diff --git a/packages/frontend-app-api/src/wiring/parameters.test.ts b/packages/frontend-app-api/src/wiring/parameters.test.ts
index 036de02252..eeb0df8530 100644
--- a/packages/frontend-app-api/src/wiring/parameters.test.ts
+++ b/packages/frontend-app-api/src/wiring/parameters.test.ts
@@ -211,7 +211,7 @@ describe('readAppExtensionParameters', () => {
         }),
       ),
     ).toThrow(
-      "Invalid extension configuration at app.extensions[0], extension ID must only contain letters, numbers, dashes, and dots, got 'core.router/routes'",
+      "Invalid extension configuration at app.extensions[0], extension ID must only contain letters, numbers, and dots; got 'core.router/routes'",
     );
   });
 });
@@ -260,10 +260,10 @@ describe('expandShorthandExtensionParameters', () => {
       disabled: false,
     });
     expect(() => run('')).toThrowErrorMatchingInlineSnapshot(
-      `"Invalid extension configuration at app.extensions[1], extension ID must only contain letters, numbers, dashes, and dots, got ''"`,
+      `"Invalid extension configuration at app.extensions[1], extension ID must only contain letters, numbers, and dots; got ''"`,
     );
     expect(() => run('core.router/routes')).toThrowErrorMatchingInlineSnapshot(
-      `"Invalid extension configuration at app.extensions[1], extension ID must only contain letters, numbers, dashes, and dots, got 'core.router/routes'"`,
+      `"Invalid extension configuration at app.extensions[1], extension ID must only contain letters, numbers, and dots; got 'core.router/routes'"`,
     );
   });
 
diff --git a/packages/frontend-app-api/src/wiring/parameters.ts b/packages/frontend-app-api/src/wiring/parameters.ts
index 1b6173fca0..60de094aee 100644
--- a/packages/frontend-app-api/src/wiring/parameters.ts
+++ b/packages/frontend-app-api/src/wiring/parameters.ts
@@ -61,10 +61,10 @@ export function expandShorthandExtensionParameters(
   }
 
   function assertValidId(id: string) {
-    if (!id.match(/^[\.a-zA-Z0-9-]+$/)) {
+    if (!id.match(/^[\.a-zA-Z0-9]+$/)) {
       throw new Error(
         errorMsg(
-          `extension ID must only contain letters, numbers, dashes, and dots, got '${id}'`,
+          `extension ID must only contain letters, numbers, and dots; got '${id}'`,
         ),
       );
     }
diff --git a/packages/frontend-plugin-api/api-report.md b/packages/frontend-plugin-api/api-report.md
index 34ca6fdb5a..3068b25437 100644
--- a/packages/frontend-plugin-api/api-report.md
+++ b/packages/frontend-plugin-api/api-report.md
@@ -19,7 +19,7 @@ export interface BackstagePlugin {
   // (undocumented)
   $$type: 'backstage-plugin';
   // (undocumented)
-  defaultExtensionInstances: ExtensionInstanceParameters[];
+  defaultExtensions: Extension<unknown>[];
   // (undocumented)
   id: string;
 }
@@ -27,7 +27,7 @@ export interface BackstagePlugin {
 // @public (undocumented)
 export interface BackstagePluginOptions {
   // (undocumented)
-  defaultExtensionInstances?: ExtensionInstanceParameters[];
+  defaultExtensions?: Extension<unknown>[];
   // (undocumented)
   id: string;
 }
@@ -61,9 +61,13 @@ export interface CreateExtensionOptions<
   >,
   TConfig,
 > {
+  // (undocumented)
+  at: string;
   // (undocumented)
   configSchema?: PortableSchema<TConfig>;
   // (undocumented)
+  disabled?: boolean;
+  // (undocumented)
   factory(options: {
     bind: ExtensionDataBind<TData>;
     config: TConfig;
@@ -74,6 +78,8 @@ export interface CreateExtensionOptions<
     };
   }): void;
   // (undocumented)
+  id: string;
+  // (undocumented)
   inputs?: TPoint;
   // (undocumented)
   output: TData;
@@ -99,6 +105,9 @@ export function createPageExtension<
         configSchema: PortableSchema<TConfig>;
       }
   ) & {
+    id: string;
+    at?: string;
+    disabled?: boolean;
     inputs?: TInputs;
     component: (props: {
       config: TConfig;
@@ -124,14 +133,20 @@ export interface Extension<TConfig> {
   // (undocumented)
   $$type: 'extension';
   // (undocumented)
+  at: string;
+  // (undocumented)
   configSchema?: PortableSchema<TConfig>;
   // (undocumented)
+  disabled: boolean;
+  // (undocumented)
   factory(options: {
     bind: ExtensionDataBind<AnyExtensionDataMap>;
     config: TConfig;
     inputs: Record<string, Array<Record<string, unknown>>>;
   }): void;
   // (undocumented)
+  id: string;
+  // (undocumented)
   inputs: Record<
     string,
     {
@@ -159,20 +174,6 @@ export type ExtensionDataValue<TData extends AnyExtensionDataMap> = {
   [K in keyof TData]: TData[K]['T'];
 };
 
-// @public (undocumented)
-export interface ExtensionInstanceParameters {
-  // (undocumented)
-  at: string;
-  // (undocumented)
-  config?: unknown;
-  // (undocumented)
-  disabled?: boolean;
-  // (undocumented)
-  extension: Extension<unknown>;
-  // (undocumented)
-  id: string;
-}
-
 // @public (undocumented)
 export type PortableSchema<TOutput> = {
   parse: (input: unknown) => TOutput;