diff --git a/tests/hermes_cli/test_active_sessions.py b/tests/hermes_cli/test_active_sessions.py
index dda461d686b..560803dc852 100644
--- a/tests/hermes_cli/test_active_sessions.py
+++ b/tests/hermes_cli/test_active_sessions.py
@@ -235,6 +235,8 @@ def test_cross_process_acquire_claims_only_one_last_slot(tmp_path, monkeypatch):
     repo_root = Path(__file__).resolve().parents[2]
     ready_dir = tmp_path / "ready"
     ready_dir.mkdir()
+    results_dir = tmp_path / "results"
+    results_dir.mkdir()
     go_file = tmp_path / "go"
     env = os.environ.copy()
     env["HERMES_HOME"] = str(home)
@@ -244,7 +246,10 @@ def test_cross_process_acquire_claims_only_one_last_slot(tmp_path, monkeypatch):
         "from pathlib import Path\n"
         "from hermes_cli.active_sessions import try_acquire_active_session\n"
         "idx = os.environ['WORKER_INDEX']\n"
+        "worker_count = int(os.environ['WORKER_COUNT'])\n"
+        "delayed_worker = os.environ.get('DELAYED_WORKER_INDEX')\n"
         "ready_dir = Path(os.environ['READY_DIR'])\n"
+        "results_dir = Path(os.environ['RESULTS_DIR'])\n"
         "go_file = Path(os.environ['GO_FILE'])\n"
         "(ready_dir / idx).write_text('ready', encoding='utf-8')\n"
         "deadline = time.time() + 10\n"
@@ -252,16 +257,24 @@ def test_cross_process_acquire_claims_only_one_last_slot(tmp_path, monkeypatch):
         "    if time.time() > deadline:\n"
         "        raise RuntimeError('timed out waiting for go file')\n"
         "    time.sleep(0.01)\n"
+        "if idx == delayed_worker:\n"
+        "    time.sleep(2.5)\n"
         "lease, message = try_acquire_active_session(\n"
         "    session_id=f'process-{idx}',\n"
         "    surface='cli',\n"
         "    config={'max_concurrent_sessions': 1},\n"
         ")\n"
         "if lease is None:\n"
+        "    (results_dir / idx).write_text('BLOCK', encoding='utf-8')\n"
         "    print('BLOCK', flush=True)\n"
         "else:\n"
+        "    (results_dir / idx).write_text('OK', encoding='utf-8')\n"
         "    print('OK', flush=True)\n"
-        "    time.sleep(2.0)\n"
+        "    deadline = time.time() + 10\n"
+        "    while len(list(results_dir.iterdir())) < worker_count:\n"
+        "        if time.time() > deadline:\n"
+        "            raise RuntimeError('timed out waiting for all workers to attempt acquire')\n"
+        "        time.sleep(0.01)\n"
         "    lease.release()\n"
     )
     workers: list[subprocess.Popen[str]] = []
@@ -269,7 +282,10 @@ def test_cross_process_acquire_claims_only_one_last_slot(tmp_path, monkeypatch):
         for index in range(6):
             worker_env = env.copy()
             worker_env["WORKER_INDEX"] = str(index)
+            worker_env["WORKER_COUNT"] = "6"
+            worker_env["DELAYED_WORKER_INDEX"] = "5"
             worker_env["READY_DIR"] = str(ready_dir)
+            worker_env["RESULTS_DIR"] = str(results_dir)
             worker_env["GO_FILE"] = str(go_file)
             workers.append(
                 subprocess.Popen(