diff --git a/vllm/v1/worker/guard_telemetry.py b/vllm/v1/worker/guard_telemetry.py
index b02a7c3d43..19cf966ac4 100644
--- a/vllm/v1/worker/guard_telemetry.py
+++ b/vllm/v1/worker/guard_telemetry.py
@@ -486,9 +486,38 @@ def prealloc(device: torch.device) -> None:
         _nb_reader.register(device, _buffers[device])
 
 
+# Readers that other modules own but that must obey the same rule: nothing reads a device tensor from a second
+# thread while a cudagraph capture is active. A module registers its starter here at import; start_reader() runs
+# them after capture, and one registered after that point (a late import) starts at once. Before v2.5 the QSA
+# clip-counter reader started on the first eager forward, i.e. BEFORE capture.
+_post_capture_hooks: list = []
+_post_capture_done = False
+
+
+def register_post_capture_hook(fn) -> None:
+    """Run fn() once after warmup and cudagraph capture (immediately if that already happened)."""
+    if _post_capture_done:
+        fn()
+    else:
+        _post_capture_hooks.append(fn)
+
+
+def run_post_capture_hooks() -> None:
+    global _post_capture_done
+    _post_capture_done = True
+    hooks, _post_capture_hooks[:] = list(_post_capture_hooks), []
+    for fn in hooks:
+        try:
+            fn()
+        except Exception:  # noqa: BLE001 -- one broken starter must not stop the others or the engine
+            logger.exception("post-capture reader start failed: %r", fn)
+
+
 def start_reader() -> None:
     """Start the cadence reader. Called AFTER warmup and cudagraph capture.
 
+    Also runs the post-capture hooks of the other readers (register_post_capture_hook), whatever the guard mode.
+
     The reader must not exist during capture. It copies device counters to the
     host, and a device-to-host copy from a second thread while a capture is
     active is exactly the call class cudaStreamCaptureModeGlobal -- the default
@@ -500,6 +529,7 @@ def start_reader() -> None:
     Between prealloc() and this call the kernels still count; nothing reads.
     """
     global _reader_started
+    run_post_capture_hooks()
     if _reader_started or _MODE == "off":
         return
     _reader_started = True