diff --git a/apps/server/src/db.ts b/apps/server/src/db.ts
index 29075322..98f37efc 100644
--- a/apps/server/src/db.ts
+++ b/apps/server/src/db.ts
@@ -57,6 +57,21 @@ export class Store {
     );
     return (result.rows[0]?.data as T | undefined) ?? null;
   }
+  async compareAndSetJsonPath<T>(
+    owner: string,
+    kind: string,
+    id: string,
+    expected: Record<string, unknown>,
+    path: string[],
+    value: unknown,
+  ): Promise<T | null> {
+    if (path.length === 0) throw new Error("compareAndSetJsonPath requires a non-empty path");
+    const result = await this.db.query(
+      "UPDATE records SET data=jsonb_set(data,$5::text[],$6::jsonb,true),updated_at=now() WHERE owner=$1 AND kind=$2 AND id=$3 AND data @> $4::jsonb RETURNING data",
+      [owner, kind, id, JSON.stringify(expected), path, JSON.stringify(value)],
+    );
+    return (result.rows[0]?.data as T | undefined) ?? null;
+  }
   async insertIfAbsent<T extends { id: string }>(
     owner: string,
     kind: string,
diff --git a/apps/server/src/engine/service.ts b/apps/server/src/engine/service.ts
index 3f2af061..9b1493db 100644
--- a/apps/server/src/engine/service.ts
+++ b/apps/server/src/engine/service.ts
@@ -39,6 +39,34 @@ import { LostLeaseError, type TaskContext, TaskWorker } from "./worker.ts";
 const hash = (text: string) => createHash("sha256").update(text).digest("hex");
 const date = () => new Date().toISOString();
 const terminal = new Set(["succeeded", "failed", "cancelled"]);
+const outcomeKey = (task: AgentTask): string | undefined => {
+  if (task.status === "succeeded") return `task-done:${task.id}`;
+  if (task.status === "failed") return `task-error:${task.id}:${task.attempts}`;
+  if (task.status === "waiting_input") return `input:${task.id}:${hash(task.question ?? "")}`;
+  if (task.status === "waiting_approval") return `review:${task.actionId}`;
+  if (task.status === "cancelled") return `cancelled:${task.id}`;
+  const notice = z
+    .object({ title: z.string(), body: z.string(), key: z.string() })
+    .safeParse(task.state.notice);
+  if ((task.status === "scheduled" || (task.status === "paused" && task.error)) && notice.success)
+    return notice.data.key;
+  return undefined;
+};
+
+const outcomeMarkerExpected = (task: AgentTask): Record<string, unknown> => {
+  const expected: Record<string, unknown> = { status: task.status };
+  if (task.status === "failed") expected.attempts = task.attempts;
+  if (task.status === "waiting_input" && task.question !== undefined)
+    expected.question = task.question;
+  if (task.status === "waiting_approval" && task.actionId !== undefined)
+    expected.actionId = task.actionId;
+  const notice = z
+    .object({ title: z.string(), body: z.string(), key: z.string() })
+    .safeParse(task.state.notice);
+  if ((task.status === "scheduled" || task.status === "paused") && notice.success)
+    expected.state = { notice: notice.data };
+  return expected;
+};
 export class AgentService {
   readonly worker: TaskWorker;
   private maintenance?: ReturnType<typeof setInterval>;
@@ -75,8 +103,12 @@ export class AgentService {
     this.refreshing = true;
     try {
       // Recover publications if the process exited after committing an outcome.
-      for (const { owner, value } of await this.db.scan<AgentTask>("tasks"))
+      // A matching durable marker means this exact outcome was already published.
+      for (const { owner, value } of await this.db.scan<AgentTask>("tasks")) {
+        const key = outcomeKey(value);
+        if (key && value.state.publishedOutcome === key) continue;
         await this.publishOutcome(owner, value);
+      }
       for (const { owner, value } of await this.db.scan<Monitor>("monitors"))
         await this.activateMonitor(owner, value);
       for (const { owner, value } of await this.db.scan<Idea>("ideas"))
@@ -900,6 +932,16 @@ export class AgentService {
         { status: "active", error: task.error },
         { status: "paused" },
       );
+    const key = outcomeKey(task);
+    if (key)
+      await this.db.compareAndSetJsonPath<AgentTask>(
+        owner,
+        "tasks",
+        task.id,
+        outcomeMarkerExpected(task),
+        ["state", "publishedOutcome"],
+        key,
+      );
   }
   private async document(
     owner: string,
diff --git a/tests/maintain-outcome.test.ts b/tests/maintain-outcome.test.ts
new file mode 100644
index 00000000..f0d01119
--- /dev/null
+++ b/tests/maintain-outcome.test.ts
@@ -0,0 +1,146 @@
+import assert from "node:assert/strict";
+import { createHash } from "node:crypto";
+import { test } from "node:test";
+import { createStore, type Store } from "../apps/server/src/db.ts";
+import { AgentService } from "../apps/server/src/engine/service.ts";
+import type { AgentNotification, AgentTask } from "../packages/domain/src/agent.ts";
+
+function task(id: string, status: AgentTask["status"], extra: Partial<AgentTask> = {}): AgentTask {
+  return {
+    id,
+    title: `Task ${id}`,
+    prompt: `Task ${id}`,
+    kind: "agent",
+    status,
+    plan: [],
+    evidence: [],
+    input: {},
+    state: {},
+    createdAt: new Date().toISOString(),
+    updatedAt: new Date().toISOString(),
+    attempts: status === "failed" ? 3 : 1,
+    error: status === "failed" ? "simulated failure" : null,
+    leaseId: null,
+    leaseUntil: null,
+    artifactIds: [],
+    ...extra,
+  };
+}
+
+function serviceWith(db: Store) {
+  const service = new AgentService(
+    db,
+    {} as never,
+    {} as never,
+    {} as never,
+    {} as never,
+    {} as never,
+  );
+  return service as unknown as { maintain(): Promise<void> };
+}
+
+async function notifications(db: Store): Promise<AgentNotification[]> {
+  return (await db.scan<AgentNotification>("notifications")).map(({ value }) => value);
+}
+
+test("maintenance recovers a lost publication once, then skips the marked row", async () => {
+  const db = await createStore();
+  try {
+    await db.put("owner", "tasks", task("task1", "succeeded", { result: "done" }));
+    const service = serviceWith(db);
+
+    await service.maintain();
+    assert.equal((await notifications(db)).filter((n) => n.taskId === "task1").length, 1);
+    assert.equal(
+      (await db.get<AgentTask>("owner", "tasks", "task1"))?.state.publishedOutcome,
+      "task-done:task1",
+    );
+
+    let taskGets = 0;
+    const originalGet = db.get.bind(db);
+    db.get = (async (owner: string, kind: string, id: string) => {
+      if (kind === "tasks") taskGets++;
+      return originalGet(owner, kind, id);
+    }) as Store["get"];
+    await service.maintain();
+    db.get = originalGet;
+    assert.equal(taskGets, 0);
+    assert.equal((await notifications(db)).filter((n) => n.taskId === "task1").length, 1);
+  } finally {
+    await db.close();
+  }
+});
+
+test("outcome marker preserves a concurrent sibling state write", async () => {
+  const db = await createStore();
+  try {
+    await db.put(
+      "owner",
+      "tasks",
+      task("task1", "succeeded", { result: "done", state: { existing: "value" } }),
+    );
+    const service = serviceWith(db);
+    const originalInsert = db.insertIfAbsent.bind(db);
+    let injected = false;
+    db.insertIfAbsent = (async (owner: string, kind: string, value: { id: string }) => {
+      if (kind === "notifications" && !injected) {
+        injected = true;
+        const latest = await db.get<AgentTask>("owner", "tasks", "task1");
+        assert.ok(latest);
+        await db.compareAndSwap(
+          "owner",
+          "tasks",
+          "task1",
+          { status: "succeeded" },
+          { state: { ...latest.state, concurrent: "kept" } },
+        );
+      }
+      return originalInsert(owner, kind, value);
+    }) as Store["insertIfAbsent"];
+
+    await service.maintain();
+    const saved = await db.get<AgentTask>("owner", "tasks", "task1");
+    assert.equal(saved?.state.existing, "value");
+    assert.equal(saved?.state.concurrent, "kept");
+    assert.equal(saved?.state.publishedOutcome, "task-done:task1");
+  } finally {
+    await db.close();
+  }
+});
+
+test("a same-status outcome change is not hidden by a stale marker", async () => {
+  const db = await createStore();
+  try {
+    await db.put("owner", "tasks", task("task1", "waiting_input", { question: "Old question?" }));
+    const service = serviceWith(db);
+    const originalInsert = db.insertIfAbsent.bind(db);
+    let changed = false;
+    db.insertIfAbsent = (async (owner: string, kind: string, value: { id: string }) => {
+      if (kind === "notifications" && !changed) {
+        changed = true;
+        await db.compareAndSwap(
+          "owner",
+          "tasks",
+          "task1",
+          { status: "waiting_input", question: "Old question?" },
+          { question: "New question?" },
+        );
+      }
+      return originalInsert(owner, kind, value);
+    }) as Store["insertIfAbsent"];
+
+    await service.maintain();
+    let saved = await db.get<AgentTask>("owner", "tasks", "task1");
+    assert.equal(saved?.question, "New question?");
+    assert.equal(saved?.state.publishedOutcome, undefined);
+
+    db.insertIfAbsent = originalInsert as Store["insertIfAbsent"];
+    await service.maintain();
+    saved = await db.get<AgentTask>("owner", "tasks", "task1");
+    const expected = `input:task1:${createHash("sha256").update("New question?").digest("hex")}`;
+    assert.equal(saved?.state.publishedOutcome, expected);
+    assert.equal((await notifications(db)).filter((n) => n.taskId === "task1").length, 2);
+  } finally {
+    await db.close();
+  }
+});