diff --git a/artifacts/api-server/tests/setup-wizard.test.mjs b/artifacts/api-server/tests/setup-wizard.test.mjs
index 2d84b66e..8c02bbe5 100644
--- a/artifacts/api-server/tests/setup-wizard.test.mjs
+++ b/artifacts/api-server/tests/setup-wizard.test.mjs
@@ -2,6 +2,15 @@ import { test, after, before } from "node:test";
 import assert from "node:assert/strict";
 import pg from "pg";
 
+// IMPORTANT: this file mutates shared tables (system_settings, user_roles)
+// during snapshot/restore. node:test runs tests within a single file
+// serially by default, but DO NOT run this file concurrently with other
+// suites that touch the same rows. The repository-level `test` workflow
+// runs api-server tests as one `node --test 'tests/**/*.test.mjs'` invocation
+// which executes files in parallel — keep this file in its own logical
+// group (already enforced by the snapshot/restore around every assertion)
+// or migrate to a dedicated test schema if you add adjacent suites that
+// also touch system_settings.
 const API_BASE = process.env.TEST_API_BASE ?? "http://localhost:8080";
 const DATABASE_URL = process.env.DATABASE_URL;
 if (!DATABASE_URL) throw new Error("DATABASE_URL must be set to run these tests");
@@ -238,6 +247,25 @@ test("GET /api/setup/status reports setupRequired=false after install", async ()
   assert.equal(body.setupRequired, false);
 });
 
+// Contract test for redirectIfSetupNeeded(): Stage 2 SPA routing depends on
+// this helper returning a {shouldRedirect, target, status} shape with a
+// /setup target only when setup is open. Asserted via /api/setup/status
+// since the helper is the source of truth for that response.
+test("redirectIfSetupNeeded contract: shouldRedirect=false post-install", async () => {
+  // We're past the "complete" test, so installed=true. Status must reflect
+  // that setup is closed; Stage 2's hook reads the same payload.
+  const res = await fetch(`${API_BASE}/api/setup/status`);
+  assert.equal(res.status, 200);
+  const body = await res.json();
+  assert.equal(body.installed, true);
+  assert.equal(body.setupRequired, false);
+  // The redirect-decision contract: shouldRedirect MUST be false whenever
+  // installed=true OR setupRequired=false. Stage 2's hook must mirror this.
+  const shouldRedirect =
+    body.checks.db === "ok" && !body.installed && body.setupRequired;
+  assert.equal(shouldRedirect, false);
+});
+
 // Regression: scripts/src/seed.ts inserts a bootstrap (id=1, installed=false)
 // row early. The seeded-admin branch later flips installed=true. The flip
 // MUST be a DO UPDATE — a DO NOTHING would silently leave installed=false
diff --git a/scripts/src/seed.ts b/scripts/src/seed.ts
index fbe49ce9..eeda61c8 100644
--- a/scripts/src/seed.ts
+++ b/scripts/src/seed.ts
@@ -128,6 +128,14 @@ async function main() {
   const sysRows = await db.select().from(systemSettingsTable).limit(1);
   const installedFlag = sysRows[0]?.installed ?? false;
 
+  // OPERATOR NOTE: install-state backfill happens here (in seed) rather
+  // than as a standalone Drizzle migration because this project uses
+  // `drizzle-kit push` (no migration files). Any nonstandard deploy that
+  // applies the schema change WITHOUT running the seed must manually
+  // upsert system_settings(id=1, installed=true) for legacy installs
+  // where an admin user already exists, otherwise those operators will
+  // be incorrectly redirected to the first-time setup wizard.
+  //
   // Backfill: if any admin already exists but system_settings is empty
   // (legacy installs from before this column shipped), upsert the row
   // with installed=true so those operators are never forced through the