diff --git a/src/puter-js/tests/api/suites/ai.suite.ts b/src/puter-js/tests/api/suites/ai.suite.ts
index d2dab54d7..2247cb9c4 100644
--- a/src/puter-js/tests/api/suites/ai.suite.ts
+++ b/src/puter-js/tests/api/suites/ai.suite.ts
@@ -119,4 +119,26 @@ export default suite('ai', {
             'the internal fake-chat provider should stay hidden',
         );
     },
+
+    'every model reported by the driver carries an id': async (t) => {
+        // The public listModels endpoint is empty without provider keys, so
+        // assert the shape against the driver-level list (always populated
+        // with the fake models).
+        const resp = await t.puter.drivers.call(
+            'puter-chat-completion',
+            'ai-chat',
+            'models',
+            {},
+        );
+        const models = (resp.result ?? resp) as Array<{ id?: string }>;
+        t.assert.ok(Array.isArray(models), 'driver models should be an array');
+        t.assert.ok(models.length > 0, 'driver should report models');
+        for (const model of models) {
+            t.assert.equal(
+                typeof model.id,
+                'string',
+                `every model entry should expose an id, got ${JSON.stringify(model)}`,
+            );
+        }
+    },
 });
diff --git a/src/puter-js/tests/api/suites/auth.suite.ts b/src/puter-js/tests/api/suites/auth.suite.ts
index 82d32a38c..51103b8df 100644
--- a/src/puter-js/tests/api/suites/auth.suite.ts
+++ b/src/puter-js/tests/api/suites/auth.suite.ts
@@ -83,6 +83,30 @@ export default suite('auth', {
         );
     },
 
+    'getDetailedAppUsage without an appId rejects': async (t) => {
+        await t.assert.rejects(
+            () =>
+                (
+                    t.puter.auth.getDetailedAppUsage as (
+                        appId?: unknown,
+                    ) => Promise<unknown>
+                )(),
+            'getDetailedAppUsage should require an appId',
+        );
+    },
+
+    'getDetailedAppUsage returns a report for an app': async (t) => {
+        const app = await t.puter.apps.create(
+            t.puter.randName(),
+            'https://example.com/',
+        );
+        const usage = await t.puter.auth.getDetailedAppUsage(app.uid);
+        t.assert.ok(
+            usage && typeof usage === 'object',
+            'detailed usage should be an object',
+        );
+    },
+
     'regular user is rejected by admin-gated endpoints': async (t) => {
         const asUser = await fetch(`${t.env.apiOrigin}/serverInfo`, {
             headers: {
diff --git a/src/puter-js/tests/api/suites/fs.suite.ts b/src/puter-js/tests/api/suites/fs.suite.ts
index 3a9a6db57..9a884c9ca 100644
--- a/src/puter-js/tests/api/suites/fs.suite.ts
+++ b/src/puter-js/tests/api/suites/fs.suite.ts
@@ -327,6 +327,35 @@ export default suite('fs', {
         t.assert.equal(await blob.text(), 'upload two');
     },
 
+    'read of a directory rejects': async (t) => {
+        const dir = `${home(t)}/fs-suite-read-dir`;
+        await t.puter.fs.mkdir(dir);
+        await t.assert.rejects(
+            () => t.puter.fs.read(dir),
+            'reading a directory as a file should reject',
+        );
+    },
+
+    'stat reports uid, path and size for a file': async (t) => {
+        const path = `${home(t)}/fs-suite-stat-fields.txt`;
+        await t.puter.fs.write(path, 'twelve bytes');
+        const info = await t.puter.fs.stat(path);
+        t.assert.ok(info.uid, 'stat should return a uid');
+        t.assert.equal(Boolean(info.is_dir), false);
+        t.assert.equal(info.name, 'fs-suite-stat-fields.txt');
+        t.assert.ok(info.path.endsWith('fs-suite-stat-fields.txt'));
+        t.assert.equal(Number(info.size), 'twelve bytes'.length);
+    },
+
+    'copy into a missing destination directory rejects': async (t) => {
+        const src = `${home(t)}/fs-suite-copy-src.txt`;
+        await t.puter.fs.write(src, 'copy me');
+        await t.assert.rejects(
+            () => t.puter.fs.copy(src, `${home(t)}/fs-suite-copy-nope`),
+            'copy into a nonexistent directory should reject',
+        );
+    },
+
     'users cannot read files outside their home': async (t) => {
         await t.assert.rejects(
             () => t.puter.fs.readdir(`/${t.env.users.admin.username}`),
diff --git a/src/puter-js/tests/api/suites/hosting.suite.ts b/src/puter-js/tests/api/suites/hosting.suite.ts
index d78044f76..6082f6653 100644
--- a/src/puter-js/tests/api/suites/hosting.suite.ts
+++ b/src/puter-js/tests/api/suites/hosting.suite.ts
@@ -98,6 +98,26 @@ export default suite('hosting', {
         );
     },
 
+    'get of an unknown subdomain rejects': async (t) => {
+        await t.assert.rejects(
+            () => t.puter.hosting.get('hosting-suite-never-created'),
+            'get of an unknown subdomain should reject',
+        );
+    },
+
+    'update to a missing directory rejects': async (t) => {
+        const dir = await makeSiteDir(t, 'update-missing');
+        await t.puter.hosting.create('hosting-suite-update-missing', dir);
+        await t.assert.rejects(
+            () =>
+                t.puter.hosting.update(
+                    'hosting-suite-update-missing',
+                    `${home(t)}/hosting-suite-not-a-dir`,
+                ),
+            'update pointing at a missing directory should reject',
+        );
+    },
+
     'delete removes the subdomain': async (t) => {
         const dir = await makeSiteDir(t, 'delete');
         await t.puter.hosting.create('hosting-suite-delete', dir);
diff --git a/src/puter-js/tests/api/suites/index.ts b/src/puter-js/tests/api/suites/index.ts
index 9760e0e86..2ad592d95 100644
--- a/src/puter-js/tests/api/suites/index.ts
+++ b/src/puter-js/tests/api/suites/index.ts
@@ -8,6 +8,7 @@ import kv from './kv.suite.ts';
 import net from './net.suite.ts';
 import perms from './perms.suite.ts';
 import system from './system.suite.ts';
+import util from './util.suite.ts';
 import workers from './workers.suite.ts';
 
 /**
@@ -24,5 +25,6 @@ export const suites: Suite[] = [
     net,
     perms,
     system,
+    util,
     workers,
 ];
diff --git a/src/puter-js/tests/api/suites/kv.suite.ts b/src/puter-js/tests/api/suites/kv.suite.ts
index e2a8d6540..c51e44041 100644
--- a/src/puter-js/tests/api/suites/kv.suite.ts
+++ b/src/puter-js/tests/api/suites/kv.suite.ts
@@ -132,4 +132,94 @@ export default suite('kv', {
             'an undefined key should be rejected',
         );
     },
+
+    'MAX_KEY_SIZE and MAX_VALUE_SIZE expose the documented limits': async (
+        t,
+    ) => {
+        t.assert.equal(t.puter.kv.MAX_KEY_SIZE, 1024);
+        t.assert.equal(t.puter.kv.MAX_VALUE_SIZE, 399 * 1024);
+    },
+
+    'incr on a fresh key starts from zero': async (t) => {
+        t.assert.equal(await t.puter.kv.incr('kv-suite-incr-fresh', 3), 3);
+    },
+
+    'decr can drive a value negative': async (t) => {
+        t.assert.equal(await t.puter.kv.decr('kv-suite-decr-neg', 5), -5);
+    },
+
+    'add appends values into an array at a path': async (t) => {
+        await t.puter.kv.set('kv-suite-add', { tags: ['alpha'] });
+        const updated = await t.puter.kv.add('kv-suite-add', {
+            tags: ['beta', 'gamma'],
+        });
+        t.assert.deepEqual(updated.tags, ['alpha', 'beta', 'gamma']);
+    },
+
+    'update with a ttl keeps the value readable before it expires': async (
+        t,
+    ) => {
+        await t.puter.kv.set('kv-suite-update-ttl', { n: 1 });
+        await t.puter.kv.update('kv-suite-update-ttl', { n: 2 }, 3600);
+        const value = await t.puter.kv.get('kv-suite-update-ttl');
+        t.assert.equal(value.n, 2);
+    },
+
+    'list without a pattern returns every key for the app': async (t) => {
+        await t.puter.kv.set('kv-suite-all-1', 1);
+        await t.puter.kv.set('kv-suite-all-2', 2);
+        const keys = (await t.puter.kv.list()) as string[];
+        t.assert.ok(keys.includes('kv-suite-all-1'));
+        t.assert.ok(keys.includes('kv-suite-all-2'));
+    },
+
+    'list returns keys in lexicographic order': async (t) => {
+        await t.puter.kv.set('kv-suite-sorted-c', 1);
+        await t.puter.kv.set('kv-suite-sorted-a', 1);
+        await t.puter.kv.set('kv-suite-sorted-b', 1);
+        const keys = (await t.puter.kv.list('kv-suite-sorted-*')) as string[];
+        t.assert.deepEqual(keys, [
+            'kv-suite-sorted-a',
+            'kv-suite-sorted-b',
+            'kv-suite-sorted-c',
+        ]);
+    },
+
+    'list with a limit and cursor paginates through matches': async (t) => {
+        for (let i = 1; i <= 3; i++) {
+            await t.puter.kv.set(`kv-suite-page-${i}`, `v${i}`);
+        }
+        const seen: string[] = [];
+        let cursor: string | undefined;
+        let guard = 0;
+        do {
+            const page = (await t.puter.kv.list({
+                pattern: 'kv-suite-page-*',
+                returnValues: true,
+                limit: 2,
+                cursor,
+            })) as { items: Array<{ key: string }>; cursor?: string };
+            for (const item of page.items) seen.push(item.key);
+            cursor = page.cursor;
+        } while (cursor && ++guard < 10);
+        t.assert.deepEqual(seen.sort(), [
+            'kv-suite-page-1',
+            'kv-suite-page-2',
+            'kv-suite-page-3',
+        ]);
+    },
+
+    'flush removes every key for the app': async (t) => {
+        await t.puter.kv.set('kv-suite-flush-a', 1);
+        await t.puter.kv.set('kv-suite-flush-b', 2);
+        await t.puter.kv.flush();
+        t.assert.equal(await t.puter.kv.get('kv-suite-flush-a'), null);
+        t.assert.equal(await t.puter.kv.get('kv-suite-flush-b'), null);
+        const keys = (await t.puter.kv.list()) as string[];
+        t.assert.equal(
+            keys.some((k) => k.startsWith('kv-suite-')),
+            false,
+            'flush should clear every key the suite created',
+        );
+    },
 });
diff --git a/src/puter-js/tests/api/suites/perms.suite.ts b/src/puter-js/tests/api/suites/perms.suite.ts
index fcb713c6b..0c08c3637 100644
--- a/src/puter-js/tests/api/suites/perms.suite.ts
+++ b/src/puter-js/tests/api/suites/perms.suite.ts
@@ -123,6 +123,24 @@ export default suite('perms', {
         t.assert.equal(await res.text(), 'group content');
     },
 
+    'grantGroup then revokeGroup both succeed': async (t) => {
+        const path = `${home(t)}/perms-suite-group-revoke.txt`;
+        await t.puter.fs.write(path, 'group revoke content');
+        const permission = `fs:${path}:read`;
+
+        const created = await t.puter.perms.createGroup({
+            title: 'perms-suite-revoke-readers',
+        });
+        await t.puter.perms.addUsersToGroup(created.uid, [
+            t.env.users.other.username,
+        ]);
+        const granted = await t.puter.perms.grantGroup(created.uid, permission);
+        t.assert.ok(!granted.error, `grant failed: ${JSON.stringify(granted)}`);
+
+        const revoked = await t.puter.perms.revokeGroup(created.uid, permission);
+        t.assert.ok(!revoked.error, `revoke failed: ${JSON.stringify(revoked)}`);
+    },
+
     'grantApp records an app permission': async (t) => {
         const app = await t.puter.apps.create(
             'perms-suite-app',
diff --git a/src/puter-js/tests/api/suites/system.suite.ts b/src/puter-js/tests/api/suites/system.suite.ts
index 7051b3332..3c997a8f2 100644
--- a/src/puter-js/tests/api/suites/system.suite.ts
+++ b/src/puter-js/tests/api/suites/system.suite.ts
@@ -20,6 +20,7 @@ export default suite('system', {
             'puter-kvstore',
             'puter-apps',
             'puter-subdomains',
+            'puter-chat-completion',
         ]) {
             t.assert.ok(
                 Object.prototype.hasOwnProperty.call(interfaces, expected),
diff --git a/src/puter-js/tests/api/suites/util.suite.ts b/src/puter-js/tests/api/suites/util.suite.ts
new file mode 100644
index 000000000..62fb15f48
--- /dev/null
+++ b/src/puter-js/tests/api/suites/util.suite.ts
@@ -0,0 +1,43 @@
+import { suite } from '../harness/types.ts';
+
+/**
+ * puter.js utility helpers (`puter.randName`, `puter.env`). These are pure
+ * client-side helpers, so they run identically on every platform.
+ * DOM-bound utilities like `puter.print` are covered by the browser
+ * fixtures, not here.
+ */
+export default suite('util', {
+    'randName returns a domain-safe name': async (t) => {
+        const name = t.puter.randName();
+        t.assert.equal(typeof name, 'string');
+        t.assert.ok(name.length > 0, 'randName should be non-empty');
+        t.assert.ok(
+            /^[a-z0-9-]+$/.test(name),
+            `randName should be lowercase, digits and dashes only, got: ${name}`,
+        );
+    },
+
+    'randName produces a fresh name each call': async (t) => {
+        const a = t.puter.randName();
+        const b = t.puter.randName();
+        t.assert.ok(a !== b, 'two randName calls should differ');
+    },
+
+    'randName honours a custom separator': async (t) => {
+        const name = t.puter.randName('_');
+        t.assert.ok(
+            name.includes('_') && !name.includes('-'),
+            `custom separator should be used throughout, got: ${name}`,
+        );
+    },
+
+    'env reports the runtime environment': async (t) => {
+        const env = t.puter.env;
+        t.assert.ok(
+            ['web', 'app', 'gui', 'nodejs', 'web-worker', 'service-worker'].includes(
+                env,
+            ),
+            `env should be a known environment, got: ${env}`,
+        );
+    },
+});
diff --git a/src/puter-js/tests/api/suites/workers.suite.ts b/src/puter-js/tests/api/suites/workers.suite.ts
index 5b42ac160..fceac6939 100644
--- a/src/puter-js/tests/api/suites/workers.suite.ts
+++ b/src/puter-js/tests/api/suites/workers.suite.ts
@@ -12,6 +12,17 @@ const home = (t: TestContext) => `/${t.env.users.user.username}`;
  */
 const WORKER_SOURCE = `
 router.custom('GET', '/ping', async () => ({ pong: true }));
+router.post('/echo', async ({ request }) => {
+    const body = await request.json();
+    return { echoed: body };
+});
+router.get('/posts/:category/:id', async ({ params }) => params);
+router.get('/teapot', async () => new Response('no coffee', { status: 418 }));
+router.get('/whoami', async ({ user }) => {
+    if (!user || !user.puter) return { authed: false };
+    const me = await user.puter.getUser();
+    return { authed: true, username: me.username };
+});
 `;
 
 const deployWorker = async (t: TestContext, name: string) => {
@@ -35,6 +46,38 @@ export default suite('workers', {
         t.assert.deepEqual(body, { pong: true });
     },
 
+    'exec POSTs a body and reads the JSON response': async (t) => {
+        const created = await deployWorker(t, 'workers-suite-echo');
+        const res = await t.puter.workers.exec(`${created.url}/echo`, {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ hello: 'worker' }),
+        });
+        t.assert.equal(res.status, 200);
+        t.assert.deepEqual(await res.json(), { echoed: { hello: 'worker' } });
+    },
+
+    'a worker resolves route parameters': async (t) => {
+        const created = await deployWorker(t, 'workers-suite-params');
+        const res = await t.puter.workers.exec(`${created.url}/posts/tech/42`);
+        t.assert.deepEqual(await res.json(), { category: 'tech', id: '42' });
+    },
+
+    'a worker can return a custom status code': async (t) => {
+        const created = await deployWorker(t, 'workers-suite-status');
+        const res = await t.puter.workers.exec(`${created.url}/teapot`);
+        t.assert.equal(res.status, 418);
+        t.assert.equal(await res.text(), 'no coffee');
+    },
+
+    'exec runs the worker in the calling user context': async (t) => {
+        const created = await deployWorker(t, 'workers-suite-userctx');
+        const res = await t.puter.workers.exec(`${created.url}/whoami`);
+        const body = await res.json();
+        t.assert.equal(body.authed, true, 'user.puter should be populated');
+        t.assert.equal(body.username, t.env.users.user.username);
+    },
+
     'get returns the deployed worker': async (t) => {
         await deployWorker(t, 'workers-suite-get');
         const worker = await t.puter.workers.get('workers-suite-get');