Use workerd's compatibility date for Cloudflare defaults

.changeset/funny-carrots-add.md

@@ -0,0 +1,6 @@
+---
+'astro': patch
+'@astrojs/cloudflare': patch
+---
+
+Updates generated and default Cloudflare `compatibility_date` values to match the installed runtime and requires Wrangler `^4.125.0`

knip.js

@@ -82,6 +82,8 @@ export default {
 				'rehype-toc',
 				'remark-code-titles',
 				'@types/http-cache-semantics',
+				// Resolved from the user's project by `astro add cloudflare`.
+				'@astrojs/cloudflare',
 				// Optional peer dep: dynamically imported in config validation for the legacy
 				// remark/rehype pipeline. Knip flags it because it's referenced from source.
 				'@astrojs/markdown-remark',

packages/astro/src/cli/add/cloudflare.ts

@@ -0,0 +1,14 @@
+import { createRequire } from 'node:module';
+import { pathToFileURL } from 'node:url';
+
+interface CloudflareInfo {
+	getLocalWorkerdCompatibilityDate(): { date: string };
+}
+
+export async function getCloudflareCompatibilityDate(root: URL): Promise<string> {
+	const require = createRequire(root);
+	const infoPath = require.resolve('@astrojs/cloudflare/info');
+	const infoUrl = pathToFileURL(infoPath).toString();
+	const infoModule = (await import(infoUrl)) as CloudflareInfo;
+	return infoModule.getLocalWorkerdCompatibilityDate().date;
+}

packages/astro/src/cli/add/index.ts

@@ -31,6 +31,7 @@ import { eventCliSession, telemetry } from '../../events/index.js';
 import { exec } from '../exec.js';
 import { createLoggerFromFlags, type Flags, flagsToAstroInlineConfig } from '../flags.js';
 import { fetchPackageJson, fetchPackageVersions } from '../install-package.js';
+import { getCloudflareCompatibilityDate } from './cloudflare.js';
 
 const { bold, cyan, dim, green, magenta, red, yellow } = colors;
 
@@ -200,7 +201,7 @@ export async function add(names: string[], { flags }: AddOptions) {
 
 					if (await askToContinue({ flags, logger })) {
 						const data = await getPackageJson();
-						let compatibilityDate = new Date().toISOString().slice(0, 10);
+						const compatibilityDate = await getCloudflareCompatibilityDate(root);
 
 						await fs.writeFile(
 							wranglerConfigURL,

packages/astro/test/units/cli/add-cloudflare.test.ts

@@ -0,0 +1,39 @@
+import assert from 'node:assert/strict';
+import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { describe, it } from 'node:test';
+import { pathToFileURL } from 'node:url';
+import { getCloudflareCompatibilityDate } from '../../../dist/cli/add/cloudflare.js';
+
+describe('astro add cloudflare', () => {
+	it('uses the compatibility date exported by the installed adapter', async () => {
+		const projectDir = await mkdtemp(join(tmpdir(), 'astro-add-cloudflare-'));
+		const adapterDir = join(projectDir, 'node_modules', '@astrojs', 'cloudflare');
+
+		try {
+			await mkdir(adapterDir, { recursive: true });
+			await writeFile(
+				join(adapterDir, 'package.json'),
+				JSON.stringify({
+					name: '@astrojs/cloudflare',
+					type: 'module',
+					exports: { './info': './info.js' },
+				}),
+			);
+			await writeFile(
+				join(adapterDir, 'info.js'),
+				`export function getLocalWorkerdCompatibilityDate() {
+	return { date: '2026-08-15', source: 'workerd' };
+}
+`,
+			);
+
+			const date = await getCloudflareCompatibilityDate(pathToFileURL(`${projectDir}/`));
+
+			assert.equal(date, '2026-08-15');
+		} finally {
+			await rm(projectDir, { recursive: true, force: true });
+		}
+	});
+});

packages/integrations/cloudflare/package.json

@@ -18,6 +18,7 @@
   "homepage": "https://docs.astro.build/en/guides/integrations-guide/cloudflare/",
   "exports": {
     ".": "./dist/index.js",
+    "./info": "./dist/info.js",
     "./entrypoints/server": "./dist/entrypoints/server.js",
     "./entrypoints/preview": "./dist/entrypoints/preview.js",
     "./entrypoints/server.js": "./dist/entrypoints/server.js",
@@ -46,16 +47,16 @@
   "dependencies": {
     "@astrojs/internal-helpers": "workspace:*",
     "@astrojs/underscore-redirects": "workspace:*",
-    "@cloudflare/vite-plugin": "^1.39.0",
+    "@cloudflare/vite-plugin": "^1.53.0",
     "piccolore": "^0.1.3",
     "vite": "^8.0.13"
   },
   "peerDependencies": {
     "astro": "^7.2.0",
-    "wrangler": "^4.83.0"
+    "wrangler": "^4.125.0"
   },
   "devDependencies": {
-    "@cloudflare/workers-types": "^4.20260526.1",
+    "@cloudflare/workers-types": "^5.20260820.1",
     "@types/node": "^22.10.6",
     "@types/prismjs": "1.26.6",
     "astro": "workspace:*",
@@ -64,7 +65,7 @@
     "devalue": "^5.8.1",
     "prismjs": "^1.30.0",
     "tinyglobby": "^0.2.15",
-    "wrangler": "^4.83.0"
+    "wrangler": "^4.125.0"
   },
   "publishConfig": {
     "provenance": true

packages/integrations/cloudflare/src/hono.ts

@@ -70,7 +70,7 @@ function getFetchState(context: HonoCloudflareContextLike): FetchState {
 export function cf(): HonoMiddlewareHandler {
 	return async (context, next) => {
 		const state = getFetchState(context);
-		const asset = await cfFetch(state, context.env, context.executionCtx);
+		const asset = await cfFetch(state, context.env, context.executionCtx as ExecutionContext);
 		if (asset) return asset;
 		await next();
 	};

packages/integrations/cloudflare/src/info.ts

@@ -0,0 +1 @@
+export { getLocalWorkerdCompatibilityDate } from '@cloudflare/vite-plugin';

packages/integrations/cloudflare/src/wrangler.ts

@@ -1,15 +1,11 @@
 import type { PluginConfig, WorkerConfig } from '@cloudflare/vite-plugin';
+import { getLocalWorkerdCompatibilityDate } from './info.js';
 
 export const DEFAULT_SESSION_KV_BINDING_NAME = 'SESSION';
 export const DEFAULT_IMAGES_BINDING_NAME = 'IMAGES';
 export const DEFAULT_ASSETS_BINDING_NAME = 'ASSETS';
 
-// Default compatibility date used when the user doesn't set one in their wrangler config.
-// The @cloudflare/vite-plugin falls back to today's date, but that can exceed the maximum
-// date supported by the bundled workerd binary (which has a ~7 day buffer from its build date),
-// causing ERR_RUNTIME_FAILURE. A hard-coded date avoids this issue.
-// This should be updated when upgrading wrangler/workerd dependencies.
-const DEFAULT_COMPATIBILITY_DATE = '2026-04-15';
+const DEFAULT_COMPATIBILITY_DATE = getLocalWorkerdCompatibilityDate().date;
 
 interface CloudflareConfigOptions {
 	sessionKVBindingName?: string | undefined;

packages/integrations/cloudflare/test/wrangler.test.ts

@@ -1,5 +1,6 @@
 import * as assert from 'node:assert/strict';
 import { describe, it } from 'node:test';
+import { getLocalWorkerdCompatibilityDate } from '../dist/info.js';
 import {
 	cloudflareConfigCustomizer,
 	DEFAULT_ASSETS_BINDING_NAME,
@@ -8,6 +9,22 @@ import {
 } from '../dist/wrangler.js';
 
 describe('cloudflareConfigCustomizer', () => {
+	describe('compatibility date', () => {
+		it('uses the date supported by the installed workerd', () => {
+			const customizer = cloudflareConfigCustomizer();
+			const result = customizer({});
+
+			assert.equal(result.compatibility_date, getLocalWorkerdCompatibilityDate().date);
+		});
+
+		it('preserves the user compatibility date', () => {
+			const customizer = cloudflareConfigCustomizer();
+			const result = customizer({ compatibility_date: '2025-01-01' });
+
+			assert.equal(result.compatibility_date, '2025-01-01');
+		});
+	});
+
 	describe('main entrypoint', () => {
 		it('sets main to the server entrypoint when none exists', () => {
 			const customizer = cloudflareConfigCustomizer();