diff --git a/packages/core/src/index.d.ts b/packages/core/src/index.d.ts
index 7289319..fba5f83 100644
--- a/packages/core/src/index.d.ts
+++ b/packages/core/src/index.d.ts
@@ -111,9 +111,47 @@ interface Metadata {
   title?: string | null
   description?: string | null
   url?: string | null
+  author?: string | null
+  lang?: string | null
+  publisher?: string | null
+  date?: string | null
+  image?: Asset | null
+  logo?: Asset | null
   [key: string]: unknown
 }
 
+/** Same shape as `?data=` / `microlink.extract` rules. */
+interface ExtractRule {
+  attr?: string | string[] | ExtractRules
+  evaluate?: string | (() => unknown)
+  selector?: string | string[]
+  selectorAll?: string | string[]
+  type?:
+    | 'audio'
+    | 'author'
+    | 'auto'
+    | 'boolean'
+    | 'date'
+    | 'description'
+    | 'email'
+    | 'image'
+    | 'ip'
+    | 'lang'
+    | 'logo'
+    | 'number'
+    | 'object'
+    | 'publisher'
+    | 'regexp'
+    | 'string'
+    | 'title'
+    | 'url'
+    | 'video'
+}
+
+interface ExtractRules {
+  [field: string]: ExtractRule | ExtractRule[]
+}
+
 interface Embed {
   html: string
   scripts?: unknown[]
@@ -121,7 +159,10 @@ interface Embed {
 }
 
 export type FunctionArgs = {
-  page: Page
+  page: Page & {
+    metadata(): Promise<Metadata>
+    extract(rules: ExtractRules): Promise<Record<string, unknown>>
+  }
   response: HTTPResponse
   headers: Record<string, string>
   url: string
@@ -163,7 +204,7 @@ interface MicrolinkClient {
   audios (url: string, options?: CollectionOptions): Promise<string[]>
   extract (
     url: string,
-    rules: Record<string, unknown>,
+    rules: ExtractRules,
     options?: Options
   ): Promise<Record<string, unknown>>
   screenshot (url: string, options?: ScreenshotOptions): Promise<Asset>
diff --git a/packages/core/test/index.test-d.ts b/packages/core/test/index.test-d.ts
index cce5d46..702d513 100644
--- a/packages/core/test/index.test-d.ts
+++ b/packages/core/test/index.test-d.ts
@@ -62,6 +62,14 @@ async function assertions (): Promise<void> {
     avatar: { selector: 'img', attr: 'src', type: 'image' }
   })
   expectAssignable<Record<string, unknown>>(data)
+  expectAssignable<Record<string, unknown>>(
+    await client.extract('https://example.com', {
+      avatar: [
+        { selector: 'meta[property="og:image"]', attr: 'content', type: 'image' },
+        { selector: 'img', attr: 'src', type: 'image' }
+      ]
+    })
+  )
 
   const news = await client.search('coffee', { type: 'news', limit: 3 })
   expectAssignable<{ results: Array<{ publisher: string }> }>(news)
@@ -79,6 +87,17 @@ async function assertions (): Promise<void> {
       expectType<boolean>(response.ok())
       expectType<Record<string, string>>(headers)
       expectType<string>(url)
+      const metadata = await page.metadata()
+      expectType<string | null | undefined>(metadata.title)
+      expectType<Record<string, unknown>>(
+        await page.extract({
+          title: { selector: 'h1', type: 'string' },
+          avatar: [
+            { selector: 'meta[property="og:image"]', attr: 'content', type: 'image' },
+            { selector: 'img', attr: 'src', type: 'image' }
+          ]
+        })
+      )
       return page.title()
     }
   )