diff --git a/src/decorators/is-boolean.spec.ts b/src/decorators/is-boolean.spec.ts
index adcd8a7..4c895ee 100644
--- a/src/decorators/is-boolean.spec.ts
+++ b/src/decorators/is-boolean.spec.ts
@@ -1,15 +1,30 @@
 import { Result } from 'true-myth';
 
-import { input, make, output } from '../../tests/helpers';
+import { generateSchemas, input, make, output } from '../../tests/helpers';
 import { IsBoolean } from '../nestjs-swagger-dto';
 
 describe('IsBoolean', () => {
-  describe('single', () => {
+  describe('normal', () => {
     class Test {
       @IsBoolean()
       booleanField!: boolean;
     }
 
+    it('generates correct schema', async () => {
+      expect(await generateSchemas([Test])).toStrictEqual({
+        Test: {
+          type: 'object',
+          properties: {
+            booleanField: {
+              type: 'boolean',
+              default: false,
+            },
+          },
+          required: ['booleanField'],
+        },
+      });
+    });
+
     it('accepts booleans', async () => {
       expect(await input(Test, { booleanField: true })).toStrictEqual(
         Result.ok(make(Test, { booleanField: true }))
@@ -50,6 +65,26 @@ describe('IsBoolean', () => {
       booleanField!: boolean;
     }
 
+    it('generates correct schema', async () => {
+      expect(await generateSchemas([Test])).toStrictEqual({
+        Test: {
+          type: 'object',
+          properties: {
+            booleanField: {
+              type: 'boolean',
+              default: false,
+            },
+          },
+          required: ['booleanField'],
+        },
+      });
+    });
+
+    it('transforms to plain', async () => {
+      const dto = make(Test, { booleanField: true });
+      expect(output(dto)).toStrictEqual({ booleanField: 'true' });
+    });
+
     it('accepts boolean strings and booleans', async () => {
       expect(await input(Test, { booleanField: 'true' })).toStrictEqual(
         Result.ok(make(Test, { booleanField: true }))
@@ -86,155 +121,4 @@ describe('IsBoolean', () => {
       }
     });
   });
-
-  describe('optional', () => {
-    class Test {
-      @IsBoolean({ optional: true })
-      booleanField?: boolean;
-    }
-
-    it('accepts boolean and undefined', async () => {
-      expect(await input(Test, { booleanField: true })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: true }))
-      );
-      expect(await input(Test, { booleanField: false })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: false }))
-      );
-      expect(await input(Test, {})).toStrictEqual(Result.ok(make(Test, {})));
-    });
-
-    it('rejects everything else', async () => {
-      const testValues: unknown[] = [
-        { booleanField: 'true' },
-        { booleanField: 'false' },
-        { booleanField: 'abc' },
-        { booleanField: 0 },
-        { booleanField: [] },
-        { booleanField: {} },
-        { booleanField: null },
-      ];
-
-      for (const testValue of testValues) {
-        expect(await input(Test, testValue)).toStrictEqual(
-          Result.err('booleanField must be a boolean value')
-        );
-      }
-    });
-  });
-
-  describe('default', () => {
-    class Test {
-      @IsBoolean({ optional: true, default: false })
-      booleanField?: boolean;
-    }
-
-    it('returns specified defaults if value is undefined', async () => {
-      expect(await input(Test, { booleanField: true })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: true }))
-      );
-      expect(await input(Test, { booleanField: false })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: false }))
-      );
-      expect(await input(Test, {})).toStrictEqual(Result.ok(make(Test, { booleanField: false })));
-    });
-  });
-
-  describe('nullable', () => {
-    class Test {
-      @IsBoolean({ nullable: true })
-      booleanField!: boolean | null;
-    }
-
-    it('accepts boolean and null', async () => {
-      expect(await input(Test, { booleanField: true })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: true }))
-      );
-      expect(await input(Test, { booleanField: false })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: false }))
-      );
-      expect(await input(Test, { booleanField: null })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: null }))
-      );
-    });
-
-    it('rejects everything else', async () => {
-      const testValues: unknown[] = [
-        { booleanField: 'true' },
-        { booleanField: 'false' },
-        { booleanField: 'abc' },
-        { booleanField: 0 },
-        { booleanField: [] },
-        { booleanField: {} },
-        {},
-      ];
-
-      for (const testValue of testValues) {
-        expect(await input(Test, testValue)).toStrictEqual(
-          Result.err('booleanField must be a boolean value')
-        );
-      }
-    });
-  });
-
-  describe('nullable and optional', () => {
-    class Test {
-      @IsBoolean({ optional: true, nullable: true })
-      booleanField?: boolean | null;
-    }
-
-    it('accepts boolean and null and undefined', async () => {
-      expect(await input(Test, { booleanField: true })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: true }))
-      );
-      expect(await input(Test, { booleanField: false })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: false }))
-      );
-      expect(await input(Test, { booleanField: null })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: null }))
-      );
-      expect(await input(Test, {})).toStrictEqual(Result.ok(make(Test, {})));
-    });
-
-    it('rejects everything else', async () => {
-      const testValues: unknown[] = [
-        { booleanField: 'true' },
-        { booleanField: 'false' },
-        { booleanField: 'abc' },
-        { booleanField: 0 },
-        { booleanField: [] },
-        { booleanField: {} },
-      ];
-
-      for (const testValue of testValues) {
-        expect(await input(Test, testValue)).toStrictEqual(
-          Result.err('booleanField must be a boolean value')
-        );
-      }
-    });
-  });
-
-  describe('array', () => {
-    class Test {
-      @IsBoolean({ isArray: true })
-      booleanField!: boolean[];
-    }
-
-    it('accepts boolean arrays', async () => {
-      expect(await input(Test, { booleanField: [true, false] })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: [true, false] }))
-      );
-      expect(await input(Test, { booleanField: [] })).toStrictEqual(
-        Result.ok(make(Test, { booleanField: [] }))
-      );
-    });
-
-    it('rejects everything else', async () => {
-      expect(await input(Test, { booleanField: true })).toStrictEqual(
-        Result.err('booleanField must be an array')
-      );
-      expect(await input(Test, { booleanField: [1, 2, 3] })).toStrictEqual(
-        Result.err('each value in booleanField must be a boolean value')
-      );
-    });
-  });
 });
diff --git a/src/decorators/is-boolean.ts b/src/decorators/is-boolean.ts
index a4187c2..1293968 100644
--- a/src/decorators/is-boolean.ts
+++ b/src/decorators/is-boolean.ts
@@ -1,7 +1,7 @@
 import { Transform } from 'class-transformer';
 import { IsBoolean as IsBooleanCV } from 'class-validator';
 
-import { Base, compose, noop } from '../core';
+import { Base, compose } from '../core';
 
 export const IsBoolean = ({
   stringified,
@@ -11,7 +11,14 @@ export const IsBoolean = ({
     { type: 'boolean' },
     base,
     IsBooleanCV({ each: !!base.isArray }),
-    stringified
-      ? Transform(({ value }) => (value === 'true' ? true : value === 'false' ? false : value))
-      : noop
+    ...(stringified
+      ? [
+          Transform(({ value }) => (value === 'true' ? true : value === 'false' ? false : value), {
+            toClassOnly: true,
+          }),
+          Transform(({ value }) => (value === undefined ? value : `${value}`), {
+            toPlainOnly: true,
+          }),
+        ]
+      : [])
   );