diff --git a/tests/integration/owner-actions.test.ts b/tests/integration/owner-actions.test.ts
new file mode 100644
index 0000000..47c4560
--- /dev/null
+++ b/tests/integration/owner-actions.test.ts
@@ -0,0 +1,81 @@
+import { describe, it, expect, beforeAll } from "vitest";
+import PocketBase from "pocketbase";
+
+import { APP_URL, DEMO, adminPb, requireServices, signIn, userPb } from "./helpers";
+
+let admin: PocketBase;
+let managerCookie: string;
+let projectId: string;
+let inboxId: string;
+
+beforeAll(async () => {
+  await requireServices();
+  admin = await adminPb();
+  managerCookie = await signIn(DEMO.managerEmail, DEMO.managerPassword);
+
+  const project = await admin
+    .collection("projects")
+    .getFirstListItem(`slug = "${DEMO.projectSlug}"`);
+  projectId = project.id;
+
+  inboxId = (
+    await admin
+      .collection("columns")
+      .getFirstListItem(`project = "${projectId}" && is_inbox = true`)
+  ).id;
+});
+
+describe("a client manager cannot write card fields the owner owns", () => {
+  it("is refused by PocketBase on a direct subtask create", async () => {
+    const card = await admin.collection("cards").getFirstListItem(
+      `project = "${projectId}"`
+    );
+    const pb = await userPb(DEMO.managerEmail, DEMO.managerPassword);
+
+    await expect(
+      pb.collection("subtasks").create({
+        card: card.id,
+        title: "injected",
+        done: false,
+        position: 1000,
+      })
+    ).rejects.toThrow();
+  });
+
+  it("is refused by PocketBase on a direct activity insert", async () => {
+    // activity.createRule is superuser-only. If this ever succeeds, someone
+    // relaxed the rule and the audit log can be forged.
+    const pb = await userPb(DEMO.managerEmail, DEMO.managerPassword);
+
+    await expect(
+      pb.collection("activity").create({
+        project: projectId,
+        actor: "x",
+        action: "card_accepted",
+      })
+    ).rejects.toThrow();
+  });
+});
+
+describe("a client request carries the flags the accept flow depends on", () => {
+  it("lands unaccepted, client-authored, with no start date", async () => {
+    const response = await fetch(`${APP_URL}/api/client/cards`, {
+      method: "POST",
+      headers: { "content-type": "application/json", cookie: managerCookie },
+      body: JSON.stringify({ project: projectId, title: "Accept-flow probe" }),
+    });
+    expect(response.status).toBe(201);
+
+    const { card } = await response.json();
+    const created = await admin.collection("cards").getOne(card.id);
+
+    expect(created.column).toBe(inboxId);
+    expect(created.accepted).toBe(false);
+    expect(created.created_by_role).toBe("client");
+    // start_date must be empty until acceptance — Phase 2 uses it to bound
+    // which commits this card may claim.
+    expect(created.start_date).toBeFalsy();
+
+    await admin.collection("cards").delete(card.id);
+  });
+});
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