Map flattened ArtifactsError and enable enhanced_error_serialization

packages/mock-servers/cloudflare/wrangler.jsonc

@@ -2,7 +2,11 @@
 	"$schema": "../../../node_modules/wrangler/config-schema.json",
 	"name": "kody-mock-cloudflare",
 	"compatibility_date": "2026-04-16",
-	"compatibility_flags": ["nodejs_compat", "global_fetch_strictly_public"],
+	"compatibility_flags": [
+		"nodejs_compat",
+		"global_fetch_strictly_public",
+		"enhanced_error_serialization",
+	],
 	"main": "./src/worker.ts",
 	"preview_urls": true,
 	"observability": { "enabled": true },

packages/worker/src/dynamic-worker-compatibility.node.test.ts

@@ -7,6 +7,9 @@ import {
 
 test('dynamic and mock Cloudflare worker compatibility match the main wrangler config', () => {
 	const mainWorker = readMainWorkerWranglerCompatibility()
+	expect(mainWorker.compatibilityFlags).toContain(
+		'enhanced_error_serialization',
+	)
 	expect(createDynamicWorkerCompatibilityOptions()).toEqual({
 		compatibilityDate: mainWorker.compatibilityDate,
 		compatibilityFlags: mainWorker.compatibilityFlags,

packages/worker/src/dynamic-worker-compatibility.ts

@@ -7,6 +7,7 @@ export const dynamicWorkerCompatibilityDate = '2026-04-16'
 export const dynamicWorkerCompatibilityFlags = [
 	'nodejs_compat',
 	'global_fetch_strictly_public',
+	'enhanced_error_serialization',
 ] as const
 
 export type DynamicWorkerCompatibilityOptions = {

packages/worker/src/repo/artifacts.node.test.ts

@@ -692,6 +692,15 @@ test('getArtifactsBinding prefers the native ARTIFACTS binding for the env names
 	await expect(binding.get('repo-unrelated-not-found')).rejects.toThrow(
 		/git: repository not found/,
 	)
+	nativeGet.mockReset()
+	nativeGet.mockImplementation(async () => {
+		throw new Error(
+			'ArtifactsError: Repository not found: repo-native-prefixed',
+		)
+	})
+	await expect(binding.get('repo-native-prefixed')).resolves.toEqual({
+		status: 'not_found',
+	})
 
 	nativeGet.mockReset()
 	nativeGet.mockImplementation(async () => {

packages/worker/src/repo/artifacts.ts

@@ -200,30 +200,53 @@ function isArtifactsBindingError(error: unknown): error is ArtifactsError {
 	)
 }
 
-function artifactsBindingErrorCode(error: unknown) {
-	if (isArtifactsBindingError(error)) return error.code
-	if (error === null || typeof error !== 'object') return null
-	const candidate = error as { name?: unknown; message?: unknown }
-	// Message fallback only for ArtifactsError with known prefixes so a
-	// generic git/HTTP "not found" cannot look like a create-safe miss.
+function readArtifactsErrorMessage(error: unknown) {
+	if (typeof error === 'string') return error
+	if (error instanceof Error) return error.message
 	if (
-		candidate.name !== 'ArtifactsError' ||
-		typeof candidate.message !== 'string'
+		error !== null &&
+		typeof error === 'object' &&
+		'message' in error &&
+		typeof error.message === 'string'
 	) {
-		return null
+		return error.message
 	}
-	if (/^Repository not found(?::|\b)/.test(candidate.message)) {
-		return 'NOT_FOUND'
-	}
-	if (/^Repository already exists(?::|\b)/.test(candidate.message)) {
+	return ''
+}
+
+function artifactsBindingErrorCode(error: unknown) {
+	if (isArtifactsBindingError(error)) return error.code
+	// JSRPC may flatten the class so `name` is Error and the message is
+	// `ArtifactsError: Repository not found: <repo>`. Strip that prefix,
+	// then require the known create-safe starts.
+	const message = readArtifactsErrorMessage(error).replace(
+		/^ArtifactsError:\s*/,
+		'',
+	)
+	if (/^Repository not found(?::|\b)/.test(message)) return 'NOT_FOUND'
+	if (/^Repository already exists(?::|\b)/.test(message)) {
 		return 'ALREADY_EXISTS'
 	}
-	if (/^Import in progress(?::|\b)/i.test(candidate.message)) {
+	if (/^Import in progress(?::|\b)/i.test(message)) {
 		return 'IMPORT_IN_PROGRESS'
 	}
 	return null
 }
 
+async function getNativeRepoOrThrow(native: Artifacts, name: string) {
+	try {
+		return await native.get(name)
+	} catch (error) {
+		const code = artifactsBindingErrorCode(error)
+		if (code === 'NOT_FOUND') {
+			throw new Error(`Artifacts repo "${name}" was not found.`, {
+				cause: error,
+			})
+		}
+		throw error
+	}
+}
+
 function adaptNativeRepoHandle(repo: ArtifactsRepo): ArtifactRepoHandle {
 	return {
 		info: async () => ({
@@ -267,19 +290,19 @@ function adaptNativeArtifactsBinding(
 ): ArtifactNamespaceBinding & Record<string, unknown> {
 	const repo = (name: string): ArtifactRepoHandle => ({
 		info: async () => {
-			const handle = await native.get(name)
+			const handle = await getNativeRepoOrThrow(native, name)
 			return adaptNativeRepoHandle(handle).info()
 		},
 		createToken: async (scope = 'write', ttl = 3600) => {
-			const handle = await native.get(name)
+			const handle = await getNativeRepoOrThrow(native, name)
 			return adaptNativeRepoHandle(handle).createToken(scope, ttl)
 		},
 		listTokens: async () => {
-			const handle = await native.get(name)
+			const handle = await getNativeRepoOrThrow(native, name)
 			return adaptNativeRepoHandle(handle).listTokens?.() ?? []
 		},
 		revokeToken: async (idOrPlaintext) => {
-			const handle = await native.get(name)
+			const handle = await getNativeRepoOrThrow(native, name)
 			await adaptNativeRepoHandle(handle).revokeToken?.(idOrPlaintext)
 		},
 	})

packages/worker/wrangler.jsonc

@@ -2,7 +2,17 @@
 	"$schema": "../../node_modules/wrangler/config-schema.json",
 	"name": "kody",
 	"compatibility_date": "2026-04-16",
-	"compatibility_flags": ["nodejs_compat", "global_fetch_strictly_public"],
+	// `enhanced_error_serialization` is date-default on 2026-04-21. Opt in
+	// explicitly so JSRPC from the Artifacts binding preserves `name`/`code`
+	// instead of flattening to `Error` + `ArtifactsError: …` message. Keep
+	// the structural matcher in `src/repo/artifacts.ts`; this flag does not
+	// restore custom prototype identity. Do not advance the date just to
+	// pick this up — 2026-04-21 also defaults `enable_python_external_sdk`.
+	"compatibility_flags": [
+		"nodejs_compat",
+		"global_fetch_strictly_public",
+		"enhanced_error_serialization",
+	],
 	// Paid default is 10_000 subrequests/invocation. The MCP Agent Durable
 	// Object keeps a long-lived session and each mutating storage_query pays
 	// several D1 + StorageRunner RPCs (entitlement baseline, sqlQuery,