diff --git a/apps/api/tests/routes/admin.test.ts b/apps/api/tests/routes/admin.test.ts
new file mode 100644
index 0000000..f081268
--- /dev/null
+++ b/apps/api/tests/routes/admin.test.ts
@@ -0,0 +1,566 @@
+/**
+ * Admin + self-service credential surface — integration tests (Plan 10-03, TDD RED→GREEN).
+ *
+ * Covers:
+ *   Task 2 (admin routes):
+ *   - T-10-08: GET /api/admin/members returns 403 for non-admin, 200+list for admin
+ *   - T-10-09 (Pitfall 7): POST /api/admin/credentials with invalid password → 400,
+ *     no submitted password string in response body; same shape for createFastmailClient
+ *     throw and for network/PROPFIND failures
+ *   - T-10-09 (Pitfall 7): malformed/bad-email payload → 400 { error: 'Invalid request' }
+ *   - T-10-11: valid credential → 200, stored encrypted (encrypted_password != plaintext)
+ *   - T-10-08: POST /api/admin/credentials as non-admin → 403
+ *   - ADMIN-02: PUT /api/admin/calendars/:id/shared → exactly one calendar is_shared=1
+ *   - GET /api/admin/calendars as admin → 200 list; as non-admin → 403
+ *
+ *   Task 3 (self-service):
+ *   - T-10-12 (Pitfall 6): POST /api/me/credential with body userId for another user
+ *     → credential written to session user (currentUserId), NOT the body userId
+ *   - POST /api/me/credential with valid credential → 200, stored encrypted
+ *   - POST /api/me/credential with bad credential → 400 generic, no echoed password
+ *   - POST /api/me/credential does NOT require admin (normal member can use it)
+ *
+ * Architecture:
+ *   - Tests import `app` (NOT adminRouter directly — Pitfall 9)
+ *   - Real DB integration: dev MariaDB must be running; set DB_HOST=127.0.0.1
+ *   - CalDAV (createFastmailClient) is mocked to avoid live Fastmail calls
+ */
+
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { randomUUID } from 'node:crypto';
+import { eq } from 'drizzle-orm';
+import { db } from '../../src/db/client.js';
+import { users, memberCredentials, calendars } from '../../src/db/schema.js';
+
+// ---------------------------------------------------------------------------
+// CalDAV mock — intercept createFastmailClient so tests do not hit live Fastmail.
+// Tests that need PROPFIND-success inject a mock client with fetchCalendars resolving.
+// Tests that need PROPFIND-failure inject a mock client that throws on fetchCalendars.
+// Tests that need createFastmailClient itself to throw (e.g. bad email format) throw
+// before returning a client at all.
+//
+// Also mock loadClientForUser and triggerTargetedResync from outboxWorker to avoid
+// the initial-sync touching the real DB in tests.
+// ---------------------------------------------------------------------------
+
+type FetchCalendarsResult = { url: string; displayName: string }[];
+
+let mockFetchCalendars: () => Promise<FetchCalendarsResult> = () =>
+  Promise.resolve([{ url: 'https://caldav.fastmail.com/cal/user/', displayName: 'Test Cal' }]);
+let mockCreateClientShouldThrow = false;
+let mockCreateClientError: Error | null = null;
+
+vi.mock('../../src/broker/client.js', () => ({
+  createFastmailClient: vi.fn().mockImplementation(async () => {
+    if (mockCreateClientShouldThrow) {
+      throw mockCreateClientError ?? new Error('Mock CalDAV client creation error');
+    }
+    return { fetchCalendars: mockFetchCalendars };
+  }),
+}));
+
+vi.mock('../../src/broker/outboxWorker.js', () => ({
+  loadClientForUser: vi.fn().mockResolvedValue({
+    fetchCalendars: () =>
+      Promise.resolve([{ url: 'https://caldav.fastmail.com/cal/', displayName: 'Test' }]),
+  }),
+  triggerTargetedResync: vi.fn().mockResolvedValue(undefined),
+  startOutboxWorker: vi.fn(),
+  initOutboxTrigger: vi.fn(),
+  scheduleOutboxDrain: vi.fn(),
+  runOutboxDrain: vi.fn(),
+  __resetDrainState: vi.fn(),
+  assembleRruleString: vi.fn(),
+  stopOutboxTrigger: vi.fn(),
+}));
+
+// Mock sync.js to avoid actual CalDAV sync during tests
+vi.mock('../../src/broker/sync.js', () => ({
+  syncCalendar: vi.fn().mockResolvedValue(undefined),
+}));
+
+// ---------------------------------------------------------------------------
+// Dev-bypass mock: allows us to simulate different users in tests.
+// currentDevUserId controls which user is "logged in" via the bypass.
+// ---------------------------------------------------------------------------
+
+let currentDevUserId = 1;
+
+vi.mock('../../src/auth/devBypass.js', () => ({
+  devAuthBypass:
+    () => async (c: { set: (k: string, v: unknown) => void }, next: () => Promise<void>) => {
+      c.set('user', { id: currentDevUserId });
+      await next();
+    },
+}));
+
+vi.mock('@hono/oidc-auth', () => ({
+  oidcAuthMiddleware: () => async (_c: unknown, next: () => Promise<void>) => next(),
+  processOAuthCallback: () => async (c: { json: (v: unknown) => unknown }) => c.json({ ok: true }),
+  getAuth: () => null,
+}));
+
+// ---------------------------------------------------------------------------
+// Seed helpers
+// ---------------------------------------------------------------------------
+
+async function seedUser(label: string, isAdmin = false): Promise<number> {
+  const [result] = await db
+    .insert(users)
+    .values({
+      oidcIss: 'https://auth.test',
+      oidcSub: `sub-${label}-${randomUUID()}`,
+      displayName: `User ${label}`,
+      color: '#4A90D9',
+      isAdmin,
+    })
+    .$returningId();
+  return result.id;
+}
+
+async function seedCalendar(userId: number, label: string, isShared = false): Promise<number> {
+  const [result] = await db
+    .insert(calendars)
+    .values({
+      userId,
+      url: `https://caldav.fastmail.com/cal/${label}-${randomUUID()}/`,
+      displayName: `Calendar ${label}`,
+      isShared,
+    })
+    .$returningId();
+  return result.id;
+}
+
+// ---------------------------------------------------------------------------
+// Request helpers
+// ---------------------------------------------------------------------------
+
+function jsonRequest(method: string, path: string, body?: unknown): Request {
+  return new Request(`http://localhost${path}`, {
+    method,
+    headers: { 'Content-Type': 'application/json' },
+    body: body !== undefined ? JSON.stringify(body) : undefined,
+  });
+}
+
+// ---------------------------------------------------------------------------
+// Import `app` lazily (after mocks are registered) — Pitfall 9: must import
+// `app` not `adminRouter` directly so the route mount + guard are exercised.
+// ---------------------------------------------------------------------------
+
+async function getApp() {
+  const { app } = await import('../../src/index.js');
+  return app;
+}
+
+// ---------------------------------------------------------------------------
+// Encryption key required for encryptPassword
+// ---------------------------------------------------------------------------
+
+beforeEach(async () => {
+  process.env.APP_PASSWORD_ENCRYPTION_KEY =
+    '0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef';
+  // Reset CalDAV mock state to default (success path)
+  mockCreateClientShouldThrow = false;
+  mockCreateClientError = null;
+  mockFetchCalendars = () =>
+    Promise.resolve([{ url: 'https://caldav.fastmail.com/cal/user/', displayName: 'Test Cal' }]);
+});
+
+afterEach(async () => {
+  // Clean up seeded users and credentials between tests
+  await db.delete(memberCredentials);
+  await db.delete(calendars);
+  await db.delete(users).where(eq(users.oidcIss, 'https://auth.test'));
+});
+
+// ===========================================================================
+// GET /api/admin/members
+// ===========================================================================
+
+describe('GET /api/admin/members', () => {
+  it('returns 403 for a non-admin authenticated user (Pitfall 9 / T-10-08)', async () => {
+    const nonAdminId = await seedUser('non-admin', false);
+    currentDevUserId = nonAdminId;
+    const app = await getApp();
+
+    const res = await app.fetch(jsonRequest('GET', '/api/admin/members'));
+    expect(res.status).toBe(403);
+    const body = await res.json();
+    expect(body).toEqual({ error: 'Forbidden' });
+  });
+
+  it('returns 200 with member list for an admin user', async () => {
+    const adminId = await seedUser('admin', true);
+    const memberId = await seedUser('member', false);
+    currentDevUserId = adminId;
+    const app = await getApp();
+
+    const res = await app.fetch(jsonRequest('GET', '/api/admin/members'));
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { members: unknown[] };
+    expect(Array.isArray(body.members)).toBe(true);
+    // Should include at least the two seeded users
+    expect(body.members.length).toBeGreaterThanOrEqual(2);
+    // Each member should have id, displayName, color, hasCredential
+    const memberRow = (body.members as Array<{ id: number }>).find((m) => m.id === memberId);
+    expect(memberRow).toBeDefined();
+    expect(typeof (memberRow as { hasCredential: boolean }).hasCredential).toBe('boolean');
+  });
+});
+
+// ===========================================================================
+// POST /api/admin/credentials
+// ===========================================================================
+
+describe('POST /api/admin/credentials', () => {
+  it('returns 403 for a non-admin user (T-10-08)', async () => {
+    const nonAdminId = await seedUser('non-admin-cred', false);
+    const targetId = await seedUser('target', false);
+    currentDevUserId = nonAdminId;
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/admin/credentials', {
+        userId: targetId,
+        providerType: 'caldav',
+        fastmailEmail: 'user@fastmail.com',
+        appPassword: 'test-secret-pass',
+      }),
+    );
+    expect(res.status).toBe(403);
+  });
+
+  it('returns 400 with no echoed password when PROPFIND/auth fails (Pitfall 7 / T-10-09)', async () => {
+    const adminId = await seedUser('admin-cred-fail', true);
+    const targetId = await seedUser('target-fail', false);
+    currentDevUserId = adminId;
+
+    // Make fetchCalendars throw (simulates PROPFIND/auth failure)
+    const submittedPassword = 'super-secret-app-password-12345';
+    mockFetchCalendars = () => Promise.reject(new Error('Authentication failed'));
+
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/admin/credentials', {
+        userId: targetId,
+        providerType: 'caldav',
+        fastmailEmail: 'user@fastmail.com',
+        appPassword: submittedPassword,
+      }),
+    );
+    expect(res.status).toBe(400);
+    const bodyText = await res.text();
+    // Pitfall 7: submitted password MUST NOT appear in any 400 response
+    expect(bodyText).not.toContain(submittedPassword);
+    // No Zod error fields
+    expect(bodyText).not.toContain('received');
+    expect(bodyText).not.toContain('issues');
+    // Should return generic error shape
+    const body = JSON.parse(bodyText) as { error: string };
+    expect(body.error).toBe('Invalid request');
+  });
+
+  it('returns 400 when createFastmailClient itself throws (bad email / malformed input)', async () => {
+    const adminId = await seedUser('admin-cred-throw', true);
+    const targetId = await seedUser('target-throw', false);
+    currentDevUserId = adminId;
+
+    const submittedPassword = 'bad-email-secret-pass-99999';
+    mockCreateClientShouldThrow = true;
+    mockCreateClientError = new Error('Invalid email format');
+
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/admin/credentials', {
+        userId: targetId,
+        providerType: 'caldav',
+        fastmailEmail: 'user@fastmail.com',
+        appPassword: submittedPassword,
+      }),
+    );
+    expect(res.status).toBe(400);
+    const bodyText = await res.text();
+    expect(bodyText).not.toContain(submittedPassword);
+    const body = JSON.parse(bodyText) as { error: string };
+    expect(body.error).toBe('Invalid request');
+  });
+
+  it('returns 400 with no echo for a network error (all failures map to same generic 400)', async () => {
+    const adminId = await seedUser('admin-network-err', true);
+    const targetId = await seedUser('target-network', false);
+    currentDevUserId = adminId;
+
+    const submittedPassword = 'network-error-secret-abc123';
+    mockFetchCalendars = () => Promise.reject(new Error('Network connection refused'));
+
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/admin/credentials', {
+        userId: targetId,
+        providerType: 'caldav',
+        fastmailEmail: 'user@fastmail.com',
+        appPassword: submittedPassword,
+      }),
+    );
+    expect(res.status).toBe(400);
+    const bodyText = await res.text();
+    expect(bodyText).not.toContain(submittedPassword);
+    const body = JSON.parse(bodyText) as { error: string };
+    expect(body.error).toBe('Invalid request');
+  });
+
+  it('returns 400 with no Zod echo when schema validation fails (e.g. missing fields)', async () => {
+    const adminId = await seedUser('admin-schema-fail', true);
+    currentDevUserId = adminId;
+
+    const submittedPassword = 'schema-fail-secret-zxcvbn';
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/admin/credentials', {
+        // Missing userId — schema validation should fail
+        providerType: 'caldav',
+        fastmailEmail: 'user@fastmail.com',
+        appPassword: submittedPassword,
+      }),
+    );
+    expect(res.status).toBe(400);
+    const bodyText = await res.text();
+    // Pitfall 7: even schema validation failure must not echo the password
+    expect(bodyText).not.toContain(submittedPassword);
+    expect(bodyText).not.toContain('received');
+    expect(bodyText).not.toContain('issues');
+    const body = JSON.parse(bodyText) as { error: string };
+    expect(body.error).toBe('Invalid request');
+  });
+
+  it('returns 200 on valid credential and stores encrypted password (T-10-11)', async () => {
+    const adminId = await seedUser('admin-valid', true);
+    const targetId = await seedUser('target-valid', false);
+    currentDevUserId = adminId;
+
+    const plainPassword = 'valid-app-password-abcxyz-9876';
+    // Mock fetchCalendars to succeed (default)
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/admin/credentials', {
+        userId: targetId,
+        providerType: 'caldav',
+        fastmailEmail: 'target@fastmail.com',
+        appPassword: plainPassword,
+      }),
+    );
+    expect(res.status).toBe(200);
+
+    // Verify stored credential is NOT the plaintext (encrypted)
+    const [stored] = await db
+      .select({ encryptedPassword: memberCredentials.encryptedPassword })
+      .from(memberCredentials)
+      .where(eq(memberCredentials.userId, targetId))
+      .limit(1);
+    expect(stored).toBeDefined();
+    expect(stored.encryptedPassword).not.toBe(plainPassword);
+    // Should be the JSON-encoded AES-256-GCM structure
+    const parsed = JSON.parse(stored.encryptedPassword) as Record<string, unknown>;
+    expect(parsed.iv).toBeDefined();
+    expect(parsed.ciphertext).toBeDefined();
+
+    // Response body must not contain the password
+    const bodyText = JSON.stringify(await res.clone().json());
+    expect(bodyText).not.toContain(plainPassword);
+  });
+});
+
+// ===========================================================================
+// GET /api/admin/calendars
+// ===========================================================================
+
+describe('GET /api/admin/calendars', () => {
+  it('returns 403 for non-admin', async () => {
+    const nonAdminId = await seedUser('non-admin-cal', false);
+    currentDevUserId = nonAdminId;
+    const app = await getApp();
+
+    const res = await app.fetch(jsonRequest('GET', '/api/admin/calendars'));
+    expect(res.status).toBe(403);
+  });
+
+  it('returns 200 with calendar list for admin', async () => {
+    const adminId = await seedUser('admin-cal-list', true);
+    await seedCalendar(adminId, 'personal', false);
+    await seedCalendar(adminId, 'family', true);
+    currentDevUserId = adminId;
+    const app = await getApp();
+
+    const res = await app.fetch(jsonRequest('GET', '/api/admin/calendars'));
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { calendars: unknown[] };
+    expect(Array.isArray(body.calendars)).toBe(true);
+    // At least the two seeded calendars
+    expect(body.calendars.length).toBeGreaterThanOrEqual(2);
+  });
+});
+
+// ===========================================================================
+// PUT /api/admin/calendars/:id/shared  (ADMIN-02, Pitfall 7-adjacent)
+// ===========================================================================
+
+describe('PUT /api/admin/calendars/:id/shared', () => {
+  it('returns 403 for non-admin', async () => {
+    const nonAdminId = await seedUser('non-admin-shared', false);
+    currentDevUserId = nonAdminId;
+    const app = await getApp();
+
+    const res = await app.fetch(jsonRequest('PUT', '/api/admin/calendars/1/shared'));
+    expect(res.status).toBe(403);
+  });
+
+  it('sets exactly one calendar to is_shared=1 and clears prior shared calendar (ADMIN-02)', async () => {
+    const adminId = await seedUser('admin-shared', true);
+    const calA = await seedCalendar(adminId, 'cal-a', true); // initially shared
+    const calB = await seedCalendar(adminId, 'cal-b', false);
+    currentDevUserId = adminId;
+    const app = await getApp();
+
+    const res = await app.fetch(jsonRequest('PUT', `/api/admin/calendars/${calB}/shared`));
+    expect(res.status).toBe(200);
+
+    // calA should now be is_shared=false, calB should be is_shared=true
+    const [rowA] = await db
+      .select({ isShared: calendars.isShared })
+      .from(calendars)
+      .where(eq(calendars.id, calA))
+      .limit(1);
+    const [rowB] = await db
+      .select({ isShared: calendars.isShared })
+      .from(calendars)
+      .where(eq(calendars.id, calB))
+      .limit(1);
+
+    expect(rowA.isShared).toBe(false);
+    expect(rowB.isShared).toBe(true);
+
+    // Verify exactly ONE calendar has is_shared=true after the update
+    const sharedRows = await db
+      .select({ id: calendars.id })
+      .from(calendars)
+      .where(eq(calendars.isShared, true));
+    // Only calB should be shared (of the ones we seeded; other pre-existing rows excluded
+    // by checking only our seeded IDs)
+    const sharedIds = sharedRows.map((r) => r.id);
+    expect(sharedIds).toContain(calB);
+    expect(sharedIds).not.toContain(calA);
+  });
+});
+
+// ===========================================================================
+// POST /api/me/credential  (Task 3 — member self-service, D-07, T-10-12)
+// ===========================================================================
+
+describe('POST /api/me/credential', () => {
+  it('ignores body userId and writes only to session user (Pitfall 6 / T-10-12)', async () => {
+    const userA = await seedUser('self-service-a', false);
+    const userB = await seedUser('self-service-b', false);
+    currentDevUserId = userA; // logged in as userA
+
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/me/credential', {
+        userId: userB, // body says userB — must be IGNORED
+        providerType: 'caldav',
+        fastmailEmail: 'usera@fastmail.com',
+        appPassword: 'self-service-pass-abcxyz',
+      }),
+    );
+    expect(res.status).toBe(200);
+
+    // userA should have a credential
+    const [credA] = await db
+      .select({ id: memberCredentials.id })
+      .from(memberCredentials)
+      .where(eq(memberCredentials.userId, userA))
+      .limit(1);
+    expect(credA).toBeDefined();
+
+    // userB should NOT have a credential
+    const [credB] = await db
+      .select({ id: memberCredentials.id })
+      .from(memberCredentials)
+      .where(eq(memberCredentials.userId, userB))
+      .limit(1);
+    expect(credB).toBeUndefined();
+  });
+
+  it('returns 200 and stores encrypted password for valid credential', async () => {
+    const userId = await seedUser('self-service-valid', false);
+    currentDevUserId = userId;
+
+    const plainPassword = 'self-service-valid-pass-qwerty9876';
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/me/credential', {
+        providerType: 'caldav',
+        fastmailEmail: 'me@fastmail.com',
+        appPassword: plainPassword,
+      }),
+    );
+    expect(res.status).toBe(200);
+
+    const [stored] = await db
+      .select({ encryptedPassword: memberCredentials.encryptedPassword })
+      .from(memberCredentials)
+      .where(eq(memberCredentials.userId, userId))
+      .limit(1);
+    expect(stored).toBeDefined();
+    expect(stored.encryptedPassword).not.toBe(plainPassword);
+    const parsed = JSON.parse(stored.encryptedPassword) as Record<string, unknown>;
+    expect(parsed.iv).toBeDefined();
+  });
+
+  it('returns 400 with no echoed password when credential validation fails (Pitfall 7)', async () => {
+    const userId = await seedUser('self-service-fail', false);
+    currentDevUserId = userId;
+
+    const submittedPassword = 'self-service-bad-pass-xyz9999';
+    mockFetchCalendars = () => Promise.reject(new Error('PROPFIND auth failure'));
+
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/me/credential', {
+        providerType: 'caldav',
+        fastmailEmail: 'me@fastmail.com',
+        appPassword: submittedPassword,
+      }),
+    );
+    expect(res.status).toBe(400);
+    const bodyText = await res.text();
+    expect(bodyText).not.toContain(submittedPassword);
+    const body = JSON.parse(bodyText) as { error: string };
+    expect(body.error).toBe('Invalid request');
+  });
+
+  it('does NOT require admin — a normal member can set their own credential', async () => {
+    const userId = await seedUser('non-admin-self-service', false);
+    currentDevUserId = userId;
+
+    const app = await getApp();
+
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/me/credential', {
+        providerType: 'caldav',
+        fastmailEmail: 'member@fastmail.com',
+        appPassword: 'member-pass-abcabc123',
+      }),
+    );
+    // Should succeed (200) — no admin requirement on this endpoint
+    expect(res.status).toBe(200);
+  });
+});