diff --git a/scripts/benchmarks/terminal.py b/scripts/benchmarks/terminal.py
index 0c92ba7244..49af0c8d42 100644
--- a/scripts/benchmarks/terminal.py
+++ b/scripts/benchmarks/terminal.py
@@ -58,6 +58,13 @@ def feed(self, chunk: str) -> None:
             self.stream.feed(self.pending)
             self.pending = ""
 
+    def prompt_ready(self) -> bool:
+        text = self.text()
+        return "agents/resume" in text or (
+            any(line.strip() == ">" for line in text.splitlines())
+            and any(line.lstrip().startswith("← manage") for line in text.splitlines())
+        )
+
     def text(self) -> str:
         return "\n".join(row.rstrip() for row in self.screen.display)
 
@@ -108,7 +115,7 @@ def settle(self, seconds: float) -> None:
             self.pump()
 
     def ready(self) -> float:
-        self.until(lambda display: "agents/resume" in display.text(), 30)
+        self.until(lambda display: display.prompt_ready(), 30)
         self.child.send("benchready")
         echoed = self.until(lambda display: "benchready" in display.text(), 5)
         self.child.send("\x7f" * len("benchready"))
diff --git a/scripts/benchmarks/tests/test_benchmarks.py b/scripts/benchmarks/tests/test_benchmarks.py
index 6a53629f6a..a66dd89dd1 100644
--- a/scripts/benchmarks/tests/test_benchmarks.py
+++ b/scripts/benchmarks/tests/test_benchmarks.py
@@ -30,7 +30,7 @@
     write_json,
 )
 from terminal import QUERIES, Display, Terminal
-from worker import environment, install, measure
+from worker import environment, install, measure, stop_agents
 
 SHA = "a" * 40
 HEAD = "b" * 40
@@ -63,7 +63,7 @@ def test_real_pty_detects_injected_startup_delays_without_submitting(self):
 import os, sys, time, tty
 tty.setraw(0)
 time.sleep(float(sys.argv[1]))
-os.write(1, b'agents/resume\\r\\n> ')
+os.write(1, sys.argv[2].encode())
 while True:
     byte = os.read(0, 1)
     if byte == b'\\x7f':
@@ -80,9 +80,9 @@ def test_real_pty_detects_injected_startup_delays_without_submitting(self):
             root = Path(directory)
             path = root / "fixture.py"
             path.write_text(script)
-            for delay in (0.05, 0.6):
+            for delay, label in ((0.05, "agents/resume\r\n> "), (0.6, ">\r\n← manage")):
                 terminal = Terminal(
-                    [sys.executable, str(path), str(delay)],
+                    [sys.executable, str(path), str(delay), label],
                     root,
                     os.environ.copy(),
                     root / f"transcript-{delay}",
@@ -93,6 +93,16 @@ def test_real_pty_detects_injected_startup_delays_without_submitting(self):
                     terminal.close()
         self.assertGreater(measurements[1] - measurements[0], 0.25)
 
+    def test_recognizes_current_and_legacy_prompt_bars(self):
+        for text in ("agents/resume\r\n> ", ">\r\n← manage        unknown  0"):
+            display = Display(lambda _reply: None)
+            display.feed(text)
+            self.assertTrue(display.prompt_ready())
+        for text in ("Loading...", ">", "← manage"):
+            display = Display(lambda _reply: None)
+            display.feed(text)
+            self.assertFalse(display.prompt_ready())
+
     def test_queries_split_at_every_boundary(self):
         for query, reply in QUERIES.items():
             for boundary in range(len(query) + 1):
@@ -590,6 +600,33 @@ def test_dispatch_from_a_feature_branch_cannot_publish_or_clean_up(self):
 
 
 class MeasurementTests(unittest.TestCase):
+    def test_cleanup_accepts_a_session_that_exits_between_list_and_stop(self):
+        stale = subprocess.CalledProcessError(
+            1, ["prime-agent", "stop", "session", "--json"], stderr="Error: Unknown active session: session\n"
+        )
+        with patch(
+            "worker.run_as",
+            side_effect=['{"sessions": [{"activeSessionId": "session"}]}', stale, '{"sessions": []}'],
+        ) as run:
+            stop_agents(Path("/fixture"))
+        self.assertEqual(run.call_count, 3)
+        self.assertEqual(run.call_args.args[1], ["prime-agent", "list", "--json"])
+
+    def test_cleanup_preserves_real_stop_failures(self):
+        for error, remaining in (
+            ("Error: Unknown active session: session\n", '{"sessions": [{"activeSessionId": "session"}]}'),
+            ("Error: connection closed\n", '{"sessions": []}'),
+            ("Error: Unknown active session: another\n", '{"sessions": []}'),
+        ):
+            with self.subTest(error=error, remaining=remaining):
+                failure = subprocess.CalledProcessError(1, ["prime-agent", "stop"], stderr=error)
+                with patch(
+                    "worker.run_as",
+                    side_effect=['{"sessions": [{"activeSessionId": "session"}]}', failure, remaining],
+                ):
+                    with self.assertRaises(subprocess.CalledProcessError):
+                        stop_agents(Path("/fixture"))
+
     def test_disk_footprint_is_measured_after_interactive_first_use(self):
         order = []
         terminal = Mock()
diff --git a/scripts/benchmarks/worker.py b/scripts/benchmarks/worker.py
index db6bb64b0c..83745625db 100644
--- a/scripts/benchmarks/worker.py
+++ b/scripts/benchmarks/worker.py
@@ -378,12 +378,20 @@ def record(
 def stop_agents(home: Path) -> None:
     listing = json.loads(run_as("benchmark1", ["prime-agent", "list", "--json"], home))
     for session in listing["sessions"]:
-        if session.get("activeSessionId"):
-            run_as(
-                "benchmark1",
-                ["prime-agent", "stop", session["activeSessionId"], "--json"],
-                home,
-            )
+        active_id = session.get("activeSessionId")
+        if not active_id:
+            continue
+        try:
+            run_as("benchmark1", ["prime-agent", "stop", active_id, "--json"], home)
+        except subprocess.CalledProcessError as error:
+            if (
+                error.returncode != 1
+                or (error.stderr or "").strip() != f"Error: Unknown active session: {active_id}"
+            ):
+                raise
+            current = json.loads(run_as("benchmark1", ["prime-agent", "list", "--json"], home))
+            if any(item.get("activeSessionId") == active_id for item in current["sessions"]):
+                raise
 
 
 def measure(request: Request, side: Side, trial: int) -> None: