diff --git a/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.test.ts b/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.test.ts
index 38e89d967b7d..7bc8a27882fd 100644
--- a/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.test.ts
+++ b/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.test.ts
@@ -378,4 +378,57 @@ describe("Matrix QA CLI runtime", () => {
       await rm(root, { force: true, recursive: true });
     }
   });
+
+  it("kills ignored-stdio descendants after manual CLI session kill", async () => {
+    if (process.platform === "win32") {
+      return;
+    }
+    const root = await mkdtemp(
+      path.join(resolvePreferredOpenClawTmpDir(), "matrix-qa-cli-session-kill-ignored-stdio-"),
+    );
+    const childPidPath = path.join(root, "child.pid");
+    const grandchildPidPath = path.join(root, "grandchild.pid");
+    let childPid: number | undefined;
+    let grandchildPid: number | undefined;
+    try {
+      await mkdir(path.join(root, "dist"));
+      await writeFile(
+        path.join(root, "dist", "index.mjs"),
+        [
+          "import { spawn } from 'node:child_process';",
+          "import { writeFileSync } from 'node:fs';",
+          `writeFileSync(${JSON.stringify(childPidPath)}, String(process.pid));`,
+          "const grandchild = spawn(process.execPath, ['-e', 'process.on(\\'SIGTERM\\', () => {}); setInterval(() => {}, 1000);'], { stdio: 'ignore' });",
+          "grandchild.unref();",
+          `writeFileSync(${JSON.stringify(grandchildPidPath)}, String(grandchild.pid));`,
+          "process.on('SIGTERM', () => process.exit(0));",
+          "setInterval(() => {}, 1000);",
+        ].join("\n"),
+      );
+
+      const session = startMatrixQaOpenClawCli({
+        args: ["matrix", "verify", "self"],
+        cwd: root,
+        env: process.env,
+        timeoutMs: 10_000,
+      });
+      await waitForFile(grandchildPidPath, 2_000);
+      await sleep(300);
+
+      session.kill();
+      await sleep(500);
+
+      childPid = Number(await readFile(childPidPath, "utf8"));
+      grandchildPid = Number(await readFile(grandchildPidPath, "utf8"));
+      expect(isProcessRunning(childPid)).toBe(false);
+      expect(isProcessRunning(grandchildPid)).toBe(false);
+    } finally {
+      for (const pid of [grandchildPid, childPid]) {
+        if (pid && isProcessRunning(pid)) {
+          process.kill(pid, "SIGKILL");
+        }
+      }
+      await rm(root, { force: true, recursive: true });
+    }
+  });
 });
diff --git a/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.ts b/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.ts
index 929078e2ca21..d6b9e9978d2f 100644
--- a/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.ts
+++ b/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.ts
@@ -148,6 +148,7 @@ export function startMatrixQaOpenClawCli(params: {
   let closed = false;
   let closeError: Error | undefined;
   let closeResult: MatrixQaCliRunResult | undefined;
+  let killRequested = false;
   let timedOut = false;
   let forceKillTimeout: NodeJS.Timeout | undefined;
   let forceSettleTimeout: NodeJS.Timeout | undefined;
@@ -187,6 +188,13 @@ export function startMatrixQaOpenClawCli(params: {
   const finishTimeout = (result: MatrixQaCliRunResult) => {
     finish(result, new Error(formatMatrixQaCliTimeoutError(result, params.timeoutMs)));
   };
+  const finishResult = (result: MatrixQaCliRunResult) => {
+    if (result.exitCode !== 0 && params.allowNonZero !== true) {
+      finish(result, new Error(formatMatrixQaCliExitError(result)));
+      return;
+    }
+    finish(result);
+  };
   const clearForcedTimeouts = () => {
     if (forceKillTimeout) {
       clearTimeout(forceKillTimeout);
@@ -197,16 +205,23 @@ export function startMatrixQaOpenClawCli(params: {
       forceSettleTimeout = undefined;
     }
   };
-
-  const timeout = setTimeout(() => {
-    timedOut = true;
-    killMatrixQaCliChild(child, "SIGTERM");
+  const finishForcedCleanup = (result: MatrixQaCliRunResult) => {
+    if (timedOut) {
+      finishTimeout(result);
+      return;
+    }
+    finishResult(result);
+  };
+  const scheduleForcedCleanup = () => {
+    if (forceKillTimeout || forceSettleTimeout) {
+      return;
+    }
     forceKillTimeout = setTimeout(() => {
       forceKillTimeout = undefined;
       killMatrixQaCliChild(child, "SIGKILL");
       forceSettleTimeout = setTimeout(() => {
         forceSettleTimeout = undefined;
-        finishTimeout(
+        finishForcedCleanup(
           buildMatrixQaCliResult({
             args: params.args,
             exitCode: 1,
@@ -215,6 +230,12 @@ export function startMatrixQaOpenClawCli(params: {
         );
       }, MATRIX_QA_CLI_TIMEOUT_FORCE_SETTLE_MS);
     }, MATRIX_QA_CLI_TIMEOUT_KILL_GRACE_MS);
+  };
+
+  const timeout = setTimeout(() => {
+    timedOut = true;
+    killMatrixQaCliChild(child, "SIGTERM");
+    scheduleForcedCleanup();
   }, params.timeoutMs);
 
   child.stdout.on("data", (chunk) => stdout.push(Buffer.from(chunk)));
@@ -241,20 +262,17 @@ export function startMatrixQaOpenClawCli(params: {
       exitCode: exitCode ?? 1,
       output: readOutput(),
     });
-    if (timedOut) {
+    if (timedOut || killRequested) {
+      // A closed parent is not proof that detached, ignored-stdio descendants are gone.
       if (isMatrixQaCliChildProcessGroupRunning(child)) {
         return;
       }
       clearForcedTimeouts();
-      finishTimeout(result);
+      finishForcedCleanup(result);
       return;
     }
     clearForcedTimeouts();
-    if (result.exitCode !== 0 && params.allowNonZero !== true) {
-      finish(result, new Error(formatMatrixQaCliExitError(result)));
-      return;
-    }
-    finish(result);
+    finishResult(result);
   });
 
   return {
@@ -310,7 +328,10 @@ export function startMatrixQaOpenClawCli(params: {
     },
     kill: () => {
       if (!closed) {
+        clearTimeout(timeout);
+        killRequested = true;
         killMatrixQaCliChild(child, "SIGTERM");
+        scheduleForcedCleanup();
       }
     },
   };