diff --git a/test/helpers/openclaw-test-instance.test.ts b/test/helpers/openclaw-test-instance.test.ts
index 97c6374e8b75..8e67fd19f7ce 100644
--- a/test/helpers/openclaw-test-instance.test.ts
+++ b/test/helpers/openclaw-test-instance.test.ts
@@ -1,4 +1,5 @@
 // OpenClaw test instance tests cover spawned test instance lifecycle.
+import { EventEmitter } from "node:events";
 import fs from "node:fs/promises";
 import path from "node:path";
 import { describe, expect, it, vi } from "vitest";
@@ -14,6 +15,16 @@ async function expectPathMissing(targetPath: string): Promise<void> {
   throw new Error(`Expected missing path: ${targetPath}`);
 }
 
+function createGatewayProcessState(
+  overrides: Partial<{ exitCode: number | null; signalCode: NodeJS.Signals | null }> = {},
+) {
+  return Object.assign(new EventEmitter(), {
+    exitCode: null as number | null,
+    signalCode: null as NodeJS.Signals | null,
+    ...overrides,
+  });
+}
+
 describe("openclaw test instance", () => {
   it("keeps only bounded child output tails in helper logs", () => {
     const stdout = testing.createBoundedStringLog();
@@ -40,8 +51,67 @@ describe("openclaw test instance", () => {
 
   it("fails startup waits immediately after signaled gateway exits", async () => {
     await expect(
-      testing.waitForPortOpen({ exitCode: null, signalCode: "SIGTERM" }, [], [], 1, 10_000),
-    ).rejects.toThrow("gateway exited before listening");
+      testing.waitForGatewayReady(
+        createGatewayProcessState({ signalCode: "SIGTERM" }),
+        [],
+        [],
+        1,
+        10_000,
+      ),
+    ).rejects.toThrow("gateway exited before readiness");
+  });
+
+  it("waits until the gateway readiness probe reports ready", async () => {
+    const fetchImpl = vi
+      .fn<typeof fetch>()
+      .mockResolvedValueOnce(
+        new Response('{"ready":false,"failing":["startup-sidecars"]}', { status: 503 }),
+      )
+      .mockResolvedValueOnce(new Response('{"ready":true,"failing":[]}', { status: 200 }));
+
+    await expect(
+      testing.waitForGatewayReady(createGatewayProcessState(), [], [], 12345, 1_000, fetchImpl),
+    ).resolves.toBeUndefined();
+
+    expect(fetchImpl).toHaveBeenCalledTimes(2);
+    expect(fetchImpl.mock.calls[0]?.[0]).toBe("http://127.0.0.1:12345/readyz");
+  });
+
+  it("keeps stalled readiness probes inside the startup deadline", async () => {
+    const fetchImpl = vi.fn<typeof fetch>((_url, init) => {
+      return new Promise((_resolve, reject) => {
+        init?.signal?.addEventListener("abort", () => reject(init.signal?.reason), { once: true });
+      });
+    });
+    const startedAt = Date.now();
+
+    await expect(
+      testing.waitForGatewayReady(createGatewayProcessState(), [], [], 12345, 25, fetchImpl),
+    ).rejects.toThrow("timeout waiting for gateway readiness");
+
+    expect(fetchImpl).toHaveBeenCalledOnce();
+    expect(Date.now() - startedAt).toBeLessThan(500);
+  });
+
+  it("aborts a stalled readiness probe when the gateway exits", async () => {
+    const processState = createGatewayProcessState();
+    const fetchImpl = vi.fn<typeof fetch>((_url, init) => {
+      return new Promise((_resolve, reject) => {
+        init?.signal?.addEventListener("abort", () => reject(init.signal?.reason), { once: true });
+      });
+    });
+    const startedAt = Date.now();
+    setTimeout(() => {
+      processState.signalCode = "SIGTERM";
+      processState.emit("exit", null, "SIGTERM");
+    }, 25);
+
+    await expect(
+      testing.waitForGatewayReady(processState, [], [], 12345, 5_000, fetchImpl),
+    ).rejects.toThrow("gateway exited before readiness");
+
+    expect(fetchImpl).toHaveBeenCalledOnce();
+    expect(Date.now() - startedAt).toBeLessThan(500);
   });
 
   it("signals test instance process groups on POSIX", () => {
diff --git a/test/helpers/openclaw-test-instance.ts b/test/helpers/openclaw-test-instance.ts
index 17152734505b..2092d8d79dd2 100644
--- a/test/helpers/openclaw-test-instance.ts
+++ b/test/helpers/openclaw-test-instance.ts
@@ -78,6 +78,10 @@ type BoundedStringLog = string[] & {
 };
 
 type OpenClawTestChildProcess = Pick<OpenClawTestProcess, "kill" | "pid">;
+type OpenClawTestProcessReadiness = Pick<OpenClawTestProcess, "exitCode" | "signalCode"> & {
+  once: (event: "exit", listener: () => void) => unknown;
+  off: (event: "exit", listener: () => void) => unknown;
+};
 
 function createBoundedStringLog(): string[] {
   const log = [] as BoundedStringLog;
@@ -213,44 +217,83 @@ const getFreePort = async () => {
   return addr.port;
 };
 
-async function waitForPortOpen(
-  proc: Pick<OpenClawTestProcess, "exitCode" | "signalCode">,
+async function waitForGatewayReady(
+  proc: OpenClawTestProcessReadiness,
   chunksOut: string[],
   chunksErr: string[],
   port: number,
   timeoutMs: number,
+  fetchImpl: typeof fetch = fetch,
 ) {
+  const exitedBeforeReadinessError = () =>
+    new Error(
+      `gateway exited before readiness (code=${String(proc.exitCode)} signal=${String(
+        proc.signalCode,
+      )})\n${formatLogs(chunksOut, chunksErr)}`,
+    );
   const startedAt = Date.now();
   while (Date.now() - startedAt < timeoutMs) {
     if (hasChildExited(proc)) {
-      throw new Error(
-        `gateway exited before listening (code=${String(proc.exitCode)} signal=${String(
-          proc.signalCode,
-        )})\n${formatLogs(chunksOut, chunksErr)}`,
-      );
+      throw exitedBeforeReadinessError();
     }
 
+    const remainingMs = timeoutMs - (Date.now() - startedAt);
+    const attemptTimeoutMs = Math.min(1_000, Math.max(1, remainingMs));
+    const probeAbort = new AbortController();
+    let attemptTimeout: ReturnType<typeof setTimeout> | undefined;
+    let handleExit = () => {};
+    const exitPromise = new Promise<never>((_resolve, reject) => {
+      handleExit = () => {
+        const error = exitedBeforeReadinessError();
+        probeAbort.abort(error);
+        reject(error);
+      };
+      proc.once("exit", handleExit);
+    });
+    const timeoutPromise = new Promise<never>((_resolve, reject) => {
+      attemptTimeout = setTimeout(() => {
+        const error = new Error("gateway readiness probe timed out");
+        probeAbort.abort(error);
+        reject(error);
+      }, attemptTimeoutMs);
+      attemptTimeout.unref?.();
+    });
     try {
-      await new Promise<void>((resolve, reject) => {
-        const socket = net.connect({ host: "127.0.0.1", port });
-        socket.once("connect", () => {
-          socket.destroy();
-          resolve();
-        });
-        socket.once("error", (err) => {
-          socket.destroy();
-          reject(err);
-        });
-      });
-      return;
+      // A dead child cannot complete readiness. Race the owner lifecycle against
+      // both HTTP headers and body parsing so a stuck probe never hides its exit.
+      const ready = await Promise.race([
+        (async () => {
+          const response = await fetchImpl(`http://127.0.0.1:${port}/readyz`, {
+            signal: probeAbort.signal,
+          });
+          const readiness: unknown = await response.json();
+          return response.ok && isRecord(readiness) && readiness.ready === true;
+        })(),
+        exitPromise,
+        timeoutPromise,
+      ]);
+      if (ready) {
+        return;
+      }
     } catch {
+      if (hasChildExited(proc)) {
+        throw exitedBeforeReadinessError();
+      }
       // keep polling
+    } finally {
+      if (attemptTimeout) {
+        clearTimeout(attemptTimeout);
+      }
+      proc.off("exit", handleExit);
     }
 
-    await sleep(10);
+    const delayMs = Math.min(10, timeoutMs - (Date.now() - startedAt));
+    if (delayMs > 0) {
+      await sleep(delayMs);
+    }
   }
   throw new Error(
-    `timeout waiting for gateway to listen on port ${port}\n${formatLogs(chunksOut, chunksErr)}`,
+    `timeout waiting for gateway readiness on port ${port}\n${formatLogs(chunksOut, chunksErr)}`,
   );
 }
 
@@ -415,7 +458,7 @@ export async function createOpenClawTestInstance(
       child.stderr?.on("data", (d) => appendLogChunk(stderr, d));
 
       try {
-        await waitForPortOpen(
+        await waitForGatewayReady(
           child,
           stdout,
           stderr,
@@ -539,5 +582,5 @@ export const testing = {
   formatLogs,
   hasChildExited,
   signalOpenClawTestProcess,
-  waitForPortOpen,
+  waitForGatewayReady,
 };
diff --git a/test/vitest/vitest.agents-paths.mjs b/test/vitest/vitest.agents-paths.mjs
index 3159532cd485..92e548393907 100644
--- a/test/vitest/vitest.agents-paths.mjs
+++ b/test/vitest/vitest.agents-paths.mjs
@@ -14,6 +14,7 @@ const coreIsolatedFiles = [
   "src/agents/model-selection.plugin-runtime.test.ts",
   "src/agents/models-config.runtime-source-snapshot.test.ts",
   "src/agents/openai-transport-stream.streaming.test.ts",
+  "src/agents/subagent-registry.announce-loop-guard.test.ts",
   "src/agents/subagent-registry-restart-recovery.test.ts",
   "src/agents/video-generation-task-status.test.ts",
 ];