diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
index 673fa766..38e97d0c 100644
--- a/DEVELOPMENT.md
+++ b/DEVELOPMENT.md
@@ -381,7 +381,7 @@ processes.
 | `OPENTAG_OTEL_SAMPLE_RATE` | `1` | Global trace head sample rate from `0` to `1` |
 | `OPENTAG_ACCESS_TOKEN_TTL_SECONDS` | `900` | Access-token lifetime |
 | `OPENTAG_REFRESH_TOKEN_TTL_SECONDS` | `2592000` | Refresh-JWT lifetime |
-| `OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID` | empty | Staging-only Account UUID allowed to use the [Onboarding Lab](./docs/staging-onboarding-lab.md) |
+| `OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID` | empty | Staging-only Account UUID allowed to reset the [Onboarding Lab](./docs/staging-onboarding-lab.md) Account; Scenario Preview needs no configuration |
 | `OPENTAG_HOME` | channel-specific | Root for lifecycle-separated `config/`, `data/`, `state/`, and `logs/` (`~/.opentag-dev` in source) |
 
 If `doctor` fails, its error category distinguishes configuration, network, HTTP, and invalid-response failures. Confirm
diff --git a/DEVELOPMENT.zh-CN.md b/DEVELOPMENT.zh-CN.md
index e4d82b35..3693d4d4 100644
--- a/DEVELOPMENT.zh-CN.md
+++ b/DEVELOPMENT.zh-CN.md
@@ -361,7 +361,7 @@ setup attempt 并记录结果，然后把一条已授权的 binding 写入数据
 | `OPENTAG_OTEL_SAMPLE_RATE` | `1` | `0` 到 `1` 的全局 trace head sample rate |
 | `OPENTAG_ACCESS_TOKEN_TTL_SECONDS` | `900` | access token 有效期 |
 | `OPENTAG_REFRESH_TOKEN_TTL_SECONDS` | `2592000` | refresh JWT 有效期 |
-| `OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID` | 空 | 仅限 staging，允许使用 [Onboarding Lab](./docs/zh-CN/staging-onboarding-lab.md) 的 Account UUID |
+| `OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID` | 空 | 仅限 staging，允许 reset [Onboarding Lab](./docs/zh-CN/staging-onboarding-lab.md) Account 的 Account UUID；Scenario Preview 不需要配置 |
 | `OPENTAG_HOME` | 随 channel 而定 | 按生命周期分层的 `config/`、`data/`、`state/`、`logs/` 根目录（源码默认为 `~/.opentag-dev`） |
 
 如果 `doctor` 失败，其错误类别会区分配置、网络、HTTP 和无效响应。请确认 Server 已启动，且配置的 URL 指向其基础地址。
diff --git a/apps/web/src/api.ts b/apps/web/src/api.ts
index 1c9a8187..db40f975 100644
--- a/apps/web/src/api.ts
+++ b/apps/web/src/api.ts
@@ -251,8 +251,8 @@ export class BrowserApi {
   }
 
   /**
-   * Reports what this Account may do in the staging Onboarding Lab, and `undefined` where the
-   * deployment configures no Lab at all — the interface is then absent, not merely closed.
+   * Reports what this Account may do in the staging Onboarding Lab, and `undefined` outside staging,
+   * where the interface is absent rather than merely closed.
    */
   async onboardingLabAccess(): Promise<OnboardingLabAccess | undefined> {
     const response = await this.fetchWithRefresh(HTTP_PATHS.internalOnboardingLab);
diff --git a/apps/web/src/internal/onboarding-lab.test.tsx b/apps/web/src/internal/onboarding-lab.test.tsx
index be1abed5..75eed7db 100644
--- a/apps/web/src/internal/onboarding-lab.test.tsx
+++ b/apps/web/src/internal/onboarding-lab.test.tsx
@@ -198,7 +198,7 @@ describe("Onboarding Lab route", () => {
 
   function installApi(
     options: {
-      configured?: boolean;
+      offered?: boolean;
       resetAvailable?: boolean;
       workspaces?: "none";
       setupCompletedAt?: string | null;
@@ -241,7 +241,7 @@ describe("Onboarding Lab route", () => {
           resetRequests += 1;
           return new Response(null, { status: 204 });
         }
-        if (options.configured === false) return new Response(null, { status: 404 });
+        if (options.offered === false) return new Response(null, { status: 404 });
         return json({ reset: options.resetAvailable !== false });
       }
       if (path.endsWith("/computers")) return json({ computers: [] });
@@ -267,8 +267,8 @@ describe("Onboarding Lab route", () => {
     expect(window.location.pathname).toBe("/internal/onboarding-lab");
   });
 
-  it("renders Not Found where the deployment configures no Lab", async () => {
-    installApi({ configured: false });
+  it("renders Not Found where the deployment offers no Lab at all", async () => {
+    installApi({ offered: false });
 
     render(<App />);
 
diff --git a/apps/web/src/router.tsx b/apps/web/src/router.tsx
index 537524de..d64453ab 100644
--- a/apps/web/src/router.tsx
+++ b/apps/web/src/router.tsx
@@ -669,9 +669,9 @@ function OnboardingRoute() {
 }
 
 /**
- * The staging-only Onboarding Lab. A deployment that configures no Lab Account is answered exactly
- * like a page that does not exist; where one is configured, every signed-in Account may read the
- * Scenario Preview, and the Server still decides which single Account may run the reset.
+ * The staging-only Onboarding Lab. A deployment outside staging is answered exactly like a page that
+ * does not exist; on staging every signed-in Account may read the Scenario Preview, and the Server
+ * still decides which single Account, if any, may run the reset.
  */
 function OnboardingLabRoute() {
   const { me, refreshMe } = useAccount();
diff --git a/docs/staging-onboarding-lab.md b/docs/staging-onboarding-lab.md
index b3d9321c..c16960d4 100644
--- a/docs/staging-onboarding-lab.md
+++ b/docs/staging-onboarding-lab.md
@@ -11,8 +11,9 @@ runtime readiness and IM bindings immediately advance the fact-derived onboardin
 return to a first-run state on its own.
 
 The Lab is not available in production and it never resets an Account other than the authenticated one. Its two halves
-are gated differently: Scenario Preview reads nothing and writes nothing, so every signed-in Account on a configured
-staging deployment may open it; the destructive reset stays limited to the single configured Lab Account.
+are gated differently: Scenario Preview reads nothing and writes nothing, so every signed-in Account on any staging
+deployment may open it, with no configuration at all; the destructive reset stays limited to the single configured Lab
+Account, and no Account owns it until a deployment names one.
 
 ## Shared staging Account
 
@@ -25,7 +26,10 @@ for keeping a personal staging login signed in at the same time.
 
 ## Configuration
 
-Add one optional Server setting to the staging deployment:
+Scenario Preview needs none. A staging deployment offers it as soon as it runs, because the scenarios are fixed
+client-side fixtures.
+
+The reset needs one optional Server setting:
 
 ```bash
 OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID=00000000-0000-0000-0000-000000000000
@@ -33,17 +37,17 @@ OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID=00000000-0000-0000-0000-000000000000
 
 | Variable | Default | Purpose |
 | --- | --- | --- |
-| `OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID` | empty | Account UUID allowed to use the staging Onboarding Lab |
+| `OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID` | empty | Account UUID allowed to reset the staging Onboarding Lab Account |
 
 Rules the Server enforces:
 
-- the value must be an Account UUID; an empty value leaves the Lab unconfigured;
+- the value must be an Account UUID; an empty value leaves the reset unowned, and Preview unaffected;
 - the setting is valid only with `OPENTAG_ENV=staging`, so configuring it in production fails Server startup;
-- when it is unset, no Lab route is registered at all;
-- every request must be authenticated; on a configured staging deployment any Account may read the Lab and see Scenario
-  Preview, and the response reports whether that Account owns the reset;
-- an unconfigured deployment, and any deployment outside staging, answers both requests like a page that does not exist;
-- only the configured Account may reset; any other Account is refused exactly like a page that does not exist;
+- every request must be authenticated; on a staging deployment any Account may read the Lab and see Scenario Preview,
+  and the response reports whether that Account owns the reset;
+- any deployment outside staging answers both requests like a page that does not exist;
+- only the configured Account may reset; every other Account, and every Account while none is configured, is refused
+  exactly like a page that does not exist;
 - reset always targets the authenticated Account and accepts no client-selected Account;
 - reset requires the normal browser CSRF protection.
 
diff --git a/docs/zh-CN/staging-onboarding-lab.md b/docs/zh-CN/staging-onboarding-lab.md
index 15cbc4cf..eca6f2de 100644
--- a/docs/zh-CN/staging-onboarding-lab.md
+++ b/docs/zh-CN/staging-onboarding-lab.md
@@ -9,7 +9,8 @@ Onboarding Lab 是仅限 staging 的页面，用于迭代首次使用体验。
 推进由事实推导出的 onboarding 流程，因此一个已完成的 Account 无法自行回到首次使用状态。
 
 Lab 在 production 不可用，也永远不会 reset 除已认证 Account 之外的任何 Account。它的两半门禁不同：Scenario Preview 不读取也不
-写入任何内容，因此在已配置的 staging 部署上，任何已登录 Account 都可以打开；破坏性的 reset 仍然只属于那个被配置的 Lab Account。
+写入任何内容，因此在任何 staging 部署上，任何已登录 Account 都可以打开，且不需要任何配置；破坏性的 reset 仍然只属于那个被配置的
+Lab Account，在部署指定之前没有任何 Account 拥有它。
 
 ## 共享 staging Account
 
@@ -21,7 +22,9 @@ Lab 在 production 不可用，也永远不会 reset 除已认证 Account 之外
 
 ## 配置
 
-在 staging 部署中增加一个可选的 Server 设置：
+Scenario Preview 不需要任何配置。staging 部署一运行就提供它，因为场景是固定的客户端 fixture。
+
+reset 需要一个可选的 Server 设置：
 
 ```bash
 OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID=00000000-0000-0000-0000-000000000000
@@ -33,13 +36,12 @@ OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID=00000000-0000-0000-0000-000000000000
 
 Server 强制执行的规则：
 
-- 取值必须是 Account UUID；空值表示 Lab 未配置；
+- 取值必须是 Account UUID；空值表示 reset 无人拥有，不影响 Preview；
 - 该设置只在 `OPENTAG_ENV=staging` 时有效，因此在 production 配置会导致 Server 启动失败；
-- 未配置时完全不注册任何 Lab 路由；
-- 每个请求都必须完成认证；在已配置的 staging 部署上，任何 Account 都可以读取 Lab 并查看 Scenario Preview，响应会说明该 Account
-  是否拥有 reset；
-- 未配置的部署，以及 staging 之外的任何部署，对两种请求的响应都与页面不存在完全一致；
-- 只有被配置的 Account 可以 reset；其他 Account 得到的拒绝与页面不存在完全一致；
+- 每个请求都必须完成认证；在 staging 部署上，任何 Account 都可以读取 Lab 并查看 Scenario Preview，响应会说明该 Account 是否
+  拥有 reset；
+- staging 之外的任何部署，对两种请求的响应都与页面不存在完全一致；
+- 只有被配置的 Account 可以 reset；其他 Account，以及尚未配置时的所有 Account，得到的拒绝与页面不存在完全一致；
 - reset 始终作用于已认证 Account，不接受客户端选择的 Account；
 - reset 需要常规的浏览器 CSRF 保护。
 
diff --git a/packages/server/src/__tests__/config.test.ts b/packages/server/src/__tests__/config.test.ts
index 78306406..eb21a0bf 100644
--- a/packages/server/src/__tests__/config.test.ts
+++ b/packages/server/src/__tests__/config.test.ts
@@ -10,7 +10,7 @@ const required = {
 };
 
 describe("parseServerConfig", () => {
-  it("registers the staging Onboarding Lab Account only for an explicit staging environment", () => {
+  it("offers the staging Onboarding Lab on every staging deployment and its reset only when configured", () => {
     const accountId = "3f2504e0-4f89-41d3-9a0c-0305e82c3301";
     expect(
       parseServerConfig({
@@ -21,10 +21,32 @@ describe("parseServerConfig", () => {
       }).stagingOnboardingLab,
     ).toEqual({ accountId });
 
+    // Scenario Preview is fixed client-side fixtures, so staging offers the Lab with no Account
+    // configured; only the reset half waits for one.
+    expect(
+      parseServerConfig({
+        ...required,
+        OPENTAG_ENV: "staging",
+        OPENTAG_PUBLIC_URL: "https://staging.example.com",
+        OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID: "",
+      }).stagingOnboardingLab,
+    ).toEqual({});
+    expect(
+      parseServerConfig({
+        ...required,
+        OPENTAG_ENV: "staging",
+        OPENTAG_PUBLIC_URL: "https://staging.example.com",
+      }).stagingOnboardingLab,
+    ).toEqual({});
+
     expect(parseServerConfig({ ...required, OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID: "" }).stagingOnboardingLab).toBe(
       undefined,
     );
     expect(parseServerConfig(required).stagingOnboardingLab).toBe(undefined);
+    expect(
+      parseServerConfig({ ...required, OPENTAG_ENV: "prod", OPENTAG_PUBLIC_URL: "https://example.com" })
+        .stagingOnboardingLab,
+    ).toBe(undefined);
 
     for (const invalid of [
       {
diff --git a/packages/server/src/__tests__/onboarding-lab-routes.test.ts b/packages/server/src/__tests__/onboarding-lab-routes.test.ts
index e99f4c05..82ca7f34 100644
--- a/packages/server/src/__tests__/onboarding-lab-routes.test.ts
+++ b/packages/server/src/__tests__/onboarding-lab-routes.test.ts
@@ -12,7 +12,11 @@ afterEach(async () => {
 });
 
 function fixture(
-  options: { environment?: "dev" | "staging" | "prod"; labAccountId?: string; registered?: boolean } = {},
+  options: {
+    environment?: "dev" | "staging" | "prod";
+    labAccountId?: string | "unconfigured";
+    registered?: boolean;
+  } = {},
 ) {
   const accountId = randomUUID();
   const labAccountId = options.labAccountId ?? accountId;
@@ -21,7 +25,7 @@ function fixture(
     agents: { suspendById: vi.fn(), deleteById: vi.fn() },
     database: {} as never,
     environment: options.environment ?? "staging",
-    labAccountId,
+    ...(labAccountId === "unconfigured" ? {} : { labAccountId }),
     workspaceAdmins: {} as never,
   });
   vi.spyOn(reset, "resetOnboarding").mockImplementation(resetOnboarding);
@@ -49,7 +53,7 @@ function browserHeaders(extra: Record<string, string> = {}) {
 }
 
 describe("internal Onboarding Lab interface", () => {
-  it("registers no Lab route when the deployment configures no Lab Account", async () => {
+  it("registers no Lab route where the deployment offers no Lab at all", async () => {
     const value = fixture({ registered: false });
 
     expect(value.app.hasRoute({ method: "GET", url: INTERNAL_ONBOARDING_LAB_PATH })).toBe(false);
@@ -77,6 +81,20 @@ describe("internal Onboarding Lab interface", () => {
     expect(read.json()).toEqual({ reset: true });
   });
 
+  it("offers Preview but no reset owner where staging configures no Lab Account", async () => {
+    const value = fixture({ labAccountId: "unconfigured" });
+
+    const [read, reset] = await Promise.all([
+      value.app.inject({ method: "GET", url: INTERNAL_ONBOARDING_LAB_PATH, headers: browserHeaders() }),
+      value.app.inject({ method: "POST", url: INTERNAL_ONBOARDING_LAB_PATH, headers: browserHeaders() }),
+    ]);
+
+    expect(read.statusCode).toBe(200);
+    expect(read.json()).toEqual({ reset: false });
+    expect(reset.statusCode).toBe(404);
+    expect(value.resetOnboarding).not.toHaveBeenCalled();
+  });
+
   it("resets the authenticated Account and never a client-selected Account", async () => {
     const value = fixture();
 
diff --git a/packages/server/src/api/internal-onboarding-lab.ts b/packages/server/src/api/internal-onboarding-lab.ts
index 5ed681f2..a587557f 100644
--- a/packages/server/src/api/internal-onboarding-lab.ts
+++ b/packages/server/src/api/internal-onboarding-lab.ts
@@ -11,11 +11,11 @@ function accountId(request: FastifyRequest): string {
 }
 
 /**
- * The staging-only Onboarding Lab interface. It is registered only when the deployment configures
- * the Lab Account, so an unconfigured deployment stays indistinguishable from one that never had
- * the feature. Reading access is open to any authenticated Account, because Scenario Preview is
- * client-side fixtures that read nothing and write nothing; the destructive reset stays closed and
- * never accepts a client-selected Account.
+ * The staging-only Onboarding Lab interface. Any staging deployment registers it, and every
+ * deployment outside staging stays indistinguishable from one that never had the feature. Reading
+ * access is open to any authenticated Account, because Scenario Preview is client-side fixtures that
+ * read nothing and write nothing; the destructive reset stays closed, is refused until a deployment
+ * configures the Account that owns it, and never accepts a client-selected Account.
  */
 export function registerInternalOnboardingLabRoutes(
   app: FastifyInstance,
diff --git a/packages/server/src/app.ts b/packages/server/src/app.ts
index 9e2a964b..9b7770a3 100644
--- a/packages/server/src/app.ts
+++ b/packages/server/src/app.ts
@@ -62,7 +62,10 @@ export interface CreateAppOptions {
   readiness?: BootstrapReadiness;
   runtime?: RuntimeRoutesOptions;
   slackEvents?: SlackEventsRouteOptions;
-  /** Registered only by a staging deployment that configures the shared Onboarding Lab Account. */
+  /**
+   * Registered by any staging deployment. Scenario Preview needs no Account configuration; the reset
+   * half is closed until the service is given the Account that owns it.
+   */
   stagingOnboardingLab?: { reset: OnboardingResetService };
   taskService?: TaskService;
   workspaceService?: WorkspaceAdminService;
diff --git a/packages/server/src/config.ts b/packages/server/src/config.ts
index b3bad996..7f4d9798 100644
--- a/packages/server/src/config.ts
+++ b/packages/server/src/config.ts
@@ -242,8 +242,12 @@ export interface ServerConfig {
   port: number;
   publicUrl: string;
   refreshTokenTtlSeconds: number;
-  /** Present only when a staging deployment configures the shared Onboarding Lab Account. */
-  stagingOnboardingLab?: { accountId: string };
+  /**
+   * Present on every staging deployment. Scenario Preview is fixed client-side fixtures, so it needs
+   * no Account configuration; `accountId` names the one Account that additionally owns the reset,
+   * and stays absent until a deployment configures it.
+   */
+  stagingOnboardingLab?: { accountId?: string };
 }
 
 export interface DatabaseConfig {
@@ -338,8 +342,12 @@ export function parseServerConfig(environment: NodeJS.ProcessEnv): ServerConfig
     port: parsed.OPENTAG_PORT,
     publicUrl: parsed.OPENTAG_PUBLIC_URL,
     refreshTokenTtlSeconds: parsed.OPENTAG_REFRESH_TOKEN_TTL_SECONDS,
-    ...(parsed.OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID
-      ? { stagingOnboardingLab: { accountId: parsed.OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID } }
+    ...(parsed.OPENTAG_ENV === "staging"
+      ? {
+          stagingOnboardingLab: parsed.OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID
+            ? { accountId: parsed.OPENTAG_STAGING_ONBOARDING_ACCOUNT_ID }
+            : {},
+        }
       : {}),
   };
 }
diff --git a/packages/server/src/index.ts b/packages/server/src/index.ts
index 4fb13640..3a52ae17 100644
--- a/packages/server/src/index.ts
+++ b/packages/server/src/index.ts
@@ -271,7 +271,7 @@ export async function startServer(): Promise<void> {
             agents: agentService,
             database,
             environment: config.environment,
-            labAccountId: config.stagingOnboardingLab.accountId,
+            ...(config.stagingOnboardingLab.accountId ? { labAccountId: config.stagingOnboardingLab.accountId } : {}),
             registry,
             workspaceAdmins,
           }),
diff --git a/packages/server/src/services/onboarding-lab/onboarding-reset-service.ts b/packages/server/src/services/onboarding-lab/onboarding-reset-service.ts
index 3764f251..8d71f7c0 100644
--- a/packages/server/src/services/onboarding-lab/onboarding-reset-service.ts
+++ b/packages/server/src/services/onboarding-lab/onboarding-reset-service.ts
@@ -49,8 +49,11 @@ export interface OnboardingResetServiceOptions {
   agents: OnboardingResetAgentLifecycle;
   database: DatabaseClient;
   environment: ChannelName;
-  /** The single staging Account this deployment may reset. */
-  labAccountId: string;
+  /**
+   * The single staging Account this deployment may reset. Absent where no Account is configured:
+   * the Lab then offers Scenario Preview alone, and no Account owns the reset.
+   */
+  labAccountId?: string;
   now?: () => Date;
   registry?: OnboardingResetConnectionRegistry;
   workspaceAdmins?: WorkspaceAdminAccess;
@@ -74,7 +77,7 @@ export class OnboardingResetService {
   readonly #agents: OnboardingResetAgentLifecycle;
   readonly #database: DatabaseClient;
   readonly #environment: ChannelName;
-  readonly #labAccountId: string;
+  readonly #labAccountId: string | undefined;
   readonly #now: () => Date;
   readonly #registry: OnboardingResetConnectionRegistry | undefined;
   readonly #workspaceAdmins: WorkspaceAdminAccess;
@@ -100,9 +103,9 @@ export class OnboardingResetService {
     return this.#environment === "staging";
   }
 
-  /** Whether this Account owns the Lab's destructive half. */
+  /** Whether this Account owns the Lab's destructive half; no Account does until one is configured. */
   allows(accountId: string): boolean {
-    return this.enabled && accountId === this.#labAccountId;
+    return this.enabled && this.#labAccountId !== undefined && accountId === this.#labAccountId;
   }
 
   async resetOnboarding(accountId: string): Promise<void> {
diff --git a/packages/shared/src/onboarding-lab.ts b/packages/shared/src/onboarding-lab.ts
index 431446f1..7972990e 100644
--- a/packages/shared/src/onboarding-lab.ts
+++ b/packages/shared/src/onboarding-lab.ts
@@ -1,9 +1,10 @@
 import { z } from "zod";
 
 /**
- * What the authenticated Account may do in the staging Onboarding Lab. The interface exists only
- * where a deployment configures the Lab Account, so reaching it at all already means the Lab is
- * configured; `reset` then reports whether this particular Account owns the destructive half.
+ * What the authenticated Account may do in the staging Onboarding Lab. The interface exists on every
+ * staging deployment, so reaching it at all means only that this is staging; `reset` reports whether
+ * this particular Account owns the destructive half, and is false for everyone until a deployment
+ * configures an Account to own it.
  */
 export const OnboardingLabAccessSchema = z
   .object({