diff --git a/.planning/phases/19-local-auth-no-oidc-mode/19-03-SUMMARY.md b/.planning/phases/19-local-auth-no-oidc-mode/19-03-SUMMARY.md
new file mode 100644
index 0000000..2725938
--- /dev/null
+++ b/.planning/phases/19-local-auth-no-oidc-mode/19-03-SUMMARY.md
@@ -0,0 +1,182 @@
+---
+phase: 19-local-auth-no-oidc-mode
+plan: "03"
+subsystem: auth
+tags: [local-auth, middleware, rate-limit, lockout, session-cookie, oidc-link, de-authelia, tdd]
+status: complete
+dependency_graph:
+  requires:
+    - verifyLocalSessionCookie / issueLocalSessionCookie / clearLocalSessionCookie (from 19-01)
+    - localCredentials Drizzle table (from 19-01)
+    - hashPassword / verifyPassword (from 19-01)
+    - linkOidcToUser / OidcLinkConflictError (from 19-02)
+  provides:
+    - localAuthMiddleware: cookie → c.set('user') middleware (AUTH-LOCAL-04)
+    - GET /api/auth/mode: pre-auth OIDC config endpoint (AUTH-LOCAL-05)
+    - POST /api/auth/local/login: rate-limited + timing-safe login (AUTH-LOCAL-03, AUTH-LOCAL-19)
+    - POST/GET /api/auth/local/logout: session cookie clear (AUTH-LOCAL-06)
+    - index.ts: pre-auth mounts + localAuthMiddleware slot + OIDC guard skip-when-user-set + /callback link branch (AUTH-LOCAL-04, AUTH-LOCAL-10)
+    - middleware.ts: de-Authelia-ized comments (AUTH-LOCAL-18)
+  affects:
+    - apps/api/src/index.ts (route mounts, middleware chain, /callback extension)
+    - apps/api/src/auth/middleware.ts (comment-only D-06 changes)
+tech_stack:
+  added: []
+  patterns:
+    - TDD RED/GREEN per task (failing test committed before implementation)
+    - In-memory loginAttempts Map: per-IP rate-limit (5→429) + lockout (10→423)
+    - DUMMY_HASH timing defense: verifyPassword always runs, even for unknown usernames (T-19-12)
+    - noEchoHook on login: Zod errors never echo submitted values (T-19-14)
+    - oidcAuthMiddleware() factory called once at construction, returned handler in skip-when-user-set wrapper (D-03)
+    - Jwt.verify on URL state param to extract linkUserId in /callback link branch (T-19-15)
+key_files:
+  created:
+    - apps/api/src/auth/localAuthMiddleware.ts
+    - apps/api/src/routes/authMode.ts
+    - apps/api/src/routes/localAuth.ts
+    - apps/api/tests/auth/localAuthMiddleware.test.ts
+    - apps/api/tests/routes/authMode.test.ts
+    - apps/api/tests/routes/localAuth.test.ts
+  modified:
+    - apps/api/src/index.ts
+    - apps/api/src/auth/middleware.ts
+decisions:
+  - "loginAttempts counter increments even on 429 responses — brute-force accumulates toward lockout (10→423) even during rate-window; original implementation only incremented on final auth check"
+  - "oidcAuthMiddleware() factory called once at app construction (not per-request) to preserve test assertion that it is called exactly once during app init"
+  - "localAuthMiddleware casts user value to typeof DEV_USER for ContextVariableMap compatibility — the narrow const type from devBypass.ts as const requires an explicit cast"
+  - "Authelia removed from 2 comments in index.ts and 2 comments in middleware.ts (D-06 / AUTH-LOCAL-18)"
+metrics:
+  duration: "~16 minutes"
+  completed: "2026-06-17"
+  tasks_completed: 3
+  tasks_total: 3
+  files_created: 6
+  files_modified: 2
+---
+
+# Phase 19 Plan 03: Auth Routes + Middleware Wiring Summary
+
+**One-liner:** localAuthMiddleware (cookie→c.set('user')), GET /api/auth/mode pre-auth endpoint, rate-limited POST /api/auth/local/login with timing-safe dummy-hash, logout, index.ts middleware chain wired with OIDC-guard skip-when-user-set and /callback link branch for linkOidcToUser, de-Authelia-ized middleware comments.
+
+## Tasks Completed
+
+| Task | RED Commit | GREEN Commit | Key Files |
+|------|-----------|-------------|-----------|
+| 1: localAuthMiddleware + GET /api/auth/mode | ac32bd4 | be7a0ae | localAuthMiddleware.ts, authMode.ts, index.ts |
+| 2: POST /api/auth/local/login (rate-limit + lockout) + logout | db66295 | c437f40 | localAuth.ts |
+| 3: index.ts wiring + /callback link branch + de-Authelia comments | — | 9b569ef | index.ts, middleware.ts |
+
+## What Was Built
+
+### Task 1: localAuthMiddleware + GET /api/auth/mode (TDD)
+
+**`apps/api/src/auth/localAuthMiddleware.ts`** — exports `localAuthMiddleware(): MiddlewareHandler`:
+- If `c.get('user')` already set (devAuthBypass ran first): no-op, calls next()
+- Calls `verifyLocalSessionCookie(c)` — returns null if no cookie / invalid / expired
+- On null: calls next() WITHOUT c.set('user') — Pitfall-1 guard; OIDC guard fires on absent key
+- On valid userId: SELECTs users row; if found, `c.set('user', {...} as typeof DEV_USER)` with matching shape
+
+**`apps/api/src/routes/authMode.ts`** — exports `authModeRouter` with GET /mode:
+- `localEnabled: true` unconditionally (D-01)
+- `oidcEnabled: Boolean(OIDC_ISSUER env)` || falls back to `app_config` oidc_issuer row
+- No auth gate — pre-auth endpoint
+
+Tests: 8 tests pass (4 middleware + 4 mode tests)
+
+### Task 2: POST /api/auth/local/login + logout (TDD)
+
+**`apps/api/src/routes/localAuth.ts`** — exports `localAuthRouter` and `loginAttempts`:
+- `POST /local/login` — zValidator + noEchoHook + per-IP loginAttempts Map
+  - lockedOut check (>= LOCKOUT_FAILURES=10) → 423 `{ error: 'Account locked' }`
+  - Rate window check (>= RATE_WINDOW_FAILURES=5, within RATE_WINDOW_SECS=60) → increments counter + 429
+  - Selects local_credentials by username; ALWAYS runs verifyPassword (DUMMY_HASH on unknown username — T-19-12)
+  - Same 401 body for wrong-password AND unknown-username (no enumeration)
+  - On success: loginAttempts.delete(ip), issueLocalSessionCookie, 200 `{ ok: true }`
+- `POST /local/logout` + `GET /local/logout` → clearLocalSessionCookie → 200 `{ ok: true }`
+
+Tests: 8 tests pass (login success/failure/enumeration/rate-limit/lockout/logout/no-echo)
+
+### Task 3: index.ts wiring + /callback link branch + de-Authelia comments
+
+**`apps/api/src/index.ts`** changes:
+- Pre-auth mounts: `app.route('/api/auth', authModeRouter)` + `app.route('/api/auth', localAuthRouter)` before devAuthBypass
+- `app.use('/api/*', localAuthMiddleware())` after devAuthBypass, before OIDC guard
+- OIDC guard wrapper: `oidcHandler = oidcAuthMiddleware()` stored once at construction, invoked per-request only when `c.get('user')` is falsy (D-03 coexistence seam)
+- `/callback` extended: reads URL `state` param, tries Jwt.verify with LOCAL_SESSION_SECRET; if `linkUserId` in payload → call linkOidcToUser after processOAuthCallback; OidcLinkConflictError → redirect `/?error=oidc-link-conflict`
+- Authelia references removed from 2 comments (D-06)
+
+**`apps/api/src/auth/middleware.ts`** changes:
+- Header: "Authelia as the identity provider" → "generic OIDC identity provider" (D-06)
+- "Authelia base URL" → "OIDC issuer URL" (D-06)
+- "Authelia's refresh_token_lifespan" → "the OIDC provider's refresh_token_lifespan" (D-06)
+
+Full suite: 446/446 tests pass; `pnpm --filter @familysync/api typecheck` exits 0.
+
+## Deviations from Plan
+
+### Auto-fixed Issues
+
+**1. [Rule 1 - Bug] Rate-limit counter not incrementing during 429 window**
+- **Found during:** Task 2 GREEN phase (Test 5 returning 429 instead of 423 for the 11th attempt)
+- **Issue:** After 5 failures, subsequent attempts returned 429 (early return) without incrementing the counter. The counter never reached LOCKOUT_FAILURES=10 because the early-return prevented accumulation.
+- **Fix:** Inside the rate-window 429 branch: increment counter, update lockedUntil, check if lockedOut (returns 423 if so), else return 429. This way brute-force attacks accumulate toward lockout even during the rate window.
+- **Files modified:** apps/api/src/routes/localAuth.ts
+- **Commit:** c437f40
+
+**2. [Rule 1 - Bug] oidcAuthMiddleware() factory called per-request in OIDC guard wrapper**
+- **Found during:** Task 3 execution — me.test.ts assertion that oidcAuthMiddleware is called exactly once during app init
+- **Issue:** Original OIDC guard wrapper called `oidcAuthMiddleware()(c, next)` per-request; existing test `wires oidcAuthMiddleware on /api/* when bypass is not active` asserts `oidcMiddlewareSpy.toHaveBeenCalledTimes(1)` (factory called once at construction).
+- **Fix:** Store `const oidcHandler = oidcAuthMiddleware()` at construction time; invoke `oidcHandler(c, next)` per-request inside the wrapper.
+- **Files modified:** apps/api/src/index.ts
+- **Commit:** 9b569ef
+
+**3. [Rule 1 - Bug] Type incompatibility: localAuthMiddleware c.set('user') type error**
+- **Found during:** Task 3 typecheck
+- **Issue:** `ContextVariableMap` maps 'user' to `typeof DEV_USER` (narrow `as const` literal). The middleware constructs `{ id: number; oidcIss: string; ... }` which TypeScript rejects as incompatible.
+- **Fix:** Add `import type { DEV_USER }` and cast with `as typeof DEV_USER` on the c.set call.
+- **Files modified:** apps/api/src/auth/localAuthMiddleware.ts
+- **Commit:** 9b569ef
+
+## Threat Surface Scan
+
+All new/modified routes in this plan:
+- `GET /api/auth/mode` — pre-auth, no credentials, no sensitive data; reads only env/app_config
+- `POST /api/auth/local/login` — new attack surface; mitigated by T-19-11 (rate-limit), T-19-12 (timing-safe dummy hash, no-enumeration 401), T-19-14 (noEchoHook)
+- `POST/GET /api/auth/local/logout` — clears cookie only; no sensitive data exposed
+
+No new trust boundaries beyond those in the plan's threat model.
+
+## TDD Gate Compliance
+
+**Task 1 (TDD):**
+- RED commit: ac32bd4 — test(19-03): add failing tests for localAuthMiddleware and GET /api/auth/mode
+- GREEN commit: be7a0ae — feat(19-03): implement localAuthMiddleware, GET /api/auth/mode...
+
+**Task 2 (TDD):**
+- RED commit: db66295 — test(19-03): add failing tests for POST /api/auth/local/login + logout
+- GREEN commit: c437f40 — feat(19-03): implement POST /api/auth/local/login (rate-limit + lockout) + logout
+
+**Task 3 (auto):** No TDD cycle required.
+
+## Known Stubs
+
+None. All new endpoints return real data and perform real operations.
+
+## Self-Check: PASSED
+
+All created files confirmed present on disk:
+- FOUND: apps/api/src/auth/localAuthMiddleware.ts
+- FOUND: apps/api/src/routes/authMode.ts
+- FOUND: apps/api/src/routes/localAuth.ts
+- FOUND: apps/api/tests/auth/localAuthMiddleware.test.ts
+- FOUND: apps/api/tests/routes/authMode.test.ts
+- FOUND: apps/api/tests/routes/localAuth.test.ts
+
+All commits confirmed in git log:
+- ac32bd4: test(19-03): add failing tests for localAuthMiddleware and GET /api/auth/mode
+- be7a0ae: feat(19-03): implement localAuthMiddleware, GET /api/auth/mode, and pre-auth route mounts
+- db66295: test(19-03): add failing tests for POST /api/auth/local/login + logout
+- c437f40: feat(19-03): implement POST /api/auth/local/login (rate-limit + lockout) + logout
+- 9b569ef: feat(19-03): wire /callback link branch, OIDC-guard skip, de-Authelia comments
+
+Test results: 446/446 pass (34 test files); `pnpm --filter @familysync/api typecheck` exits 0.
diff --git a/apps/api/src/auth/localAuthMiddleware.ts b/apps/api/src/auth/localAuthMiddleware.ts
new file mode 100644
index 0000000..b952137
--- /dev/null
+++ b/apps/api/src/auth/localAuthMiddleware.ts
@@ -0,0 +1,98 @@
+/**
+ * localAuthMiddleware.ts — local-session cookie → c.set('user') middleware (AUTH-LOCAL-04).
+ *
+ * Reads the `local-session` cookie, validates the JWT, fetches the users row,
+ * and populates `c.get('user')` with the same shape as devAuthBypass so that all
+ * downstream routes work unchanged.
+ *
+ * Mount in index.ts AFTER devAuthBypass() and BEFORE the OIDC guard:
+ *   app.use('/api/*', devAuthBypass());
+ *   app.use('/api/*', localAuthMiddleware());   ← HERE
+ *   if (!devBypassActive) {
+ *     app.use('/api/*', oidcAuthMiddleware());  ← skip if c.get('user') set
+ *   }
+ *
+ * Security contract:
+ *   - If c.get('user') is already set (devAuthBypass ran first): no-op passthrough.
+ *     This is Test 4 — dev user is not overwritten.
+ *   - If no 'local-session' cookie is present: pure passthrough WITHOUT calling
+ *     c.set('user', undefined). The OIDC guard fires on falsy c.get('user') only when
+ *     the value was never set — calling c.set('user', undefined) would suppress it.
+ *     This is Pitfall-1 / Test 2.
+ *   - If cookie is valid but the users row is gone: passthrough (no crash).
+ *     This is Test 3.
+ *
+ * ContextVariableMap: the `user` shape is declared in devBypass.ts. Import it as a
+ * side-effect so c.set('user', ...) is typed correctly throughout this file.
+ */
+
+// Side-effect import: extends ContextVariableMap with the `user` key (Pitfall — shared shape).
+import './devBypass.js';
+import type { MiddlewareHandler } from 'hono';
+import { eq } from 'drizzle-orm';
+import { db } from '../db/client.js';
+import { users } from '../db/schema.js';
+import { verifyLocalSessionCookie } from './localSession.js';
+import type { DEV_USER } from './devBypass.js';
+
+/**
+ * Returns a Hono MiddlewareHandler that:
+ *   1. Checks if c.get('user') is already set — no-op if so (devAuthBypass-first).
+ *   2. Calls verifyLocalSessionCookie(c) — returns null if no cookie / invalid / expired.
+ *   3. On null: calls next() WITHOUT setting user (pure passthrough — OIDC guard can fire).
+ *   4. On valid userId: SELECTs the users row; if found, c.set('user', {...}); always next().
+ */
+export function localAuthMiddleware(): MiddlewareHandler {
+  return async (c, next) => {
+    // If a prior middleware (devAuthBypass) already set the user, do not overwrite.
+    if (c.get('user')) {
+      await next();
+      return;
+    }
+
+    // Verify the local-session JWT cookie — returns userId or null.
+    // verifyLocalSessionCookie returns null (never throws) on any error (Pitfall 9 guard).
+    const userId = await verifyLocalSessionCookie(c);
+
+    if (userId === null) {
+      // No valid local session — pass through WITHOUT setting c.get('user').
+      // CRITICAL: Do NOT call c.set('user', undefined) — that sets the key to undefined
+      // which is falsy but "set", breaking the OIDC guard's c.get('user') check (Pitfall 1).
+      await next();
+      return;
+    }
+
+    // Load the users row to populate the same shape as DEV_USER.
+    const [row] = await db
+      .select({
+        id: users.id,
+        oidcIss: users.oidcIss,
+        oidcSub: users.oidcSub,
+        displayName: users.displayName,
+        color: users.color,
+      })
+      .from(users)
+      .where(eq(users.id, userId))
+      .limit(1);
+
+    if (!row) {
+      // userId from JWT but no users row (deleted user) — passthrough without setting user.
+      await next();
+      return;
+    }
+
+    // Populate c.get('user') with the same shape as DEV_USER (devBypass.ts ContextVariableMap).
+    // oidcIss/oidcSub: local users have nullable oidcIss/oidcSub — use fallback strings so the
+    // shape is compatible with typeof DEV_USER at runtime. Cast required because ContextVariableMap
+    // is narrowed to the const DEV_USER literal type.
+    c.set('user', {
+      id: row.id,
+      oidcIss: row.oidcIss ?? 'local',
+      oidcSub: row.oidcSub ?? String(row.id),
+      displayName: row.displayName ?? null,
+      color: row.color ?? '#4A90D9',
+    } as typeof DEV_USER);
+
+    await next();
+  };
+}
diff --git a/apps/api/src/auth/middleware.ts b/apps/api/src/auth/middleware.ts
index 1737635..d730a94 100644
--- a/apps/api/src/auth/middleware.ts
+++ b/apps/api/src/auth/middleware.ts
@@ -1,12 +1,12 @@
 /**
  * OIDC authentication middleware wiring.
  *
- * Configures @hono/oidc-auth for Authelia as the identity provider.
+ * Configures @hono/oidc-auth for the generic OIDC identity provider (D-06).
  *
  * Required env vars:
  *   OIDC_AUTH_SECRET          — 32+ char random string for JWT cookie signing (T-02-03)
- *   OIDC_ISSUER               — Authelia base URL (middleware fetches /.well-known/openid-configuration)
- *   OIDC_CLIENT_ID            — registered client ID in Authelia
+ *   OIDC_ISSUER               — OIDC issuer URL (middleware fetches /.well-known/openid-configuration)
+ *   OIDC_CLIENT_ID            — registered client ID at the OIDC provider
  *   OIDC_CLIENT_SECRET        — PLAIN text secret (NOT the pbkdf2 hash — see Pitfall 7)
  *   OIDC_REDIRECT_URI         — https://familysync.<domain>/callback
  *   OIDC_AUTH_EXTERNAL_URL    — https://familysync.<domain> — MANDATORY behind Pangolin (Pitfall 1)
@@ -30,7 +30,7 @@
  *   Every OIDC_AUTH_REFRESH_INTERVAL (default 15 min) the middleware calls
  *   the token endpoint with the stored refresh token — no iframe required (D-12).
  *   Session lifespan is governed by OIDC_AUTH_EXPIRES (default 1 day) and
- *   Authelia's refresh_token_lifespan.
+ *   the OIDC provider's refresh_token_lifespan.
  *
  * Scopes: openid, profile, email only — no 'groups' scope (D-11).
  *
diff --git a/apps/api/src/index.ts b/apps/api/src/index.ts
index 214822f..205afe7 100644
--- a/apps/api/src/index.ts
+++ b/apps/api/src/index.ts
@@ -11,17 +11,23 @@ import { listsRouter, listItemsRouter } from './routes/lists.js';
 import { pushRouter } from './routes/push.js';
 import { adminRouter } from './routes/admin.js';
 import { setupRouter } from './routes/setup.js';
+import { authModeRouter } from './routes/authMode.js';
+import { localAuthRouter } from './routes/localAuth.js';
 import {
   oidcAuthMiddleware,
   processOAuthCallback,
   oidcConfigFallbackMiddleware,
 } from './auth/middleware.js';
 import { devAuthBypass } from './auth/devBypass.js';
+import { localAuthMiddleware } from './auth/localAuthMiddleware.js';
 import { persistSessionCookie } from './auth/persistSessionCookie.js';
 import { startBrokerPoller } from './broker/poller.js';
 import { startOutboxWorker, initOutboxTrigger } from './broker/outboxWorker.js';
 import { startReminderScheduler } from './broker/reminderScheduler.js';
 import { assertNotDevBypassInProduction, assertLocalSessionSecretSet } from './lib/bootGuards.js';
+import { getAuth } from './auth/middleware.js';
+import { Jwt } from 'hono/utils/jwt';
+import { linkOidcToUser, OidcLinkConflictError } from './auth/linkOidc.js';
 import webpush from 'web-push';
 
 export const app = new Hono();
@@ -36,8 +42,63 @@ if (devBypassActive) {
 }
 
 // OIDC callback — must be registered BEFORE oidcAuthMiddleware so the
-// authorization-code exchange is not itself intercepted by the auth check (T-02-02)
-app.get('/callback', (c) => processOAuthCallback(c));
+// authorization-code exchange is not itself intercepted by the auth check (T-02-02).
+//
+// Phase 19 — link mode (AUTH-LOCAL-10, T-19-15):
+// When POST /api/me/link-oidc initiates a link flow, a signed JWT state is included
+// in the authorization URL as the `state` parameter. On callback, we read that raw URL
+// state param, try to decode it as our signed JWT, and if it carries `linkUserId`, we
+// call linkOidcToUser after processOAuthCallback establishes the OIDC session.
+//
+// Security: the signed state JWT prevents CSRF (T-19-09); linkOidcToUser preflight
+// prevents account takeover via conflict (T-19-15 / T-19-08).
+//
+// Normal (non-link) callbacks are unaffected — processOAuthCallback is called in all paths.
+app.get('/callback', async (c) => {
+  // Attempt to extract linkUserId from the signed state param BEFORE processOAuthCallback
+  // consumes it. The state param may be our signed JWT (link mode) or a random string (normal).
+  let linkUserId: number | null = null;
+  const rawState = c.req.query('state');
+  if (rawState) {
+    const secret = process.env.LOCAL_SESSION_SECRET;
+    if (secret) {
+      try {
+        const payload = await Jwt.verify(rawState, secret, 'HS256');
+        if (typeof payload.linkUserId === 'number') {
+          linkUserId = payload.linkUserId;
+        }
+      } catch {
+        // Not our signed link state — normal OIDC callback, proceed normally.
+      }
+    }
+  }
+
+  // Process the OIDC authorization-code exchange (sets the OIDC session cookie + redirects).
+  const callbackResponse = await processOAuthCallback(c);
+
+  // Link mode: after session is established, bind the OIDC identity to the local user.
+  if (linkUserId !== null) {
+    try {
+      const auth = await getAuth(c);
+      if (auth) {
+        const iss = (auth.iss as string | undefined) ?? '';
+        const sub = auth.sub ?? '';
+        await linkOidcToUser(linkUserId, iss, sub);
+        // On success: user is now OIDC-only; normal redirect via callbackResponse proceeds.
+      }
+    } catch (err) {
+      if (err instanceof OidcLinkConflictError) {
+        // 409: iss+sub already linked to a different user — redirect to conflict error page.
+        // UI-SPEC Surface 13 error copy: "This OIDC identity is already linked to another account."
+        return c.redirect('/?error=oidc-link-conflict');
+      }
+      // Unexpected error during link binding — log and continue with normal redirect.
+      console.error('[callback] linkOidcToUser unexpected error:', err instanceof Error ? err.message : String(err));
+    }
+  }
+
+  return callbackResponse;
+});
 
 // GET /health — unauthenticated, mounted BEFORE the OIDC guard (T-01-03, T-02-05)
 app.route('/health', healthRouter);
@@ -48,15 +109,26 @@ app.route('/health', healthRouter);
 // 423 lock after setup is complete (SETUP-04 / D-10).
 app.route('/api/setup', setupRouter);
 
+// Phase 19 — pre-auth auth routes: GET /api/auth/mode and POST /api/auth/local/login, /logout.
+// Mounted BEFORE devAuthBypass so they are reachable without a session (D-01 / AUTH-LOCAL-05).
+app.route('/api/auth', authModeRouter);
+app.route('/api/auth', localAuthRouter);
+
 // Dev-auth bypass — no-op passthrough unless DEV_AUTH_BYPASS=true AND NODE_ENV!='production'.
 // When active, injects DEV_USER into the Hono context and the OIDC guard is NOT mounted.
 // Must be mounted BEFORE oidcAuthMiddleware (T-02-01 mitigation; see auth/devBypass.ts).
 app.use('/api/*', devAuthBypass());
 
+// Phase 19 — local-session middleware: sets c.get('user') from 'local-session' JWT cookie.
+// No-op passthrough when no cookie is present — the OIDC guard fires for unauthenticated.
+// Runs AFTER devAuthBypass (which may set c.get('user') first) and BEFORE the OIDC guard.
+// The OIDC guard below is wrapped to skip when c.get('user') is already set (Pitfall 1 guard).
+app.use('/api/*', localAuthMiddleware());
+
 // Protect all /api/* routes with OIDC session middleware (AUTH-01, T-02-05).
-// Skipped entirely when devBypassActive so that local dev works without Authelia.
+// Skipped entirely when devBypassActive so that local dev works without the OIDC provider.
 // In production devBypassActive is always false — OIDC is unconditionally mounted.
-// Unauthenticated requests receive a 302 redirect to Authelia's authorize endpoint.
+// Unauthenticated requests receive a 302 redirect to the OIDC authorize endpoint.
 // OIDC_AUTH_EXTERNAL_URL is MANDATORY behind Pangolin to construct the correct
 // redirect_uri (Pitfall 1). Set it to https://familysync.<domain>.
 if (!devBypassActive) {
@@ -67,7 +139,21 @@ if (!devBypassActive) {
   // A2 CONFIRMED: oidcAuthMiddleware() reads process.env per-request (call time), so
   // injecting into process.env here is safe and effective (see auth/middleware.ts A2 note).
   app.use('/api/*', oidcConfigFallbackMiddleware);
-  app.use('/api/*', oidcAuthMiddleware());
+  // Phase 19 / D-03: OIDC guard wrapped to skip when c.get('user') is already set.
+  // A valid local-session (or dev-bypass) user must NOT be 302-redirected to the OIDC
+  // provider — the skip-when-set wrapper is the coexistence seam (D-03 / RESEARCH Pitfall 1).
+  //
+  // IMPORTANT: oidcAuthMiddleware() factory is called ONCE at app construction time (not per
+  // request) to match the prior behavior and keep test assertions about "called once" valid.
+  // The returned handler is stored and invoked per-request inside the wrapper.
+  const oidcHandler = oidcAuthMiddleware();
+  app.use('/api/*', async (c, next) => {
+    if (c.get('user')) {
+      await next();
+      return;
+    }
+    await oidcHandler(c, next);
+  });
   // Re-issues the session-scoped oidc-auth cookie as persistent so PWA sessions survive close (AUTH-02).
   app.use('/api/*', persistSessionCookie());
 }
@@ -76,7 +162,7 @@ if (!devBypassActive) {
 
 // GET /api/login — login entry point for the PWA.
 // Flow (production): unauthenticated top-level nav hits the OIDC guard above,
-// which 302-redirects to Authelia. After login, Authelia POSTs to /callback,
+// which 302-redirects to the OIDC provider. After login, the provider POSTs to /callback,
 // the middleware sets a `continue` cookie pointing back to /api/login, and the
 // browser follows it here — now authenticated. The handler then redirects to /
 // so the SPA boots with a valid session. Under DEV_AUTH_BYPASS the guard is not
diff --git a/apps/api/src/routes/authMode.ts b/apps/api/src/routes/authMode.ts
new file mode 100644
index 0000000..a4dcadd
--- /dev/null
+++ b/apps/api/src/routes/authMode.ts
@@ -0,0 +1,50 @@
+/**
+ * authMode.ts — GET /api/auth/mode pre-auth endpoint (AUTH-LOCAL-05).
+ *
+ * Returns { localEnabled: boolean, oidcEnabled: boolean } reflecting the current
+ * authentication configuration. This endpoint is intentionally reachable before
+ * authentication (same pre-auth pattern as GET /api/setup/status).
+ *
+ * Mount in index.ts BEFORE devAuthBypass and OIDC guard:
+ *   app.route('/api/auth', authModeRouter);   ← pre-auth
+ *
+ * Response contract:
+ *   - localEnabled: always true — local auth is the default, always available (D-01).
+ *   - oidcEnabled: true when OIDC_ISSUER env var is set, OR when app_config has
+ *     an oidc_issuer row (supports wizard-configured OIDC before container restart).
+ *
+ * No auth gate, no isSetupLocked() check — the PWA fetches this on app load before
+ * knowing if the user is authenticated.
+ */
+
+import { Hono } from 'hono';
+import { eq } from 'drizzle-orm';
+import { db } from '../db/client.js';
+import { appConfig } from '../db/schema.js';
+
+export const authModeRouter = new Hono();
+
+/**
+ * GET /  (mounted as /api/auth, so effective path is GET /api/auth/mode)
+ *
+ * Checks OIDC_ISSUER env var first (process.env is cheapest); falls back to
+ * app_config DB row if env var is absent (wizard-configured OIDC).
+ */
+authModeRouter.get('/mode', async (c) => {
+  // localEnabled: always true (D-01)
+  // oidcEnabled: env var first, then app_config fallback
+  const issuerFromEnv = process.env.OIDC_ISSUER;
+  let oidcEnabled = Boolean(issuerFromEnv);
+
+  if (!oidcEnabled) {
+    // Check app_config for oidc_issuer (wizard-written, pre-restart-fallback pattern from middleware.ts)
+    const [row] = await db
+      .select({ value: appConfig.value })
+      .from(appConfig)
+      .where(eq(appConfig.key, 'oidc_issuer'))
+      .limit(1);
+    oidcEnabled = Boolean(row?.value);
+  }
+
+  return c.json({ localEnabled: true, oidcEnabled });
+});
diff --git a/apps/api/src/routes/localAuth.ts b/apps/api/src/routes/localAuth.ts
new file mode 100644
index 0000000..5069c99
--- /dev/null
+++ b/apps/api/src/routes/localAuth.ts
@@ -0,0 +1,164 @@
+/**
+ * localAuth.ts — local authentication routes (AUTH-LOCAL-03, AUTH-LOCAL-06).
+ *
+ * Routes:
+ *   POST /api/auth/local/login  — rate-limited credential verify + session cookie issue
+ *   POST /api/auth/local/logout — clear local-session cookie
+ *   GET  /api/auth/local/logout — alias for POST /logout (some browsers prefer GET)
+ *
+ * Mounted in index.ts as app.route('/api/auth', localAuthRouter) BEFORE any auth middleware.
+ * This means POST /api/auth/local/login is reachable without a session (pre-auth, per D-01).
+ *
+ * Security (T-19-11, T-19-12, T-19-14):
+ *   - noEchoHook on login: Zod errors NEVER return received values (T-19-14 / Pitfall 7).
+ *   - Dummy-hash timing defense: verifyPassword is always called, even for unknown usernames,
+ *     to prevent timing-oracle username enumeration attacks (T-19-12 / RESEARCH Pitfall 2).
+ *   - Same 401 body for wrong password AND unknown username — no field discrimination (T-19-12).
+ *   - Per-IP in-memory rate-limiting: 5 failures → 429; 10 failures → 423 (T-19-11).
+ *   - Lockout (423) cleared only by admin password reset — no self-service unlock.
+ */
+
+import { Hono } from 'hono';
+import type { Context } from 'hono';
+import { zValidator } from '@hono/zod-validator';
+import { z } from 'zod';
+import { eq } from 'drizzle-orm';
+import { db } from '../db/client.js';
+import { localCredentials } from '../db/schema.js';
+import { verifyPassword, hashPassword } from '../auth/localCredentials.js';
+import { issueLocalSessionCookie, clearLocalSessionCookie } from '../auth/localSession.js';
+
+export const localAuthRouter = new Hono();
+
+// ---------------------------------------------------------------------------
+// noEchoHook — NEVER return Zod validation error details for the login route.
+// Zod's error object contains issues[].received which may echo the submitted password.
+// Always return { error: 'Invalid request' } 400, no other fields (T-19-14).
+// ---------------------------------------------------------------------------
+
+const noEchoHook = (result: { success: boolean }, c: Context) => {
+  if (!result.success) {
+    return c.json({ error: 'Invalid request' }, 400);
+  }
+};
+
+// ---------------------------------------------------------------------------
+// Zod schema for login body
+// ---------------------------------------------------------------------------
+
+const loginSchema = z.object({
+  username: z.string().min(1).max(128).trim(),
+  password: z.string().min(1).max(1000),
+});
+
+// ---------------------------------------------------------------------------
+// Per-IP rate-limiting state (in-memory Map — household scale, no Redis needed).
+//
+// State shape per IP: { count, lockedUntil (epoch ms), lockedOut (bool) }
+//   count >= RATE_WINDOW_FAILURES AND Date.now() < lockedUntil → 429
+//   count >= LOCKOUT_FAILURES → 423 (permanent until admin reset)
+//   Success → delete entry (clears counter)
+//
+// RATE_WINDOW_FAILURES: 5 failures → 60s cooldown (429)
+// LOCKOUT_FAILURES:    10 failures → account locked (423)
+// ---------------------------------------------------------------------------
+
+export const loginAttempts = new Map<string, { count: number; lockedUntil: number; lockedOut: boolean }>();
+
+const RATE_WINDOW_FAILURES = 5;
+const RATE_WINDOW_SECS = 60;
+const LOCKOUT_FAILURES = 10;
+
+// Pre-computed dummy hash used to run verifyPassword on unknown-username paths
+// (timing defense — prevents timing-oracle username enumeration, RESEARCH Pitfall 2).
+// Computed once at module load time; the actual value is never used for auth.
+const DUMMY_HASH = hashPassword('dummy-constant-time-filler-xyzzy');
+
+// ---------------------------------------------------------------------------
+// POST /local/login  →  POST /api/auth/local/login
+// ---------------------------------------------------------------------------
+
+localAuthRouter.post('/local/login', zValidator('json', loginSchema, noEchoHook), async (c) => {
+  // Derive client IP from Pangolin-set X-Forwarded-For header; fall back to host header.
+  const ip = c.req.header('x-forwarded-for')?.split(',')[0]?.trim()
+    ?? c.req.raw.headers.get('host')
+    ?? 'unknown';
+
+  const attempt = loginAttempts.get(ip);
+
+  // 423: account locked (>= LOCKOUT_FAILURES total failures, admin must reset)
+  // Check lockedOut FIRST — lockout takes precedence over rate window.
+  if (attempt?.lockedOut) {
+    return c.json({ error: 'Account locked' }, 423);
+  }
+
+  // 429: rate window — >= RATE_WINDOW_FAILURES failures within the cooldown window.
+  // Increment the counter even on 429 so continued brute-force accumulates toward lockout.
+  if (attempt && attempt.count >= RATE_WINDOW_FAILURES && Date.now() < attempt.lockedUntil) {
+    attempt.count += 1;
+    attempt.lockedUntil = Date.now() + RATE_WINDOW_SECS * 1000;
+    attempt.lockedOut = attempt.count >= LOCKOUT_FAILURES;
+    loginAttempts.set(ip, attempt);
+    if (attempt.lockedOut) {
+      return c.json({ error: 'Account locked' }, 423);
+    }
+    return c.json({ error: 'Too many attempts' }, 429);
+  }
+
+  const { username, password } = c.req.valid('json');
+
+  // Look up local_credentials by username
+  let cred: { userId: number; passwordHash: string } | undefined;
+  try {
+    const [found] = await db
+      .select({ userId: localCredentials.userId, passwordHash: localCredentials.passwordHash })
+      .from(localCredentials)
+      .where(eq(localCredentials.username, username))
+      .limit(1);
+    cred = found;
+  } catch (err) {
+    console.error('[localAuth/POST /local/login] DB error:', err instanceof Error ? err.message : String(err));
+    return c.json({ error: 'Service unavailable' }, 503);
+  }
+
+  // ALWAYS run verifyPassword — even for unknown usernames — to prevent timing-oracle
+  // username enumeration (T-19-12 / RESEARCH Pitfall 2). Use a pre-computed dummy hash
+  // so the scrypt work is always performed regardless of whether username was found.
+  const valid = cred
+    ? verifyPassword(cred.passwordHash, password)
+    : verifyPassword(DUMMY_HASH, password);
+
+  if (!valid || !cred) {
+    // Increment failure counter
+    const cur = loginAttempts.get(ip) ?? { count: 0, lockedUntil: 0, lockedOut: false };
+    cur.count += 1;
+    cur.lockedUntil = Date.now() + RATE_WINDOW_SECS * 1000;
+    cur.lockedOut = cur.count >= LOCKOUT_FAILURES;
+    loginAttempts.set(ip, cur);
+    // Same 401 body for wrong password AND unknown username — no field discrimination (T-19-12)
+    return c.json({ error: 'Invalid credentials' }, 401);
+  }
+
+  // Success: clear failure counter, issue the local-session JWT cookie, return ok
+  loginAttempts.delete(ip);
+  try {
+    await issueLocalSessionCookie(c, cred.userId);
+  } catch (err) {
+    console.error('[localAuth/POST /local/login] Cookie issue error:', err instanceof Error ? err.message : String(err));
+    return c.json({ error: 'Service unavailable' }, 503);
+  }
+  return c.json({ ok: true }, 200);
+});
+
+// ---------------------------------------------------------------------------
+// POST /local/logout  →  POST /api/auth/local/logout
+// GET  /local/logout  →  GET  /api/auth/local/logout (browser-redirect alias)
+// ---------------------------------------------------------------------------
+
+async function handleLogout(c: Context) {
+  clearLocalSessionCookie(c);
+  return c.json({ ok: true }, 200);
+}
+
+localAuthRouter.post('/local/logout', handleLogout);
+localAuthRouter.get('/local/logout', handleLogout);
diff --git a/apps/api/tests/auth/localAuthMiddleware.test.ts b/apps/api/tests/auth/localAuthMiddleware.test.ts
new file mode 100644
index 0000000..4dc9590
--- /dev/null
+++ b/apps/api/tests/auth/localAuthMiddleware.test.ts
@@ -0,0 +1,246 @@
+/**
+ * localAuthMiddleware() — unit tests (Plan 19-03, TDD RED → GREEN).
+ *
+ * Covers:
+ *   Test 1: valid local-session cookie for an existing user → c.get('user') set; next() called
+ *   Test 2: no cookie → pure passthrough; c.get('user') NOT set (OIDC guard fall-through intact)
+ *   Test 3: cookie with valid JWT but userId has no users row → passthrough (no crash)
+ *   Test 4: c.get('user') already set (devAuthBypass ran first) → not overwritten; next() called
+ *
+ * Security:
+ *   - Test 2 is the Pitfall-1 guard: middleware must NEVER call c.set('user', undefined).
+ *     The OIDC guard only fires when c.get('user') is falsy; setting it to undefined
+ *     would suppress the OIDC guard for unauthenticated requests.
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { Hono } from 'hono';
+
+// ---------------------------------------------------------------------------
+// Mock DB — avoids real DB connections in this middleware unit-test
+// ---------------------------------------------------------------------------
+
+const mockDbSelectResult: Array<{
+  id: number;
+  oidcIss: string | null;
+  oidcSub: string | null;
+  displayName: string | null;
+  color: string;
+}> = [];
+
+vi.mock('../../src/db/client.js', () => ({
+  db: {
+    select: vi.fn().mockReturnValue({
+      from: vi.fn().mockReturnValue({
+        where: vi.fn().mockReturnValue({
+          limit: vi.fn().mockImplementation(() => Promise.resolve(mockDbSelectResult)),
+        }),
+      }),
+    }),
+  },
+}));
+
+// ---------------------------------------------------------------------------
+// Mock verifyLocalSessionCookie — controls what userId the cookie yields
+// ---------------------------------------------------------------------------
+
+let mockVerifyResult: number | null = null;
+
+vi.mock('../../src/auth/localSession.js', () => ({
+  verifyLocalSessionCookie: vi.fn().mockImplementation(() => Promise.resolve(mockVerifyResult)),
+  issueLocalSessionCookie: vi.fn(),
+  clearLocalSessionCookie: vi.fn(),
+}));
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+async function getMiddleware() {
+  const { localAuthMiddleware } = await import('../../src/auth/localAuthMiddleware.js');
+  return localAuthMiddleware;
+}
+
+function makeApp(middleware: ReturnType<typeof vi.fn>, presetUser?: unknown) {
+  const app = new Hono();
+
+  if (presetUser !== undefined) {
+    // Simulate devAuthBypass having already set c.get('user')
+    app.use('/api/*', async (c, next) => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      c.set('user', presetUser as any);
+      await next();
+    });
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-call
+  app.use('/api/*', middleware());
+
+  let capturedUser: unknown = 'NOT_SET_SENTINEL';
+  let nextCalled = false;
+
+  app.get('/api/test', (c) => {
+    capturedUser = c.get('user');
+    nextCalled = true;
+    return c.json({ ok: true });
+  });
+
+  return { app, getCapturedUser: () => capturedUser, wasNextCalled: () => nextCalled };
+}
+
+// ---------------------------------------------------------------------------
+
+describe('localAuthMiddleware', () => {
+  beforeEach(() => {
+    mockVerifyResult = null;
+    mockDbSelectResult.splice(0);
+    vi.resetModules();
+  });
+
+  afterEach(() => {
+    vi.resetModules();
+  });
+
+  it('Test 1: valid local-session cookie for existing user → sets c.get("user") and calls next', async () => {
+    mockVerifyResult = 42;
+    mockDbSelectResult.push({
+      id: 42,
+      oidcIss: 'local',
+      oidcSub: '42',
+      displayName: 'Test User',
+      color: '#4A90D9',
+    });
+
+    const localAuthMiddleware = await getMiddleware();
+    const { app } = makeApp(localAuthMiddleware);
+
+    const res = await app.request('/api/test');
+    expect(res.status).toBe(200);
+
+    // Re-import to inspect captured value via the route handler's closure
+    // We verify by checking response — route returns 200 only if next() was called
+    // The actual user value is verified via the app route handler
+    const body = (await res.json()) as { ok: boolean };
+    expect(body.ok).toBe(true);
+  });
+
+  it('Test 1b: user shape from DB row is correct (id, oidcIss, oidcSub, displayName, color)', async () => {
+    mockVerifyResult = 7;
+    mockDbSelectResult.push({
+      id: 7,
+      oidcIss: 'https://auth.example.com',
+      oidcSub: 'sub-abc',
+      displayName: 'Alice',
+      color: '#FF5733',
+    });
+
+    const localAuthMiddleware = await getMiddleware();
+    const app = new Hono();
+    let capturedUser: unknown;
+
+    app.use('/api/*', localAuthMiddleware());
+    app.get('/api/test', (c) => {
+      capturedUser = c.get('user');
+      return c.json({ ok: true });
+    });
+
+    const res = await app.request('/api/test');
+    expect(res.status).toBe(200);
+    expect(capturedUser).toBeDefined();
+    const u = capturedUser as { id: number; oidcIss: string; oidcSub: string; displayName: string | null; color: string };
+    expect(u.id).toBe(7);
+    expect(u.oidcIss).toBe('https://auth.example.com');
+    expect(u.oidcSub).toBe('sub-abc');
+    expect(u.displayName).toBe('Alice');
+    expect(u.color).toBe('#FF5733');
+  });
+
+  it('Test 2: no cookie → pure passthrough; c.get("user") remains unset (Pitfall-1 guard)', async () => {
+    mockVerifyResult = null; // No cookie / invalid
+
+    const localAuthMiddleware = await getMiddleware();
+    const app = new Hono();
+    let capturedUser: unknown = 'NOT_SET_SENTINEL';
+    let nextCalled = false;
+
+    app.use('/api/*', localAuthMiddleware());
+    app.get('/api/test', (c) => {
+      capturedUser = c.get('user');
+      nextCalled = true;
+      return c.json({ ok: true });
+    });
+
+    const res = await app.request('/api/test');
+    expect(res.status).toBe(200);
+    expect(nextCalled).toBe(true);
+    // CRITICAL: user must remain UNSET (undefined), NOT set to undefined explicitly.
+    // The OIDC guard checks c.get('user') — if it's undefined (not set), the guard fires.
+    // The middleware must call next() without c.set('user') on the no-cookie path.
+    expect(capturedUser).toBeUndefined();
+  });
+
+  it('Test 3: valid cookie but userId has no users row → passthrough (no crash)', async () => {
+    mockVerifyResult = 999; // Valid JWT payload, userId=999
+    mockDbSelectResult.splice(0); // No DB row for userId 999
+
+    const localAuthMiddleware = await getMiddleware();
+    const app = new Hono();
+    let capturedUser: unknown = 'NOT_SET_SENTINEL';
+    let nextCalled = false;
+
+    app.use('/api/*', localAuthMiddleware());
+    app.get('/api/test', (c) => {
+      capturedUser = c.get('user');
+      nextCalled = true;
+      return c.json({ ok: true });
+    });
+
+    const res = await app.request('/api/test');
+    expect(res.status).toBe(200);
+    expect(nextCalled).toBe(true);
+    // No row found — should passthrough without setting user
+    expect(capturedUser).toBeUndefined();
+  });
+
+  it('Test 4: c.get("user") already set (devAuthBypass ran first) → not overwritten; next() called', async () => {
+    const preExistingUser = {
+      id: 1,
+      oidcIss: 'dev',
+      oidcSub: 'dev-user',
+      displayName: 'Dev User',
+      color: '#4A90D9',
+    };
+
+    // Even if verifyLocalSessionCookie would succeed, the existing user must not be overwritten
+    mockVerifyResult = 99; // A DIFFERENT userId
+    mockDbSelectResult.push({
+      id: 99,
+      oidcIss: 'local',
+      oidcSub: '99',
+      displayName: 'Another User',
+      color: '#FF0000',
+    });
+
+    const localAuthMiddleware = await getMiddleware();
+    const app = new Hono();
+    let capturedUser: unknown;
+
+    // Simulate devAuthBypass having set the user first
+    app.use('/api/*', async (c, next) => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      c.set('user', preExistingUser as any);
+      await next();
+    });
+    app.use('/api/*', localAuthMiddleware());
+    app.get('/api/test', (c) => {
+      capturedUser = c.get('user');
+      return c.json({ ok: true });
+    });
+
+    const res = await app.request('/api/test');
+    expect(res.status).toBe(200);
+    // User must remain the dev-bypass user, not overwritten
+    expect(capturedUser).toEqual(preExistingUser);
+    expect((capturedUser as typeof preExistingUser).id).toBe(1);
+  });
+});
diff --git a/apps/api/tests/routes/authMode.test.ts b/apps/api/tests/routes/authMode.test.ts
new file mode 100644
index 0000000..19fe7fe
--- /dev/null
+++ b/apps/api/tests/routes/authMode.test.ts
@@ -0,0 +1,123 @@
+/**
+ * GET /api/auth/mode — unit tests (Plan 19-03, TDD RED → GREEN).
+ *
+ * Covers:
+ *   Test 5: returns { localEnabled:true, oidcEnabled:false } when no oidc_issuer in env or app_config
+ *   Test 6: returns { oidcEnabled:true } when OIDC_ISSUER env var is set
+ *   Test 6b: returns { oidcEnabled:true } when oidc_issuer is in app_config (no env var)
+ *
+ * Pre-auth surface: reachable without OIDC session (same as /api/setup/status).
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+
+// ---------------------------------------------------------------------------
+// DB mock — controls app_config rows returned for oidc_issuer
+// ---------------------------------------------------------------------------
+
+let mockAppConfigOidcIssuer: string | null = null;
+
+vi.mock('../../src/db/client.js', () => ({
+  db: {
+    execute: vi.fn().mockResolvedValue([[{ '1': 1 }]]),
+    select: vi.fn().mockImplementation(() => ({
+      from: vi.fn().mockReturnValue({
+        where: vi.fn().mockReturnValue({
+          limit: vi.fn().mockImplementation(() => {
+            if (mockAppConfigOidcIssuer) {
+              return Promise.resolve([{ value: mockAppConfigOidcIssuer }]);
+            }
+            return Promise.resolve([]);
+          }),
+        }),
+      }),
+    })),
+    insert: vi.fn().mockReturnValue({
+      values: vi.fn().mockReturnValue({
+        onDuplicateKeyUpdate: vi.fn().mockResolvedValue(undefined),
+      }),
+    }),
+  },
+}));
+
+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: vi.fn().mockResolvedValue(null),
+}));
+
+vi.mock('../../src/auth/devBypass.js', () => ({
+  devAuthBypass:
+    () => async (_c: unknown, next: () => Promise<void>) => next(),
+}));
+
+vi.mock('../../src/auth/localAuthMiddleware.js', () => ({
+  localAuthMiddleware:
+    () => async (_c: unknown, next: () => Promise<void>) => next(),
+}));
+
+// ---------------------------------------------------------------------------
+// Env snapshot
+// ---------------------------------------------------------------------------
+
+const originalOidcIssuer = process.env.OIDC_ISSUER;
+
+beforeEach(() => {
+  mockAppConfigOidcIssuer = null;
+  delete process.env.OIDC_ISSUER;
+  vi.resetModules();
+});
+
+afterEach(() => {
+  if (originalOidcIssuer === undefined) {
+    delete process.env.OIDC_ISSUER;
+  } else {
+    process.env.OIDC_ISSUER = originalOidcIssuer;
+  }
+  vi.resetModules();
+});
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+describe('GET /api/auth/mode', () => {
+  it('Test 5: returns { localEnabled:true, oidcEnabled:false } when no oidc_issuer in env or app_config', async () => {
+    delete process.env.OIDC_ISSUER;
+    mockAppConfigOidcIssuer = null;
+
+    const { app } = await import('../../src/index.js');
+    const res = await app.request('/api/auth/mode');
+
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { localEnabled: boolean; oidcEnabled: boolean };
+    expect(body.localEnabled).toBe(true);
+    expect(body.oidcEnabled).toBe(false);
+  });
+
+  it('Test 6: returns { oidcEnabled:true } when OIDC_ISSUER env var is set', async () => {
+    process.env.OIDC_ISSUER = 'https://auth.example.com';
+    mockAppConfigOidcIssuer = null;
+
+    const { app } = await import('../../src/index.js');
+    const res = await app.request('/api/auth/mode');
+
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { localEnabled: boolean; oidcEnabled: boolean };
+    expect(body.localEnabled).toBe(true);
+    expect(body.oidcEnabled).toBe(true);
+  });
+
+  it('Test 6b: returns { oidcEnabled:true } when oidc_issuer is in app_config (no env var)', async () => {
+    delete process.env.OIDC_ISSUER;
+    mockAppConfigOidcIssuer = 'https://auth-from-config.example.com';
+
+    const { app } = await import('../../src/index.js');
+    const res = await app.request('/api/auth/mode');
+
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { localEnabled: boolean; oidcEnabled: boolean };
+    expect(body.localEnabled).toBe(true);
+    expect(body.oidcEnabled).toBe(true);
+  });
+});
diff --git a/apps/api/tests/routes/localAuth.test.ts b/apps/api/tests/routes/localAuth.test.ts
new file mode 100644
index 0000000..9e2a33a
--- /dev/null
+++ b/apps/api/tests/routes/localAuth.test.ts
@@ -0,0 +1,313 @@
+/**
+ * POST /api/auth/local/login + POST/GET /api/auth/local/logout — tests (Plan 19-03, TDD RED → GREEN).
+ *
+ * Covers:
+ *   Test 1: valid username+password → 200 { ok:true } + Set-Cookie for local-session
+ *   Test 2: wrong password → 401 { error: 'Invalid credentials' }
+ *   Test 3: unknown username → 401 with SAME body as Test 2 (no enumeration / no field discrimination)
+ *   Test 4: 5 consecutive failures from one IP → 6th returns 429
+ *   Test 5: 10 failures → 423 (lockedOut); a cleared map resets the counter
+ *   Test 6: POST /api/auth/local/logout clears the local-session cookie (expired Set-Cookie)
+ *   Test 6b: GET /api/auth/local/logout (alias) also clears the local-session cookie
+ *   Test 7 (no-echo): malformed body (missing password) → 400 { error: 'Invalid request' };
+ *          body must NOT contain submitted value or Zod 'received' field
+ *
+ * Architecture:
+ *   Tests mock DB client and issueLocalSessionCookie/clearLocalSessionCookie.
+ *   loginAttempts Map is imported directly and cleared between tests.
+ *   IP is derived from x-forwarded-for header.
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+
+// ---------------------------------------------------------------------------
+// Mock DB client
+// ---------------------------------------------------------------------------
+
+type LocalCredRow = { userId: number; passwordHash: string } | undefined;
+let mockCredRow: LocalCredRow;
+
+vi.mock('../../src/db/client.js', () => ({
+  db: {
+    execute: vi.fn().mockResolvedValue([[{ '1': 1 }]]),
+    select: vi.fn().mockImplementation(() => ({
+      from: vi.fn().mockReturnValue({
+        where: vi.fn().mockReturnValue({
+          limit: vi.fn().mockImplementation(() =>
+            Promise.resolve(mockCredRow ? [mockCredRow] : [])
+          ),
+        }),
+      }),
+    })),
+    insert: vi.fn().mockReturnValue({
+      values: vi.fn().mockReturnValue({
+        onDuplicateKeyUpdate: vi.fn().mockResolvedValue(undefined),
+      }),
+    }),
+  },
+}));
+
+// ---------------------------------------------------------------------------
+// Mock localSession helpers — track calls and control cookie behavior
+// ---------------------------------------------------------------------------
+
+let issueSessionCalled = false;
+let issuedUserId: number | null = null;
+let clearSessionCalled = false;
+
+vi.mock('../../src/auth/localSession.js', () => ({
+  issueLocalSessionCookie: vi.fn().mockImplementation(
+    (_c: unknown, userId: number) => {
+      issueSessionCalled = true;
+      issuedUserId = userId;
+      // Simulate setting a cookie on the context
+      return Promise.resolve();
+    }
+  ),
+  clearLocalSessionCookie: vi.fn().mockImplementation((_c: unknown) => {
+    clearSessionCalled = true;
+  }),
+  verifyLocalSessionCookie: vi.fn().mockResolvedValue(null),
+}));
+
+// ---------------------------------------------------------------------------
+// Mock devAuthBypass and OIDC — standard passthrough for route tests
+// ---------------------------------------------------------------------------
+
+vi.mock('../../src/auth/devBypass.js', () => ({
+  devAuthBypass:
+    () => async (_c: unknown, next: () => Promise<void>) => next(),
+}));
+
+vi.mock('../../src/auth/localAuthMiddleware.js', () => ({
+  localAuthMiddleware:
+    () => async (_c: unknown, next: () => Promise<void>) => 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: vi.fn().mockResolvedValue(null),
+}));
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+function makeLoginRequest(body: Record<string, string>, ip = '1.2.3.4'): Request {
+  return new Request('http://localhost/api/auth/local/login', {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json',
+      'x-forwarded-for': ip,
+    },
+    body: JSON.stringify(body),
+  });
+}
+
+async function getApp() {
+  const { app } = await import('../../src/index.js');
+  return app;
+}
+
+// ---------------------------------------------------------------------------
+// Test state
+// ---------------------------------------------------------------------------
+
+const originalNodeEnv = process.env.NODE_ENV;
+const originalBypass = process.env.DEV_AUTH_BYPASS;
+const originalSecret = process.env.LOCAL_SESSION_SECRET;
+
+beforeEach(async () => {
+  // Use dev-bypass mode so no OIDC redirect occurs
+  process.env.NODE_ENV = 'test';
+  process.env.DEV_AUTH_BYPASS = 'true';
+  // Provide a valid LOCAL_SESSION_SECRET for the session helpers
+  process.env.LOCAL_SESSION_SECRET = 'test-secret-that-is-at-least-32-chars!!';
+
+  issueSessionCalled = false;
+  issuedUserId = null;
+  clearSessionCalled = false;
+  mockCredRow = undefined;
+
+  vi.resetModules();
+
+  // Clear the rate-limit map between tests
+  const { loginAttempts } = await import('../../src/routes/localAuth.js');
+  loginAttempts.clear();
+});
+
+afterEach(() => {
+  process.env.NODE_ENV = originalNodeEnv;
+  if (originalBypass === undefined) delete process.env.DEV_AUTH_BYPASS;
+  else process.env.DEV_AUTH_BYPASS = originalBypass;
+  if (originalSecret === undefined) delete process.env.LOCAL_SESSION_SECRET;
+  else process.env.LOCAL_SESSION_SECRET = originalSecret;
+  vi.resetModules();
+});
+
+// ---------------------------------------------------------------------------
+// Import verifyPassword/hashPassword for test credential setup
+// ---------------------------------------------------------------------------
+
+async function getLocalCredentials() {
+  return import('../../src/auth/localCredentials.js');
+}
+
+// ===========================================================================
+// POST /api/auth/local/login
+// ===========================================================================
+
+describe('POST /api/auth/local/login', () => {
+  it('Test 1: valid username+password → 200 { ok:true } and issueLocalSessionCookie called', async () => {
+    const { hashPassword } = await getLocalCredentials();
+    const hash = hashPassword('correcthorse');
+    mockCredRow = { userId: 5, passwordHash: hash };
+
+    const app = await getApp();
+    const res = await app.fetch(makeLoginRequest({ username: 'alice', password: 'correcthorse' }));
+
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { ok: boolean };
+    expect(body.ok).toBe(true);
+    expect(issueSessionCalled).toBe(true);
+    expect(issuedUserId).toBe(5);
+  });
+
+  it('Test 2: wrong password → 401 { error: "Invalid credentials" }', async () => {
+    const { hashPassword } = await getLocalCredentials();
+    const hash = hashPassword('correcthorse');
+    mockCredRow = { userId: 5, passwordHash: hash };
+
+    const app = await getApp();
+    const res = await app.fetch(makeLoginRequest({ username: 'alice', password: 'wrongpassword' }));
+
+    expect(res.status).toBe(401);
+    const body = (await res.json()) as { error: string };
+    expect(body.error).toBe('Invalid credentials');
+    expect(issueSessionCalled).toBe(false);
+  });
+
+  it('Test 3: unknown username → 401 with SAME body as wrong password (no enumeration)', async () => {
+    mockCredRow = undefined; // No credential row found
+
+    const app = await getApp();
+    const res = await app.fetch(makeLoginRequest({ username: 'unknown-user', password: 'anypassword' }));
+
+    expect(res.status).toBe(401);
+    const body = (await res.json()) as { error: string };
+    // CRITICAL: same body as wrong-password case (Test 2) — no field discrimination
+    expect(body.error).toBe('Invalid credentials');
+    expect(issueSessionCalled).toBe(false);
+  });
+
+  it('Test 4: 5 consecutive failures → 6th attempt returns 429', async () => {
+    mockCredRow = undefined; // Always unknown — every attempt fails
+
+    const app = await getApp();
+
+    // 5 failures to trigger the rate window
+    for (let i = 0; i < 5; i++) {
+      const res = await app.fetch(
+        makeLoginRequest({ username: 'alice', password: 'wrong' }, '10.0.0.1')
+      );
+      expect(res.status).toBe(401);
+    }
+
+    // 6th attempt from same IP → 429
+    const res6 = await app.fetch(
+      makeLoginRequest({ username: 'alice', password: 'wrong' }, '10.0.0.1')
+    );
+    expect(res6.status).toBe(429);
+    const body = (await res6.json()) as { error: string };
+    expect(body.error).toBe('Too many attempts');
+  });
+
+  it('Test 5: 10 failures → 423 (account locked); cleared map resets counter', async () => {
+    mockCredRow = undefined;
+
+    const app = await getApp();
+
+    // 10 failures from same IP → lockout
+    for (let i = 0; i < 10; i++) {
+      await app.fetch(
+        makeLoginRequest({ username: 'alice', password: 'wrong' }, '10.0.0.2')
+      );
+    }
+
+    // 11th attempt → 423 (locked)
+    const res11 = await app.fetch(
+      makeLoginRequest({ username: 'alice', password: 'wrong' }, '10.0.0.2')
+    );
+    expect(res11.status).toBe(423);
+    const body = (await res11.json()) as { error: string };
+    expect(body.error).toBe('Account locked');
+
+    // Clear the map (simulates admin reset) → counter gone → next attempt is 401 again (not locked)
+    const { loginAttempts } = await import('../../src/routes/localAuth.js');
+    loginAttempts.delete('10.0.0.2');
+
+    const resAfterReset = await app.fetch(
+      makeLoginRequest({ username: 'alice', password: 'wrong' }, '10.0.0.2')
+    );
+    expect(resAfterReset.status).toBe(401);
+  });
+
+  it('Test 7 (no-echo): malformed body (missing password) → 400 { error: "Invalid request" }; body has no echoed value or Zod received field', async () => {
+    const app = await getApp();
+    // Body with username but missing password (Zod will reject)
+    const res = await app.fetch(
+      new Request('http://localhost/api/auth/local/login', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json', 'x-forwarded-for': '1.2.3.4' },
+        body: JSON.stringify({ username: 'mysecretusername' }),
+      })
+    );
+
+    expect(res.status).toBe(400);
+    const bodyText = await res.text();
+    const parsed = JSON.parse(bodyText) as { error: string };
+    expect(parsed.error).toBe('Invalid request');
+    // CRITICAL (no-echo): the response must NOT contain the submitted value or Zod 'received' field
+    expect(bodyText).not.toContain('mysecretusername');
+    expect(bodyText).not.toContain('received');
+  });
+});
+
+// ===========================================================================
+// POST /api/auth/local/logout + GET /api/auth/local/logout
+// ===========================================================================
+
+describe('POST /api/auth/local/logout', () => {
+  it('Test 6: POST /logout → 200 { ok:true } and clearLocalSessionCookie called', async () => {
+    const app = await getApp();
+    const res = await app.fetch(
+      new Request('http://localhost/api/auth/local/logout', {
+        method: 'POST',
+        headers: { 'x-forwarded-for': '1.2.3.4' },
+      })
+    );
+
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { ok: boolean };
+    expect(body.ok).toBe(true);
+    expect(clearSessionCalled).toBe(true);
+  });
+});
+
+describe('GET /api/auth/local/logout', () => {
+  it('Test 6b: GET /logout (alias) → 200 { ok:true } and clearLocalSessionCookie called', async () => {
+    const app = await getApp();
+    const res = await app.fetch(
+      new Request('http://localhost/api/auth/local/logout', {
+        method: 'GET',
+        headers: { 'x-forwarded-for': '1.2.3.4' },
+      })
+    );
+
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { ok: boolean };
+    expect(body.ok).toBe(true);
+    expect(clearSessionCalled).toBe(true);
+  });
+});