diff --git a/tests/p0/aud0-outbox.test.ts b/tests/p0/aud0-outbox.test.ts
new file mode 100644
index 0000000..c584194
--- /dev/null
+++ b/tests/p0/aud0-outbox.test.ts
@@ -0,0 +1,155 @@
+import { describe, expect, it } from "vitest";
+
+import type { Aud0Client, Aud0Event } from "@/src/clients/aud0-client";
+import {
+  Aud0OutboxDispatcher,
+  openLineageIdempotencyKey,
+  outboxId,
+  type Aud0OutboxRecord,
+  type Aud0OutboxRepository,
+  type Aud0OutboxStats,
+} from "@/src/evidence/aud0-outbox";
+import type { OpenLineageRunEvent } from "@/src/lineage/openlineage";
+import { SiaxError } from "@/src/platform/errors";
+
+const event: Aud0Event = {
+  event_id: "evt-1",
+  event_type: "0pt.test",
+  tenant_id: "tenant-a",
+  project_id: "project-a",
+  actor_id: "tester",
+  app_id: "0pt",
+  capability_id: "0pt.test.v1",
+  resource_type: "test",
+  resource_id: "r1",
+  risk_level: "L1",
+  created_at: "2026-09-07T12:00:00.000Z",
+  idempotency_key: "idem-1",
+};
+
+const ol: OpenLineageRunEvent = {
+  eventType: "COMPLETE",
+  eventTime: "2026-09-07T12:00:00.000Z",
+  producer: "https://git.siax.io/sax3l/0pt",
+  run: { runId: "run-1" },
+  job: { namespace: "0pt", name: "0pt.test.v1" },
+  inputs: [],
+  outputs: [],
+};
+
+class FakeRepo implements Aud0OutboxRepository {
+  claimed: Aud0OutboxRecord[] = [];
+  delivered: string[] = [];
+  dead: Array<{ id: string; error: string }> = [];
+  retried: Array<{ id: string; error: string; delayMs: number }> = [];
+
+  async enqueueEvent(): Promise<Aud0OutboxRecord> { throw new Error("unused"); }
+  async enqueueOpenLineage(): Promise<Aud0OutboxRecord> { throw new Error("unused"); }
+  async claimPending(): Promise<Aud0OutboxRecord[]> { return this.claimed; }
+  async markDelivered(id: string): Promise<void> { this.delivered.push(id); }
+  async markRetry(id: string, _worker: string, error: string, delayMs: number): Promise<void> {
+    this.retried.push({ id, error, delayMs });
+  }
+  async markDead(id: string, _worker: string, error: string): Promise<void> {
+    this.dead.push({ id, error });
+  }
+  async stats(): Promise<Aud0OutboxStats> { return { pending: this.claimed.length, delivered: 0, dead: 0 }; }
+}
+
+function row(
+  kind: "event" | "openlineage",
+  payload: Aud0Event | OpenLineageRunEvent,
+  overrides: Partial<Aud0OutboxRecord> = {},
+): Aud0OutboxRecord {
+  return {
+    outbox_id: "obx-1",
+    tenant_id: "tenant-a",
+    app_id: "0pt",
+    evidence_kind: kind,
+    idempotency_key: "idem-1",
+    payload,
+    status: "pending",
+    attempts: 1,
+    next_attempt_at: "2026-09-07T12:00:00.000Z",
+    created_at: "2026-09-07T12:00:00.000Z",
+    updated_at: "2026-09-07T12:00:00.000Z",
+    ...overrides,
+  };
+}
+
+function client(impl?: Partial<Aud0Client>): Aud0Client {
+  return {
+    async ingestEvent(input) { return input; },
+    async ingestOpenLineageEvent(tenantId, _appId, input) {
+      return { tenant_id: tenantId, run_id: input.run.runId, job: input.job.name, event_id: "aud0-1" };
+    },
+    async ingestLineageEvent(input) { return input; },
+    ...impl,
+  };
+}
+
+describe("AUD0 durable outbox", () => {
+  it("derives stable tenant-bound outbox ids", () => {
+    expect(outboxId("tenant-a", "event", "k1")).toBe(outboxId("tenant-a", "event", "k1"));
+    expect(outboxId("tenant-a", "event", "k1")).not.toBe(outboxId("tenant-b", "event", "k1"));
+    expect(outboxId("tenant-a", "event", "k1")).not.toBe(outboxId("tenant-a", "openlineage", "k1"));
+  });
+
+  it("uses logical OpenLineage run+eventType identity rather than delivery time", () => {
+    expect(openLineageIdempotencyKey(ol)).toBe("ol:run-1:COMPLETE");
+    expect(openLineageIdempotencyKey({ ...ol, eventTime: "2030-01-01T00:00:00Z" })).toBe("ol:run-1:COMPLETE");
+  });
+
+  it("marks a successfully delivered generic event delivered", async () => {
+    const repo = new FakeRepo();
+    repo.claimed = [row("event", event)];
+    let calls = 0;
+    const dispatcher = new Aud0OutboxDispatcher(repo, client({
+      async ingestEvent(input) { calls += 1; return input; },
+    }), "worker-a");
+
+    expect(await dispatcher.sweep()).toEqual({ claimed: 1, delivered: 1, dead: 0, retried: 0 });
+    expect(calls).toBe(1);
+    expect(repo.delivered).toEqual(["obx-1"]);
+  });
+
+  it("retries network/dependency failures with bounded exponential backoff", async () => {
+    const repo = new FakeRepo();
+    repo.claimed = [row("openlineage", ol, { attempts: 4 })];
+    const dispatcher = new Aud0OutboxDispatcher(repo, client({
+      async ingestOpenLineageEvent() {
+        throw new SiaxError("DEPENDENCY_UNAVAILABLE", "aud0", "offline");
+      },
+    }), "worker-a");
+
+    expect(await dispatcher.sweep()).toEqual({ claimed: 1, delivered: 0, dead: 0, retried: 1 });
+    expect(repo.retried[0].delayMs).toBe(8_000);
+    expect(repo.retried[0].error).toBe("DEPENDENCY_UNAVAILABLE:aud0");
+  });
+
+  it("parks permanent 4xx-style failures dead instead of poisoning the queue", async () => {
+    const repo = new FakeRepo();
+    repo.claimed = [row("event", event)];
+    const dispatcher = new Aud0OutboxDispatcher(repo, client({
+      async ingestEvent() {
+        throw new SiaxError("INVALID_REQUEST", "aud0", "bad event");
+      },
+    }), "worker-a");
+
+    expect(await dispatcher.sweep()).toEqual({ claimed: 1, delivered: 0, dead: 1, retried: 0 });
+    expect(repo.dead).toEqual([{ id: "obx-1", error: "INVALID_REQUEST:aud0" }]);
+  });
+
+  it("fails closed on an immutable tenant/app envelope mismatch before calling AUD0", async () => {
+    const repo = new FakeRepo();
+    repo.claimed = [row("event", { ...event, tenant_id: "tenant-b" })];
+    let calls = 0;
+    const dispatcher = new Aud0OutboxDispatcher(repo, client({
+      async ingestEvent(input) { calls += 1; return input; },
+    }), "worker-a");
+
+    expect(await dispatcher.sweep()).toEqual({ claimed: 1, delivered: 0, dead: 1, retried: 0 });
+    expect(calls).toBe(0);
+    expect(repo.dead[0].error).toBe("PERMANENT_FAILURE:0pt.aud0_outbox");
+  });
+});