeStringSlice,
+		StringValues: make([]string, 0, val.Len()),
+	}
+
+	for i := 0; i < val.Len(); i++ {
+		result.StringValues = append(result.StringValues, val.Index(i).String())
+	}
+
+	return result
+}
diff --git a/protocol/marshal_test.go b/protocol/marshal_test.go
new file mode 100644
index 0000000..5bba671
--- /dev/null
+++ b/protocol/marshal_test.go
@@ -0,0 +1,220 @@
+package protocol_test
+
+import (
+	"testing"
+
+	rpcv1 "code.icb4dc0.de/buildr/api/generated/rpc/v1"
+	"code.icb4dc0.de/buildr/common/protocol"
+)
+
+func TestMarshal_Bool_Success(t *testing.T) {
+	input := struct {
+		IsDeleted bool
+	}{
+		IsDeleted: true,
+	}
+
+	spec, err := protocol.Marshal(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	nameVal, ok := spec.Values["IsDeleted"]
+	if !ok {
+		t.Fatal("IsDeleted not found")
+	}
+
+	if nameVal.Type != rpcv1.ModuleSpec_ValueTypeSingle {
+		t.Fatalf("Expected single value type, got %v", nameVal.Type)
+	}
+
+	if s, ok := nameVal.SingleValue.(*rpcv1.ModuleSpec_Value_BoolValue); !ok {
+		t.Fatalf("Expected string value, got %v", nameVal.SingleValue)
+	} else if !s.BoolValue {
+		t.Errorf("Expected bool value to be true, got %t", s.BoolValue)
+	}
+}
+
+func TestMarshal_BoolSlice_Success(t *testing.T) {
+	input := struct {
+		IsDeleted []bool
+	}{
+		IsDeleted: []bool{true},
+	}
+
+	spec, err := protocol.Marshal(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	nameVal, ok := spec.Values["IsDeleted"]
+	if !ok {
+		t.Fatal("IsDeleted not found")
+	}
+
+	if nameVal.Type != rpcv1.ModuleSpec_ValueTypeBoolSlice {
+		t.Fatalf("Expected bool slice value type, got %v", nameVal.Type)
+	}
+
+	if len(nameVal.BoolValues) < 1 {
+		t.Fatalf("Expected at least one bool value, got %d", len(nameVal.BoolValues))
+	}
+
+	if !nameVal.BoolValues[0] {
+		t.Errorf("Expected bool value to be true, got %t", nameVal.BoolValues[0])
+	}
+}
+
+func TestMarshal_Int_Success(t *testing.T) {
+	input := struct {
+		Age int
+	}{
+		Age: 42,
+	}
+
+	spec, err := protocol.Marshal(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	nameVal, ok := spec.Values["Age"]
+	if !ok {
+		t.Fatal("Age not found")
+	}
+
+	if nameVal.Type != rpcv1.ModuleSpec_ValueTypeSingle {
+		t.Fatalf("Expected single value type, got %v", nameVal.Type)
+	}
+
+	if s, ok := nameVal.SingleValue.(*rpcv1.ModuleSpec_Value_IntValue); !ok {
+		t.Fatalf("Expected string value, got %v", nameVal.SingleValue)
+	} else if s.IntValue != 42 {
+		t.Errorf("Expected int value to be 42, got %d", s.IntValue)
+	}
+}
+
+func TestMarshal_IntSlice_Success(t *testing.T) {
+	input := struct {
+		Ages []int
+	}{
+		Ages: []int{42},
+	}
+
+	spec, err := protocol.Marshal(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	nameVal, ok := spec.Values["Ages"]
+	if !ok {
+		t.Fatal("Ages not found")
+	}
+
+	if nameVal.Type != rpcv1.ModuleSpec_ValueTypeIntSlice {
+		t.Fatalf("Expected int slice value type, got %v", nameVal.Type)
+	}
+
+	if len(nameVal.IntValues) < 1 {
+		t.Fatalf("Expected at least one bool value, got %d", len(nameVal.BoolValues))
+	}
+
+	if nameVal.IntValues[0] != 42 {
+		t.Errorf("Expected int value to be 52, got %d", nameVal.IntValues[0])
+	}
+}
+
+func TestMarshal_StringField_Success(t *testing.T) {
+	input := struct {
+		Name string
+	}{
+		Name: "John Doe",
+	}
+
+	spec, err := protocol.Marshal(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	nameVal, ok := spec.Values["Name"]
+	if !ok {
+		t.Fatal("Name not found")
+	}
+
+	if nameVal.Type != rpcv1.ModuleSpec_ValueTypeSingle {
+		t.Fatalf("Expected single value type, got %v", nameVal.Type)
+	}
+
+	if s, ok := nameVal.SingleValue.(*rpcv1.ModuleSpec_Value_StringValue); !ok {
+		t.Fatalf("Expected string value, got %v", nameVal.SingleValue)
+	} else if s.StringValue != "John Doe" {
+		t.Errorf("Expected string value to be John Doe, got %s", s.StringValue)
+	}
+}
+
+func TestMarshal_Float64_Success(t *testing.T) {
+	input := struct {
+		Pi float64
+	}{
+		Pi: 3.14,
+	}
+
+	spec, err := protocol.Marshal(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	nameVal, ok := spec.Values["Pi"]
+	if !ok {
+		t.Fatal("Pi not found")
+	}
+
+	if nameVal.Type != rpcv1.ModuleSpec_ValueTypeSingle {
+		t.Fatalf("Expected single value type, got %v", nameVal.Type)
+	}
+
+	if s, ok := nameVal.SingleValue.(*rpcv1.ModuleSpec_Value_DoubleValue); !ok {
+		t.Fatalf("Expected double value, got %v", nameVal.SingleValue)
+	} else if s.DoubleValue-3.14 > 0.000001 {
+		t.Errorf("Expected double value to be 3.14, got %f", s.DoubleValue)
+	}
+}
+
+func TestMarshal_NestedStruct_Success(t *testing.T) {
+	type Address struct {
+		City string
+	}
+	input := struct {
+		Address Address
+	}{
+		Address: Address{
+			City: "New York",
+		},
+	}
+
+	spec, err := protocol.Marshal(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	addressVal, ok := spec.Values["Address"]
+	if !ok {
+		t.Fatal("Address not found")
+	}
+
+	if addressVal.Type != rpcv1.ModuleSpec_ValueTypeObject {
+		t.Fatalf("Expected object value type, got %v", addressVal.Type)
+	}
+
+	cityVal, ok := addressVal.ComplexValue["City"]
+	if !ok {
+		t.Fatal("City not found")
+	}
+
+	if cityVal.Type != rpcv1.ModuleSpec_ValueTypeSingle {
+		t.Fatalf("Expected single value type, got %v", cityVal.Type)
+	}
+
+	if cityVal.SingleValue.(*rpcv1.ModuleSpec_Value_StringValue).StringValue != "New York" {
+		t.Errorf("Expected string value to be New York, got %s", cityVal.SingleValue.(*rpcv1.ModuleSpec_Value_StringValue).StringValue)
+	}
+}
diff --git a/protocol/unmarshal.go b/protocol/unmarshal.go
new file mode 100644
index 0000000..d1d5275
--- /dev/null
+++ b/protocol/unmarshal.go
@@ -0,0 +1,193 @@
+package protocol
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strings"
+
+	rpcv1 "code.icb4dc0.de/buildr/api/generated/rpc/v1"
+)
+
+var (
+	ErrUnmatchingType = errors.New("field type does not match wire value")
+)
+
+func Unmarshal(input *rpcv1.ModuleSpec, into any) error {
+
+	if u, ok := into.(SpecUnmarshaler); ok {
+		return u.UnmarshalModuleSpec(input)
+	}
+
+	val := reflect.ValueOf(into)
+
+	switch val.Kind() {
+	case reflect.Ptr:
+	default:
+		return errors.New("into value must be a pointer")
+	}
+	return unmarshal(input.Values, val.Elem(), reflect.TypeOf(into).Elem())
+}
+
+func unmarshal(input map[string]*rpcv1.ModuleSpec_Value, into reflect.Value, intoType reflect.Type) error {
+	for i := 0; i < intoType.NumField(); i++ {
+		tf := intoType.Field(i)
+		if !tf.IsExported() {
+			continue
+		}
+
+		val, ok := input[strings.ToLower(tf.Name)]
+		if !ok {
+			continue
+		}
+
+		if into.Type().Kind() == reflect.Pointer {
+			if u, ok := into.Elem().Field(i).Interface().(SpecValueUnmarshaler); ok {
+				if err := u.UnmarshalSpecValue(val); err != nil {
+					return err
+				}
+				continue
+			}
+		} else {
+			if u, ok := into.Field(i).Interface().(SpecValueUnmarshaler); ok {
+				if err := u.UnmarshalSpecValue(val); err != nil {
+					return err
+				}
+				continue
+			}
+		}
+
+		if mapped, err := mapSpecValueTo(val, tf.Type); err != nil {
+			return err
+		} else if into.Type().Kind() == reflect.Pointer {
+			into.Elem().Field(i).Set(mapped)
+		} else {
+			into.Field(i).Set(mapped)
+		}
+	}
+
+	return nil
+}
+
+func mapSpecValueTo(val *rpcv1.ModuleSpec_Value, targetType reflect.Type) (reflect.Value, error) {
+	switch val.Type {
+	case rpcv1.ModuleSpec_ValueTypeUnknown:
+		return reflect.Value{}, fmt.Errorf("%w: expected %s", ErrUnmatchingType, targetType.String())
+	case rpcv1.ModuleSpec_ValueTypeObject:
+		if targetType.Kind() == reflect.Struct {
+			structVal := reflect.New(targetType)
+			if err := unmarshal(val.ComplexValue, structVal, targetType); err != nil {
+				return reflect.Value{}, err
+			} else {
+				return structVal.Elem(), nil
+			}
+		} else if targetType.Kind() == reflect.Pointer && targetType.Elem().Kind() == reflect.Struct {
+			structVal := reflect.New(targetType.Elem())
+			if err := unmarshal(val.ComplexValue, structVal, targetType.Elem()); err != nil {
+				return reflect.Value{}, err
+			} else {
+				return structVal, nil
+			}
+		} else {
+			return reflect.Value{}, fmt.Errorf("%w: expected struct, got %s", ErrUnmatchingType, val.Type)
+		}
+	case rpcv1.ModuleSpec_ValueTypeMap:
+		if targetType.Kind() != reflect.Map {
+			return reflect.Value{}, fmt.Errorf("%w: expected map, got %v", ErrUnmatchingType, targetType)
+		}
+
+		mapVal := reflect.MakeMap(targetType)
+
+		for k, v := range val.ComplexValue {
+			if mappedVal, err := mapSpecValueTo(v, targetType.Elem()); err != nil {
+				return reflect.Value{}, err
+			} else {
+				mapVal.SetMapIndex(reflect.ValueOf(k), mappedVal)
+			}
+		}
+
+		return mapVal, nil
+
+	case rpcv1.ModuleSpec_ValueTypeSingle:
+		switch sv := val.SingleValue.(type) {
+		case *rpcv1.ModuleSpec_Value_BoolValue:
+			if targetType.Kind() != reflect.Bool {
+				return reflect.Value{}, fmt.Errorf("%w: expected bool, got %v", ErrUnmatchingType, targetType)
+			}
+			return reflect.ValueOf(sv.BoolValue), nil
+		case *rpcv1.ModuleSpec_Value_StringValue:
+			if targetType.Kind() != reflect.String {
+				return reflect.Value{}, fmt.Errorf("%w: expected string, got %v", ErrUnmatchingType, targetType)
+			}
+			return reflect.ValueOf(sv.StringValue), nil
+		case *rpcv1.ModuleSpec_Value_IntValue:
+			if targetType.Kind() != reflect.Int {
+				return reflect.Value{}, fmt.Errorf("%w: expected int, got %v", ErrUnmatchingType, targetType)
+			}
+			return reflect.ValueOf(int(sv.IntValue)), nil
+		case *rpcv1.ModuleSpec_Value_DoubleValue:
+			if targetType.Kind() != reflect.Float64 {
+				return reflect.Value{}, fmt.Errorf("%w: expected float64, got %v", ErrUnmatchingType, targetType)
+			}
+			return reflect.ValueOf(sv.DoubleValue), nil
+		}
+	case rpcv1.ModuleSpec_ValueTypeBoolSlice:
+		if targetType.Kind() != reflect.Slice {
+			return reflect.Value{}, fmt.Errorf("%w: expected slice, got %v", ErrUnmatchingType, targetType)
+		} else if targetType.Elem().Kind() != reflect.Bool {
+			return reflect.Value{}, fmt.Errorf("%w: expected bool, got %v", ErrUnmatchingType, targetType.Elem())
+		}
+		return reflect.ValueOf(val.BoolValues), nil
+	case rpcv1.ModuleSpec_ValueTypeStringSlice:
+		if targetType.Kind() != reflect.Slice {
+			return reflect.Value{}, fmt.Errorf("%w: expected slice, got %v", ErrUnmatchingType, targetType)
+		} else if targetType.Elem().Kind() != reflect.String {
+			return reflect.Value{}, fmt.Errorf("%w: expected string, got %v", ErrUnmatchingType, targetType.Elem())
+		}
+		return reflect.ValueOf(val.StringValues), nil
+	case rpcv1.ModuleSpec_ValueTypeIntSlice:
+		if targetType.Kind() != reflect.Slice {
+			return reflect.Value{}, fmt.Errorf("%w: expected slice, got %v", ErrUnmatchingType, targetType)
+		}
+		switch targetType.Elem().Kind() {
+		case reflect.Int:
+			return reflect.ValueOf(convertNumericSlice[int64, int](val.IntValues)), nil
+		case reflect.Int8:
+			return reflect.ValueOf(convertNumericSlice[int64, int8](val.IntValues)), nil
+		case reflect.Int16:
+			return reflect.ValueOf(convertNumericSlice[int64, int16](val.IntValues)), nil
+		case reflect.Int32:
+			return reflect.ValueOf(convertNumericSlice[int64, int32](val.IntValues)), nil
+		case reflect.Int64:
+			return reflect.ValueOf(val.IntValues), nil
+		default:
+			return reflect.Value{}, fmt.Errorf("%w: expected int, got %v", ErrUnmatchingType, targetType.Elem())
+		}
+	case rpcv1.ModuleSpec_ValueTypeDoubleSlice:
+		if targetType.Kind() != reflect.Slice {
+			return reflect.Value{}, fmt.Errorf("%w: expected slice, got %v", ErrUnmatchingType, targetType)
+		}
+		switch targetType.Elem().Kind() {
+		case reflect.Float32:
+			return reflect.ValueOf(convertNumericSlice[float64, float32](val.DoubleValues)), nil
+		case reflect.Float64:
+			return reflect.ValueOf(val.DoubleValues), nil
+		default:
+			return reflect.Value{}, fmt.Errorf("%w: expected int, got %v", ErrUnmatchingType, targetType.Elem())
+		}
+	}
+
+	return reflect.Value{}, nil
+}
+
+type numeric interface {
+	Integer | Float
+}
+
+func convertNumericSlice[TIn numeric, TOut numeric](input []TIn) []TOut {
+	output := make([]TOut, len(input))
+	for i, v := range input {
+		output[i] = TOut(v)
+	}
+	return output
+}
diff --git a/protocol/unmarshal_test.go b/protocol/unmarshal_test.go
new file mode 100644
index 0000000..1f1369c
--- /dev/null
+++ b/protocol/unmarshal_test.go
@@ -0,0 +1,515 @@
+package protocol_test
+
+import (
+	"testing"
+
+	rpcv1 "code.icb4dc0.de/buildr/api/generated/rpc/v1"
+	"code.icb4dc0.de/buildr/common/protocol"
+)
+
+func TestUnmarshal_Bool_Success(t *testing.T) {
+	target := struct {
+		Delete bool
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"delete": {
+				Type: rpcv1.ModuleSpec_ValueTypeSingle,
+				SingleValue: &rpcv1.ModuleSpec_Value_BoolValue{
+					BoolValue: true,
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if !target.Delete {
+		t.Errorf("Expected Delete to be true")
+	}
+}
+
+func TestUnmarshal_Bool_Err(t *testing.T) {
+	target := struct {
+		Delete string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"delete": {
+				Type: rpcv1.ModuleSpec_ValueTypeSingle,
+				SingleValue: &rpcv1.ModuleSpec_Value_BoolValue{
+					BoolValue: true,
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		t.Log(err.Error())
+	}
+}
+
+func TestUnmarshal_Bool_Slice_Success(t *testing.T) {
+	target := struct {
+		Delete []bool
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"delete": {
+				Type:       rpcv1.ModuleSpec_ValueTypeBoolSlice,
+				BoolValues: []bool{true},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if len(target.Delete) < 1 {
+		t.Errorf("Expected Delete to have at least one element")
+	} else if !target.Delete[0] {
+		t.Errorf("Expected Delete[0] to be true")
+	}
+}
+
+func TestUnmarshal_Bool_Slice_Err(t *testing.T) {
+	target := struct {
+		Delete []string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"delete": {
+				Type:       rpcv1.ModuleSpec_ValueTypeBoolSlice,
+				BoolValues: []bool{true},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		t.Log(err.Error())
+	}
+}
+
+func TestUnmarshal_String_Success(t *testing.T) {
+	target := struct {
+		Name string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"name": {
+				Type: rpcv1.ModuleSpec_ValueTypeSingle,
+				SingleValue: &rpcv1.ModuleSpec_Value_StringValue{
+					StringValue: "Ted",
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if target.Name != "Ted" {
+		t.Errorf("Expected Name to be 'Ted'")
+	}
+}
+
+func TestUnmarshal_String_Err(t *testing.T) {
+	target := struct {
+		Name int
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"name": {
+				Type: rpcv1.ModuleSpec_ValueTypeSingle,
+				SingleValue: &rpcv1.ModuleSpec_Value_StringValue{
+					StringValue: "Ted",
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		t.Log(err.Error())
+	}
+}
+
+func TestUnmarshal_String_Slice_Success(t *testing.T) {
+	target := struct {
+		Names []string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"names": {
+				Type:         rpcv1.ModuleSpec_ValueTypeStringSlice,
+				StringValues: []string{"Ted"},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if len(target.Names) < 1 {
+		t.Errorf("Expected Names to have at least one element")
+	} else if target.Names[0] != "Ted" {
+		t.Errorf("Expected Names[0] to be 'Ted'")
+	}
+}
+
+func TestUnmarshal_String_Slice_Err(t *testing.T) {
+	target := struct {
+		Names []int
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"names": {
+				Type:         rpcv1.ModuleSpec_ValueTypeStringSlice,
+				StringValues: []string{"Ted"},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		t.Log(err.Error())
+	}
+}
+
+func TestUnmarshal_Int_Success(t *testing.T) {
+	target := struct {
+		Age int
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"age": {
+				Type: rpcv1.ModuleSpec_ValueTypeSingle,
+				SingleValue: &rpcv1.ModuleSpec_Value_IntValue{
+					IntValue: 42,
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if target.Age != 42 {
+		t.Errorf("Expected Age to be 42")
+	}
+}
+
+func TestUnmarshal_Int_Err(t *testing.T) {
+	target := struct {
+		Age string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"age": {
+				Type: rpcv1.ModuleSpec_ValueTypeSingle,
+				SingleValue: &rpcv1.ModuleSpec_Value_IntValue{
+					IntValue: 42,
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		t.Log(err.Error())
+	}
+}
+
+func TestUnmarshal_Int_Slice_Success(t *testing.T) {
+	target := struct {
+		Ages []int
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"ages": {
+				Type:      rpcv1.ModuleSpec_ValueTypeIntSlice,
+				IntValues: []int64{42},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if len(target.Ages) < 1 {
+		t.Errorf("Expected Ages to have at least one element")
+	} else if target.Ages[0] != 42 {
+		t.Errorf("Expected Ages[0] to be 42")
+	}
+}
+
+func TestUnmarshal_Int_Slice_Err(t *testing.T) {
+	target := struct {
+		Ages []string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"ages": {
+				Type:      rpcv1.ModuleSpec_ValueTypeIntSlice,
+				IntValues: []int64{42},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		t.Log(err.Error())
+	}
+}
+
+func TestUnmarshal_Double_Success(t *testing.T) {
+	target := struct {
+		Pi float64
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"Pi": {
+				Type: rpcv1.ModuleSpec_ValueTypeSingle,
+				SingleValue: &rpcv1.ModuleSpec_Value_DoubleValue{
+					DoubleValue: 3.14,
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if target.Pi-3.14 > 0.0000001 {
+		t.Errorf("Expected Pi to be 3.14")
+	}
+}
+
+func TestUnmarshal_Double_Err(t *testing.T) {
+	target := struct {
+		Pi string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"pi": {
+				Type: rpcv1.ModuleSpec_ValueTypeSingle,
+				SingleValue: &rpcv1.ModuleSpec_Value_DoubleValue{
+					DoubleValue: 3.14,
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		t.Log(err.Error())
+	}
+}
+
+func TestUnmarshal_Double_Slice_Success(t *testing.T) {
+	target := struct {
+		Pis []float64
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"pis": {
+				Type:         rpcv1.ModuleSpec_ValueTypeDoubleSlice,
+				DoubleValues: []float64{3.14},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if len(target.Pis) < 1 {
+		t.Errorf("Expected Pis to have at least one element")
+	} else if target.Pis[0]-3.14 > 0.0000001 {
+		t.Errorf("Expected Pis[0] to be 3.14")
+	}
+}
+
+func TestUnmarshal_Double_Slice_Err(t *testing.T) {
+	target := struct {
+		Pis []string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"pis": {
+				Type:         rpcv1.ModuleSpec_ValueTypeDoubleSlice,
+				DoubleValues: []float64{3.14},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		t.Log(err.Error())
+	}
+}
+
+func TestUnmarshal_NestedStruct_Success(t *testing.T) {
+	target := struct {
+		Address struct {
+			City string
+		}
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"address": {
+				Type: rpcv1.ModuleSpec_ValueTypeObject,
+				ComplexValue: map[string]*rpcv1.ModuleSpec_Value{
+					"city": {
+						Type: rpcv1.ModuleSpec_ValueTypeSingle,
+						SingleValue: &rpcv1.ModuleSpec_Value_StringValue{
+							StringValue: "New York",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if target.Address.City != "New York" {
+		t.Errorf("Expected City to be 'New York'")
+	}
+}
+
+func TestUnmarshal_NestedStructPointer_Success(t *testing.T) {
+	target := struct {
+		Address *struct {
+			City string
+		}
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"address": {
+				Type: rpcv1.ModuleSpec_ValueTypeObject,
+				ComplexValue: map[string]*rpcv1.ModuleSpec_Value{
+					"city": {
+						Type: rpcv1.ModuleSpec_ValueTypeSingle,
+						SingleValue: &rpcv1.ModuleSpec_Value_StringValue{
+							StringValue: "New York",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if target.Address.City != "New York" {
+		t.Errorf("Expected City to be 'New York'")
+	}
+}
+
+func TestUnmarshal_Map_Success(t *testing.T) {
+	target := struct {
+		Values map[string]string
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"values": {
+				Type: rpcv1.ModuleSpec_ValueTypeMap,
+				ComplexValue: map[string]*rpcv1.ModuleSpec_Value{
+					"City": {
+						Type: rpcv1.ModuleSpec_ValueTypeSingle,
+						SingleValue: &rpcv1.ModuleSpec_Value_StringValue{
+							StringValue: "New York",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if target.Values["City"] != "New York" {
+		t.Errorf("Expected City to be 'New York'")
+	}
+}
+
+func TestUnmarshal_NestedMap_Success(t *testing.T) {
+	target := struct {
+		City struct {
+			Labels map[string]string
+		}
+	}{}
+
+	spec := &rpcv1.ModuleSpec{
+		Values: map[string]*rpcv1.ModuleSpec_Value{
+			"city": {
+				Type: rpcv1.ModuleSpec_ValueTypeObject,
+				ComplexValue: map[string]*rpcv1.ModuleSpec_Value{
+					"labels": {
+						Type: rpcv1.ModuleSpec_ValueTypeMap,
+						ComplexValue: map[string]*rpcv1.ModuleSpec_Value{
+							"Region": {
+								Type: rpcv1.ModuleSpec_ValueTypeSingle,
+								SingleValue: &rpcv1.ModuleSpec_Value_StringValue{
+									StringValue: "west",
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	if err := protocol.Unmarshal(spec, &target); err != nil {
+		t.Errorf("Failed to unmarshal: %v", err)
+	}
+
+	if target.City.Labels["Region"] != "west" {
+		t.Errorf("Expected 'Region' to be 'west'")
+	}
+}
diff --git a/renovate.json b/renovate.json
new file mode 100644
index 0000000..89cc11e
--- /dev/null
+++ b/renovate.json
@@ -0,0 +1,18 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    ":dependencyDashboard",
+    ":ignoreModulesAndTests",
+    ":semanticPrefixFixDepsChoreOthers",
+    ":autodetectPinVersions",
+    ":prHourlyLimit2",
+    ":prConcurrentLimit10",
+    "group:monorepos",
+    "group:recommended",
+    "workarounds:all"
+  ],
+  "postUpdateOptions": [
+    "gomodTidy1.17",
+    "gomodUpdateImportPaths"
+  ]
+}