diff --git a/packages/alchemy/src/Cloudflare/Workers/Worker.ts b/packages/alchemy/src/Cloudflare/Workers/Worker.ts
index 6c3b47778e..a1fa062fa7 100644
--- a/packages/alchemy/src/Cloudflare/Workers/Worker.ts
+++ b/packages/alchemy/src/Cloudflare/Workers/Worker.ts
@@ -7,7 +7,6 @@ import * as Data from "effect/Data";
 import * as Effect from "effect/Effect";
 import type * as Layer from "effect/Layer";
 import * as Redacted from "effect/Redacted";
-import * as Bundle from "../../Bundle/Bundle.ts";
 import { type MemoOptions } from "../../Command/Memo.ts";
 import type { Dependencies } from "../../Dependencies.ts";
 import type { InputProps } from "../../Input.ts";
@@ -45,7 +44,7 @@ import type {
   WorkerBindingResource,
   WorkerBindings,
 } from "./WorkerBinding.ts";
-import { type ModuleRule } from "./WorkerBundle.ts";
+import { type ModuleRule, type WorkerBuildOptions } from "./WorkerBundle.ts";
 import {
   makeWorkerRuntimeContext,
   type WorkerRuntimeContext,
@@ -478,10 +477,13 @@ export interface WorkerProps<
    */
   routes?: WorkerRouteConfig[];
   /**
-   * Extra bundler options applied on top of the standard rolldown input/output
-   * options used to build this Worker. See {@link Bundle.BundleExtraOptions}.
+   * Extra bundler options applied on top of the standard rolldown
+   * input/output options used to build this Worker. Includes the generic
+   * bundle extras (pure-annotation packages, bundle analyzer) plus an
+   * `output` field of rolldown output overrides (e.g. `codeSplitting`
+   * groups) merged over Alchemy's defaults. See {@link WorkerBuildOptions}.
    */
-  build?: Bundle.BundleExtraOptions;
+  build?: WorkerBuildOptions;
   /**
    * Whether to bundle {@link main} with rolldown before upload.
    *
diff --git a/packages/alchemy/src/Cloudflare/Workers/WorkerBundle.ts b/packages/alchemy/src/Cloudflare/Workers/WorkerBundle.ts
index aa0e650256..969a5a8497 100644
--- a/packages/alchemy/src/Cloudflare/Workers/WorkerBundle.ts
+++ b/packages/alchemy/src/Cloudflare/Workers/WorkerBundle.ts
@@ -20,6 +20,25 @@ import {
   type DurableObjectExport,
 } from "./DurableObject.ts";
 
+/**
+ * Bundler options for a Worker: the generic {@link Bundle.BundleExtraOptions}
+ * plus rolldown output overrides merged over Alchemy's defaults.
+ */
+export interface WorkerBuildOptions extends Bundle.BundleExtraOptions {
+  /**
+   * Rolldown output options merged over Alchemy's defaults. Use this to
+   * control chunking (`codeSplitting`), minification, etc.
+   */
+  output?: rolldown.OutputOptions;
+  /**
+   * Forwarded to rolldown's `preserveEntrySignatures` input option. Some
+   * `output.codeSplitting` configurations require relaxing it (e.g.
+   * `includeDependenciesRecursively: false` needs `"allow-extension"`).
+   * Workers must keep their entry exports, so never pass `false`.
+   */
+  preserveEntrySignatures?: rolldown.InputOptions["preserveEntrySignatures"];
+}
+
 export interface WorkerBundleOptions {
   id: string;
   main: string;
@@ -36,7 +55,7 @@ export interface WorkerBundleOptions {
         exports: Record<string, DurableObjectExport | WorkflowExport>;
       };
   stack: { name: string; stage: string };
-  extraOptions: Bundle.BundleExtraOptions | undefined;
+  extraOptions: WorkerBuildOptions | undefined;
 }
 
 export const WorkerBundle = Effect.gen(function* () {
@@ -48,6 +67,7 @@ export const WorkerBundle = Effect.gen(function* () {
     const realMain = yield* sanitizeMain(options.main);
     const inputOptions: rolldown.InputOptions = {
       input: realMain,
+      preserveEntrySignatures: options.extraOptions?.preserveEntrySignatures,
       // Forever-devtool native modules that vite/chokidar reference behind
       // runtime guards. Rolldown resolves before tree-shaking, so the dead
       // `require('../pkg')` (lightningcss < 1.32) and `require('fsevents')`
@@ -89,7 +109,17 @@ export const WorkerBundle = Effect.gen(function* () {
       sourcemap: "hidden",
       minify: true,
       keepNames: true,
+      // Rolldown's default chunking can split top-level initializer modules
+      // (e.g. Drizzle `pgTable` schemas) away from the classes they read,
+      // and workerd then evaluates a reader before its imported binding is
+      // initialized — the script fails Cloudflare startup validation with
+      // `ScriptStartupError: Cannot access '<minified>' before
+      // initialization` (#749). `strictExecutionOrder` wraps cross-chunk
+      // modules so evaluation follows ESM semantics regardless of how the
+      // graph was chunked. See DrizzleSchemaChunks.test.ts.
+      strictExecutionOrder: true,
       dir: `.alchemy/bundles/${options.id}`,
+      ...options.extraOptions?.output,
     };
     return { inputOptions, outputOptions, extraOptions: options.extraOptions };
   });
diff --git a/packages/alchemy/test/Cloudflare/Workers/DrizzleSchemaChunks.test.ts b/packages/alchemy/test/Cloudflare/Workers/DrizzleSchemaChunks.test.ts
new file mode 100644
index 0000000000..f4e22256b3
--- /dev/null
+++ b/packages/alchemy/test/Cloudflare/Workers/DrizzleSchemaChunks.test.ts
@@ -0,0 +1,118 @@
+import * as Cloudflare from "@/Cloudflare";
+import * as Alchemy from "@/index.ts";
+import * as Test from "@/Test/Alchemy";
+import { expect } from "alchemy-test";
+import * as Effect from "effect/Effect";
+import * as FileSystem from "effect/FileSystem";
+import * as Path from "effect/Path";
+import * as Schedule from "effect/Schedule";
+import * as HttpClient from "effect/unstable/http/HttpClient";
+import { fileURLToPath } from "node:url";
+
+const fixtureMain = fileURLToPath(
+  new URL("./fixtures/drizzle-schema-chunks/worker.ts", import.meta.url),
+);
+
+const { test, beforeAll, afterAll, deploy, destroy } = Test.make({
+  providers: Cloudflare.providers(),
+});
+
+/**
+ * Regression stack for https://github.com/alchemy-run/alchemy/issues/749.
+ *
+ * The `build` options force the *cyclic* chunk layout from the issue: the
+ * schema group captures only the schema modules
+ * (`includeDependenciesRecursively: false`), so `drizzle-orm` stays in the
+ * entry chunk and the graph becomes `worker.js -> auth-*.js -> worker.js`.
+ * ESM evaluation then runs the schema chunk before drizzle's class bindings
+ * initialize. Without WorkerBundle's default `strictExecutionOrder: true`,
+ * Cloudflare rejects the upload with `ScriptStartupError: Cannot access
+ * '<minified>' before initialization` — so the deploy in `beforeAll` is
+ * itself the regression assertion. (An acyclic split — e.g. drizzle in its
+ * own chunk imported by the schema chunk — would NOT regress: plain import
+ * order already evaluates it correctly.)
+ */
+const Stack = Alchemy.Stack(
+  "DrizzleSchemaChunksTestStack",
+  { providers: Cloudflare.providers(), state: Cloudflare.state() },
+  Effect.gen(function* () {
+    const worker = yield* Cloudflare.Worker("DrizzleSchemaChunks", {
+      main: fixtureMain,
+      compatibility: { date: "2026-06-24", flags: ["nodejs_compat"] },
+      build: {
+        // Required by `includeDependenciesRecursively: false`; rolldown
+        // rejects it under the default "strict".
+        preserveEntrySignatures: "allow-extension",
+        output: {
+          cleanDir: true,
+          codeSplitting: {
+            groups: [
+              {
+                name: "auth",
+                test: "drizzle-schema-chunks/(schema|auth)/",
+                includeDependenciesRecursively: false,
+              },
+            ],
+          },
+        },
+      },
+    });
+    return { url: worker.url.as<string>() };
+  }),
+);
+
+const bundleDir = Effect.gen(function* () {
+  const path = yield* Path.Path;
+  return path.resolve(".alchemy/bundles/DrizzleSchemaChunks");
+});
+
+// `cleanDir: true` on the stack's output options drops chunks from previous
+// runs, so the chunk-layout assertions below can't pass on stale files.
+const stack = beforeAll(deploy(Stack));
+afterAll.skipIf(!!process.env.NO_DESTROY)(destroy(Stack));
+
+test(
+  "code splitting options are applied and produce the cyclic layout",
+  Effect.gen(function* () {
+    const fs = yield* FileSystem.FileSystem;
+    const path = yield* Path.Path;
+    const dir = yield* bundleDir;
+    const files = yield* fs.readDirectory(dir);
+
+    // The schema modules landed in their own chunk...
+    const authChunk = files.find((f) => /^auth-.*\.js$/.test(f));
+    expect(authChunk).toBeDefined();
+
+    // ...which imports the entry back (drizzle-orm stayed in `worker.js`):
+    // the cyclic `worker.js <-> auth-*.js` graph that TDZ-crashed workerd
+    // startup in #749 before `strictExecutionOrder` became the default.
+    const authContent = yield* fs.readFileString(path.join(dir, authChunk!));
+    expect(authContent).toMatch(/from\s*"\.\/worker\.js"/);
+  }),
+);
+
+test(
+  "worker with drizzle schema modules split into their own chunk deploys and serves (#749)",
+  Effect.gen(function* () {
+    const { url } = yield* stack;
+
+    // The worker evaluated its cross-chunk schema at startup and serves.
+    const client = yield* HttpClient.HttpClient;
+    const body = yield* client.get(url).pipe(
+      Effect.flatMap((res) => res.text),
+      Effect.retry({
+        schedule: Schedule.exponential("500 millis"),
+        times: 5,
+      }),
+      // Fresh workers.dev URLs can serve placeholder pages while propagating.
+      Effect.repeat({
+        schedule: Schedule.exponential("500 millis"),
+        until: (b) => b.includes('"ok":true'),
+        times: 10,
+      }),
+      Effect.orDie,
+    );
+    expect(body).toContain('"ok":true');
+  }),
+  { timeout: 180_000 },
+);
diff --git a/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/README.md b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/README.md
new file mode 100644
index 0000000000..f22fbd0c9c
--- /dev/null
+++ b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/README.md
@@ -0,0 +1,49 @@
+# drizzle-schema-chunks
+
+Fixture for [#749](https://github.com/alchemy-run/alchemy/issues/749).
+
+Cloudflare Worker `ScriptStartupError` after Alchemy/Rolldown bundling when
+top-level Drizzle schema modules are code-split into a chunk separate from
+`drizzle-orm`. Cross-chunk evaluation in workerd leaves class bindings
+incomplete (`PgSerialBuilder is not a constructor`, or the classic
+`Cannot access '<minified>' before initialization` TDZ).
+
+## Layout
+
+Mirrors the reporter's monorepo shape:
+
+- `schema/*` — db package tables (`pgTable` at module scope)
+- `auth/*` — auth package tables that cross-import the db schema
+- `worker.ts` — Worker entry that imports the full graph
+
+## How the test pins the fix
+
+Small graphs stay single-chunk under Alchemy's default Worker bundler, so
+`DrizzleSchemaChunks.test.ts` deploys a stack whose `Cloudflare.Worker`
+*forces* the issue's chunk layout via `build` options: the schema group
+captures only the schema modules (`includeDependenciesRecursively: false`),
+leaving `drizzle-orm` in the entry chunk. The resulting graph is **cyclic**
+(`worker.js -> auth-*.js -> worker.js`), so ESM evaluation runs the schema
+chunk before drizzle's class bindings initialize — the TDZ. Cloudflare's
+script-startup validation runs on exactly those chunks at upload, so the
+deploy itself is the regression assertion; the test then verifies the
+cyclic layout on disk and fetches the worker.
+
+The cycle is essential: an *acyclic* split (e.g. drizzle in its own chunk
+imported by the schema chunk) evaluates correctly under plain import order
+and never triggers the bug, with or without `strictExecutionOrder`. Setting
+`strictExecutionOrder: false` on the stack's `build.output` restores the
+exact issue error:
+
+```
+ScriptStartupError: Uncaught ReferenceError: Cannot access 'a' before initialization
+  at auth-BFaahPAe.js:1:110
+```
+
+## The fix
+
+`WorkerBundle` sets `strictExecutionOrder: true` on its rolldown output
+options, which wraps cross-chunk modules so evaluation follows ESM semantics
+regardless of how the graph was chunked. Before that default, this exact
+split failed Cloudflare startup validation. The user-side `advancedChunks`
+grouping workaround from the issue is no longer necessary.
diff --git a/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/auth/invitations.ts b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/auth/invitations.ts
new file mode 100644
index 0000000000..02e7c6a8cc
--- /dev/null
+++ b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/auth/invitations.ts
@@ -0,0 +1,13 @@
+import { integer, pgTable, serial, text, timestamp } from "drizzle-orm/pg-core";
+import { users } from "../schema/users.ts";
+
+/**
+ * Mirrors the issue #749 layout: auth package schema modules that construct
+ * Drizzle tables at module scope and cross-import the db schema.
+ */
+export const invitations = pgTable("invitations", {
+  id: serial("id").primaryKey(),
+  email: text("email").notNull(),
+  invitedBy: integer("invited_by").references(() => users.id),
+  createdAt: timestamp("created_at").defaultNow(),
+});
diff --git a/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/auth/workspace.ts b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/auth/workspace.ts
new file mode 100644
index 0000000000..afb8d9a754
--- /dev/null
+++ b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/auth/workspace.ts
@@ -0,0 +1,15 @@
+import { integer, pgTable, serial, text } from "drizzle-orm/pg-core";
+import { users } from "../schema/users.ts";
+import { invitations } from "./invitations.ts";
+
+export const workspaces = pgTable("workspaces", {
+  id: serial("id").primaryKey(),
+  name: text("name").notNull(),
+  ownerId: integer("owner_id").references(() => users.id),
+});
+
+export const workspaceInvites = pgTable("workspace_invites", {
+  id: serial("id").primaryKey(),
+  workspaceId: integer("workspace_id").references(() => workspaces.id),
+  invitationId: integer("invitation_id").references(() => invitations.id),
+});
diff --git a/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/sessions.ts b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/sessions.ts
new file mode 100644
index 0000000000..5163989c6f
--- /dev/null
+++ b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/sessions.ts
@@ -0,0 +1,10 @@
+import { integer, pgTable, serial, text } from "drizzle-orm/pg-core";
+import { users } from "./users.ts";
+
+export const sessions = pgTable("sessions", {
+  id: serial("id").primaryKey(),
+  userId: integer("user_id")
+    .notNull()
+    .references(() => users.id),
+  token: text("token").notNull(),
+});
diff --git a/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/users.ts b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/users.ts
new file mode 100644
index 0000000000..46f250cd5e
--- /dev/null
+++ b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/users.ts
@@ -0,0 +1,12 @@
+import { pgTable, serial, text, timestamp } from "drizzle-orm/pg-core";
+
+/**
+ * Top-level `pgTable(...)` — evaluated at module init. When Rolldown puts
+ * this module in a separate chunk from `drizzle-orm`, workerd can observe
+ * incomplete cross-chunk bindings during startup (#749).
+ */
+export const users = pgTable("users", {
+  id: serial("id").primaryKey(),
+  email: text("email").notNull(),
+  createdAt: timestamp("created_at").defaultNow(),
+});
diff --git a/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/waitlist.ts b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/waitlist.ts
new file mode 100644
index 0000000000..ffdb124c94
--- /dev/null
+++ b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/schema/waitlist.ts
@@ -0,0 +1,9 @@
+import { boolean, integer, pgTable, serial, text } from "drizzle-orm/pg-core";
+import { users } from "./users.ts";
+
+export const waitlist = pgTable("waitlist", {
+  id: serial("id").primaryKey(),
+  email: text("email").notNull(),
+  approved: boolean("approved").default(false),
+  referredBy: integer("referred_by").references(() => users.id),
+});
diff --git a/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/worker.ts b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/worker.ts
new file mode 100644
index 0000000000..ab80f8901b
--- /dev/null
+++ b/packages/alchemy/test/Cloudflare/Workers/fixtures/drizzle-schema-chunks/worker.ts
@@ -0,0 +1,31 @@
+/**
+ * Plain Worker entry that imports a multi-module Drizzle schema graph with
+ * top-level `pgTable(...)` initializers — the shape that triggers #749 when
+ * Rolldown splits those schema modules into a chunk away from `drizzle-orm`.
+ *
+ * See `DrizzleSchemaChunks.test.ts` for the forced-split repro and the
+ * grouping workaround.
+ */
+import { invitations } from "./auth/invitations.ts";
+import { workspaces, workspaceInvites } from "./auth/workspace.ts";
+import { sessions } from "./schema/sessions.ts";
+import { users } from "./schema/users.ts";
+import { waitlist } from "./schema/waitlist.ts";
+
+export default {
+  async fetch() {
+    const tables = [
+      users,
+      sessions,
+      waitlist,
+      invitations,
+      workspaces,
+      workspaceInvites,
+    ];
+    return Response.json({
+      ok: true,
+      count: tables.length,
+      userCols: Object.keys(users),
+    });
+  },
+};