diff --git a/CHANGELOG.md b/CHANGELOG.md
index c7d865f213e..0086c644e4f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@ Docs: https://docs.openclaw.ai
 
 - Subagents: honor `sessions_spawn` with `expectsCompletionMessage: false` by skipping parent completion handoff delivery while still running child cleanup. Fixes #75848. Thanks @alfredjbclaw.
 - Gateway/logging: keep deferred channel startup logs on the subsystem logger, so Slack, Discord, Telegram, and voice-call startup messages keep timestamped prefixes. Thanks @vincentkoc.
+- ACP/Discord: suppress completion announce delivery for inline thread-bound ACP session runs, so Discord thread-bound ACP replies are not delivered twice. Fixes #60780. Thanks @solavrc.
 - Discord/threads: ignore webhook-authored copies in already-bound Discord session threads even when the webhook id differs, preventing PluralKit proxy copies from creating duplicate turn pressure. Fixes #52005. Thanks @acgh213.
 - Discord/threads: return the created thread as partial success when the follow-up initial message fails, so agents do not retry thread creation and create empty duplicate threads. Fixes #48450. Thanks @dahifi.
 - Discord/components: consume every button or select in a non-reusable component message after the first authorized click, so single-use panels cannot fire sibling callbacks. Fixes #54227. Thanks @fujiwarakasei.
diff --git a/src/agents/acp-spawn.test.ts b/src/agents/acp-spawn.test.ts
index 2e2986fd8b2..4053115dca6 100644
--- a/src/agents/acp-spawn.test.ts
+++ b/src/agents/acp-spawn.test.ts
@@ -688,6 +688,7 @@ describe("spawnAcpDirect", () => {
     expect(accepted.childSessionKey).toMatch(/^agent:codex:acp:/);
     expect(accepted.runId).toBe("run-1");
     expect(accepted.mode).toBe("session");
+    expect(accepted.inlineDelivery).toBe(true);
     const patchCall = hoisted.callGatewayMock.mock.calls
       .map((call: unknown[]) => call[0] as { method?: string; params?: Record<string, unknown> })
       .find((request) => request.method === "sessions.patch");
diff --git a/src/agents/acp-spawn.ts b/src/agents/acp-spawn.ts
index 266ea458b46..ad0a57bf9bc 100644
--- a/src/agents/acp-spawn.ts
+++ b/src/agents/acp-spawn.ts
@@ -145,6 +145,7 @@ type SpawnAcpResultFields = {
   childSessionKey?: string;
   runId?: string;
   mode?: SpawnAcpMode;
+  inlineDelivery?: boolean;
   streamLogPath?: string;
   note?: string;
 };
@@ -1494,6 +1495,7 @@ export async function spawnAcpDirect(
     childSessionKey: sessionKey,
     runId: childRunId,
     mode: spawnMode,
+    ...(deliveryPlan.useInlineDelivery ? { inlineDelivery: true } : {}),
     note: spawnMode === "session" ? ACP_SPAWN_SESSION_ACCEPTED_NOTE : ACP_SPAWN_ACCEPTED_NOTE,
   };
 }
diff --git a/src/agents/tools/sessions-spawn-tool.test.ts b/src/agents/tools/sessions-spawn-tool.test.ts
index 4e4f1ef8ada..db695e92620 100644
--- a/src/agents/tools/sessions-spawn-tool.test.ts
+++ b/src/agents/tools/sessions-spawn-tool.test.ts
@@ -471,6 +471,44 @@ describe("sessions_spawn tool", () => {
     );
   });
 
+  it("suppresses completion announces for inline ACP session delivery", async () => {
+    registerAcpBackendForTest();
+    hoisted.spawnAcpDirectMock.mockResolvedValueOnce({
+      status: "accepted",
+      childSessionKey: "agent:codex:acp:1",
+      runId: "run-acp",
+      mode: "session",
+      inlineDelivery: true,
+    });
+    const tool = createSessionsSpawnTool({
+      agentSessionKey: "agent:main:main",
+      agentChannel: "discord",
+      agentAccountId: "default",
+      agentTo: "channel:parent-channel",
+      agentThreadId: "child-thread",
+    });
+
+    await tool.execute("call-inline-acp", {
+      runtime: "acp",
+      task: "investigate",
+      agentId: "codex",
+      thread: true,
+      mode: "session",
+    });
+
+    expect(hoisted.registerSubagentRunMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        runId: "run-acp",
+        childSessionKey: "agent:codex:acp:1",
+        requesterSessionKey: "agent:main:main",
+        task: "investigate",
+        cleanup: "keep",
+        spawnMode: "session",
+        expectsCompletionMessage: false,
+      }),
+    );
+  });
+
   it("rejects ACP runtime calls from sandboxed requester sessions", async () => {
     registerAcpBackendForTest();
     const tool = createSessionsSpawnTool({
diff --git a/src/agents/tools/sessions-spawn-tool.ts b/src/agents/tools/sessions-spawn-tool.ts
index ce2636e3b9f..3d5b52bda90 100644
--- a/src/agents/tools/sessions-spawn-tool.ts
+++ b/src/agents/tools/sessions-spawn-tool.ts
@@ -334,6 +334,9 @@ export function createSessionsSpawnTool(
             to: opts?.agentTo,
             threadId: opts?.agentThreadId,
           });
+          const shouldExpectCompletionMessage = result.inlineDelivery
+            ? false
+            : expectsCompletionMessage;
           try {
             registerSubagentRun({
               runId: childRunId,
@@ -345,7 +348,7 @@ export function createSessionsSpawnTool(
               cleanup: trackedCleanup,
               label: label || undefined,
               runTimeoutSeconds,
-              expectsCompletionMessage,
+              expectsCompletionMessage: shouldExpectCompletionMessage,
               spawnMode: trackedSpawnMode,
             });
           } catch (err) {