diff --git a/src/puter-js/src/lib/networkUtils.blob.test.js b/src/puter-js/src/lib/networkUtils.blob.test.js
new file mode 100644
index 000000000..6eca42d2b
--- /dev/null
+++ b/src/puter-js/src/lib/networkUtils.blob.test.js
@@ -0,0 +1,76 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { randomBytes } from 'node:crypto';
+import { driverCall } from './networkUtils.js';
+
+const SIZE = 1024 * 1024;
+
+function installBlobXHR(blob) {
+    class FakeXHR {
+        _listeners = {};
+        status = 0;
+        readyState = 0;
+        responseType = '';
+        upload = { addEventListener() {} };
+        open() {}
+        setRequestHeader() {}
+        addEventListener(type, fn) {
+            (this._listeners[type] ??= []).push(fn);
+        }
+        getResponseHeader(name) {
+            return name.toLowerCase() === 'content-type' ? 'video/mp4' : null;
+        }
+        abort() {}
+        send() {
+            queueMicrotask(() => {
+                this.status = 200;
+                this.response = blob;
+                this.readyState = 4;
+                for (const fn of this._listeners.readystatechange ?? [])
+                    fn.call(this);
+                for (const fn of this._listeners.load ?? []) fn.call(this);
+            });
+        }
+    }
+    globalThis.XMLHttpRequest = FakeXHR;
+}
+
+let savedXHR;
+beforeEach(() => {
+    savedXHR = globalThis.XMLHttpRequest;
+    globalThis.puter = {
+        authToken: 't',
+        APIOrigin: 'https://api.test',
+        env: 'nodejs',
+    };
+});
+afterEach(() => {
+    globalThis.XMLHttpRequest = savedXHR;
+    delete globalThis.puter;
+    vi.restoreAllMocks();
+});
+
+describe('successful blob driver call', () => {
+    it('returns the blob without decoding it to text', async () => {
+        const blob = new Blob([randomBytes(SIZE)], { type: 'video/mp4' });
+        installBlobXHR(blob);
+        const textSpy = vi.spyOn(Blob.prototype, 'text');
+
+        const t0 = performance.now();
+        const result = await driverCall(
+            {
+                iface: 'puter-video-generation',
+                method: 'generate',
+                args: {},
+                puter: globalThis.puter,
+            },
+            { responseType: 'blob' },
+        );
+        const ms = performance.now() - t0;
+
+        expect(result).toBe(blob);
+        expect(textSpy).not.toHaveBeenCalled();
+        process.stdout.write(
+            `driverCall on a ${SIZE / 1024 / 1024} MiB blob: ${ms.toFixed(1)} ms\n`,
+        );
+    });
+});
diff --git a/src/puter-js/src/lib/networkUtils.bodyToken.test.js b/src/puter-js/src/lib/networkUtils.bodyToken.test.js
new file mode 100644
index 000000000..dd55c65ba
--- /dev/null
+++ b/src/puter-js/src/lib/networkUtils.bodyToken.test.js
@@ -0,0 +1,120 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { fsRequest } from '../modules/FileSystem/operations/scaffold.js';
+import { driverCallEnvelope } from './networkUtils.js';
+
+function installFakeXHR(responses) {
+    const requests = [];
+    class FakeXHR {
+        _listeners = {};
+        _headers = {};
+        responseType = '';
+        status = 200;
+        readyState = 0;
+        upload = { addEventListener() {} };
+        open(method, url) {
+            this.method = method;
+            this.url = url;
+        }
+        setRequestHeader(name, value) {
+            this._headers[name.toLowerCase()] = value;
+        }
+        addEventListener(type, fn) {
+            (this._listeners[type] ??= []).push(fn);
+        }
+        getResponseHeader(name) {
+            return name.toLowerCase() === 'content-type'
+                ? 'application/json'
+                : null;
+        }
+        abort() {}
+        send(body) {
+            this.body = body;
+            requests.push(this);
+            const next = responses.shift();
+            queueMicrotask(() => {
+                this.status = next.status;
+                this.responseText = JSON.stringify(next.body);
+                this.response = this.responseText;
+                this.readyState = 4;
+                this.onreadystatechange?.();
+                for (const fn of this._listeners.readystatechange ?? [])
+                    fn.call(this);
+                for (const fn of this._listeners.load ?? [])
+                    fn.call(this, { target: this });
+            });
+        }
+    }
+    globalThis.XMLHttpRequest = FakeXHR;
+    return requests;
+}
+
+const authFailed = { status: 401, body: { code: 'token_auth_failed' } };
+
+let savedXHR;
+beforeEach(() => {
+    savedXHR = globalThis.XMLHttpRequest;
+    globalThis.puter = {
+        authToken: 'stale',
+        APIOrigin: 'https://api.test',
+        env: 'web',
+        resetAuthToken: vi.fn(() => {
+            globalThis.puter.authToken = null;
+        }),
+        ui: {
+            authenticateWithPuter: vi.fn(async () => {
+                globalThis.puter.authToken = 'fresh';
+            }),
+        },
+    };
+});
+afterEach(() => {
+    globalThis.XMLHttpRequest = savedXHR;
+    delete globalThis.puter;
+    vi.restoreAllMocks();
+});
+
+describe('reauth replay of body-token requests', () => {
+    it('fs /stat rebuilds its body token after sign-in', async () => {
+        const requests = installFakeXHR([
+            authFailed,
+            { status: 200, body: { success: true, result: 'ok' } },
+        ]);
+        const fsModule = {
+            APIOrigin: 'https://api.test',
+            get authToken() {
+                return puter.authToken;
+            },
+        };
+        await expect(
+            fsRequest.call(fsModule, {
+                endpoint: '/stat',
+                authHeader: false,
+                body: { path: '/u/x', auth_token: fsModule.authToken },
+            }),
+        ).resolves.toEqual({ success: true, result: 'ok' });
+
+        expect(puter.ui.authenticateWithPuter).toHaveBeenCalledTimes(1);
+        expect(puter.authToken).toBe('fresh');
+        expect(requests).toHaveLength(2);
+        expect(JSON.parse(requests[1].body).auth_token).toBe('fresh');
+        expect(requests[1]._headers.authorization).toBeUndefined();
+    });
+
+    it('puter.drivers.call rebuilds its body token after sign-in', async () => {
+        const requests = installFakeXHR([
+            authFailed,
+            { status: 200, body: { success: true, result: 'ok' } },
+        ]);
+        const result = await driverCallEnvelope({
+            puter: globalThis.puter,
+            iface: 'puter-kvstore',
+            method: 'get',
+            args: { key: 'k' },
+        });
+
+        expect(puter.ui.authenticateWithPuter).toHaveBeenCalledTimes(1);
+        expect(requests).toHaveLength(2);
+        expect(JSON.parse(requests[1].body).auth_token).toBe('fresh');
+        expect(result).toEqual({ success: true, result: 'ok' });
+    });
+});
diff --git a/src/puter-js/src/lib/networkUtils.js b/src/puter-js/src/lib/networkUtils.js
index 92bbdc2ad..f5921116d 100644
--- a/src/puter-js/src/lib/networkUtils.js
+++ b/src/puter-js/src/lib/networkUtils.js
@@ -88,18 +88,26 @@ function resolveBackgroundReauth(resp, sentToken) {
  *   reauth-recoverable 401 and the caller should handle it normally.
  */
 async function resolveReauth(resp, { interactive = true, sentToken } = {}) {
+    const needsReauth =
+        resp?.code === 'reauth_required' || resp?.code === 'token_auth_failed';
+    if (
+        needsReauth &&
+        sentToken &&
+        puter.authToken &&
+        sentToken !== puter.authToken
+    ) {
+        return { action: 'replay' };
+    }
+    if (
+        needsReauth &&
+        puter.env === 'app' &&
+        !puter.isGodmodeToken_?.(sentToken ?? puter.authToken)
+    ) {
+        return { action: 'reject', error: { status: 401, ...resp } };
+    }
     // A godmode app's token expires on schedule and the desktop renews it.
     // Asking shows no UI, so background requests ask too.
-    if (
-        (resp?.code === 'reauth_required' ||
-            resp?.code === 'token_auth_failed') &&
-        puter.env === 'app' &&
-        puter.isGodmodeToken_?.(sentToken ?? puter.authToken)
-    ) {
-        // Renewed while this request was in flight.
-        if (sentToken && puter.authToken && sentToken !== puter.authToken) {
-            return { action: 'replay' };
-        }
+    if (needsReauth && puter.env === 'app') {
         try {
             await puter.triggerReauth({
                 reason: resp.reason ?? 'token_expired',
@@ -293,6 +301,22 @@ function buildXhr(spec, { readSafe = false } = {}) {
     const origSend = xhr.send.bind(xhr);
     xhr.send = function (body) {
         spec.body = body;
+        // Body-token requests: builders that know the token say so, so large
+        // driver bodies aren't parsed just to read it.
+        if (typeof spec.bodyAuthToken === 'function') {
+            const token = spec.bodyAuthToken();
+            if (typeof token === 'string' && token) spec._sentAuthToken = token;
+        } else if (
+            typeof body === 'string' &&
+            body.startsWith('{') &&
+            body.includes('"auth_token"')
+        ) {
+            try {
+                const token = JSON.parse(body).auth_token;
+                if (typeof token === 'string' && token)
+                    spec._sentAuthToken = token;
+            } catch {}
+        }
         // An upload listener makes the browser preflight a cross-origin
         // request. One carrying a bearer is preflighted already; driver calls
         // go out as simple requests and must stay that way.
@@ -768,7 +792,7 @@ async function classifyRetry(outcome, ctx) {
     if (outcome.networkError) return transientRetry(ctx);
 
     const { xhr, status } = outcome;
-    if (outcome.parsed === undefined) {
+    if (outcome.parsed === undefined && [401, 403, 429].includes(status)) {
         outcome.parsed = await bodyJson(xhr).catch(() => null);
     }
     const parsed = outcome.parsed;
@@ -929,6 +953,10 @@ function dedupe(key, factory, { windowMs = 2000 } = {}) {
  * @param {Object} [opts.headers] - Extra request headers (undefined/null values
  *   skipped).
  * @param {string | Blob | ArrayBuffer | FormData | null} [opts.body]
+ * @param {() => string | Blob | ArrayBuffer | FormData | null} [opts.buildBody]
+ *   Rebuilds the body for each attempt.
+ * @param {() => string | null | undefined} [opts.bodyAuthToken] The token the
+ *   built body carries, recorded for reauth.
  * @param {'' | 'text' | 'json' | 'blob' | 'arraybuffer'} [opts.responseType='']
  *   Default is `''`
  * @param {boolean} [opts.withCredentials=true] Default is `true`
@@ -957,6 +985,8 @@ function fetchUrl(url, opts = {}) {
         method = 'GET',
         headers = {},
         body = null,
+        buildBody,
+        bodyAuthToken,
         responseType = '',
         withCredentials = true,
         signal,
@@ -981,6 +1011,8 @@ function fetchUrl(url, opts = {}) {
         withCredentials,
         responseType,
         body,
+        buildBody,
+        bodyAuthToken,
         signal,
         logId,
         interactiveReauth,
@@ -1252,6 +1284,7 @@ async function driverCall(call, opts = {}) {
         responseType,
         // Rebuilt per attempt, so a reauth replay carries the fresh token.
         buildBody: () => callBody(call, puter),
+        bodyAuthToken: () => puter.authToken,
         timeout,
         signal,
     };
@@ -1320,7 +1353,8 @@ async function driverCallEnvelope(call) {
         const resp = await fetchUrl(`${puter.APIOrigin}/drivers/call`, {
             method: 'POST',
             headers: { 'Content-Type': DRIVER_CONTENT_TYPE },
-            body: callBody(call, puter),
+            buildBody: () => callBody(call, puter),
+            bodyAuthToken: () => puter.authToken,
         });
 
         // TODO: parser for Content-Type
diff --git a/src/puter-js/src/lib/networkUtils.reauth.test.js b/src/puter-js/src/lib/networkUtils.reauth.test.js
new file mode 100644
index 000000000..74a8e814c
--- /dev/null
+++ b/src/puter-js/src/lib/networkUtils.reauth.test.js
@@ -0,0 +1,122 @@
+// @vitest-environment jsdom
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+vi.mock('socket.io-client', () => ({
+    io: () => ({
+        on: vi.fn(),
+        off: vi.fn(),
+        emit: vi.fn(),
+        disconnect: vi.fn(),
+    }),
+}));
+vi.mock('./polyfills/localStorage.js', () => ({ default: {} }));
+vi.mock('./polyfills/xhrshim.js', () => ({ default: class {} }));
+
+const STORAGE_KEY = 'puter.auth.token.v2';
+const b64url = (value) => Buffer.from(value).toString('base64url');
+const jwt = (payload) =>
+    `${b64url('{"alg":"HS256"}')}.${b64url(JSON.stringify(payload))}.sig`;
+const APP_TOKEN = jwt({
+    t: 'au',
+    v: '2',
+    au: Buffer.alloc(16, 1).toString('base64'),
+});
+
+const origDefine = customElements.define.bind(customElements);
+customElements.define = (name, cls) =>
+    customElements.get(name) || origDefine(name, cls);
+
+const origParent = Object.getOwnPropertyDescriptor(globalThis, 'parent');
+const origXHR = globalThis.XMLHttpRequest;
+class StubXHR {
+    open() {}
+    setRequestHeader() {}
+    addEventListener() {}
+    send() {}
+}
+
+let parentPost;
+beforeEach(() => {
+    localStorage.clear();
+    sessionStorage.clear();
+    parentPost = vi.fn();
+    Object.defineProperty(globalThis, 'parent', {
+        value: { postMessage: parentPost },
+        configurable: true,
+    });
+    Object.defineProperty(document, 'readyState', {
+        value: 'loading',
+        configurable: true,
+    });
+    globalThis.XMLHttpRequest = StubXHR;
+});
+afterEach(() => {
+    vi.useRealTimers();
+    if (origParent) Object.defineProperty(globalThis, 'parent', origParent);
+    delete document.readyState;
+    globalThis.XMLHttpRequest = origXHR;
+    vi.restoreAllMocks();
+});
+
+describe('reauth_required in a non-godmode app', () => {
+    it('rejects promptly without asking the desktop to renew a regular app token', async () => {
+        history.replaceState(
+            null,
+            '',
+            `/app/index.html?puter.app_instance_id=i&puter.auth.token=${APP_TOKEN}`,
+        );
+        vi.resetModules();
+        const { puter } = await import('../index.js');
+        const { resolveReauth } = await import('./networkUtils.js');
+        expect(puter.env).toBe('app');
+        expect(puter.authToken).toBe(APP_TOKEN);
+        parentPost.mockClear();
+
+        vi.useFakeTimers();
+        let settled;
+        const pending = resolveReauth(
+            { code: 'reauth_required', reason: 'session_revoked' },
+            { interactive: true, sentToken: APP_TOKEN },
+        ).then((v) => {
+            settled = v;
+        });
+
+        await pending;
+        expect(parentPost).not.toHaveBeenCalled();
+        expect(puter.authToken).toBe(APP_TOKEN);
+        expect(settled).toMatchObject({
+            action: 'reject',
+            error: { code: 'reauth_required' },
+        });
+    });
+});
+
+describe('token_auth_failed for a request sent before a sign-in finished (web)', () => {
+    it('replays with the fresh token without opening another sign-in', async () => {
+        vi.resetModules();
+        const { resolveReauth } = await import('./networkUtils.js');
+        globalThis.puter = {
+            env: 'web',
+            // Another call's sign-in already installed this one.
+            authToken: 'fresh',
+            resetAuthToken: vi.fn(() => {
+                globalThis.puter.authToken = null;
+            }),
+            ui: {
+                authenticateWithPuter: vi.fn(async () => {
+                    globalThis.puter.authToken = 'second';
+                }),
+            },
+        };
+        const verdict = await resolveReauth(
+            { code: 'token_auth_failed' },
+            { interactive: true, sentToken: 'stale' },
+        );
+        expect(verdict).toEqual({ action: 'replay' });
+        expect(globalThis.puter.resetAuthToken).not.toHaveBeenCalled();
+        expect(
+            globalThis.puter.ui.authenticateWithPuter,
+        ).not.toHaveBeenCalled();
+        delete globalThis.puter;
+    });
+});
diff --git a/src/puter-js/src/lib/utils.js b/src/puter-js/src/lib/utils.js
index ea1342b8a..fa58302c9 100644
--- a/src/puter-js/src/lib/utils.js
+++ b/src/puter-js/src/lib/utils.js
@@ -72,7 +72,7 @@ function replayXhr (response, success_cb, error_cb, resolve_func, reject_func) {
     const newSpec = { ...spec, _replayed: true };
     const newXhr = buildXhr(newSpec);
     setupXhrEventHandlers(newXhr, success_cb, error_cb, resolve_func, reject_func);
-    newXhr.send(spec.body);
+    newXhr.send(typeof newSpec.buildBody === 'function' ? newSpec.buildBody() : spec.body);
     return true;
 }
 
diff --git a/src/puter-js/src/modules/FileSystem/operations/scaffold.js b/src/puter-js/src/modules/FileSystem/operations/scaffold.js
index 91fd9ebf2..b1895b86e 100644
--- a/src/puter-js/src/modules/FileSystem/operations/scaffold.js
+++ b/src/puter-js/src/modules/FileSystem/operations/scaffold.js
@@ -182,7 +182,12 @@ export async function fsRequest (spec) {
             }
         }, rejectWithPrompt);
 
-        xhr.send(body === undefined ? undefined : JSON.stringify(body));
+        const buildBody = () => body === undefined ? undefined : JSON.stringify({
+            ...body,
+            ...(Object.hasOwn(body, 'auth_token') ? { auth_token: this.authToken } : {}),
+        });
+        if (xhr._puterReq) xhr._puterReq.buildBody = buildBody;
+        xhr.send(buildBody());
     });
 }