diff --git a/.planning/phases/03-event-write-back-pwa-install/03-09-SUMMARY.md b/.planning/phases/03-event-write-back-pwa-install/03-09-SUMMARY.md
new file mode 100644
index 0000000..48065fd
--- /dev/null
+++ b/.planning/phases/03-event-write-back-pwa-install/03-09-SUMMARY.md
@@ -0,0 +1,93 @@
+---
+phase: 03-event-write-back-pwa-install
+plan: "09"
+subsystem: api-events-router
+tags: [tdd, gap-closure, auth, schema, zod, oidc]
+dependency_graph:
+  requires: []
+  provides:
+    - canonical-event-schema-title-start-end
+    - async-resolveUserId-with-upsertUser
+  affects:
+    - apps/api/src/routes/events.ts
+    - apps/api/tests/routes/events.test.ts
+    - plan-03-10 (outbox worker reads title/start/end from payload)
+tech_stack:
+  added: []
+  patterns:
+    - "TDD RED→GREEN per task"
+    - "vi.hoisted() for configurable per-test auth mocks"
+    - "async resolveUserId with upsertUser for OIDC path"
+key_files:
+  modified:
+    - apps/api/src/routes/events.ts
+    - apps/api/tests/routes/events.test.ts
+decisions:
+  - "D-CR01: Server adopts client field names title/start/end — one canonical name set end-to-end, no rename map"
+  - "D-CR06: resolveUserId async; dev-bypass path unchanged; OIDC path calls upsertUser(iss,sub,email)"
+metrics:
+  duration_minutes: 6
+  completed_date: "2026-06-06"
+  tasks_completed: 2
+  files_modified: 2
+---
+
+# Phase 03 Plan 09: Route Schema + OIDC Resolution Fix Summary
+
+Fix the events router's two blockers that made the write path dead on arrival: align the server zod schema to the PWA's `CreateEventPayload` shape (title/start/end), and implement real OIDC iss/sub → users.id resolution on all five write handlers via `upsertUser`.
+
+## Tasks Completed
+
+| Task | Name | Commit | Files |
+|------|------|--------|-------|
+| 1 RED | Add contract tests for canonical title/start/end | 944693f | events.test.ts |
+| 1 GREEN | Rename eventFieldsSchema to title/start/end (CR-01) | 99cb169 | events.ts, events.test.ts |
+| 2 RED | Add OIDC path tests — resolveUserId must call upsertUser | 6d1d338 | events.test.ts |
+| 2 GREEN | Async resolveUserId with upsertUser on all 5 handlers (CR-06) | fac3a21 | events.ts |
+
+## Verification
+
+- `cd apps/api && npx vitest run tests/routes/events.test.ts`: 19 tests pass
+- `npx tsc --noEmit` in apps/api: clean (no errors)
+- `grep -n 'summary\|dtstart\|dtend' eventFieldsSchema`: CLEAN (no old names)
+- `grep -c 'For now return 401' events.ts`: 0 stubs remain
+- `grep -c 'upsertUser' events.ts`: 3 (import + call in resolveUserId)
+
+## Decisions Made
+
+- **D-CR01**: Server adopts client field names `title/start/end`. No internal rename map — one canonical name set end-to-end from PWA through events router to calendarOutbox payload to outbox worker (plan 03-10).
+- **D-CR06**: `resolveUserId` is now async. Dev-bypass path (`c.get('user')`) is unchanged. Production OIDC path calls `getAuth(c)` then `upsertUser(iss, sub, email)` to resolve DB user id. Returns null only when no session exists.
+
+## Deviations from Plan
+
+### Auto-fixed Issues
+
+None. The plan was executed exactly as written, including updating the three existing write tests that previously used the old field names (`summary/dtstart/dtend`) — this was the correct fix since those tests were testing against the wrong boundary (as the review noted).
+
+### Test Infrastructure Deviation (Rule 3)
+
+The worktree has no `node_modules` — the pnpm workspace installs them in the main repo. Created a symlink `apps/api/node_modules → /home/luc/Projects/familysync/apps/api/node_modules` so vitest could run from within the worktree. This is a standard git-worktree-with-pnpm-workspace setup requirement.
+
+## TDD Gate Compliance
+
+Both tasks followed RED→GREEN strictly:
+- Task 1: `test(03-09)` commit (944693f) → `feat(03-09)` commit (99cb169)
+- Task 2: `test(03-09)` commit (6d1d338) → `feat(03-09)` commit (fac3a21)
+
+## Known Stubs
+
+None. All changes are functional code.
+
+## Threat Flags
+
+No new network endpoints, auth paths, file access patterns, or schema changes introduced. The resolveUserId change closes a security gap (CR-06) by ensuring unauthenticated requests correctly 401 while authenticated OIDC sessions get through.
+
+## Self-Check: PASSED
+
+- events.ts: FOUND
+- events.test.ts: FOUND
+- 03-09-SUMMARY.md: FOUND
+- 944693f (test RED task1): FOUND
+- 99cb169 (feat GREEN task1): FOUND
+- 6d1d338 (test RED task2): FOUND
+- fac3a21 (feat GREEN task2): FOUND
diff --git a/apps/api/src/routes/events.ts b/apps/api/src/routes/events.ts
index 1e22c32..ae6e743 100644
--- a/apps/api/src/routes/events.ts
+++ b/apps/api/src/routes/events.ts
@@ -30,6 +30,7 @@ import { db } from '../db/client.js'
 import { calendarEvents, calendars, users, calendarOutbox } from '../db/schema.js'
 import { expandOccurrences } from '../broker/expand.js'
 import { getAuth } from '../auth/middleware.js'
+import { upsertUser } from '../auth/user.js'
 // Side-effect import: brings in the ContextVariableMap augmentation for c.get('user')
 import '../auth/devBypass.js'
 
@@ -43,15 +44,30 @@ const MAX_WINDOW_DAYS = 90
 
 // ---------------------------------------------------------------------------
 // Auth helper — shared by all write endpoints
-// Returns the numeric userId from dev-bypass context; null if not present.
-// The OIDC path requires a separate getAuth(c) call — only the dev-bypass path
-// injects c.get('user'). Write handlers check this first, then fall back to getAuth.
-// ---------------------------------------------------------------------------
+//
+// Resolution order (D-10, CR-06):
+//   1. Dev-bypass path: c.get('user') is set by devAuthBypass() middleware when
+//      DEV_AUTH_BYPASS=true. Return its .id directly — no OIDC round-trip.
+//   2. OIDC path: call getAuth(c). If null → unauthenticated, return null.
+//      Otherwise extract iss/sub/email and call upsertUser — which writes the
+//      user row on first login and returns the existing row on subsequent calls.
+//      Identity is keyed on oidc_iss + oidc_sub (D-10), never email.
+//   3. Callers emit 401 when resolveUserId returns null.
+//
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-function resolveUserId(c: any): number | null {
+async function resolveUserId(c: any): Promise<number | null> {
   const devUser = c.get('user') as { id: number } | undefined
   if (devUser) return devUser.id
-  return null
+
+  const auth = await getAuth(c)
+  if (!auth) return null
+
+  const iss = (auth.iss as string | undefined) ?? ''
+  const sub = auth.sub ?? ''
+  const email = typeof auth.email === 'string' ? auth.email : undefined
+
+  const user = await upsertUser(iss, sub, email)
+  return user?.id ?? null
 }
 
 // ---------------------------------------------------------------------------
@@ -64,12 +80,19 @@ const eventsQuerySchema = z.object({
   end: z.string().regex(/^\d{4}-\d{2}-\d{2}$/),
 })
 
-/** Shared event field validation (V5 — bounded lengths, T-03-08). */
+/**
+ * Shared event field validation (V5 — bounded lengths, T-03-08).
+ *
+ * Field names match the PWA CreateEventPayload (apps/pwa/src/api/client.ts:119-128)
+ * exactly — title/start/end — so no rename map is needed end-to-end (CR-01).
+ * The stored payload JSON uses these same names; the outbox worker (plan 03-10)
+ * reads title/start/end when building the VEVENT.
+ */
 const eventFieldsSchema = z.object({
-  summary: z.string().min(1).max(255),
+  title: z.string().min(1).max(255),
   allDay: z.boolean(),
-  dtstart: z.string().min(1).max(64), // ISO string or DATE
-  dtend: z.string().min(1).max(64),
+  start: z.string().min(1).max(64), // ISO string or DATE (YYYY-MM-DD for allDay)
+  end: z.string().min(1).max(64),
   location: z.string().max(2000).optional(),
   description: z.string().max(2000).optional(),
   recurrence: z.enum(['none', 'daily', 'weekly', 'monthly', 'yearly']).optional(),
@@ -189,16 +212,8 @@ eventsRouter.get('/', zValidator('query', eventsQuerySchema), async (c) => {
 // Does NOT build a VEVENT and does NOT call Fastmail — that is the worker's job (D-12).
 // ---------------------------------------------------------------------------
 eventsRouter.post('/create', zValidator('json', eventFieldsSchema), async (c) => {
-  // Auth: dev bypass first, then OIDC session.
-  const currentUserId = resolveUserId(c as Parameters<typeof resolveUserId>[0])
-  if (currentUserId === null) {
-    // Fall through to getAuth for OIDC path
-    const auth = await getAuth(c)
-    if (!auth) return c.json({ error: 'Unauthorized' }, 401)
-    // In production OIDC path, we'd look up the user row by iss+sub.
-    // For now return 401 if OIDC auth is not backed by a DB user here.
-    return c.json({ error: 'Unauthorized' }, 401)
-  }
+  const currentUserId = await resolveUserId(c)
+  if (currentUserId === null) return c.json({ error: 'Unauthorized' }, 401)
 
   const payload = c.req.valid('json')
 
@@ -266,12 +281,8 @@ eventsRouter.post('/create', zValidator('json', eventFieldsSchema), async (c) =>
 // Returns 202 immediately (D-05). Does NOT call Fastmail (D-12).
 // ---------------------------------------------------------------------------
 eventsRouter.patch('/:uid/edit', zValidator('json', eventFieldsSchema), async (c) => {
-  const currentUserId = resolveUserId(c as Parameters<typeof resolveUserId>[0])
-  if (currentUserId === null) {
-    const auth = await getAuth(c)
-    if (!auth) return c.json({ error: 'Unauthorized' }, 401)
-    return c.json({ error: 'Unauthorized' }, 401)
-  }
+  const currentUserId = await resolveUserId(c)
+  if (currentUserId === null) return c.json({ error: 'Unauthorized' }, 401)
 
   const uid = c.req.param('uid')
   const payload = c.req.valid('json')
@@ -370,12 +381,8 @@ eventsRouter.patch('/:uid/edit', zValidator('json', eventFieldsSchema), async (c
 // Returns 202 immediately (D-05). Does NOT call Fastmail (D-12).
 // ---------------------------------------------------------------------------
 eventsRouter.delete('/:uid', async (c) => {
-  const currentUserId = resolveUserId(c as Parameters<typeof resolveUserId>[0])
-  if (currentUserId === null) {
-    const auth = await getAuth(c)
-    if (!auth) return c.json({ error: 'Unauthorized' }, 401)
-    return c.json({ error: 'Unauthorized' }, 401)
-  }
+  const currentUserId = await resolveUserId(c)
+  if (currentUserId === null) return c.json({ error: 'Unauthorized' }, 401)
 
   const uid = c.req.param('uid')
 
@@ -435,12 +442,8 @@ eventsRouter.delete('/:uid', async (c) => {
 // Returns { uid, status: 'done' } when no outbox row exists (nothing pending = settled).
 // ---------------------------------------------------------------------------
 eventsRouter.get('/sync-status', zValidator('query', syncStatusQuerySchema), async (c) => {
-  const currentUserId = resolveUserId(c as Parameters<typeof resolveUserId>[0])
-  if (currentUserId === null) {
-    const auth = await getAuth(c)
-    if (!auth) return c.json({ error: 'Unauthorized' }, 401)
-    return c.json({ error: 'Unauthorized' }, 401)
-  }
+  const currentUserId = await resolveUserId(c)
+  if (currentUserId === null) return c.json({ error: 'Unauthorized' }, 401)
 
   const { uid } = c.req.valid('query')
 
@@ -488,12 +491,8 @@ eventsRouter.get('/sync-status', zValidator('query', syncStatusQuerySchema), asy
 // Response: { calendars: [{ url, displayName, color, isShared }] }
 // ---------------------------------------------------------------------------
 eventsRouter.get('/writable-calendars', async (c) => {
-  const currentUserId = resolveUserId(c as Parameters<typeof resolveUserId>[0])
-  if (currentUserId === null) {
-    const auth = await getAuth(c)
-    if (!auth) return c.json({ error: 'Unauthorized' }, 401)
-    return c.json({ error: 'Unauthorized' }, 401)
-  }
+  const currentUserId = await resolveUserId(c)
+  if (currentUserId === null) return c.json({ error: 'Unauthorized' }, 401)
 
   try {
     // D-03 writable set: own personal calendars + shared Family calendar.
diff --git a/apps/api/tests/routes/events.test.ts b/apps/api/tests/routes/events.test.ts
index 9284754..1a2a082 100644
--- a/apps/api/tests/routes/events.test.ts
+++ b/apps/api/tests/routes/events.test.ts
@@ -25,12 +25,33 @@ import {
   SAMPLE_VEVENT_RECURRING_ALLDAY,
 } from '../helpers/db.js'
 
+// ---------------------------------------------------------------------------
+// Configurable getAuth and devBypass so individual tests can control the auth
+// path without reloading the module. Uses vi.hoisted() to avoid TDZ issues
+// (D-03-04-hoisting: vi.hoisted() required when test file has static imports of
+// modules that vi.mock() references in their factory callbacks).
+// ---------------------------------------------------------------------------
+
+// getAuthImpl: default returns null (unauthenticated); CR-06 OIDC tests override it.
+const { getAuthImpl, devBypassInjectUser } = vi.hoisted(() => ({
+  getAuthImpl: { fn: null as (() => unknown) | null },
+  devBypassInjectUser: { active: true }, // true = inject dev user; false = passthrough
+}))
+
 // Mock @hono/oidc-auth so tests do not need a live Authelia instance.
 // The mock makes oidcAuthMiddleware a no-op passthrough.
+// getAuth delegates to getAuthImpl.fn so per-test overrides work at call time.
 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,
+  getAuth: () => (getAuthImpl.fn ? getAuthImpl.fn() : null),
+}))
+
+// Mock upsertUser for the OIDC path — CR-06 tests override mockUpsertUser.fn.
+const mockUpsertUserFn = vi.fn()
+vi.mock('../../src/auth/user.js', () => ({
+  upsertUser: (...args: unknown[]) => mockUpsertUserFn(...args),
+  COLOR_PALETTE: ['#4A90D9', '#E8734A', '#5BA85A', '#9B6DC5', '#E8A840', '#3AAFA9'],
 }))
 
 // ---------------------------------------------------------------------------
@@ -81,6 +102,11 @@ beforeEach(() => {
   mockDbRows = []
   vi.clearAllMocks()
 
+  // Reset auth stubs to safe defaults for each test
+  getAuthImpl.fn = null         // getAuth returns null (unauthenticated)
+  devBypassInjectUser.active = true  // inject dev user (most tests use dev bypass)
+  mockUpsertUserFn.mockResolvedValue({ id: 42, oidcIss: 'https://auth.example.com', oidcSub: 'sub-abc', displayName: 'OIDC User', color: '#E8734A' })
+
   // Restore select chain (vi.clearAllMocks wipes mockImplementation)
   mockWhereFn.mockImplementation(() => Promise.resolve(mockDbRows))
   mockInnerJoin2Fn.mockReturnValue({ where: mockWhereFn })
@@ -243,15 +269,16 @@ describe('GET /api/events', () => {
 //   - We mock '../auth/devBypass.js' to inject a fixed user into context.
 // ---------------------------------------------------------------------------
 
-// Mock devAuthBypass to inject a fixed dev user in ALL test requests.
-// This mirrors what DEV_AUTH_BYPASS=true does in the real app but without
-// requiring env-var manipulation across test isolation.
+// Mock devAuthBypass: delegates to devBypassInjectUser.active flag so CR-06 tests
+// can simulate the OIDC path by setting devBypassInjectUser.active = false.
 vi.mock('../../src/auth/devBypass.js', async (importOriginal) => {
   const original = await importOriginal<typeof import('../../src/auth/devBypass.js')>()
   return {
     ...original,
     devAuthBypass: () => async (c: { set: (k: string, v: unknown) => void }, next: () => Promise<void>) => {
-      c.set('user', { id: 1, oidcIss: 'dev', oidcSub: 'dev-user', displayName: 'Dev User', color: '#4A90D9' })
+      if (devBypassInjectUser.active) {
+        c.set('user', { id: 1, oidcIss: 'dev', oidcSub: 'dev-user', displayName: 'Dev User', color: '#4A90D9' })
+      }
       await next()
     },
   }
@@ -289,10 +316,10 @@ describe('POST /api/events/create', () => {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({
-        summary: 'New event',
+        title: 'New event',
         allDay: false,
-        dtstart: '2026-06-15T10:00:00Z',
-        dtend: '2026-06-15T11:00:00Z',
+        start: '2026-06-15T10:00:00Z',
+        end: '2026-06-15T11:00:00Z',
         calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
       }),
     })
@@ -324,10 +351,10 @@ describe('POST /api/events/create', () => {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({
-        summary: 'Unauthorized write',
+        title: 'Unauthorized write',
         allDay: false,
-        dtstart: '2026-06-15T10:00:00Z',
-        dtend: '2026-06-15T11:00:00Z',
+        start: '2026-06-15T10:00:00Z',
+        end: '2026-06-15T11:00:00Z',
         calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/other@fm.com/Personal/',
       }),
     })
@@ -363,10 +390,10 @@ describe('PATCH /api/events/:uid/edit', () => {
       method: 'PATCH',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({
-        summary: 'Updated title',
+        title: 'Updated title',
         allDay: false,
-        dtstart: '2026-06-15T10:00:00Z',
-        dtend: '2026-06-15T11:00:00Z',
+        start: '2026-06-15T10:00:00Z',
+        end: '2026-06-15T11:00:00Z',
         calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
       }),
     })
@@ -446,6 +473,160 @@ describe('GET /api/events/sync-status', () => {
   })
 })
 
+// ---------------------------------------------------------------------------
+// CR-01 contract tests — canonical client payload shape (title/start/end)
+//
+// The PWA sends {title, start, end, allDay, recurrence} — the exact
+// CreateEventPayload shape from apps/pwa/src/api/client.ts:119-128.
+// These tests assert the server schema accepts that shape (202), NOT 400.
+// RED before Task 1 schema rename; GREEN after.
+// ---------------------------------------------------------------------------
+describe('CR-01: canonical client payload (title/start/end) accepted by server', () => {
+  beforeEach(() => {
+    // Seed a calendar row for calendar ownership check in create
+    mockDbRows = [
+      {
+        id: 1,
+        url: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
+        displayName: 'Default',
+        color: '#4A90D9',
+        userId: 1,
+        isShared: false,
+      },
+    ]
+    const mockSimpleWhere = vi.fn().mockImplementation(() => Promise.resolve(mockDbRows))
+    mockFromFn.mockReturnValue({ where: mockSimpleWhere })
+    mockSelectFn.mockReturnValue({ from: mockFromFn })
+  })
+
+  it('POST /create with exact CreateEventPayload shape {title,start,end,allDay,recurrence} returns 202 not 400', async () => {
+    // This mirrors the exact payload apps/pwa/src/api/client.ts CreateEventPayload sends
+    const { app } = await import('../../src/index.js')
+    const res = await app.request('/api/events/create', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        title: 'Team standup',
+        allDay: false,
+        start: '2026-06-15T10:00:00Z',
+        end: '2026-06-15T10:30:00Z',
+        recurrence: 'none',
+        calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
+      }),
+    })
+    expect(res.status).toBe(202)
+    const body = await res.json() as { uid: string }
+    expect(body).toHaveProperty('uid')
+  })
+
+  it('PATCH /:uid/edit with exact CreateEventPayload shape {title,start,end,allDay,recurrence} returns 202 not 400', async () => {
+    // Seed an event row for edit lookup
+    mockDbRows = [
+      {
+        uid: 'uid-cr01@familysync',
+        etag: '"etag-cr01"',
+        objectUrl: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/uid-cr01.ics',
+        calendarId: 1,
+        calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
+        userId: 1,
+      },
+    ]
+    const mockSimpleWhere = vi.fn().mockImplementation(() => Promise.resolve(mockDbRows))
+    mockFromFn.mockReturnValue({ where: mockSimpleWhere })
+    mockSelectFn.mockReturnValue({ from: mockFromFn })
+
+    const { app } = await import('../../src/index.js')
+    const res = await app.request('/api/events/uid-cr01%40familysync/edit', {
+      method: 'PATCH',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        title: 'Updated standup',
+        allDay: false,
+        start: '2026-06-15T10:00:00Z',
+        end: '2026-06-15T10:30:00Z',
+        recurrence: 'weekly',
+        calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
+      }),
+    })
+    expect(res.status).toBe(202)
+  })
+})
+
+// ---------------------------------------------------------------------------
+// CR-06 contract tests — real OIDC iss/sub → users.id resolution on write handlers
+//
+// The current handler returns 401 unconditionally when c.get('user') is null,
+// even if getAuth() returns a valid OIDC session. These tests assert:
+//   - OIDC session (no dev bypass) → resolveUserId calls upsertUser → 202 (not 401)
+//   - No session at all → 401 (still unauthenticated)
+//
+// RED before Task 2 resolveUserId async rewrite; GREEN after.
+// ---------------------------------------------------------------------------
+describe('CR-06: OIDC iss/sub → users.id resolution on write handlers', () => {
+  beforeEach(() => {
+    // Disable dev bypass — simulate production OIDC path
+    devBypassInjectUser.active = false
+
+    // Seed a calendar row for the create endpoint's ownership check
+    mockDbRows = [
+      {
+        id: 1,
+        url: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
+        displayName: 'Default',
+        color: '#4A90D9',
+        userId: 42, // matches the upserted user id
+        isShared: false,
+      },
+    ]
+    const mockSimpleWhere = vi.fn().mockImplementation(() => Promise.resolve(mockDbRows))
+    mockFromFn.mockReturnValue({ where: mockSimpleWhere })
+    mockSelectFn.mockReturnValue({ from: mockFromFn })
+  })
+
+  it('POST /create with valid OIDC session (no dev bypass) returns 202, not 401', async () => {
+    // getAuth returns a real OIDC payload — upsertUser resolves user.id = 42
+    getAuthImpl.fn = () => ({ iss: 'https://auth.example.com', sub: 'sub-abc', email: 'user@example.com' })
+    mockUpsertUserFn.mockResolvedValue({ id: 42, oidcIss: 'https://auth.example.com', oidcSub: 'sub-abc', displayName: 'OIDC User', color: '#E8734A' })
+
+    const { app } = await import('../../src/index.js')
+    const res = await app.request('/api/events/create', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        title: 'OIDC event',
+        allDay: false,
+        start: '2026-06-15T10:00:00Z',
+        end: '2026-06-15T10:30:00Z',
+        recurrence: 'none',
+        calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
+      }),
+    })
+    // Handler must NOT return 401 — the OIDC session is valid and resolves a user
+    expect(res.status).toBe(202)
+    // upsertUser was called with the OIDC iss/sub
+    expect(mockUpsertUserFn).toHaveBeenCalledWith('https://auth.example.com', 'sub-abc', 'user@example.com')
+  })
+
+  it('POST /create with no session (getAuth returns null) returns 401', async () => {
+    // getAuth returns null → no session; should return 401
+    getAuthImpl.fn = () => null
+
+    const { app } = await import('../../src/index.js')
+    const res = await app.request('/api/events/create', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        title: 'Unauthenticated event',
+        allDay: false,
+        start: '2026-06-15T10:00:00Z',
+        end: '2026-06-15T10:30:00Z',
+        recurrence: 'none',
+      }),
+    })
+    expect(res.status).toBe(401)
+  })
+})
+
 // ---------------------------------------------------------------------------
 // GET /api/events/writable-calendars
 // ---------------------------------------------------------------------------