diff --git a/apps/api/src/routes/setup.ts b/apps/api/src/routes/setup.ts
index 737c597..e6c7b01 100644
--- a/apps/api/src/routes/setup.ts
+++ b/apps/api/src/routes/setup.ts
@@ -193,10 +193,17 @@ setupRouter.post('/validate/oidc', async (c) => {
 // ---------------------------------------------------------------------------
 // POST /api/setup/validate/vapid
 //
-// Validates VAPID key pair structure by calling webpush.setVapidDetails().
-// Reads BOTH keys ONLY from process.env — NEVER from app_config (T-12-06 / D-01 / SC-3).
-// VAPID_PRIVATE_KEY is never returned in any response.
-// Returns 200 { ok: true } on structural validity, 400 { ok: false } on failure.
+// Validates the operator-entered VAPID public key (app_config.vapid_public_key)
+// against the configured key pair:
+//   1. Equality (gap 2): the submitted public key MUST equal process.env.VAPID_PUBLIC_KEY.
+//      A wrong/typoed key (e.g. "BH123") now fails the row and gates Continue — push
+//      would silently break in production otherwise (SETUP-02).
+//   2. Structural: webpush.setVapidDetails() validates the env pair's byte structure.
+//
+// VAPID_PRIVATE_KEY is read ONLY from process.env — NEVER from app_config or returned
+// (T-12-06 / D-01 / SC-3). The equality check compares the submitted PUBLIC key to the
+// env PUBLIC key only — the private key is never compared or echoed.
+// Returns 200 { ok: true } on success, 400 { ok: false } on any failure.
 // ---------------------------------------------------------------------------
 
 setupRouter.post('/validate/vapid', async (c) => {
@@ -210,6 +217,23 @@ setupRouter.post('/validate/vapid', async (c) => {
     return c.json({ ok: false, error: 'VAPID_PRIVATE_KEY and VAPID_PUBLIC_KEY env vars must be set' }, 400);
   }
 
+  // Gap 2: assert the operator-submitted public key matches the env public key BEFORE
+  // the structural check. Read the submitted key from app_config (same idiom as validate/oidc).
+  const [submittedRow] = await db
+    .select({ value: appConfig.value })
+    .from(appConfig)
+    .where(eq(appConfig.key, 'vapid_public_key'))
+    .limit(1);
+
+  const submittedPublicKey = submittedRow?.value;
+  if (!submittedPublicKey || submittedPublicKey !== publicKey) {
+    return c.json({
+      ok: false,
+      error:
+        'VAPID public key does not match the configured key pair. Paste the exact VAPID_PUBLIC_KEY printed by `npm run generate-secrets`.',
+    }, 400);
+  }
+
   try {
     // setVapidDetails runs validatePrivateKey (32-byte check) and validatePublicKey (65-byte check)
     // internally — this is the library's own structural validation (Pattern 7).