---
phase: 260610-k1z
plan: 01
subsystem: auth
tags: [oidc, session, cookie, pwa, persistence]
dependency_graph:
  requires: [@hono/oidc-auth oidcAuthJwt context var]
  provides: [persistSessionCookie middleware, AUTH-02]
  affects: [apps/api/src/index.ts]
tech_stack:
  added: []
  patterns: [hono-middleware, cookie-upgrade]
key_files:
  created:
    - apps/api/src/auth/persistSessionCookie.ts
    - apps/api/tests/auth/persistSessionCookie.test.ts
  modified:
    - apps/api/src/index.ts
decisions:
  - "Set-before-next ordering: cookie re-issued before await next() so any future downstream logout/delete wins as the last Set-Cookie"
  - "Guard on c.get('oidcAuthJwt'): falsy path does nothing — no resurrection of deleted/absent cookies"
  - "Conditional domain: domain key absent (not undefined) when OIDC_COOKIE_DOMAIN unset — mirrors library logic"
metrics:
  duration: ~5m
  completed: "2026-06-10T18:32:47Z"
  tasks_completed: 2
  files_changed: 3
---

# Phase 260610-k1z Plan 01: Persist OIDC Session Cookie with Max-Age Summary

**One-liner:** Hono middleware that upgrades the session-scoped oidc-auth cookie (no maxAge) set by @hono/oidc-auth to a persistent cookie with Max-Age, SameSite=Lax, guarded to never resurrect absent/deleted cookies.

## What Was Built

`persistSessionCookie()` is a thin Hono `MiddlewareHandler` mounted immediately after `oidcAuthMiddleware()` in `index.ts` (inside the `!devBypassActive` block). It reads `c.get('oidcAuthJwt')` — a context key set by @hono/oidc-auth only on requests where a valid session was created or refreshed — and re-issues the same signed JWT as a persistent Set-Cookie (adding `Max-Age` + `SameSite=Lax`). When `oidcAuthJwt` is falsy (logged-out, no session, unauthenticated), it is a pure passthrough: no cookie is emitted.

## Tasks Completed

| Task | Name | Commit | Files |
|------|------|--------|-------|
| 1 | Create persistSessionCookie() middleware | aabcb5d | apps/api/src/auth/persistSessionCookie.ts |
| 2 | Wire into index.ts + unit tests | 8343fad | apps/api/src/index.ts, apps/api/tests/auth/persistSessionCookie.test.ts |

## Verification Results

### typecheck
```
$ pnpm --filter @familysync/api typecheck
$ tsc --noEmit
(exit 0 — no output)
```

### vitest run tests/auth/
```
 RUN  v4.1.8 /home/luc/Projects/familysync/apps/api

 Test Files  3 passed (3)
      Tests  14 passed (14)
   Start at  14:32:33
   Duration  2.45s (transform 162ms, setup 1.74s, import 142ms, tests 152ms, environment 0ms)
```

All 3 auth test files pass (devBypass, user, persistSessionCookie). 14/14 tests green including:
- Test A (persist path): truthy oidcAuthJwt → Set-Cookie with Max-Age, SameSite=Lax, HttpOnly, Secure
- Test B (guard path): absent oidcAuthJwt → no oidc-auth Set-Cookie emitted
- Guard variant: empty string oidcAuthJwt → no resurrection

## Deviations from Plan

None — plan executed exactly as written.

## Known Stubs

None.

## Threat Flags

None. The new middleware only re-issues a cookie that @hono/oidc-auth already set; it does not open new network endpoints or auth paths.

## Self-Check: PASSED

- [x] apps/api/src/auth/persistSessionCookie.ts exists
- [x] apps/api/tests/auth/persistSessionCookie.test.ts exists
- [x] apps/api/src/index.ts contains `persistSessionCookie()`
- [x] Commit aabcb5d exists
- [x] Commit 8343fad exists
- [x] typecheck exits 0
- [x] vitest tests/auth/ all pass
