diff --git a/typecheck/builtin/bool.go b/typecheck/builtin/bool.go
index bf35dd7..2d5ae07 100644
--- a/typecheck/builtin/bool.go
+++ b/typecheck/builtin/bool.go
@@ -17,7 +17,28 @@ func (Bool) Checker(typeName string) typecheck.CheckerFunc {
 		return nil
 	}
 	return func(value interface{}) bool {
-		_, isBool := value.(bool)
+		_, isBool := readBool(value)
 		return isBool
 	}
 }
+
+// readBool tries to read a serialized boolean and returns whether it succeeded.
+func readBool(value interface{}) (bool, bool) {
+	switch cast := value.(type) {
+	case bool:
+		return cast, true
+
+	case string:
+		strVal := string(cast)
+		return strVal == "true", strVal == "true" || strVal == "false"
+
+	case []byte:
+		strVal := string(cast)
+		return strVal == "true", strVal == "true" || strVal == "false"
+
+	default:
+		return false, false
+	}
+
+	return false, false
+}
diff --git a/typecheck/builtin/bool_test.go b/typecheck/builtin/bool_test.go
new file mode 100644
index 0000000..8e63344
--- /dev/null
+++ b/typecheck/builtin/bool_test.go
@@ -0,0 +1,115 @@
+package builtin_test
+
+import (
+	"fmt"
+	"testing"
+
+	"git.xdrm.io/go/aicra/typecheck/builtin"
+)
+
+func TestBool_New(t *testing.T) {
+	t.Parallel()
+
+	inst := interface{}(builtin.NewBool())
+
+	switch cast := inst.(type) {
+	case *builtin.Bool:
+		return
+	default:
+		t.Errorf("expect %T ; got %T", &builtin.Bool{}, cast)
+	}
+}
+
+func TestBool_AvailableTypes(t *testing.T) {
+	t.Parallel()
+
+	inst := builtin.NewBool()
+
+	tests := []struct {
+		Type    string
+		Handled bool
+	}{
+		{"bool", true},
+		{"Bool", false},
+		{"boolean", false},
+		{" bool", false},
+		{"bool ", false},
+		{" bool ", false},
+	}
+
+	for _, test := range tests {
+		t.Run(test.Type, func(t *testing.T) {
+			checker := inst.Checker(test.Type)
+			if checker == nil {
+				if test.Handled {
+					t.Errorf("expect %q to be handled", test.Type)
+					t.Fail()
+				}
+				return
+			}
+
+			if !test.Handled {
+				t.Errorf("expect %q NOT to be handled", test.Type)
+				t.Fail()
+			}
+		})
+	}
+
+}
+
+func TestBool_Values(t *testing.T) {
+	t.Parallel()
+
+	const typeName = "bool"
+
+	checker := builtin.NewBool().Checker(typeName)
+	if checker == nil {
+		t.Errorf("expect %q to be handled", typeName)
+		t.Fail()
+	}
+
+	tests := []struct {
+		Value interface{}
+		Valid bool
+	}{
+		{true, true},
+		{false, true},
+		{1, false},
+		{0, false},
+		{-1, false},
+
+		// json number
+		{"-1", false},
+		{"0", false},
+		{"1", false},
+
+		// json string
+		{"true", true},
+		{"false", true},
+		{[]byte("true"), true},
+		{[]byte("false"), true},
+
+		{"string", false},
+		{[]byte("bytes"), false},
+		{-0.1, false},
+		{0.1, false},
+		{nil, false},
+	}
+
+	for i, test := range tests {
+		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
+			if checker(test.Value) {
+				if !test.Valid {
+					t.Errorf("expect value to be invalid")
+					t.Fail()
+				}
+				return
+			}
+			if test.Valid {
+				t.Errorf("expect value to be valid")
+				t.Fail()
+			}
+		})
+	}
+
+}
diff --git a/typecheck/builtin/float64.go b/typecheck/builtin/float64.go
index 7dc849c..081ac06 100644
--- a/typecheck/builtin/float64.go
+++ b/typecheck/builtin/float64.go
@@ -45,6 +45,11 @@ func readFloat(value interface{}) (float64, bool) {
 		floatVal, err := num.Float64()
 		return floatVal, err == nil
 
+	case []byte:
+		num := json.Number(cast)
+		floatVal, err := num.Float64()
+		return floatVal, err == nil
+
 		// unknown type
 	default:
 		return 0, false
diff --git a/typecheck/builtin/int.go b/typecheck/builtin/int.go
index 806838f..a64c0df 100644
--- a/typecheck/builtin/int.go
+++ b/typecheck/builtin/int.go
@@ -49,6 +49,12 @@ func readInt(value interface{}) (int, bool) {
 		num := json.Number(cast)
 		intVal, err := num.Int64()
 		return int(intVal), err == nil
+		// serialized string -> try to convert to float
+
+	case []byte:
+		num := json.Number(cast)
+		intVal, err := num.Int64()
+		return int(intVal), err == nil
 
 		// unknown type
 	default:
diff --git a/typecheck/builtin/string.go b/typecheck/builtin/string.go
index 1c9ae19..02501a1 100644
--- a/typecheck/builtin/string.go
+++ b/typecheck/builtin/string.go
@@ -61,6 +61,12 @@ func (s String) Checker(typeName string) typecheck.CheckerFunc {
 
 		// check type
 		strValue, isString := value.(string)
+		byteSliceValue, isByteSlice := value.([]byte)
+		if !isString && isByteSlice {
+			strValue = string(byteSliceValue)
+			isString = true
+		}
+
 		if !isString {
 			return false
 		}
diff --git a/typecheck/builtin/string_test.go b/typecheck/builtin/string_test.go
index 3a0912f..048485b 100644
--- a/typecheck/builtin/string_test.go
+++ b/typecheck/builtin/string_test.go
@@ -87,7 +87,7 @@ func TestString_AnyLength(t *testing.T) {
 		Valid bool
 	}{
 		{"string", true},
-		{[]byte("bytes"), false},
+		{[]byte("bytes"), true},
 		{1, false},
 		{0.1, false},
 		{nil, false},
diff --git a/typecheck/builtin/uint.go b/typecheck/builtin/uint.go
index fbbaf38..7feb9a4 100644
--- a/typecheck/builtin/uint.go
+++ b/typecheck/builtin/uint.go
@@ -53,6 +53,15 @@ func readUint(value interface{}) (uint, bool) {
 		overflows := floatVal < 0 || floatVal > math.MaxUint64
 		return uint(floatVal), !overflows
 
+	case []byte:
+		num := json.Number(cast)
+		floatVal, err := num.Float64()
+		if err != nil {
+			return 0, false
+		}
+		overflows := floatVal < 0 || floatVal > math.MaxUint64
+		return uint(floatVal), !overflows
+
 		// unknown type
 	default:
 		return 0, false