diff --git a/src-tsp/main.tsp b/src-tsp/main.tsp
index ed79515..49ca88c 100644
--- a/src-tsp/main.tsp
+++ b/src-tsp/main.tsp
@@ -5,126 +5,127 @@ using TypeSpec.JsonSchema;
 
 @jsonSchema("recipe-v1.json")
 model Recipe {
-    /**
-     * The image name. Used when publishing to GHCR as `ghcr.io/user/name`.
-     */
-    name: string;
+  /**
+   * The image name. Used when publishing to GHCR as `ghcr.io/user/name`.
+   */
+  name: string;
 
-    /**
-     * The image description. Published to GHCR in the image metadata.
-     */
-    description: string;
+  /**
+   * The image description. Published to GHCR in the image metadata.
+   */
+  description: string;
 
-    /**
-     * Allows setting custom tags on the recipe’s final image.
-     * Adding tags to this property will override the `latest` and timestamp tags.
-     */
-    `alt-tags`?: Array<string>;
+  /**
+   * Allows setting custom tags on the recipe’s final image.
+   * Adding tags to this property will override the `latest` and timestamp tags.
+   */
+  `alt-tags`?: Array<string>;
 
-    /**
-     * The [OCI](https://opencontainers.org/) image to base your custom image on.
-     * Only atomic Fedora images and those based on them are officially supported.
-     * Universal Blue is recommended. [A list of Universal Blue's images](https://universal-blue.org/images/) can be found on their website
-     * BlueBuild-built images can be used as well.
-     */
-    `base-image`: string;
+  /**
+   * The [OCI](https://opencontainers.org/) image to base your custom image on.
+   * Only atomic Fedora images and those based on them are officially supported.
+   * Universal Blue is recommended. [A list of Universal Blue's images](https://universal-blue.org/images/) can be found on their website
+   * BlueBuild-built images can be used as well.
+   */
+  `base-image`: string;
 
-    /**
-     * The tag of the base image to build on.
-     * Used to select a version explicitly (`40`) or to always use the latest stable version (`latest`).
-     * A list of all available tags can be viewed by pasting your `base-image` url into your browser.
-     */
-    `image-version`: string | integer;
+  /**
+   * The tag of the base image to build on.
+   * Used to select a version explicitly (`40`) or to always use the latest stable version (`latest`).
+   * A list of all available tags can be viewed by pasting your `base-image` url into your browser.
+   */
+  `image-version`: string | integer;
 
-    /**
-     * The tag to pull for the bluebuild cli. This is mostly used for
-     * trying out specific versions of the cli without compiling it locally.
-     **/
-    `blue-build-tag`?: string;
+  /**
+   * The tag to pull for the bluebuild cli. This is mostly used for
+   * trying out specific versions of the cli without compiling it locally.
+   **/
+  `blue-build-tag`?: string;
 
-    /**
-     * A list of [stages](https://blue-build.org/reference/stages/) that are executed before the build of the final image.
-     * This is useful for compiling programs from source without polluting the final bootable image.
-     */
-    stages?: Array<Stage | ImportedModule>;
+  /**
+   * A list of [stages](https://blue-build.org/reference/stages/) that are executed before the build of the final image.
+   * This is useful for compiling programs from source without polluting the final bootable image.
+   */
+  stages?: Array<Stage | ImportedModule>;
 
-    /**
-     * A list of [modules](https://blue-build.org/reference/module/) that is executed in order. Multiple of the same module can be included.
-     *
-     * Each item in this list should have at least a `type:` or be specified to be included from an external file in the `recipes/` directory with `from-file:`.
-     */
-    modules: Array<Module>;
+  /**
+   * A list of [modules](https://blue-build.org/reference/module/) that is executed in order. Multiple of the same module can be included.
+   *
+   * Each item in this list should have at least a `type:` or be specified to be included from an external file in the `recipes/` directory with `from-file:`.
+   */
+  modules: Array<Module>;
 }
 
 @jsonSchema("stage-list-v1.json")
 model StageList {
-    /**
-     * A list of [stages](https://blue-build.org/reference/stages/) that are executed before the build of the final image.
-     * This is useful for compiling programs from source without polluting the final bootable image.
-     */
-    stages: Array<Stage | ImportedModule>;
+  /**
+   * A list of [stages](https://blue-build.org/reference/stages/) that are executed before the build of the final image.
+   * This is useful for compiling programs from source without polluting the final bootable image.
+   */
+  stages: Array<Stage | ImportedModule>;
 }
 
 @jsonSchema("stage-v1.json")
 model Stage {
-    /**
-     * The name of the stage. This is used when referencing
-     * the stage when using the from: property in the [`copy` module](https://blue-build.org/reference/modules/copy/).
-     */
-    name: string;
+  /**
+   * The name of the stage. This is used when referencing
+   * the stage when using the from: property in the [`copy` module](https://blue-build.org/reference/modules/copy/).
+   */
+  name: string;
 
-    /** The full image ref (image name + tag). This will be set in the FROM statement of the stage. */
-    from: string;
+  /** The full image ref (image name + tag). This will be set in the FROM statement of the stage. */
+  from: string;
 
-    /** Allows a user to pass in an array of strings that are passed directly into the [`SHELL` instruction](https://docs.docker.com/reference/dockerfile/#shell). */
-    shell?: string;
+  /** Allows a user to pass in an array of strings that are passed directly into the [`SHELL` instruction](https://docs.docker.com/reference/dockerfile/#shell). */
+  shell?: string;
 
-    /**
-     * The list of modules to execute. The exact same syntax used by the main recipe `modules:` property.
-     */
-    modules: Array<Module>;
+  /**
+   * The list of modules to execute. The exact same syntax used by the main recipe `modules:` property.
+   */
+  modules: Array<Module>;
 }
 
 @jsonSchema("module-list-v1.json")
 model ModuleList {
-    /**
-     * A list of [modules](https://blue-build.org/reference/module/) that is executed in order. Multiple of the same module can be included.
-     *
-     * Each item in this list should have at least a `type:` or be specified to be included from an external file in the `recipes/` directory with `from-file:`.
-     */
-    modules: Array<Module>;
+  /**
+   * A list of [modules](https://blue-build.org/reference/module/) that is executed in order. Multiple of the same module can be included.
+   *
+   * Each item in this list should have at least a `type:` or be specified to be included from an external file in the `recipes/` directory with `from-file:`.
+   */
+  modules: Array<Module>;
 }
 
 @jsonSchema("module-v1.json")
+@oneOf
 union Module {
-    RepoModule,
-    CustomModule,
-    ImportedModule,
+  RepoModule,
+  CustomModule,
+  ImportedModule,
 }
 
 model ModuleDefaults {
-    /** Whether to disabling caching for this layer.
-     * https://blue-build.org/reference/module/#no-cache-optional
-     */
-    `no-cache`?: boolean = false;
+  /** Whether to disabling caching for this layer.
+   * https://blue-build.org/reference/module/#no-cache-optional
+   */
+  `no-cache`?: boolean = false;
 }
 
 model CustomModule {
-    /** This is not a built-in module. */
-    type: string;
+  /** This is not a built-in module. */
+  type: string;
 
-    /** The URL of the module repository (an OCI image) to pull the module from.
-     * https://blue-build.org/reference/module/#source-optional
-     */
-    source?: string;
+  /** The URL of the module repository (an OCI image) to pull the module from.
+   * https://blue-build.org/reference/module/#source-optional
+   */
+  source: string;
 
-    ...ModuleDefaults;
-    ...Record<unknown>;
+  ...ModuleDefaults;
+  ...Record<unknown>;
 }
 
 model ImportedModule {
-    /** The path to another file containing module configuration to import here.
-     * https://blue-build.org/how-to/multiple-files/
-     */
-    `from-file`: string;
+  /** The path to another file containing module configuration to import here.
+   * https://blue-build.org/how-to/multiple-files/
+   */
+  `from-file`: string;
 }