diff --git a/packages/core/package.json b/packages/core/package.json
index 01776b8..aa0e8e1 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -57,6 +57,7 @@
   "devDependencies": {
     "ava": "latest",
     "proxyquire": "latest",
+    "puppeteer-core": "25",
     "tinyspawn": "latest",
     "tsd": "latest"
   },
diff --git a/packages/core/src/index.d.ts b/packages/core/src/index.d.ts
index 2e4d095..7289319 100644
--- a/packages/core/src/index.d.ts
+++ b/packages/core/src/index.d.ts
@@ -1,3 +1,6 @@
+import type { HTTPResponse, Page } from 'puppeteer-core' with {
+  'resolution-mode': 'import'
+}
 import createGoogleClient from '@microlink/google'
 
 type GoogleClient = ReturnType<typeof createGoogleClient>
@@ -117,7 +120,15 @@ interface Embed {
   [key: string]: unknown
 }
 
-type FunctionInput = string | ((args: Record<string, unknown>) => unknown)
+export type FunctionArgs = {
+  page: Page
+  response: HTTPResponse
+  headers: Record<string, string>
+  url: string
+  [key: string]: any
+}
+
+export type FunctionInput = (args: FunctionArgs) => any
 
 interface FunctionResult<T = unknown> {
   isFulfilled: boolean
@@ -169,6 +180,11 @@ interface MicrolinkClient {
     code: FunctionInput,
     options?: Options
   ): Promise<FunctionResult<T>>
+  function<T = unknown> (
+    url: string,
+    code: string,
+    options?: Options
+  ): Promise<FunctionResult<T>>
 }
 
 interface create {
diff --git a/packages/core/test/index.test-d.ts b/packages/core/test/index.test-d.ts
index 5f3314a..cce5d46 100644
--- a/packages/core/test/index.test-d.ts
+++ b/packages/core/test/index.test-d.ts
@@ -71,6 +71,18 @@ async function assertions (): Promise<void> {
 
   const fnResult = await client.function('https://example.com', '() => 1')
   expectType<boolean>(fnResult.isFulfilled)
+
+  const title = await client.function(
+    'https://example.com',
+    async ({ page, response, headers, url }) => {
+      expectType<Promise<string>>(page.title())
+      expectType<boolean>(response.ok())
+      expectType<Record<string, string>>(headers)
+      expectType<string>(url)
+      return page.title()
+    }
+  )
+  expectType<boolean>(title.isFulfilled)
 }
 
 void assertions()
diff --git a/packages/function/src/index.d.ts b/packages/function/src/index.d.ts
index 62de41a..7922c81 100644
--- a/packages/function/src/index.d.ts
+++ b/packages/function/src/index.d.ts
@@ -39,11 +39,15 @@ export type FunctionRejected = {
 
 export type FunctionResponse = FunctionFulfilled | FunctionRejected
 
-export type FunctionInput = (args: {
+export type FunctionArgs = {
   page: Page
   response: HTTPResponse
+  headers: Record<string, string>
+  url: string
   [key: string]: any
-}) => any
+}
+
+export type FunctionInput = (args: FunctionArgs) => any
 
 declare function microlinkFunction(
   fn: FunctionInput,
diff --git a/packages/function/test/index.test-d.ts b/packages/function/test/index.test-d.ts
index 9cc48ba..40a8ed7 100644
--- a/packages/function/test/index.test-d.ts
+++ b/packages/function/test/index.test-d.ts
@@ -39,4 +39,6 @@ microlinkFn(() => document.getElementsByTagName('*').length)
 microlinkFn(({ page }) => page.title())
 microlinkFn(() => 420)
 microlinkFn(({ response }) => response.ok())
+microlinkFn(({ headers }) => headers['user-agent'])
+microlinkFn(({ url }) => url)
 microlinkFn(({ name }) => `Greetings, ${name}`)