diff --git a/CHANGELOG.md b/CHANGELOG.md
index 77f1561f7f4..1c3327c8520 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Agents/Subagents: preserve `threadId` on internal nested subagent announce injections (`deliver: false`) so parent orchestrators keep root thread context when relaying completion updates. (#22118)
 - Slack/Threading: sessions: keep parent-session forking and thread-history context active beyond first turn by removing first-turn-only gates in session init, thread-history fetch, and reply prompt context injection. (#23843, #23090) Thanks @vincentkoc and @Taskle.
 - Slack/Threading: respect `replyToMode` when Slack auto-populates top-level `thread_ts`, and ignore inline `replyToId` directive tags when `replyToMode` is `off` so thread forcing stays disabled unless explicitly configured. (#23839, #23320, #23513) Thanks @vincentkoc and @dorukardahan.
 - Slack/Extension: forward `message read` `threadId` to `readMessages` and use delivery-context `threadId` as outbound `thread_ts` fallback so extension replies/reads stay in the correct Slack thread. (#22216, #22485, #23836) Thanks @vincentkoc, @lan17 and @dorukardahan.
diff --git a/src/agents/subagent-announce.format.test.ts b/src/agents/subagent-announce.format.test.ts
index a612e9fca02..51ca08c5b04 100644
--- a/src/agents/subagent-announce.format.test.ts
+++ b/src/agents/subagent-announce.format.test.ts
@@ -1130,7 +1130,7 @@ describe("subagent announce formatting", () => {
       childRunId: "run-worker-queued",
       requesterSessionKey: "agent:main:subagent:orchestrator",
       requesterDisplayKey: "agent:main:subagent:orchestrator",
-      requesterOrigin: { channel: "whatsapp", to: "+1555", accountId: "acct" },
+      requesterOrigin: { channel: "whatsapp", to: "+1555", accountId: "acct", threadId: "777" },
       ...defaultOutcomeAnnounce,
     });
 
@@ -1142,6 +1142,7 @@ describe("subagent announce formatting", () => {
     expect(call?.params?.deliver).toBe(false);
     expect(call?.params?.channel).toBeUndefined();
     expect(call?.params?.to).toBeUndefined();
+    expect(call?.params?.threadId).toBe("777");
   });
 
   it.each([
@@ -1278,7 +1279,12 @@ describe("subagent announce formatting", () => {
       childSessionKey: "agent:main:subagent:worker",
       childRunId: "run-worker",
       requesterSessionKey: "agent:main:subagent:orchestrator",
-      requesterOrigin: { channel: "whatsapp", accountId: "acct-123", to: "+1555" },
+      requesterOrigin: {
+        channel: "whatsapp",
+        accountId: "acct-123",
+        to: "+1555",
+        threadId: "thread-1",
+      },
       requesterDisplayKey: "agent:main:subagent:orchestrator",
       ...defaultOutcomeAnnounce,
     });
@@ -1289,6 +1295,7 @@ describe("subagent announce formatting", () => {
     expect(call?.params?.deliver).toBe(false);
     expect(call?.params?.channel).toBeUndefined();
     expect(call?.params?.to).toBeUndefined();
+    expect(call?.params?.threadId).toBe("thread-1");
   });
 
   it("keeps completion-mode announce internal for nested requester subagent sessions", async () => {
@@ -1299,7 +1306,12 @@ describe("subagent announce formatting", () => {
       childSessionKey: "agent:main:subagent:orchestrator:subagent:worker",
       childRunId: "run-worker-nested-completion",
       requesterSessionKey: "agent:main:subagent:orchestrator",
-      requesterOrigin: { channel: "whatsapp", accountId: "acct-123", to: "+1555" },
+      requesterOrigin: {
+        channel: "whatsapp",
+        accountId: "acct-123",
+        to: "+1555",
+        threadId: "thread-2",
+      },
       requesterDisplayKey: "agent:main:subagent:orchestrator",
       expectsCompletionMessage: true,
       ...defaultOutcomeAnnounce,
@@ -1312,6 +1324,7 @@ describe("subagent announce formatting", () => {
     expect(call?.params?.deliver).toBe(false);
     expect(call?.params?.channel).toBeUndefined();
     expect(call?.params?.to).toBeUndefined();
+    expect(call?.params?.threadId).toBe("thread-2");
     const message = typeof call?.params?.message === "string" ? call.params.message : "";
     expect(message).toContain(
       "Convert this completion into a concise internal orchestration update for your parent agent",
diff --git a/src/agents/subagent-announce.ts b/src/agents/subagent-announce.ts
index e900f8be5f0..8bf794f5bbe 100644
--- a/src/agents/subagent-announce.ts
+++ b/src/agents/subagent-announce.ts
@@ -490,7 +490,9 @@ async function sendAnnounce(item: AnnounceQueueItem) {
       channel: requesterIsSubagent ? undefined : origin?.channel,
       accountId: requesterIsSubagent ? undefined : origin?.accountId,
       to: requesterIsSubagent ? undefined : origin?.to,
-      threadId: requesterIsSubagent ? undefined : threadId,
+      // Keep thread context on internal nested announce injections so parent
+      // orchestrators can continue thread-aware delivery after processing.
+      threadId,
       deliver: !requesterIsSubagent,
       idempotencyKey,
     },
@@ -713,7 +715,9 @@ async function sendSubagentAnnounceDirectly(params: {
         channel: params.requesterIsSubagent ? undefined : directOrigin?.channel,
         accountId: params.requesterIsSubagent ? undefined : directOrigin?.accountId,
         to: params.requesterIsSubagent ? undefined : directOrigin?.to,
-        threadId: params.requesterIsSubagent ? undefined : threadId,
+        // Preserve root thread context even when we intentionally keep nested
+        // announce delivery internal (`deliver=false`).
+        threadId,
         idempotencyKey: params.directIdempotencyKey,
       },
       expectFinal: true,