diff --git a/.changeset/short-deploy-token.md b/.changeset/short-deploy-token.md
new file mode 100644
index 00000000..3a4918bd
--- /dev/null
+++ b/.changeset/short-deploy-token.md
@@ -0,0 +1,6 @@
+---
+"@cloudhal/api": patch
+"@cloudhal/cli": patch
+---
+
+A `CLOUDHAL_DEPLOY_TOKEN` shorter than 32 characters no longer makes every `/api` request fail with 500. Only `/api/admin` is disabled (503 `deploy_token_invalid`): the error is logged once, `/api/health` reports `problems: ["deploy_token_invalid"]`, and sign-in and Studio keep working. The Workers Builds setup steps and the Deploy button guide now say not to edit `CLOUDHAL_DEPLOY_TOKEN`, because every build replaces it.
diff --git a/docs/guides/deploy-button.md b/docs/guides/deploy-button.md
index c1dd8b65..bbff4aa0 100644
--- a/docs/guides/deploy-button.md
+++ b/docs/guides/deploy-button.md
@@ -18,6 +18,8 @@ A local `cloudhal deploy` prints a one-time setup link. In Workers Builds the bu
 
 Until an owner exists, sign-up needs that token. Once the owner exists, sign-up is closed whatever the token is.
 
+**Do not edit `CLOUDHAL_DEPLOY_TOKEN`.** It sits next to `CLOUDHAL_SETUP_TOKEN` in the same list, but it is the deployment token, and every build replaces it. The owner account needs only `CLOUDHAL_SETUP_TOKEN`. If `CLOUDHAL_DEPLOY_TOKEN` is changed to a value shorter than 32 characters, the admin Worker switches off its deploy endpoints (`/api/admin`), and `/api/health` reports `"problems": ["deploy_token_invalid"]`. Studio, sign-in and publishing keep working. To fix it, retry the latest build or push a commit: the build sets a new token.
+
 ## How `cloudhal deploy` behaves in Workers Builds
 
 Workers Builds sets `WORKERS_CI=1`. Every build starts from a fresh clone, with no `.cloudhal/` folder: no local site, no `secrets.json`, no `state.json`. With `WORKERS_CI=1`, `cloudhal deploy`:
diff --git a/packages/api/src/app.ts b/packages/api/src/app.ts
index 6a04c356..b8a52848 100644
--- a/packages/api/src/app.ts
+++ b/packages/api/src/app.ts
@@ -15,7 +15,7 @@ import type { ApiDeps, Env } from "./context.ts";
 import { errorHandler, unauthorized } from "./errors.ts";
 import { PLAYGROUND_PRINCIPAL, playgroundGuard } from "./playground.ts";
 import { activity, deploymentActivity } from "./routes/activity.ts";
-import { adminRoutes } from "./routes/admin.ts";
+import { mountAdmin } from "./routes/admin-mount.ts";
 import { agentKeys } from "./routes/agent-keys.ts";
 import { aiRoutes } from "./routes/ai.ts";
 import { analytics } from "./routes/analytics.ts";
@@ -210,19 +210,12 @@ export function createApi(deps: ApiDeps) {
       c.res.headers.set("cache-control", "no-store");
   });
 
-  app.get("/api/health", (c) => c.json({ ok: true }));
+  const problems = mountAdmin(app, deps);
+  app.get("/api/health", (c) => c.json(problems.length ? { ok: true, problems } : { ok: true }));
   if (deps.authHandler) {
     const handler = deps.authHandler;
     app.on(["GET", "POST"], "/api/auth/*", (c) => handler(c.req.raw));
   }
-  if (deps.admin) {
-    if (deps.admin.deployToken.length < 32)
-      throw new Error("admin.deployToken must be at least 32 characters");
-    app.route(
-      "/api/admin",
-      adminRoutes(deps.admin.deployToken, deps.admin.storage, deps.ai?.transport, deps.mcp?.render),
-    );
-  }
 
   app.get("/api/me", meHandler(membership));
 
@@ -270,7 +263,7 @@ export function createApi(deps: ApiDeps) {
           mcp: Boolean(deps.mcp),
           activity: Boolean(deps.audit ?? deps.mcp?.audit),
           previewLinks: Boolean(deps.preview),
-          deployTransfer: Boolean(deps.admin),
+          deployTransfer: Boolean(deps.admin) && problems.length === 0,
           approvals: Boolean(deps.mcp?.approvals),
           elevationRequests: Boolean(deps.mcp?.approvals && deps.agentKeys),
           members: Boolean(deps.staff),
diff --git a/packages/api/src/routes/admin-mount.ts b/packages/api/src/routes/admin-mount.ts
new file mode 100644
index 00000000..f31d492d
--- /dev/null
+++ b/packages/api/src/routes/admin-mount.ts
@@ -0,0 +1,40 @@
+/**
+ * Mounts `/api/admin` behind the deploy token. A deploy token shorter than 32 characters (an owner
+ * who edited CLOUDHAL_DEPLOY_TOKEN instead of CLOUDHAL_SETUP_TOKEN) switches off only the admin
+ * routes: the rest of the API, sign-in included, keeps working and `/api/health` names the problem.
+ */
+import type { Hono } from "hono";
+import type { ApiDeps, Env } from "../context.ts";
+import { adminRoutes } from "./admin.ts";
+
+export const MIN_DEPLOY_TOKEN_LENGTH = 32;
+
+/** Health problems the admin mount found; empty when the admin routes are served or not wanted. */
+export type AdminProblem = "deploy_token_invalid";
+
+export function mountAdmin(app: Hono<Env>, deps: ApiDeps): AdminProblem[] {
+  if (!deps.admin) return [];
+  const { deployToken, storage } = deps.admin;
+  if (deployToken.length >= MIN_DEPLOY_TOKEN_LENGTH) {
+    app.route(
+      "/api/admin",
+      adminRoutes(deployToken, storage, deps.ai?.transport, deps.mcp?.render),
+    );
+    return [];
+  }
+  console.error(
+    `cloudhal: CLOUDHAL_DEPLOY_TOKEN is shorter than ${MIN_DEPLOY_TOKEN_LENGTH} characters; /api/admin is disabled ` +
+      "(push, pull, owner transfer). Do not edit CLOUDHAL_DEPLOY_TOKEN; deploy again to set it " +
+      "(Workers Builds: retry the build). The owner setup token is CLOUDHAL_SETUP_TOKEN.",
+  );
+  app.all("/api/admin/*", (c) =>
+    c.json(
+      {
+        error: "deploy_token_invalid",
+        message: `CLOUDHAL_DEPLOY_TOKEN must be at least ${MIN_DEPLOY_TOKEN_LENGTH} characters; admin endpoints are disabled`,
+      },
+      503,
+    ),
+  );
+  return ["deploy_token_invalid"];
+}
diff --git a/packages/api/test/admin.test.ts b/packages/api/test/admin.test.ts
index e6f8cbbd..f3763490 100644
--- a/packages/api/test/admin.test.ts
+++ b/packages/api/test/admin.test.ts
@@ -3,7 +3,7 @@ import { SiteGraphStore, seedStarterSite } from "@cloudhal/core-ts";
 import { makePng } from "@cloudhal/core-ts/media/fixtures";
 import { MemoryBlobStore } from "@cloudhal/storage";
 import { BetterSqlite3Driver } from "@cloudhal/storage/sqlite";
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 import { createApi } from "../src/app.ts";
 
 const TOKEN = "deploy-token-for-tests-0123456789abcdef";
@@ -238,9 +238,41 @@ describe("admin bundle endpoints", () => {
 
     expect((await put(bundle.replace(site.id, "site_other0000001"))).status).toBe(400);
     expect((await put(bundle, "?mode=yolo")).status).toBe(400);
-    expect(() =>
-      createApi({ store: a.store, admin: { deployToken: "short", storage: a } }),
-    ).toThrow(/32/);
+  });
+});
+
+describe("short deploy token", () => {
+  it("disables only /api/admin, logs once and reports it on /api/health", async () => {
+    const b = await backend();
+    const errors = vi.spyOn(console, "error").mockImplementation(() => {});
+    try {
+      const app = createApi({ store: b.store, admin: { deployToken: "short", storage: b } });
+      expect(errors).toHaveBeenCalledTimes(1);
+      expect(String(errors.mock.calls[0]?.[0])).toMatch(/CLOUDHAL_DEPLOY_TOKEN.*32/);
+
+      const health = await app.request("/api/health");
+      expect(health.status).toBe(200);
+      expect(await health.json()).toEqual({ ok: true, problems: ["deploy_token_invalid"] });
+
+      for (const token of ["short", TOKEN]) {
+        const res = await app.request("/api/admin/sites", {
+          headers: { authorization: `Bearer ${token}` },
+        });
+        expect(res.status).toBe(503);
+        expect(((await res.json()) as { error: string }).error).toBe("deploy_token_invalid");
+      }
+      // The rest of the API still answers (here: unauthenticated, not a crash).
+      expect((await app.request("/api/me")).status).toBeLessThan(500);
+      expect(errors).toHaveBeenCalledTimes(1);
+    } finally {
+      errors.mockRestore();
+    }
+  });
+
+  it("keeps /api/health plain with a valid token", async () => {
+    const b = await backend();
+    const app = createApi({ store: b.store, admin: { deployToken: TOKEN, storage: b } });
+    expect(await (await app.request("/api/health")).json()).toEqual({ ok: true });
   });
 });
 
diff --git a/packages/cli/src/commands/deploy/workers-builds.ts b/packages/cli/src/commands/deploy/workers-builds.ts
index 60dc7be2..1da13bfd 100644
--- a/packages/cli/src/commands/deploy/workers-builds.ts
+++ b/packages/cli/src/commands/deploy/workers-builds.ts
@@ -142,5 +142,7 @@ export function setupInstructions(adminUrl: string, adminWorker: string): string
     "     edit CLOUDHAL_SETUP_TOKEN and set a random value of your own (32 characters or more),",
     `     or run \`npx wrangler secret put CLOUDHAL_SETUP_TOKEN --name ${adminWorker}\``,
     `  2. open ${login}<that value>`,
+    "Do not edit CLOUDHAL_DEPLOY_TOKEN: every build replaces it, and a changed value switches off",
+    "the deploy endpoints (/api/admin). The owner account only needs CLOUDHAL_SETUP_TOKEN.",
   ].join("\n");
 }
diff --git a/scripts/size-baseline.json b/scripts/size-baseline.json
index 56427416..b6922d1a 100644
--- a/scripts/size-baseline.json
+++ b/scripts/size-baseline.json
@@ -304,7 +304,7 @@
       "params": 5
     },
     "packages/api/src/app.ts::createApi": {
-      "lines": 224
+      "lines": 217
     },
     "packages/api/src/build-turn.ts::runBuildTurn": {
       "lines": 260