diff --git a/packages/backend-test-utils/api-report.md b/packages/backend-test-utils/api-report.md
index 4a27ac21a9..03df9de264 100644
--- a/packages/backend-test-utils/api-report.md
+++ b/packages/backend-test-utils/api-report.md
@@ -4,6 +4,7 @@
 
 ```ts
 /// <reference types="jest" />
+/// <reference types="node" />
 
 import { Backend } from '@backstage/backend-app-api';
 import { BackendFeature } from '@backstage/backend-plugin-api';
@@ -33,6 +34,37 @@ import { UrlReaderService } from '@backstage/backend-plugin-api';
 // @public (undocumented)
 export function isDockerDisabledForTests(): boolean;
 
+// @public
+export class MockDirectory {
+  addContent(root: MockDirectoryContent): Promise<void>;
+  cleanup: () => Promise<void>;
+  clear: () => Promise<void>;
+  content(
+    options?: MockDirectoryContentOptions,
+  ): Promise<MockDirectoryContent | undefined>;
+  static create(options?: MockDirectoryCreateOptions): MockDirectory;
+  static mockOsTmpDir(): MockDirectory;
+  get path(): string;
+  resolve(...paths: string[]): string;
+  setContent(root: MockDirectoryContent): Promise<void>;
+}
+
+// @public
+export type MockDirectoryContent = {
+  [name in string]: MockDirectoryContent | string | Buffer;
+};
+
+// @public
+export interface MockDirectoryContentOptions {
+  path?: string;
+  shouldReadAsText?: boolean | ((path: string, buffer: Buffer) => boolean);
+}
+
+// @public
+export interface MockDirectoryCreateOptions {
+  root?: string;
+}
+
 // @public (undocumented)
 export namespace mockServices {
   // (undocumented)
diff --git a/packages/backend-test-utils/src/filesystem/MockDirectory.ts b/packages/backend-test-utils/src/filesystem/MockDirectory.ts
index 2ef61b3d0c..81a65783fb 100644
--- a/packages/backend-test-utils/src/filesystem/MockDirectory.ts
+++ b/packages/backend-test-utils/src/filesystem/MockDirectory.ts
@@ -129,7 +129,7 @@ export class MockDirectory {
    * })
    * ```
    */
-  static create(options?: MockDirectoryCreateOptions) {
+  static create(options?: MockDirectoryCreateOptions): MockDirectory {
     const root =
       options?.root ??
       fs.mkdtempSync(joinPath(getTmpDir(), 'backstage-tmp-test-dir-'));
@@ -156,7 +156,7 @@ export class MockDirectory {
    *
    * @returns
    */
-  static mockOsTmpDir() {
+  static mockOsTmpDir(): MockDirectory {
     const mocker = MockDirectory.create();
     const origTmpdir = os.tmpdir;
     os.tmpdir = () => mocker.path;
@@ -180,14 +180,14 @@ export class MockDirectory {
   /**
    * The path to the root of the mock directory
    */
-  get path() {
+  get path(): string {
     return this.#root;
   }
 
   /**
    * Resolves a path relative to the root of the mock directory.
    */
-  resolve(...paths: string[]) {
+  resolve(...paths: string[]): string {
     return resolvePath(this.#root, ...paths);
   }
 
@@ -207,7 +207,7 @@ export class MockDirectory {
    * });
    * ```
    */
-  async setContent(root: MockDirectoryContent) {
+  async setContent(root: MockDirectoryContent): Promise<void> {
     await this.cleanup();
 
     return this.addContent(root);
@@ -229,7 +229,7 @@ export class MockDirectory {
    * });
    * ```
    */
-  async addContent(root: MockDirectoryContent) {
+  async addContent(root: MockDirectoryContent): Promise<void> {
     const entries = this.#transformInput(root);
 
     for (const entry of entries) {
@@ -324,14 +324,14 @@ export class MockDirectory {
   /**
    * Clears the content of the mock directory, ensuring that the directory itself exists.
    */
-  clear = async () => {
+  clear = async (): Promise<void> => {
     await this.setContent({});
   };
 
   /**
    * Removes the mock directory and all its contents.
    */
-  cleanup = async () => {
+  cleanup = async (): Promise<void> => {
     await fs.rm(this.#root, { recursive: true, force: true });
   };
 
diff --git a/packages/backend-test-utils/src/filesystem/index.ts b/packages/backend-test-utils/src/filesystem/index.ts
index f0b05641f5..d1077db980 100644
--- a/packages/backend-test-utils/src/filesystem/index.ts
+++ b/packages/backend-test-utils/src/filesystem/index.ts
@@ -14,4 +14,9 @@
  * limitations under the License.
  */
 
-export { MockDirectory } from './MockDirectory';
+export {
+  MockDirectory,
+  type MockDirectoryContent,
+  type MockDirectoryContentOptions,
+  type MockDirectoryCreateOptions,
+} from './MockDirectory';