diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7e91f0745f3..b2f0a816216 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -79,6 +79,9 @@ Docs: https://docs.openclaw.ai
 - ACP/sessions_spawn: reject normal OpenClaw config agent ids when callers
   explicitly request `runtime="acp"`, while allowing agents configured with
   `runtime.type="acp"` to resolve to their ACP harness id. Fixes #63914.
+- ACP/sessions_spawn: apply `runTimeoutSeconds` to ACP child turns and dispatch
+  those turns on the background subagent lane, so quota-stalled ACP harnesses do
+  not occupy the main agent lane indefinitely. Fixes #68823.
 - ACP/models: document that non-Codex ACP model overrides require adapter
   support for ACP `models` plus `session/set_model`, so unsupported harnesses
   fail clearly instead of silently falling back to their defaults.
diff --git a/docs/tools/acp-agents.md b/docs/tools/acp-agents.md
index 4b6ceda4cbb..a7fa215743a 100644
--- a/docs/tools/acp-agents.md
+++ b/docs/tools/acp-agents.md
@@ -336,6 +336,7 @@ Interface details:
 - `resumeSessionId` (optional): resume an existing ACP session instead of creating a new one. The agent replays its conversation history via `session/load`. Requires `runtime: "acp"`.
 - `streamTo` (optional): `"parent"` streams initial ACP run progress summaries back to the requester session as system events.
   - When available, accepted responses include `streamLogPath` pointing to a session-scoped JSONL log (`<sessionId>.acp-stream.jsonl`) you can tail for full relay history.
+- `runTimeoutSeconds` (optional): aborts the ACP child turn after N seconds. `0` keeps the turn on the gateway's no-timeout path. The same value is applied to the Gateway run and ACP runtime so stalled/quota-exhausted harnesses do not occupy the parent agent lane indefinitely.
 - `model` (optional): explicit model override for the ACP child session. Codex ACP spawns normalize OpenClaw Codex refs such as `openai-codex/gpt-5.4` to Codex ACP startup config before `session/new`; slash forms such as `openai-codex/gpt-5.4/high` also set Codex ACP reasoning effort. Other harnesses must advertise ACP `models` and support `session/set_model`; otherwise OpenClaw/acpx fails clearly instead of silently falling back to the target agent default.
 - `thinking` (optional): explicit thinking/reasoning effort for the ACP child session. For Codex ACP, `minimal` maps to low effort, `low`/`medium`/`high`/`xhigh` map directly, and `off` omits the reasoning-effort startup override.
 
@@ -359,6 +360,7 @@ One-shot ACP sessions spawned by another agent run are background children, simi
 
 - The parent asks for work with `sessions_spawn({ runtime: "acp", mode: "run" })`.
 - The child runs in its own ACP harness session.
+- Child turns run on the same background lane used by native sub-agent spawns, so a slow ACP harness does not block unrelated main-session work.
 - Completion reports back through the internal task-completion announce path.
 - The parent rewrites the child result in normal assistant voice when a user-facing reply is useful.
 
diff --git a/src/agents/acp-spawn.test.ts b/src/agents/acp-spawn.test.ts
index a573fc54363..059dfd96afc 100644
--- a/src/agents/acp-spawn.test.ts
+++ b/src/agents/acp-spawn.test.ts
@@ -168,6 +168,8 @@ type AgentCallParams = {
   channel?: string;
   to?: string;
   threadId?: string;
+  lane?: string;
+  timeout?: number;
 };
 type CrossAgentWorkspaceFixture = {
   workspaceRoot: string;
@@ -330,6 +332,12 @@ function expectAgentGatewayCall(overrides: AgentCallParams): void {
   expect(agentCall?.params?.channel).toBe(overrides.channel);
   expect(agentCall?.params?.to).toBe(overrides.to);
   expect(agentCall?.params?.threadId).toBe(overrides.threadId);
+  if (Object.hasOwn(overrides, "lane")) {
+    expect(agentCall?.params?.lane).toBe(overrides.lane);
+  }
+  if (Object.hasOwn(overrides, "timeout")) {
+    expect(agentCall?.params?.timeout).toBe(overrides.timeout);
+  }
 }
 
 function resolveMatrixRoomTargetForTest(value: string | undefined): string | undefined {
@@ -701,6 +709,7 @@ describe("spawnAcpDirect", () => {
     expect(agentCall?.params?.to).toBe("channel:child-thread");
     expect(agentCall?.params?.threadId).toBe("child-thread");
     expect(agentCall?.params?.deliver).toBe(true);
+    expect(agentCall?.params?.lane).toBe("subagent");
     expect(hoisted.initializeSessionMock).toHaveBeenCalledWith(
       expect.objectContaining({
         sessionKey: expect.stringMatching(/^agent:codex:acp:/),
@@ -742,6 +751,33 @@ describe("spawnAcpDirect", () => {
     );
   });
 
+  it("applies ACP spawn run timeout to runtime options and dispatch", async () => {
+    const result = await spawnAcpDirect(
+      {
+        task: "Investigate flaky tests",
+        agentId: "codex",
+        runTimeoutSeconds: 45,
+      },
+      {
+        agentSessionKey: "agent:main:main",
+      },
+    );
+
+    expectAcceptedSpawn(result);
+    expect(hoisted.initializeSessionMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        sessionKey: expect.stringMatching(/^agent:codex:acp:/),
+        agent: "codex",
+        runtimeOptions: {
+          timeoutSeconds: 45,
+        },
+      }),
+    );
+    const agentCall = findAgentGatewayCall();
+    expect(agentCall?.params?.lane).toBe("subagent");
+    expect(agentCall?.params?.timeout).toBe(45);
+  });
+
   it("rejects OpenClaw config agent ids when runtime=acp targets a native agent", async () => {
     replaceSpawnConfig({
       ...createDefaultSpawnConfig(),
diff --git a/src/agents/acp-spawn.ts b/src/agents/acp-spawn.ts
index f7b753ac34d..fd4529d52c0 100644
--- a/src/agents/acp-spawn.ts
+++ b/src/agents/acp-spawn.ts
@@ -70,6 +70,7 @@ import {
   startAcpSpawnParentStreamRelay,
 } from "./acp-spawn-parent-stream.js";
 import { resolveAgentConfig, resolveDefaultAgentId } from "./agent-scope.js";
+import { AGENT_LANE_SUBAGENT } from "./lanes.js";
 import { resolveSandboxRuntimeStatus } from "./sandbox/runtime-status.js";
 import { resolveRequesterOriginForChild } from "./spawn-requester-origin.js";
 import { resolveSpawnedWorkspaceInheritance } from "./spawned-context.js";
@@ -99,6 +100,7 @@ export type SpawnAcpParams = {
   resumeSessionId?: string;
   model?: string;
   thinking?: string;
+  runTimeoutSeconds?: number;
   cwd?: string;
   mode?: SpawnAcpMode;
   thread?: boolean;
@@ -854,6 +856,7 @@ async function initializeAcpSpawnRuntime(params: {
   resumeSessionId?: string;
   model?: string;
   thinking?: string;
+  runTimeoutSeconds?: number;
   cwd?: string;
 }): Promise<AcpSpawnInitializedRuntime> {
   const storePath = resolveStorePath(params.cfg.session?.store, { agentId: params.targetAgentId });
@@ -879,10 +882,11 @@ async function initializeAcpSpawnRuntime(params: {
     mode: params.runtimeMode,
     resumeSessionId: params.resumeSessionId,
     runtimeOptions:
-      params.model || params.thinking
+      params.model || params.thinking || params.runTimeoutSeconds
         ? {
             ...(params.model ? { model: params.model } : {}),
             ...(params.thinking ? { thinking: params.thinking } : {}),
+            ...(params.runTimeoutSeconds ? { timeoutSeconds: params.runTimeoutSeconds } : {}),
           }
         : undefined,
     cwd: params.cwd,
@@ -1229,6 +1233,7 @@ export async function spawnAcpDirect(
       resumeSessionId: params.resumeSessionId,
       model: params.model,
       thinking: params.thinking,
+      runTimeoutSeconds: params.runTimeoutSeconds,
       cwd: runtimeCwd,
     });
     initializedRuntime = initializedSession.runtimeCloseHandle;
@@ -1312,6 +1317,8 @@ export async function spawnAcpDirect(
         threadId: deliveryPlan.threadId,
         idempotencyKey: childIdem,
         deliver: deliveryPlan.useInlineDelivery,
+        lane: AGENT_LANE_SUBAGENT,
+        ...(params.runTimeoutSeconds != null ? { timeout: params.runTimeoutSeconds } : {}),
         label: params.label || undefined,
       },
       timeoutMs: 10_000,
diff --git a/src/agents/tools/sessions-spawn-tool.test.ts b/src/agents/tools/sessions-spawn-tool.test.ts
index d570f02080b..cb5bd843bfe 100644
--- a/src/agents/tools/sessions-spawn-tool.test.ts
+++ b/src/agents/tools/sessions-spawn-tool.test.ts
@@ -221,6 +221,7 @@ describe("sessions_spawn tool", () => {
       task: "investigate the failing CI run",
       agentId: "codex",
       cwd: "/workspace",
+      runTimeoutSeconds: 45,
       thread: true,
       mode: "session",
       streamTo: "parent",
@@ -236,6 +237,7 @@ describe("sessions_spawn tool", () => {
         task: "investigate the failing CI run",
         agentId: "codex",
         cwd: "/workspace",
+        runTimeoutSeconds: 45,
         thread: true,
         mode: "session",
         streamTo: "parent",
diff --git a/src/agents/tools/sessions-spawn-tool.ts b/src/agents/tools/sessions-spawn-tool.ts
index 1372fbd2231..576da3abc53 100644
--- a/src/agents/tools/sessions-spawn-tool.ts
+++ b/src/agents/tools/sessions-spawn-tool.ts
@@ -260,6 +260,7 @@ export function createSessionsSpawnTool(
             resumeSessionId,
             model: modelOverride,
             thinking: thinkingOverrideRaw,
+            runTimeoutSeconds,
             cwd,
             mode: mode === "run" || mode === "session" ? mode : undefined,
             thread,