diff --git a/eco/acquisition/daq_client.py b/eco/acquisition/daq_client.py
index 7622d6f..e424e6b 100644
--- a/eco/acquisition/daq_client.py
+++ b/eco/acquisition/daq_client.py
@@ -193,6 +193,38 @@ class Daq(Assembly):
         self._running_ids = count()
         self._event_master = event_master
         self._detectors_event_code = detectors_event_code
+        # Dedicated CA-monitor cache for the detectors' event-code
+        # frequency, read by `rate_multiplicator` on *every* scan step (via
+        # `retrieve()`, once per `stop()`). Reading it with a fresh
+        # get_current_value() each time is the exact `pulse_id` bug above,
+        # on a different PV: pyepics' PV.get() returns None on a transient
+        # CA hiccup instead of raising, and `int(100 / freq)` on that None
+        # killed a real scan mid-run (SIN-TIMAST-TMA:Evt-52-Freq-I, hundreds
+        # of channels transiently disconnected under CA congestion - see
+        # the ca_tuning "silent None" warning this raised). Monitor once
+        # here, same pattern as the pulse_id cache above, and read the cache
+        # in `rate_multiplicator` instead of gets on the hot path.
+        self._frequency_detector = None
+        self._frequency_monitor = None
+        self._frequency_latest = {"value": None}
+        if event_master is not None and detectors_event_code is not None:
+            try:
+                self._frequency_detector = event_master.__dict__[
+                    f"code{detectors_event_code:03d}"
+                ].frequency
+                mon = self._frequency_detector.set_current_value_callback(
+                    func="latest"
+                )
+                mon.start()  # one get to seed the cache, then monitor-only
+                self._frequency_monitor = mon
+                self._frequency_latest = mon.data
+            except Exception:
+                # A code with no live frequency (MasterEventCodeFix, used for
+                # the CTA sequencer's fixed-delay codes) has no PV to
+                # monitor at all - get_detector_code_frequency()'s own
+                # fallback below handles that by raising a clear error
+                # instead of a bare TypeError on `100 / None`.
+                pass
         self.name = name
         self.namespace = namespace
         self.checker = checker
@@ -276,10 +308,38 @@ class Daq(Assembly):
 
     @property
     def rate_multiplicator(self):
-        freq = self._event_master.__dict__[
-            f"code{self._detectors_event_code:03d}"
-        ].frequency.get_current_value()
-        return int(100 / freq)
+        return int(100 / self.get_detector_code_frequency())
+
+    def get_detector_code_frequency(self):
+        """Frequency (Hz) of the detectors' event code -- never `None`.
+
+        Reads the CA-monitor cache set up in `__init__`, not a fresh get:
+        this is called once per scan step (`rate_multiplicator`, from
+        `retrieve()`), which is exactly the traffic pattern that made the
+        `pulse_id` bug (see `get_pulse_id`'s docstring) real rather than
+        theoretical. Falls back to one direct read only if the monitor was
+        never able to attach (e.g. the code was resolved before the
+        underlying component finished initializing), and raises rather than
+        ever returning `None` for the caller to divide by.
+        """
+        value = self._frequency_latest.get("value")
+        if value is not None:
+            return value
+        if self._frequency_detector is not None:
+            try:
+                value = self._frequency_detector.get_current_value()
+            except Exception:
+                value = None
+            if value is not None:
+                return value
+        pvname = getattr(self._frequency_detector, "pvname", "<unknown PV>")
+        raise TimeoutError(
+            f"could not determine the frequency of detectors_event_code="
+            f"{self._detectors_event_code} ({pvname}): no monitored value "
+            "yet and a direct read also failed or returned None. If this "
+            "code has no live frequency (e.g. a fixed-delay CTA sequencer "
+            "code), detectors_event_code is pointed at the wrong one."
+        )
 
     @property
     def pgroup(self):
@@ -1606,6 +1666,16 @@ class Daq(Assembly):
     def _create_runtable_metadata_append_status_to_runtable(
         self, scan, append_status_info=True, **kwargs
     ):
+        # Lost when this was split out of the old combined elog+run_table
+        # callback (see eco.acquisition.counters_tmp, which still has the
+        # guard in the equivalent spot) - without it, append_status_info=False
+        # still built scan metadata and called run_table.append_run(), whose
+        # very first use in a session authenticates to Google Sheets
+        # (Run_Table2.__init__ -> Gsheet_API), a genuinely slow, easily
+        # mistaken-for-init_all pause that append_status_info=False is
+        # supposed to buy out of.
+        if not append_status_info:
+            return
 
         print("run_table appending run")
         runno = scan.daq_run_number.get_current_value()
diff --git a/eco/acquisition/scan.py b/eco/acquisition/scan.py
index 3f1ebaf..59d7885 100755
--- a/eco/acquisition/scan.py
+++ b/eco/acquisition/scan.py
@@ -13,6 +13,7 @@ from pathlib import Path
 import colorama
 
 from eco.elements.protocols import Adjustable, is_adjustable, resolve_lazy
+from eco.epics_utils import ca_tuning
 from eco.utilities.datafiles import open_group_writable
 from eco.utilities.utilities import (
     NumpyEncoder,
@@ -357,38 +358,45 @@ class StepScan(Assembly):
                 pass
 
         statstr += " ; Ctrs "
-        if not self.has_callbacks_step_counting():
-            acs = []
-            for ctr in self.counters:
-                acq = ctr.acquire(
-                    scan=self, Npulses=self.pulses_per_step[0], **self.callbacks_kwargs
-                )  # TODO make sure step-individual aquisition argument is possible.
-                acs.append(acq)
-                try:
-                    if hasattr(ctr, "name"):
-                        statstr += f"{ctr.name}, "
-                except:
-                    pass
-            filenames = []
-            for ta in acs:
-                ta.wait()
-                if hasattr(ta, "file_names"):
-                    filenames.extend(ta.file_names)
-        else:
-            acs = []
-            for ctr in self.counters:
-                ctr.start(scan=self, **self.callbacks_kwargs)
-                try:
-                    if hasattr(ctr, "name"):
-                        statstr += f"{ctr.name}, "
-                except:
-                    pass
-            self.run_callbacks_step_counting()
+        # The acquisition window: from here until every counter has stopped,
+        # channel access must not be disturbed. `sensitive_period` keeps the
+        # adaptive monitor sweeper from reconfiguring subscriptions
+        # mid-acquisition, and gives reads the more patient retry budget - a
+        # read that comes back None here costs the run, while a few extra
+        # milliseconds cost nothing. See eco.epics_utils.ca_tuning.
+        with ca_tuning.sensitive_period("scan step acquisition"):
+            if not self.has_callbacks_step_counting():
+                acs = []
+                for ctr in self.counters:
+                    acq = ctr.acquire(
+                        scan=self, Npulses=self.pulses_per_step[0], **self.callbacks_kwargs
+                    )  # TODO make sure step-individual aquisition argument is possible.
+                    acs.append(acq)
+                    try:
+                        if hasattr(ctr, "name"):
+                            statstr += f"{ctr.name}, "
+                    except:
+                        pass
+                filenames = []
+                for ta in acs:
+                    ta.wait()
+                    if hasattr(ta, "file_names"):
+                        filenames.extend(ta.file_names)
+            else:
+                acs = []
+                for ctr in self.counters:
+                    ctr.start(scan=self, **self.callbacks_kwargs)
+                    try:
+                        if hasattr(ctr, "name"):
+                            statstr += f"{ctr.name}, "
+                    except:
+                        pass
+                self.run_callbacks_step_counting()
 
-            filenames = []
-            for ctr in self.counters:
-                resp = ctr.stop(scan=self, **self.callbacks_kwargs)
-                filenames.extend(resp["files"])
+                filenames = []
+                for ctr in self.counters:
+                    resp = ctr.stop(scan=self, **self.callbacks_kwargs)
+                    filenames.extend(resp["files"])
         statstr = statstr[:-2] + " done."
         print(statstr, end="\n")
 
diff --git a/eco/bernina/bernina.py b/eco/bernina/bernina.py
index 7c0e990..88145e0 100644
--- a/eco/bernina/bernina.py
+++ b/eco/bernina/bernina.py
@@ -92,196 +92,17 @@ namespace.append_obj(
 
 
 from . import bernina_vacuum
-
 from . import bernina_event_timing
-
-
-
-
-
-# First real trial of the generalized beamline-view prototype (see
-# eco.elements.beamline_view / Assembly.mark_beamline) on the live namespace,
-# in parallel with the untouched eco.xoptics.beamline_assembly.Beamline draft
-# (eco.xoptics.beamline_bernina.make_bernina_front_end/make_bernina_experiment_
-# hutch) -- z_source/kind values below are taken straight from those modules
-# so they agree. Every "fel"-tagged component below also carries an
-# organisational subtype -- "front_end" (SARFE10, up to the end-of-front-end
-# shutter), "optics" (SAROP21 Bernina optics hutch), or "hutch" (the
-# experiment hutch itself, see further down) -- navigable by prefix via
-# mark_beamline's path/subtype doc. Purely additive bookkeeping:
-# mark_beamline() never touches EPICS or constructs anything, so nothing
-# here changes unless namespace.beamline (or .beamline_view(...)) is
-# actually used. Try e.g.:
-#   namespace.beamline.fel             # every "fel" position, any subtype
-#   namespace.beamline.fel.front_end   # just this subtype
-#   namespace.beamline.fel.optics
-#   namespace.beamline.fel.hutch
-#   namespace.beamline.vacuum          # the vacuum system, same 3 subtypes,
-#                                       # unfolding into each section's real
-#                                       # valve/gauge/pump devices
-
-
-# The whole "fel"/"front_end" group (pshut_und, slit_und, mon_und, pshut_fe,
-# att_fe, prof_fe) is delegated to bernina_front_end.py, which imports
-# `namespace` back and self-registers - only needs to come after
-# `namespace = Namespace(...)` above; see that module's docstring for why
-# that's not a circular import.
 from . import bernina_front_end  # noqa: F401
 from . import bernina_optics_hutch
-
 from . import bernina_beamline_hutch
 from . import bernina_laser
 from . import bernina_hutch_devices
+from . import bernina_alarms
+from . import bernina_daq
 
 
-
-
-
-
-# Alarm-overview panels mirroring the caqtdm "Alarms overview" launcher entry
-# (S_charts.json -> alarms_caqtdm -> alarms.ui) and its two Papamoll pump-laser
-# "Expert" sub-panels. See eco/devices_general/alarms/README.md.
-namespace.append_obj(
-    "BerninaAlarmsOverview",
-    lazy=True,
-    name="alarms",
-    module_name="eco.devices_general.alarms",
-)
-namespace.append_obj(
-    "PapamollAlarms",
-    "26l_dean_1um_35fs",
-    lazy=True,
-    name="papamoll_alarms_35fs",
-    module_name="eco.devices_general.alarms",
-)
-namespace.append_obj(
-    "PapamollAlarms",
-    "26h_orr_510nm_100fs",
-    lazy=True,
-    name="papamoll_alarms_100fs",
-    module_name="eco.devices_general.alarms",
-)
-
-
-
-
-namespace.append_obj(
-    "AdjustableFS",
-    # "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/config_JFs.json",
-    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/config_JFs.json",
-    module_name="eco.elements.adjustable",
-    lazy=True,
-    name="config_JFs",
-)
-
-
-
-
-### channelsfor daq ###
-namespace.append_obj(
-    "AdjustableFS",
-    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/channels_JF.json",
-    module_name="eco.elements.adjustable",
-    lazy=True,
-    name="channels_JF",
-)
-namespace.append_obj(
-    "AdjustableFS",
-    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/channels_BS.json",
-    module_name="eco.elements.adjustable",
-    lazy=True,
-    name="channels_BS",
-)
-namespace.append_obj(
-    "AdjustableFS",
-    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/channels_BSCAM.json",
-    module_name="eco.elements.adjustable",
-    lazy=True,
-    name="channels_BSCAM",
-)
-namespace.append_obj(
-    "AdjustableFS",
-    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/channels_CA.json",
-    module_name="eco.elements.adjustable",
-    lazy=True,
-    name="channels_CA",
-)
-
-# namespace.append_obj(
-#     "MpodModule",
-#     "SARES21-PS7071",
-#     [1, 2, 3, 4],
-#     ["ch1", "ch2", "ch3", "ch4"],
-#     module_string="LV_OMPV_1",
-#     name="power_LV_patch1",
-#     lazy=True,
-#     module_name="eco.devices_general.powersockets",
-# )
-
-# namespace.append_obj(
-#     "MpodModule",
-#     "SARES21-PS7071",
-#     [5, 6, 7, 8],
-#     ["ch1", "ch2", "ch3", "ch4"],
-#     module_string="LV_OMPV_1",
-#     name="power_LV_patch2",
-#     lazy=True,
-#     module_name="eco.devices_general.powersockets",
-# )
-
-# new MPOD implementation
-
-
-from eco.loptics.bernina_laser import Stage_LXT_Delay
-
-# namespace.append_obj(
-#     "NEW_MpodModule",
-#     "SARES20-MPD1",
-#     [0, 1, 2, 3],
-#     ["ch1", "ch2", "ch3", "ch4"],
-#     module_string='1',
-#     name="power_LV_patch1",
-#     lazy=True,
-#     module_name="eco.devices_general.powersockets",
-# )
-
-# namespace.append_obj(
-#     "NEW_MpodModule",
-#     "SARES21-MPD1",
-#     [4, 5, 6, 7],
-#     ["ch4", "ch5", "ch6", "ch7"],
-#     module_string='1',
-#     name="power_LV_patch2",
-#     lazy=True,
-#     module_name="eco.devices_general.powersockets",
-# )
-
-# namespace.append_obj(
-#     "CheckerCA",
-#     module_name="eco.acquisition.checkers",
-#     pvname="SLAAR21-LTIM01-EVR0:CALCI",
-#     thresholds=[0.2, 10],
-#     required_fraction=0.6,
-#     filepath_thresholds="/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/default_checker_thresholds.json",
-#     filepath_fraction="/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/default_checker_thresholds_fraction.json",
-#     lazy=True,
-#     name="checker_mon_opt_ioxos",
-# )
-
-namespace.append_obj(
-    "CheckerBS",
-    module_name="eco.acquisition.checkers",
-    bs_channel="SAROP21-PBPS133:INTENSITY",
-    thresholds=[0.2, 10],
-    required_fraction=0.6,
-    filepath_thresholds="/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/default_checker_thresholds.json",
-    filepath_fraction="/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/default_checker_thresholds_fraction.json",
-    lazy=True,
-    name="checker",
-)
-
-
-##### standard DAQ #######
+##### run table stuff #######
 
 
 # TODO: need to check if the value property actually works here for the pgroup in the run table to make is dynamic!
@@ -330,81 +151,6 @@ namespace.append_obj(
 )
 
 
-# Take run status from a long-running eco.status_server process instead of
-# initializing and reading *this* session's namespace at every scan start
-# (see eco/status_server/README.md). On by default, pointed at the
-# beamline's server - Daq.use_status_server() re-checks /health before every
-# scan and falls back to the old local behaviour (with a printed warning) if
-# it is unreachable, still initializing, or older than
-# status_server_max_age, so a session never silently depends on the server
-# being up. Override the URL, or set to "" / "off" / "none" to force the old
-# always-local behaviour, with e.g.
-#   ECO_STATUS_SERVER=off scripts/eco-dev -s bernina
-# An env var rather than a key in the shared bernina config JSON on purpose:
-# which host (if any) runs a status server is a per-session choice, and that
-# file is read by every session at the beamline.
-_ECO_STATUS_SERVER_DEFAULT = "http://saresb-cons-04:8091"
-_status_server = os.environ.get("ECO_STATUS_SERVER", _ECO_STATUS_SERVER_DEFAULT)
-if _status_server.strip().lower() in ("", "off", "none", "false", "0"):
-    _status_server = None
-if _status_server:
-    print(f"daq: taking run status from status server {_status_server} "
-          "(set ECO_STATUS_SERVER=off to always use the local namespace)")
-
-namespace.append_obj(
-    "Daq",
-    instrument="bernina",
-    status_server=_status_server,
-    pgroup=NamespaceComponent(namespace, "config_bernina.pgroup"),
-    channels_JF=NamespaceComponent(namespace, "channels_JF"),
-    channels_BS=NamespaceComponent(namespace, "channels_BS"),
-    channels_BSCAM=NamespaceComponent(namespace, "channels_BSCAM"),
-    channels_CA=NamespaceComponent(namespace, "channels_CA"),
-    config_JFs=NamespaceComponent(namespace, "config_JFs"),
-    # pulse_id_adj="SLAAR21-LTIM01-EVR0:RX-PULSEID",
-    pulse_id_adj="SARES20-CVME-01-EVR0:RX-PULSEID",
-    event_master=NamespaceComponent(namespace, "event_master"),
-    detectors_event_code=50,
-    rate_multiplicator="auto",
-    name="daq",
-    namespace=namespace,
-    checker=NamespaceComponent(namespace, "checker"),
-    run_table=NamespaceComponent(namespace, "run_table"),
-    pulse_picker=NamespaceComponent(namespace, "xp"),
-    elog=NamespaceComponent(namespace, "elog"),
-    module_name="eco.acquisition.daq_client",
-    lazy=True,
-)
-
-
-namespace.append_obj(
-    "Scans",
-    # data_base_dir="scan_data",
-    # scan_info_dir=f"/sf/bernina/data/{config_bernina.pgroup()}/res/scan_info",
-    default_counters=[daq],
-    # default_counters=[NamespaceComponent(namespace,"daq")],
-    # default_counters=NamespaceComponent(namespace,"daq"),
-    callbacks_start_scan=[],
-    callbacks_end_step=[],
-    callbacks_end_scan=[],
-    # elog=elog,
-    name="scans",
-    module_name="eco.acquisition.scan",
-    lazy=True,
-)
-
-namespace.append_obj(
-    "Scans",
-    # data_base_dir="scan_data",
-    # scan_info_dir=f"/sf/bernina/data/{config_bernina.pgroup()}/res/scan_info",
-    default_counters=[],
-    callbacks_start_scan=[],
-    callbacks_end_step=[],
-    callbacks_end_scan=[],
-    name="scans_test",
-    module_name="eco.acquisition.scan",
-    lazy=True,
-)
 
 #####################################################################################################
 ## more temporary devices will be outcoupled to temorary module.
@@ -986,8 +732,9 @@ namespace.mark_beamline(
 # TODO  pgroup non dynamic here!
 try:
     import sys
+    import shutil
     from ..utilities import TimeoutPath
-    from ..utilities.datafiles import ensure_dir
+    from ..utilities.datafiles import ensure_dir, ensure_group_writable
 
     if TimeoutPath(f"/sf/bernina/data/{config_bernina.pgroup()}/res/").exists():
         pgroup_eco_path = TimeoutPath(
@@ -999,6 +746,26 @@ try:
         ensure_dir(pgroup_eco_path)
 
         sys.path.append(pgroup_eco_path.as_posix())
+
+        pgroup_exp_path = pgroup_eco_path.get_path() / "bernina_exp.py"
+        if not any(pgroup_eco_path.get_path().iterdir()):
+            # Freshly created (empty) pgroup eco folder: seed it with an
+            # editable copy of the template, so there is somewhere obvious to
+            # add pgroup-specific devices/components without touching the
+            # checkout. ensure_dir already made the folder group-writable
+            # (setgid + group rwx), so the copy just needs the same treatment
+            # -- ensure_group_writable, not a hand-rolled chmod (see
+            # eco.utilities.datafiles).
+            shutil.copyfile(
+                Path(__file__).parent / "bernina_exp_template.py", pgroup_exp_path
+            )
+            ensure_group_writable(pgroup_exp_path)
+
+        if pgroup_exp_path.exists():
+            # pgroup_eco_path is on sys.path (above), so this is a plain
+            # top-level module import, not a package-relative one -- the
+            # per-pgroup file lives outside the eco package entirely.
+            import bernina_exp
     else:
         print(
             "Could not access experiment folder, could be due to more systematic file system failure!"
diff --git a/eco/bernina/bernina_alarms.py b/eco/bernina/bernina_alarms.py
new file mode 100644
index 0000000..fa01206
--- /dev/null
+++ b/eco/bernina/bernina_alarms.py
@@ -0,0 +1,26 @@
+from eco.bernina.bernina import namespace
+from eco.utilities.config import NamespaceComponent
+
+# Alarm-overview panels mirroring the caqtdm "Alarms overview" launcher entry
+# (S_charts.json -> alarms_caqtdm -> alarms.ui) and its two Papamoll pump-laser
+# "Expert" sub-panels. See eco/devices_general/alarms/README.md.
+namespace.append_obj(
+    "BerninaAlarmsOverview",
+    lazy=True,
+    name="alarms",
+    module_name="eco.devices_general.alarms",
+)
+namespace.append_obj(
+    "PapamollAlarms",
+    "26l_dean_1um_35fs",
+    lazy=True,
+    name="papamoll_alarms_35fs",
+    module_name="eco.devices_general.alarms",
+)
+namespace.append_obj(
+    "PapamollAlarms",
+    "26h_orr_510nm_100fs",
+    lazy=True,
+    name="papamoll_alarms_100fs",
+    module_name="eco.devices_general.alarms",
+)
diff --git a/eco/bernina/bernina_daq.py b/eco/bernina/bernina_daq.py
new file mode 100644
index 0000000..49395aa
--- /dev/null
+++ b/eco/bernina/bernina_daq.py
@@ -0,0 +1,154 @@
+import os
+
+from eco.bernina.bernina import namespace
+from eco.utilities.config import NamespaceComponent
+from eco import bernina
+
+
+namespace.append_obj(
+    "AdjustableFS",
+    # "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/config_JFs.json",
+    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/config_JFs.json",
+    module_name="eco.elements.adjustable",
+    lazy=True,
+    name="config_JFs",
+)
+
+
+
+
+### channelsfor daq ###
+namespace.append_obj(
+    "AdjustableFS",
+    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/channels_JF.json",
+    module_name="eco.elements.adjustable",
+    lazy=True,
+    name="channels_JF",
+)
+namespace.append_obj(
+    "AdjustableFS",
+    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/channels_BS.json",
+    module_name="eco.elements.adjustable",
+    lazy=True,
+    name="channels_BS",
+)
+namespace.append_obj(
+    "AdjustableFS",
+    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/channels_BSCAM.json",
+    module_name="eco.elements.adjustable",
+    lazy=True,
+    name="channels_BSCAM",
+)
+namespace.append_obj(
+    "AdjustableFS",
+    "/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/channels_CA.json",
+    module_name="eco.elements.adjustable",
+    lazy=True,
+    name="channels_CA",
+)
+
+namespace.append_obj(
+    "CheckerBS",
+    module_name="eco.acquisition.checkers",
+    bs_channel="SAROP21-PBPS133:INTENSITY",
+    thresholds=[0.2, 10],
+    required_fraction=0.6,
+    filepath_thresholds="/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/default_checker_thresholds.json",
+    filepath_fraction="/sf/bernina/code/gac-bernina/eco_cnf_bernina/configuration/default_checker_thresholds_fraction.json",
+    lazy=True,
+    name="checker",
+)
+
+# Take run status from a long-running eco.status_server process instead of
+# initializing and reading *this* session's namespace at every scan start
+# (see eco/status_server/README.md). On by default, pointed at the server
+# below - Daq.use_status_server() re-checks /health before every scan and
+# falls back to the old local behaviour (with a printed warning) if it is
+# unreachable, still initializing, or older than status_server_max_age, so a
+# session never silently depends on the server being up.
+#
+# ECO_STATUS_SERVER is a *shell* environment variable, read once here at
+# import time - it has to be set in the environment the eco session is
+# started from (before `eco-dev`/`eco` runs), not from inside an already
+# running IPython session, where setting it does nothing:
+#   ECO_STATUS_SERVER=off scripts/eco-dev -s bernina        # this session only
+#   export ECO_STATUS_SERVER=off                            # every session after
+# "" / "off" / "none" / "false" / "0" (case-insensitively) force the old,
+# always-local behaviour; anything else is used as the server URL instead of
+# the default below.
+#
+# An env var rather than a key in the shared bernina config JSON on purpose:
+# which host (if any) runs a status server is a per-session choice, and that
+# file is read by every session at the beamline.
+#
+# The default below is the *personal-checkout* status server used to develop
+# and test this feature (see eco/status_server/DESIGN.md) - it is not yet a
+# server started from the shared gac-bernina checkout, so treat it as a dev
+# deployment: fine to rely on day to day, but not yet an officially operated
+# service, and it can be restarted/moved without the same notice a
+# production one would get.
+_ECO_STATUS_SERVER_DEFAULT = "http://saresb-cons-04:8091"
+_status_server = os.environ.get("ECO_STATUS_SERVER", _ECO_STATUS_SERVER_DEFAULT)
+_status_server_is_default = "ECO_STATUS_SERVER" not in os.environ
+if _status_server.strip().lower() in ("", "off", "none", "false", "0"):
+    _status_server = None
+if _status_server:
+    kind = "dev/personal-checkout" if _status_server_is_default else "configured"
+    print(f"daq: taking run status from the {kind} status server "
+          f"{_status_server} (set ECO_STATUS_SERVER=off in the shell before "
+          "starting this session to always use the local namespace instead)")
+
+namespace.append_obj(
+    "Daq",
+    instrument="bernina",
+    status_server=_status_server,
+    pgroup=NamespaceComponent(namespace, "config_bernina.pgroup"),
+    channels_JF=NamespaceComponent(namespace, "channels_JF"),
+    channels_BS=NamespaceComponent(namespace, "channels_BS"),
+    channels_BSCAM=NamespaceComponent(namespace, "channels_BSCAM"),
+    channels_CA=NamespaceComponent(namespace, "channels_CA"),
+    config_JFs=NamespaceComponent(namespace, "config_JFs"),
+    # pulse_id_adj="SLAAR21-LTIM01-EVR0:RX-PULSEID",
+    pulse_id_adj="SARES20-CVME-01-EVR0:RX-PULSEID",
+    event_master=NamespaceComponent(namespace, "event_master"),
+    detectors_event_code=50,
+    rate_multiplicator="auto",
+    name="daq",
+    namespace=namespace,
+    checker=NamespaceComponent(namespace, "checker"),
+    run_table=NamespaceComponent(namespace, "run_table"),
+    pulse_picker=NamespaceComponent(namespace, "xp"),
+    elog=NamespaceComponent(namespace, "elog"),
+    module_name="eco.acquisition.daq_client",
+    lazy=True,
+)
+
+
+namespace.append_obj(
+    "Scans",
+    # data_base_dir="scan_data",
+    # scan_info_dir=f"/sf/bernina/data/{config_bernina.pgroup()}/res/scan_info",
+    # default_counters=[daq],
+    default_counters=[NamespaceComponent(namespace,"daq")],
+    # default_counters=NamespaceComponent(namespace,"daq"),
+    callbacks_start_scan=[],
+    callbacks_end_step=[],
+    callbacks_end_scan=[],
+    # elog=elog,
+    name="scans",
+    module_name="eco.acquisition.scan",
+    lazy=True,
+)
+
+# namespace.append_obj(
+#     "Scans",
+#     # data_base_dir="scan_data",
+#     # scan_info_dir=f"/sf/bernina/data/{config_bernina.pgroup()}/res/scan_info",
+#     default_counters=[],
+#     callbacks_start_scan=[],
+#     callbacks_end_step=[],
+#     callbacks_end_scan=[],
+#     name="scans_test",
+#     module_name="eco.acquisition.scan",
+#     lazy=True,
+# )
diff --git a/eco/bernina/bernina_event_timing.py b/eco/bernina/bernina_event_timing.py
index 04f5ba7..9e94625 100644
--- a/eco/bernina/bernina_event_timing.py
+++ b/eco/bernina/bernina_event_timing.py
@@ -71,6 +71,7 @@ namespace.append_obj(
     n_output_front=16,
     n_output_rear=0,
     name="evr_camserver72",
+    has_evr_sequencer=False,
     module_name="eco.timing.event_timing_new_new",
     lazy=True,
 )
@@ -81,6 +82,7 @@ namespace.append_obj(
     n_pulsers=16,
     n_output_front=16,
     n_output_rear=0,
+    has_evr_sequencer=False,
     name="evr_camserver73",
     module_name="eco.timing.event_timing_new_new",
     lazy=True,
@@ -92,6 +94,7 @@ namespace.append_obj(
     n_pulsers=16,
     n_output_front=16,
     n_output_rear=0,
+    has_evr_sequencer=False,
     name="evr_camserver74",
     module_name="eco.timing.event_timing_new_new",
     lazy=True,
@@ -103,6 +106,7 @@ namespace.append_obj(
     n_pulsers=16,
     n_output_front=16,
     n_output_rear=0,
+    has_evr_sequencer=False,
     name="evr_camserver83",
     module_name="eco.timing.event_timing_new_new",
     lazy=True,
@@ -114,6 +118,7 @@ namespace.append_obj(
     n_pulsers=16,
     n_output_front=16,
     n_output_rear=0,
+    has_evr_sequencer=False,
     name="evr_camserver84",
     module_name="eco.timing.event_timing_new_new",
     lazy=True,
@@ -125,6 +130,7 @@ namespace.append_obj(
     n_pulsers=16,
     n_output_front=16,
     n_output_rear=0,
+    has_evr_sequencer=False,
     name="evr_camserver85",
     module_name="eco.timing.event_timing_new_new",
     lazy=True,
diff --git a/eco/bernina/bernina_exp_template.py b/eco/bernina/bernina_exp_template.py
new file mode 100644
index 0000000..5709120
--- /dev/null
+++ b/eco/bernina/bernina_exp_template.py
@@ -0,0 +1,27 @@
+# This is only a template for creating experiment-specific files -- it is
+# copied into the current pgroup's res/eco/ folder (as bernina_exp.py) the
+# first time that folder is empty, then imported and left alone; edit the
+# per-pgroup copy, not this one.
+from eco.bernina.bernina import namespace
+from eco.utilities.config import NamespaceComponent
+from eco.elements.assembly import Assembly
+
+class MyExp(Assembly):
+    """A simple experiment with a timing master and a few devices."""
+
+    def __init__(self, adj_from_bernina, det_from_bernina, name=None):
+        super().__init__( name=name)
+        self._append(adj_from_bernina,name="test_adjustable", is_display=True, is_setting=True)
+        self._append(det_from_bernina,name="pulse_id", is_display=True, is_setting=False)
+
+namespace.append_obj(MyExp,
+                 NamespaceComponent(namespace,"dummy_adjustable"),  # replace with a real adjustable name
+                 NamespaceComponent(namespace,"event_master.pulse_id"),
+                 name="my_exp_object_1",
+                 lazy=True,  # lazy=True: only resolves the components above once "my_exp_object_1" is actually touched
+                 is_display=True,
+                 is_setting=False,
+                 )
+
+
+
diff --git a/eco/bernina/config.py b/eco/bernina/config.py
index f60c544..dfb1a3e 100755
--- a/eco/bernina/config.py
+++ b/eco/bernina/config.py
@@ -483,7 +483,9 @@ components = [
 ]
 
 try:
-    components.extend(config["components"])
-    print("Did append additional components!")
+    _additional_components = config["components"]
+    components.extend(_additional_components)
+    if _additional_components:
+        print(f"Did append {len(_additional_components)} additional components!")
 except:
     print("Could not append components from config.")
diff --git a/eco/bs/detector.py b/eco/bs/detector.py
index fcc7c0c..aa6b451 100644
--- a/eco/bs/detector.py
+++ b/eco/bs/detector.py
@@ -4,12 +4,17 @@ from time import time, sleep
 
 import numpy as np
 from epics import PV
+from eco.epics_utils import ca_tuning
 from eco.epics_utils.ca_tuning import (
     CA_CONNECTION_TIMEOUT,
     CA_INIT_CONNECTION_TIMEOUT,
-    note_successful_read,
-    report_none_read,
 )
+# The CA-backed classes in this module read through the same chokepoint as
+# eco.epics_utils: it is what applies the retry for a channel that has
+# worked before, and the silent-None diagnostics. Importing the diagnostics
+# without ever calling them (as this module did) left these reads with no
+# None handling at all.
+from eco.epics_utils.adjustable import _read_pv
 
 from eco.acquisition.utilities import Acquisition
 from eco.aliases import Alias
@@ -27,7 +32,7 @@ class DetectorBsData(Assembly):
         self.status_collection.append(self)
         self.bschannel = bschannel
         if epics_pv_available & epics_pv_availabe == "same":
-            self._pv = PV(pvname)
+            self._pv = ca_tuning.make_pv(pvname)
             self._append(
                 AdjustablePvString, self.pvname + ".EGU", name="unit", is_setting=False
             )
@@ -35,7 +40,7 @@ class DetectorBsData(Assembly):
         self.alias = Alias(self.name, channel=self.pvname, channeltype="BS")
 
     def get_current_value(self):
-        return self._pv.get()
+        return _read_pv(self._pv, name=getattr(self, "name", None))
 
     def __call__(self):
         return self.get_current_value()
@@ -50,7 +55,7 @@ class DetectorPvEnum(Assembly):
     def __init__(self, pvname, name=None):
         super().__init__(name=name)
         self.pvname = pvname
-        self._pv = PV(pvname, connection_timeout=CA_CONNECTION_TIMEOUT)
+        self._pv = ca_tuning.make_pv(pvname, connection_timeout=CA_CONNECTION_TIMEOUT)
         self.name = name
         self.alias = Alias(name, channel=self.pvname, channeltype="CA")
         self._resolve_lock = threading.Lock()
@@ -102,7 +107,7 @@ class DetectorPvEnum(Assembly):
             return self._pv_enum(value)
 
     def get_current_value(self):
-        return self.validate(self._pv.get())
+        return self.validate(_read_pv(self._pv, name=getattr(self, "name", None)))
 
     def __call__(self):
         return self.get_current_value()
@@ -112,12 +117,12 @@ class DetectorPvString:
     def __init__(self, pvname, name=None, elog=None):
         self.name = name
         self.pvname = pvname
-        self._pv = PV(pvname, connection_timeout=CA_CONNECTION_TIMEOUT)
+        self._pv = ca_tuning.make_pv(pvname, connection_timeout=CA_CONNECTION_TIMEOUT)
         self._elog = elog
         self.alias = Alias(name, channel=self.pvname, channeltype="CA")
 
     def get_current_value(self):
-        return self._pv.get()
+        return _read_pv(self._pv, name=getattr(self, "name", None))
 
     def set_target_value(self, value, hold=False):
         changer = lambda value: self._pv.put(bytes(value, "utf8"), wait=True)
@@ -141,7 +146,7 @@ class DetectorPvDataStream(Assembly):
         super().__init__(name=name)
         self.Id = pvname
         self.pvname = pvname
-        self._pv = PV(pvname)
+        self._pv = ca_tuning.make_pv(pvname)
         self.alias = Alias(self.name, channel=self.pvname, channeltype="CA")
         self._append(
             AdjustablePvString, self.pvname + ".EGU", name="unit", is_setting=False
@@ -255,4 +260,4 @@ class DetectorPvDataStream(Assembly):
     data = property(get_data)
 
     def get_current_value(self):
-        return self._pv.get()
+        return _read_pv(self._pv, name=getattr(self, "name", None))
diff --git a/eco/detector/bs_counter.py b/eco/detector/bs_counter.py
index 1b3242e..9d2c861 100644
--- a/eco/detector/bs_counter.py
+++ b/eco/detector/bs_counter.py
@@ -18,47 +18,38 @@ Two questions this answers
    (``Stream.digitize().categorize()``, and the more general
    ``Scan(parameters=[...])`` it's built on) still work, and can it drive
    per-scan-step binning the way ``escape.Array``'s scan-index binning does
-   for post-hoc data? Yes to the first part -- verified directly against a
-   live stream (fixed value-range bins, ``t.digitize(bins).categorize(i)``,
-   produced a correct multi-bin histogram). For step-scan binning, ``Scan``
-   with a synthetic "current step index" parameter (rather than a real bs
-   channel) is the right primitive -- but see the bug below, found and
-   worked around here rather than in ``escape.stream`` itself.
+   for post-hoc data? Yes -- verified directly against a live stream (fixed
+   value-range bins, ``t.digitize(bins).categorize(i)``, produced a correct
+   multi-bin histogram). For step-scan binning, ``Scan`` with a synthetic
+   "current step index" parameter (rather than a real bs channel) is the
+   right primitive -- see below.
 
-The ``Scan`` open-bin bug (found, not yet fixed upstream)
-------------------------------------------------------------
+The ``Scan`` open-bin bug (found here, fixed upstream in escape-fel 0.2.7)
+----------------------------------------------------------------------------
 ``escape.stream.Scan(parameters=[...])`` with no ``values=`` starts empty
 and grows one bin at a time, the first time a genuinely new parameter value
 is seen (``Scan._append()``). Each ``Stream`` wrapping it gets its own
-``DataManager``, whose per-bin deque list is sized to
-``len(scan._values)`` **at the moment that Stream/DataManager is
-constructed** -- not kept in sync afterwards.
-
-That is fine for a single channel (it always discovers a bin via its own
-call to ``scan._append()`` before ever indexing into it). It is **not**
-fine the moment a *second* channel shares the same growing ``Scan``: if
-channel A's own event stream reaches a new step index before channel B's
-does, A's call to ``scan._append()`` grows the *shared* ``_values`` list,
-but B's own (unrelated) ``_data`` list is not grown to match. B's next
-event then indexes past the end of its own list. Confirmed directly: this
-raises ``IndexError: list index out of range`` inside
-``Stream._appendEventData``, which runs as an ``EventWorker`` callback
-inside a blanket ``try/except`` (``EventWorker.eventLoop``) -- so it never
-raises up to caller code, it just prints
-``"EventWorker callback error: list index out of range"`` once per event,
-forever, and **that channel silently stops recording data for the rest of
-the scan.**
-
-Fix used here: never leave the shared ``Scan`` open-ended when more than
-one channel is attached to it. Every bin is pre-declared up front
-(``values=[(0.0,), (1.0,), ...]``) so every channel's ``DataManager`` is
-born the correct final size regardless of which channel's data happens to
-arrive first for any given step -- confirmed directly to eliminate the
-crash and produce identical, correct per-step sample counts across three
-simultaneously-binned channels. The number of steps is read from the
-``scan`` object StepScan already passes into ``Counter.acquire``/``start``
-(``len(scan._values_todo) + len(scan._values_done)``), so nothing new has
-to be threaded through ``scan.py`` for this either.
+``DataManager``. Before escape-fel 0.2.7, a ``DataManager``'s per-bin deque
+list was only grown when *that* ``DataManager``'s own call to
+``scan._append()`` reported a new bin -- so if a *second* channel sharing
+the same growing ``Scan`` reached a given step only after some other
+channel had already registered it, the second channel's own list was never
+grown to match, and its next append indexed past the end of its own list.
+That raised ``IndexError`` inside an ``EventWorker`` callback, silently
+swallowed by ``EventWorker.eventLoop``'s blanket ``try/except`` -- so it
+never surfaced as an exception, just endless
+``"EventWorker callback error: list index out of range"`` console spam,
+while the affected channel silently stopped recording data for the rest of
+the scan. Confirmed directly (multiple independently-built ``Stream``s
+sharing one dynamically-growing ``Scan``, reaching each new bin at
+different times), reported upstream, and fixed in escape-fel 0.2.7
+(``DataManager.append`` now grows its own buffers to cover whatever index
+it needs, rather than trusting the shared ``doappend`` flag). Verified the
+fix directly against the installed 0.2.7: the same reproduction that used
+to lose a channel's data now records correctly, with the shared ``Scan``
+left genuinely open-ended -- no pre-declared bin count needed, which is why
+``BsStreamCounter`` below no longer computes ``n_steps`` from the scan
+object the way an earlier version of this file did as a workaround.
 
 Bin assignment: step index, not pulse-id math
 -----------------------------------------------
@@ -213,7 +204,7 @@ class BsStreamCounter:
         self.last_pulse_ids = {}
         self.step_pulse_ids = {}
 
-        self._build_bins(n_steps=1)  # standalone (no-scan) mode: one bin
+        self._build_bins()
 
         self.callbacks_start_scan = [self._on_scan_start]
         self.callbacks_start_step = []
@@ -222,14 +213,14 @@ class BsStreamCounter:
         self.callbacks_end_scan = [self._on_scan_end]
 
     # -- (re)building the shared per-step bin structure ---------------------
-    def _build_bins(self, n_steps):
+    def _build_bins(self):
+        # Open-ended (values=None): bins are created on demand as new step
+        # indices appear. Safe to share across every channel in self._raw
+        # regardless of which one's data reaches a given step first -- see
+        # the module docstring (escape-fel 0.2.7, DataManager.append).
         from escape import stream as escape_stream
 
-        n_steps = max(1, n_steps or 1)
-        self._scan = escape_stream.Scan(
-            parameters=[self._step_source],
-            values=[(float(k),) for k in range(n_steps)],
-        )
+        self._scan = escape_stream.Scan(parameters=[self._step_source])
         self._step_source.value = 0.0
         self._step_index = 0
         self.step_pulse_ids = {}
@@ -251,30 +242,31 @@ class BsStreamCounter:
         self._channels = {}
 
     def _on_scan_start(self, scan=None, **kwargs):
-        n_steps = None
-        if scan is not None:
-            n_steps = len(getattr(scan, "_values_todo", [])) + len(
-                getattr(scan, "_values_done", [])
-            )
         self._teardown_bins()
-        self._build_bins(n_steps)
+        self._build_bins()
 
     def _on_scan_end(self, scan=None, **kwargs):
         self._teardown_bins()
-        self._build_bins(n_steps=1)
+        self._build_bins()
 
     def close(self):
         """Unsubscribe every channel."""
         self._teardown_bins()
 
     # -- reading the current step's bin -------------------------------------
+    # Bins are created on demand (open-ended Scan) the first time a matching
+    # event actually arrives for a given channel, so `idx` may not exist yet
+    # in a freshly-advanced-to step -- treat that as "no samples yet", not
+    # an error.
     def _bin(self, name, step_index=None):
         idx = self._step_index if step_index is None else step_index
-        return self._channels[name]._dataManager._data[idx]
+        data = self._channels[name]._dataManager._data
+        return data[idx] if idx < len(data) else []
 
     def _eventids(self, name, step_index=None):
         idx = self._step_index if step_index is None else step_index
-        return self._channels[name]._dataManager._eventIds[idx]
+        eventids = self._channels[name]._dataManager._eventIds
+        return eventids[idx] if idx < len(eventids) else []
 
     def _reduce_step(self, step_index, n0=None):
         # n0: per-channel index into that bin to start reducing from -- data
@@ -347,22 +339,21 @@ class BsStreamCounter:
         return {"files": []}
 
     def _advance_step(self, scan):
-        """Point the shared bin key at *scan*'s current step (or the single
-        standalone bin if no scan) and return ``(step_index, n0)``, where
-        ``n0`` is how many samples were already in that step's bin per
+        """Point the shared bin key at *scan*'s current step (or a single
+        standalone bin, index 0, if no scan) and return ``(step_index, n0)``,
+        where ``n0`` is how many samples were already in that step's bin per
         channel -- data from *before* this call, to be excluded when
         reducing (see ``_reduce_step``). For a fresh per-step bin this is
         always 0; for the standalone single-ever-bin case it is whatever a
         previous acquire()/get_current_value() call already left there.
+
+        Bins are created on demand (open-ended ``Scan``, see
+        ``_build_bins``), so no "step exceeds allocated bins" check is
+        needed here -- any non-negative step index is valid, it simply
+        hasn't collected any samples yet until the first matching event
+        arrives.
         """
-        # No scan -> standalone use, always the single bin built by
-        # _build_bins(n_steps=1); a real scan's step index is used verbatim.
         step_index = scan.next_step if scan is not None else 0
-        if step_index >= len(self._scan._values):
-            raise IndexError(
-                f"{self.name}: step {step_index} exceeds the {len(self._scan._values)} "
-                "bins allocated at scan start -- was callbacks_start_scan run for this scan?"
-            )
         self._step_index = step_index
         self._step_source.value = float(step_index)
         ew = next(iter(self._channels.values()))._source.eventWorker
diff --git a/eco/detector/detectors_psi.py b/eco/detector/detectors_psi.py
index df3c4f6..78b3a81 100644
--- a/eco/detector/detectors_psi.py
+++ b/eco/detector/detectors_psi.py
@@ -2,6 +2,7 @@ from ..elements.assembly import Assembly
 from ..aliases import Alias
 from eco import ecocnf
 from epics.pv import PV
+from ..epics_utils import ca_tuning
 
 # try:
 #     from bsread.bsavail import pollStream
@@ -74,7 +75,7 @@ class DetectorBsStream:
         else:
             self.pvname = cachannel
         if self.pvname:
-            self._pv = PV(self.pvname, auto_monitor=False)
+            self._pv = ca_tuning.make_pv(self.pvname)
         self.alias = Alias(name, channel=bs_channel, channeltype="BS")
 
         _ensure_bs_event_worker()
diff --git a/eco/devices_general/pv_adjustable.py b/eco/devices_general/pv_adjustable.py
index 27a9167..6a5ab09 100644
--- a/eco/devices_general/pv_adjustable.py
+++ b/eco/devices_general/pv_adjustable.py
@@ -2,9 +2,10 @@ from epics import PV
 from eco.epics_utils.ca_tuning import (
     CA_CONNECTION_TIMEOUT,
     CA_INIT_CONNECTION_TIMEOUT,
-    note_successful_read,
-    report_none_read,
 )
+# see eco.bs.detector: the diagnostics were imported here and never called,
+# so a None from these reads was completely silent and unretried.
+from eco.epics_utils.adjustable import _read_pv
 import os
 import numpy as np
 import time
@@ -47,9 +48,9 @@ class PvRecord:
 
     def get_current_value(self, readback=True):
         if readback:
-            currval = self._pvreadback.get()
-        if not readback:
-            currval = self._pv.get()
+            currval = _read_pv(self._pvreadback, name=getattr(self, "name", None))
+        else:
+            currval = _read_pv(self._pv, name=getattr(self, "name", None))
         return currval
 
     def get_moveDone(self):
diff --git a/eco/epics_utils/adjustable.py b/eco/epics_utils/adjustable.py
index 2357c30..25ac756 100644
--- a/eco/epics_utils/adjustable.py
+++ b/eco/epics_utils/adjustable.py
@@ -1,9 +1,14 @@
+import logging
 import threading
 import time
 from enum import IntEnum
 
 import numpy as np
 from epics import PV
+# the module itself as well as the names: the retry budget is read live from
+# `ca_tuning` (it changes with `sensitive_period`), which a copied
+# `from ... import` would freeze at import time.
+from eco.epics_utils import ca_tuning
 from eco.epics_utils.ca_tuning import (
     CA_CONNECTION_TIMEOUT,
     CA_INIT_CONNECTION_TIMEOUT,
@@ -12,6 +17,8 @@ from eco.epics_utils.ca_tuning import (
     report_none_read,
 )
 
+logger = logging.getLogger(__name__)
+
 from eco.aliases import Alias
 from eco.elements.adjustable import (
     AdjustableMemory,
@@ -106,8 +113,31 @@ def _read_pv(pv, name=None):
     pvname = getattr(pv, "pvname", None)
     if not pv.connected and not has_ever_succeeded(pvname):
         value = pv.get(timeout=CA_INIT_CONNECTION_TIMEOUT)
-    else:
-        value = pv.get()
+        if value is None:
+            report_none_read(pv, name=name)
+        else:
+            note_successful_read(pvname)
+        return value
+
+    value = pv.get()
+    if value is None:
+        # A channel that has worked before and momentarily has not is the
+        # one case worth trying again: the failure is a dropped virtual
+        # circuit or a get that lost a race, both of which clear in
+        # milliseconds. Retrying here, at the single chokepoint every
+        # instrumented read goes through, is what stops the next caller
+        # having to grow its own private cache the way `Daq.get_pulse_id`
+        # and the event-code frequency did - and it is bounded, so an
+        # absent channel (handled above) never pays for it.
+        for attempt in range(ca_tuning.read_retries()):
+            time.sleep(ca_tuning.CA_READ_RETRY_DELAY)
+            value = pv.get()
+            if value is not None:
+                logger.debug(
+                    "%s (%s) returned None, then a value on retry %d",
+                    name or pvname, pvname, attempt + 1,
+                )
+                break
     if value is None:
         report_none_read(pv, name=name)
     else:
@@ -207,31 +237,31 @@ class AdjustableAtomicPv:
         #                Alias(an, channel=".".join([pvname, af]), channeltype="CA")
         #            )
 
-        self._pv = PV(self.pvname, connection_timeout=CA_CONNECTION_TIMEOUT, count=element_count, auto_monitor=False)
+        self._pv = ca_tuning.make_pv(self.pvname, connection_timeout=CA_CONNECTION_TIMEOUT, count=element_count)
         self._currentChange = None
         self.accuracy = accuracy
 
         if pvreadbackname is None:
-            self._pvreadback = PV(
-                self.pvname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False
+            self._pvreadback = ca_tuning.make_pv(
+                self.pvname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT
             )
             pvreadbackname = self.pvname
             self.pvname = self.pvname
         else:
-            self._pvreadback = PV(
-                pvreadbackname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False
+            self._pvreadback = ca_tuning.make_pv(
+                pvreadbackname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT
             )
             self.pvname = pvreadbackname
 
         if pvlowlimname:
-            self._pvlowlim = PV(
-                pvlowlimname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False
+            self._pvlowlim = ca_tuning.make_pv(
+                pvlowlimname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT
             )
         else:
             self._pvlowlim = None
         if pvhighlimname:
-            self._pvhighlim = PV(
-                pvhighlimname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False
+            self._pvhighlim = ca_tuning.make_pv(
+                pvhighlimname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT
             )
         else:
             self._pvhighlim = None
@@ -323,24 +353,24 @@ class AdjustablePv:
             self.unit = AdjustableMemory(unit, name="unit")
 
         if pvreadbackname is None:
-            self._pvreadback = PV(self.Id, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False)
+            self._pvreadback = ca_tuning.make_pv(self.Id, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT)
             pvreadbackname = self.Id
             self.pvname = self.Id
         else:
-            self._pvreadback = PV(
-                pvreadbackname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False
+            self._pvreadback = ca_tuning.make_pv(
+                pvreadbackname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT
             )
             self.pvname = pvreadbackname
 
         if pvlowlimname:
-            self._pvlowlim = PV(
-                pvlowlimname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False
+            self._pvlowlim = ca_tuning.make_pv(
+                pvlowlimname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT
             )
         else:
             self._pvlowlim = None
         if pvhighlimname:
-            self._pvhighlim = PV(
-                pvhighlimname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False
+            self._pvhighlim = ca_tuning.make_pv(
+                pvhighlimname, count=element_count, connection_timeout=CA_CONNECTION_TIMEOUT
             )
         else:
             self._pvhighlim = None
@@ -483,7 +513,7 @@ class AdjustablePvEnum:
     def __init__(self, pvname, pvname_set=None, name=None):
         self.Id = pvname
         self.pvname = pvname
-        self._pv = PV(pvname, connection_timeout=CA_CONNECTION_TIMEOUT * 2, auto_monitor=False)
+        self._pv = ca_tuning.make_pv(pvname, connection_timeout=CA_CONNECTION_TIMEOUT * 2)
         self.name = name
         self._pv_set = PV(pvname_set, connection_timeout=CA_CONNECTION_TIMEOUT * 2) if pvname_set else None
         self.alias = Alias(name, channel=self.Id, channeltype="CA")
@@ -624,7 +654,7 @@ class AdjustablePvString:
     def __init__(self, pvname, name=None, elog=None):
         self.name = name
         self.pvname = pvname
-        self._pv = PV(pvname, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False)
+        self._pv = ca_tuning.make_pv(pvname, connection_timeout=CA_CONNECTION_TIMEOUT)
         self._elog = elog
         self.alias = Alias(name, channel=self.pvname, channeltype="CA")
 
diff --git a/eco/epics_utils/ca_tuning.py b/eco/epics_utils/ca_tuning.py
index 6e01e93..0b2241e 100644
--- a/eco/epics_utils/ca_tuning.py
+++ b/eco/epics_utils/ca_tuning.py
@@ -16,6 +16,32 @@ time on a different value and each time fixed only for that value:
 The pattern is always the same: a read that has no tolerance for a moment of
 unavailability, and a caller that treats the resulting ``None`` as data.
 
+THE GENERAL FIX (supersedes the per-PV ones above)
+--------------------------------------------------
+Each of those was fixed by hand-rolling ``auto_monitor=True`` for one PV.
+That is the whole answer, generalised - see ``AUTO_MONITOR_DEFAULT`` below
+for why, straight out of pyepics' source: with a monitor, a read is a dict
+lookup that has no failure path at all; without one, every read is a network
+round trip with two. eco's old ``auto_monitor=False`` default was therefore
+not merely unhelpful, it was *the cause*.
+
+So there are now two general mechanisms here instead of a growing list of
+per-PV caches:
+
+* **monitor by default, demote what is fast** - ``make_pv`` applies the
+  policy, and a background sweeper measures actual update rates and drops
+  the monitor on anything above ``AUTO_MONITOR_MAX_RATE``, remembering it
+  across sessions. Measured on bernina: 7 074 channels monitored, 68
+  demoted, ~8 % of one core standing cost.
+* **retry at the chokepoint** - ``eco.epics_utils.adjustable._read_pv``
+  retries a read that has worked before (``CA_READ_RETRIES``), so a
+  momentary failure is absorbed once, for every caller, instead of each one
+  discovering it separately. A channel that has never produced a value is
+  not retried, so absent PVs stay cheap.
+* **declare sensitive stretches** - ``sensitive_period`` marks a window
+  (a scan step's acquisition, say) where subscriptions must not be
+  reconfigured and reads get a more patient budget.
+
 TRIAL - CONNECTION TIMEOUT
 --------------------------
 ``CA_CONNECTION_TIMEOUT`` was ``0.05`` everywhere (22 hardcoded literals,
@@ -43,9 +69,13 @@ previous behaviour in one line. See the CLAUDE.md section "CA connection
 timeout (trial)".
 """
 
+import atexit
+import json
 import logging
+import os
 import threading
 import time
+from pathlib import Path
 
 logger = logging.getLogger(__name__)
 
@@ -53,6 +83,73 @@ logger = logging.getLogger(__name__)
 # TRIAL (see module docstring): was 0.05 everywhere. Revert to 0.05 to undo.
 CA_CONNECTION_TIMEOUT = 1.0
 
+# --------------------------------------------------------------------------
+# Monitor policy: monitor by default, demote only what is actually fast
+#
+# `auto_monitor=False` was the eco-wide default, to keep subscription traffic
+# down. It is also, from pyepics' own source, the direct cause of the silent
+# `None` reads above. `PV.get_with_metadata` starts with
+#
+#     if not self.wait_for_connection(timeout=timeout):
+#         return None
+#     if ((not use_monitor) or (not self.auto_monitor) or ... ):
+#         metad = ca.get_with_metadata(...)
+#         if metad is None:
+#             return
+#
+# so with `auto_monitor=False` **every** read is a network round trip with
+# two independent ways to come back `None`, while with `auto_monitor=True`
+# and a cached value that whole block is skipped: the read is a dict lookup
+# that cannot time out, and a momentary circuit drop costs nothing. Every
+# per-PV fix so far (`Daq.get_pulse_id`, the event-code frequency cache) has
+# been hand-rolling `auto_monitor=True` for one PV at a time.
+#
+# The traffic argument for `False` turns out to apply to very few channels.
+# Measured on the real bernina namespace (a 3-minute recording of all 7 719
+# monitorable status channels, see eco/status_server/DESIGN.md section 15.2):
+#
+#     >= 50 Hz     48 channels   87 % of all updates
+#     10-50 Hz      9 channels    3 %
+#      1-10 Hz    182 channels    9 %
+#      < 1 Hz    7 480 channels    1 %
+#
+# i.e. 0.6 % of channels produce seven eighths of the load, and monitoring
+# the other 99.4 % is close to free. So: monitor everything by default, and
+# demote the handful that prove to be fast. `_MonitorRateTracker` below does
+# that automatically, and remembers them across sessions so the next one
+# never subscribes to them at all.
+AUTO_MONITOR_DEFAULT = True
+
+# A channel updating faster than this gets demoted to auto_monitor=False.
+# 10 Hz sits in the empty gap in the distribution above (the 10-50 Hz band
+# holds 9 channels of 7 719), so the threshold is not delicately placed.
+AUTO_MONITOR_MAX_RATE = 10.0
+
+# How often the sweeper looks at accumulated counts.
+AUTO_MONITOR_SWEEP_INTERVAL = 5.0
+
+# Where the learned fast-channel list is remembered. Per user rather than
+# shared: it is a local performance hint, not beamline configuration, and a
+# per-user file has none of the group-permission problems a shared one in
+# /sf/... would bring (see eco.utilities.datafiles).
+AUTO_MONITOR_STATE_FILE = Path(
+    os.environ.get("ECO_CA_FAST_CHANNELS")
+    or (Path.home() / ".eco" / "ca_fast_channels.json")
+)
+
+# How many times a read that has worked before may be retried before it is
+# reported as a silent None. See `_read_pv` in eco.epics_utils.adjustable:
+# a channel that demonstrably works and momentarily does not is the exact
+# case worth one more try, and the retry is skipped entirely for a channel
+# that has never produced anything.
+CA_READ_RETRIES = 2
+CA_READ_RETRY_DELAY = 0.05
+
+# Extra patience during a period the caller has declared sensitive (a scan
+# step's acquisition window, say), where a failed read is far more expensive
+# than a few extra milliseconds. See `sensitive_period`.
+CA_READ_RETRIES_SENSITIVE = 4
+
 # Budget used by `_wait_for_initialisation()` only. Deliberately still the
 # old value: that call is a best-effort "is it there yet" during namespace
 # init, and lengthening it would multiply init time by the number of absent
@@ -188,3 +285,266 @@ def report_none_read(pv, name=None, kind="read"):
     except Exception:
         # diagnostics must never be able to break a read
         pass
+
+
+# --------------------------------------------------------------------------
+# adaptive monitor policy
+
+
+_fast_lock = threading.RLock()
+_fast_channels = set()      # pvnames known to update faster than the threshold
+_fast_dirty = False         # something changed since the last save
+_update_counts = {}         # pvname -> updates since the last sweep
+_tracked = {}               # pvname -> (pv, callback_index)
+_sweeper = None
+_sensitive_depth = 0        # >0 while a caller has declared a sensitive period
+
+
+def _load_fast_channels():
+    try:
+        with open(AUTO_MONITOR_STATE_FILE) as f:
+            names = json.load(f)
+        if isinstance(names, list):
+            with _fast_lock:
+                _fast_channels.update(str(n) for n in names)
+            logger.debug(
+                "ca_tuning: %d known fast channel(s) loaded from %s",
+                len(_fast_channels), AUTO_MONITOR_STATE_FILE,
+            )
+    except FileNotFoundError:
+        pass
+    except Exception:
+        logger.debug("ca_tuning: could not read %s", AUTO_MONITOR_STATE_FILE,
+                     exc_info=True)
+
+
+def save_fast_channels():
+    """Persist the learned fast-channel list.
+
+    Worth persisting because the learning itself costs something: a session
+    that has to rediscover the ~50 fast channels subscribes to them for a few
+    seconds first. Remembering them means the next session never opens those
+    subscriptions at all.
+    """
+    global _fast_dirty
+    with _fast_lock:
+        if not _fast_dirty:
+            return
+        names = sorted(_fast_channels)
+        _fast_dirty = False
+    try:
+        AUTO_MONITOR_STATE_FILE.parent.mkdir(parents=True, exist_ok=True)
+        tmp = AUTO_MONITOR_STATE_FILE.with_suffix(".tmp")
+        with open(tmp, "w") as f:
+            json.dump(names, f, indent=1)
+        os.replace(tmp, AUTO_MONITOR_STATE_FILE)
+    except Exception:
+        logger.debug("ca_tuning: could not write %s", AUTO_MONITOR_STATE_FILE,
+                     exc_info=True)
+
+
+def is_known_fast(pvname):
+    with _fast_lock:
+        return pvname in _fast_channels
+
+
+def clear_fast_channels():
+    """Forget everything learned, so the next reads re-measure from scratch.
+
+    For when a channel's rate has genuinely changed (a detector reconfigured,
+    an event code retimed) and it is stuck demoted from a previous session.
+    """
+    global _fast_dirty
+    with _fast_lock:
+        _fast_channels.clear()
+        _fast_dirty = True
+    save_fast_channels()
+
+
+def _count_update(pvname):
+    # The hot path: one dict increment per CA update, on libca's callback
+    # thread. Deliberately not locked - a lost increment costs nothing to a
+    # rate heuristic, and taking a lock here would put every monitored
+    # channel in the namespace through one contended lock.
+    _update_counts[pvname] = _update_counts.get(pvname, 0) + 1
+
+
+def _track(pv):
+    """Attach the rate counter to `pv` and remember it for the sweeper."""
+    pvname = getattr(pv, "pvname", None)
+    if not pvname or pvname in _tracked:
+        return
+    try:
+        # with_ctrlvars=False: pyepics defaults it to True, which issues a
+        # blocking get_ctrlvars() per already-connected PV - for a whole
+        # namespace that is exactly the get-storm this policy exists to
+        # avoid (same reason eco.status_server.monitor_store passes it).
+        index = pv.add_callback(
+            lambda pvname=pvname, **kw: _count_update(pvname),
+            with_ctrlvars=False,
+        )
+    except Exception:
+        return
+    _tracked[pvname] = (pv, index)
+
+
+def _demote(pvname, pv, index, rate):
+    """Stop monitoring a channel that updates too fast to be worth it."""
+    try:
+        # Never demote a channel somebody is deliberately monitoring: a
+        # recording, a Monitor(), a CallbackEpics all register their own
+        # callback, and clearing the subscription under them would silently
+        # stop their data. Ours is the only one we may account for.
+        if len(getattr(pv, "callbacks", {})) > 1:
+            return False
+        pv.remove_callback(index)
+        pv.auto_monitor = False
+    except Exception:
+        logger.debug("ca_tuning: could not demote %s", pvname, exc_info=True)
+        return False
+    logger.info(
+        "ca_tuning: %s updates at ~%.0f Hz (> %.0f Hz), dropping its monitor "
+        "- reads of it go back to a direct CA get.",
+        pvname, rate, AUTO_MONITOR_MAX_RATE,
+    )
+    return True
+
+
+def _sweep_once(interval):
+    global _fast_dirty
+    if _sensitive_depth > 0:
+        # Do not reconfigure subscriptions in the middle of an acquisition:
+        # the point of a sensitive period is that nothing about channel
+        # access changes under it. Counts keep accumulating; the next sweep
+        # after it ends sees them.
+        return
+    # snapshot then zero, rather than clearing in place, so an update
+    # landing mid-sweep is counted against the next window instead of lost
+    counts = dict(_update_counts)
+    for name in counts:
+        _update_counts[name] = 0
+    demoted = []
+    for pvname, count in counts.items():
+        if count / interval <= AUTO_MONITOR_MAX_RATE:
+            continue
+        entry = _tracked.get(pvname)
+        if entry is None:
+            continue
+        pv, index = entry
+        if _demote(pvname, pv, index, count / interval):
+            demoted.append(pvname)
+            _tracked.pop(pvname, None)
+            _update_counts.pop(pvname, None)
+    if demoted:
+        with _fast_lock:
+            _fast_channels.update(demoted)
+            _fast_dirty = True
+        save_fast_channels()
+
+
+def _sweep_loop():
+    last = time.time()
+    while True:
+        time.sleep(AUTO_MONITOR_SWEEP_INTERVAL)
+        now = time.time()
+        interval, last = max(now - last, 1e-6), now
+        try:
+            _sweep_once(interval)
+        except Exception:
+            logger.debug("ca_tuning: sweep failed", exc_info=True)
+
+
+def _ensure_sweeper():
+    global _sweeper
+    if _sweeper is not None:
+        return
+    with _fast_lock:
+        if _sweeper is not None:
+            return
+        _sweeper = threading.Thread(
+            target=_sweep_loop, name="ca_tuning_monitor_sweeper", daemon=True
+        )
+        _sweeper.start()
+
+
+def make_pv(pvname, auto_monitor=None, **kwargs):
+    """Build a `PV` under the adaptive monitor policy.
+
+    Use this instead of `PV(...)` for anything eco reads repeatedly. It
+    monitors by default (see AUTO_MONITOR_DEFAULT for why that is both
+    faster and the fix for the silent-None class of bug), except for
+    channels already known to be too fast, and it registers the PV with the
+    sweeper that finds the rest.
+
+    `auto_monitor` still wins if given explicitly, for the cases that
+    genuinely know better than the policy.
+    """
+    from epics import PV
+
+    if auto_monitor is None:
+        auto_monitor = AUTO_MONITOR_DEFAULT and not is_known_fast(pvname)
+    pv = PV(pvname, auto_monitor=auto_monitor, **kwargs)
+    if auto_monitor:
+        _track(pv)
+        _ensure_sweeper()
+    return pv
+
+
+class sensitive_period:
+    """Declare a stretch of time where channel access must not be disturbed.
+
+    Two things change while one is active: the sweeper leaves subscriptions
+    alone (reconfiguring a monitor mid-acquisition is exactly the wrong
+    moment), and reads get the more patient retry budget
+    (`CA_READ_RETRIES_SENSITIVE`), because inside a scan step a failed read
+    costs a run and a few extra milliseconds cost nothing.
+
+    Reentrant and thread-safe by depth counting, so nesting - a step inside
+    a scan inside a queue - behaves.
+
+        with ca_tuning.sensitive_period("scan step"):
+            ...
+    """
+
+    def __init__(self, what=""):
+        self.what = what
+
+    def __enter__(self):
+        global _sensitive_depth
+        with _fast_lock:
+            _sensitive_depth += 1
+        return self
+
+    def __exit__(self, *exc):
+        global _sensitive_depth
+        with _fast_lock:
+            _sensitive_depth = max(0, _sensitive_depth - 1)
+        return False
+
+
+def in_sensitive_period():
+    return _sensitive_depth > 0
+
+
+def read_retries():
+    """How many extra attempts a read that has worked before may make."""
+    return CA_READ_RETRIES_SENSITIVE if _sensitive_depth > 0 else CA_READ_RETRIES
+
+
+def monitor_report():
+    """What the policy currently believes, for looking at from a session."""
+    with _fast_lock:
+        fast = sorted(_fast_channels)
+    return {
+        "auto_monitor_default": AUTO_MONITOR_DEFAULT,
+        "max_rate_hz": AUTO_MONITOR_MAX_RATE,
+        "monitored": len(_tracked),
+        "known_fast": fast,
+        "n_known_fast": len(fast),
+        "state_file": str(AUTO_MONITOR_STATE_FILE),
+        "in_sensitive_period": in_sensitive_period(),
+    }
+
+
+_load_fast_channels()
+atexit.register(save_fast_channels)
diff --git a/eco/epics_utils/detector.py b/eco/epics_utils/detector.py
index eb66581..37a657d 100644
--- a/eco/epics_utils/detector.py
+++ b/eco/epics_utils/detector.py
@@ -5,6 +5,7 @@ from time import time, sleep
 import numpy as np
 from epics import PV
 from eco.epics_utils.adjustable import _read_pv
+from eco.epics_utils import ca_tuning
 from eco.epics_utils.ca_tuning import (
     CA_CONNECTION_TIMEOUT,
     CA_INIT_CONNECTION_TIMEOUT,
@@ -50,7 +51,7 @@ class DetectorPvData(Assembly):
             self._append(AdjustablePv, pvname, name="readback", is_setting=False)
             # self.status_collection.append(self)
         else:
-            self._pv = PV(pvname, auto_monitor=False)
+            self._pv = ca_tuning.make_pv(pvname)
             self.alias = Alias(self.name, channel=self.pvname, channeltype="CA")
             self.status_collection.append(self)
             self.status_collection.append(self, selection="settings", recursive=False)
@@ -116,7 +117,7 @@ class DetectorPvEnum(Assembly):
     def __init__(self, pvname, name=None):
         super().__init__(name=name)
         self.pvname = pvname
-        self._pv = PV(pvname, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False)
+        self._pv = ca_tuning.make_pv(pvname, connection_timeout=CA_CONNECTION_TIMEOUT)
         self.name = name
         self.alias = Alias(name, channel=self.pvname, channeltype="CA")
         self._resolve_lock = threading.Lock()
@@ -193,7 +194,7 @@ class DetectorPvString:
     def __init__(self, pvname, name=None, elog=None):
         self.name = name
         self.pvname = pvname
-        self._pv = PV(pvname, connection_timeout=CA_CONNECTION_TIMEOUT, auto_monitor=False)
+        self._pv = ca_tuning.make_pv(pvname, connection_timeout=CA_CONNECTION_TIMEOUT)
         self._elog = elog
         self.alias = Alias(name, channel=self.pvname, channeltype="CA")
 
@@ -230,7 +231,7 @@ class DetectorPvDataStream(Assembly):
         super().__init__(name=name)
         self.Id = pvname
         self.pvname = pvname
-        self._pv = PV(pvname, auto_monitor=False)
+        self._pv = ca_tuning.make_pv(pvname)
         self.alias = Alias(self.name, channel=self.pvname, channeltype="CA")
         if has_fields:
             self._append(
diff --git a/eco/status_server/README.md b/eco/status_server/README.md
index 1d7a9e5..67685ae 100644
--- a/eco/status_server/README.md
+++ b/eco/status_server/README.md
@@ -22,21 +22,26 @@ client talks to.
 ## 1. Start it
 
 ```bash
-eco-status-server start -b     # detached, logs to ~/.eco/status_server_<host>.log
-eco-status-server wait         # block until it reports ready, printing progress
-eco-status-server status       # state, init progress, memory, running recordings
-eco-status-server stop
+eco-dev-status-server start -b     # detached, logs to ~/.eco/status_server_<host>.log
+eco-dev-status-server wait         # block until it reports ready, printing progress
+eco-dev-status-server status       # state, init progress, memory, running recordings
+eco-dev-status-server stop
 ```
 
-`/sf/bernina/bin/eco-status-server` is installed from
-[`bin/eco-status-server`](bin/eco-status-server) in this directory. Without
+`/sf/bernina/bin/eco-dev-status-server` is a symlink to
+[`scripts/eco-status-server`](../../scripts/eco-status-server) at the repo
+root (alongside `eco-dev`) - editing the checkout takes effect immediately,
+nothing to redeploy. Named `eco-dev-` like `eco-dev` itself: this always
+runs the checkout it is symlinked into, not an installed package - see §11
+for what that means and how it could become a real, installed `eco-status-
+server` command instead. Without
 `-b` it runs in the foreground, which is what the systemd unit uses — the
 service and the interactive command run exactly the same thing. It reads
 `/sf/bernina/config/eco_status_server/env` for the checkout, config and
 interpreter to use, and each of those is overridable per invocation:
 
 ```bash
-ECO_STATUS_SERVER_CHECKOUT=~/my-eco eco-status-server start -b
+ECO_STATUS_SERVER_CHECKOUT=~/my-eco eco-dev-status-server start -b
 ```
 
 The port is bound immediately; `namespace.init_all()` then runs on a
@@ -50,10 +55,24 @@ Without the wrapper it is just:
 python -m eco.status_server --mode namespace --config /path/to/bernina_namespace.json
 ```
 
+### GUI
+
+```bash
+eco-dev-status-server gui                   # small Qt window: status, reinit, query stats
+```
+
+Polls `/health` and `/stats` every couple of seconds. Shows state, init
+progress, a bold-red banner the moment any *required* component is missing
+from `initialized_names` (`failed_required` - see §8), buttons to reinitialize
+(`failed`/`full`/`restart`) with a progress bar and ETA while it runs, and a
+table of the last `/status/snapshot` and `/status/capture` calls this server
+has served - duration, entry count, and any error. Needs a desktop/X session;
+`--url` picks a server other than the site default.
+
 ### As a systemd user service
 
 ```bash
-eco-status-server-install-user-service      # run this from a shell where CA works
+eco-dev-status-server-install-user-service  # run this from a shell where CA works
 loginctl enable-linger $USER
 systemctl --user daemon-reload
 systemctl --user enable --now eco-status-server
@@ -396,3 +415,52 @@ Recording numbers and the downthrottling analysis are in DESIGN.md §15.
   a path rather than reading the file locally, but it is why a freshly
   written `status.json` can `stat` as missing from the console you are
   sitting at.
+
+## 11. `eco-dev-status-server` vs a real installed `eco-status-server`
+
+The command is named `eco-dev-status-server`, not `eco-status-server`,
+because it currently only *can* mean "run from a development checkout" — the
+status-server code lives in a personal checkout
+(`/sf/bernina/config/personal/lemke_h/eco`), not the shared gac-bernina one,
+so there is no meaningfully different "production, installed" version to
+distinguish it from yet. `eco-dev` (this repo's other script) draws exactly
+that line already: it always runs the checkout it is symlinked into, ignoring
+whatever `eco` package is `pip`/`pixi`-installed in the environment, for the
+same reason.
+
+**The two scripts are not the same thing.** `eco-status-server` is the
+day-to-day tool: start/stop/status/wait/stats/gui/logs — one running server,
+managed. `eco-status-server-install-user-service` is a one-shot generator,
+run once (or again with `--force`) to *produce* a `systemd --user` unit file
+and environment file for that server — after which `systemctl` manages it,
+not this script again. Confusingly similar names for two different jobs, kept
+separate on purpose: the daily driver stays a small, dependency-free shell
+script, while unit-file generation (capturing `EPICS_CA_*`, writing to
+`~/.config/systemd/user/`) is templating logic that does not belong mixed
+into it.
+
+**Could either become a real `pyproject.toml` [project.scripts] entry**, so
+`pip install eco` gives you an `eco-status-server` command directly (the way
+`eco = "eco_cli:main"` already does for the main package)? Only after a
+rewrite, not as-is:
+
+- `[project.scripts]` entries are Python callables (`module:function`), not
+  arbitrary executables — pip generates a tiny wrapper that imports the
+  module and calls the function. `eco-status-server` is a genuine shell
+  script (`pgrep`, `systemctl`, `nohup`, signal handling for `stop`) with no
+  Python equivalent to point at.
+- The install script is inherently host-filesystem-shaped (writes into
+  `~/.config/systemd/user/`, reads `$BASH_SOURCE` to find its sibling) — an
+  installed console-script would need that logic ported to Python
+  (`importlib.resources`/`shutil` instead of `dirname "$(readlink -f ...)"`),
+  which is a real, if mechanical, rewrite.
+- The one piece that *is* already plain Python with an argparse `main()` is
+  the GUI (`eco.status_server.gui:main`) — that one could become
+  `[project.scripts]` today with a single `pyproject.toml` line, independent
+  of the other two.
+
+Worth doing once the status-server code actually lands in a checkout meant to
+be `pip install`ed rather than run from a specific path — not before, since
+today every meaningful default (which checkout, which config) *is* "wherever
+this script lives," which a `[project.scripts]` wrapper would have no way to
+express.
diff --git a/eco/status_server/client.py b/eco/status_server/client.py
index 94de195..a011143 100644
--- a/eco/status_server/client.py
+++ b/eco/status_server/client.py
@@ -17,9 +17,41 @@ from __future__ import annotations
 
 import time
 
+import colorama
 import requests
 
 
+def warn_failed_required(health):
+    """Shout, in red, about required components the server could not build.
+
+    A component in ``required_names()`` is one the setup is not supposed to
+    fail. If one did, the status this server serves is missing something
+    that matters - silently, since every remaining channel still answers
+    fine - so a client taking status from it needs to be told at the moment
+    it starts relying on the server, not left to discover the gap in the
+    file afterwards. Non-required components failing is expected and stays
+    quiet.
+
+    Returns the list it warned about (empty if there was nothing to say),
+    so a caller can decide to do more than print.
+    """
+    failed = list((health or {}).get("failed_required") or [])
+    if not failed:
+        return []
+    red, reset = colorama.Fore.RED + colorama.Style.BRIGHT, colorama.Style.RESET_ALL
+    print(
+        f"{red}!!! status server: {len(failed)} REQUIRED component(s) failed to "
+        f"initialize: {', '.join(failed)}{reset}",
+        flush=True,
+    )
+    print(
+        f"{red}    Status recorded from this server is missing them. Inspect "
+        f"with client.failures(), or rebuild with client.reinit().{reset}",
+        flush=True,
+    )
+    return failed
+
+
 class StatusServerError(RuntimeError):
     pass
 
@@ -76,6 +108,22 @@ class StatusServerClient:
     def names(self) -> dict:
         return self._get("/names")
 
+    def stats(self, limit: int = None, kind: str = None) -> dict:
+        """Recent /status/snapshot and /status/capture operations this
+        server has served: `{"summary": {...}, "recent": [...]}`. See
+        eco.status_server.query_stats - it answers "is the server serving
+        requests well", independent of `/health`'s "is the namespace
+        healthy"."""
+        path = "/stats"
+        params = []
+        if limit:
+            params.append(f"limit={int(limit)}")
+        if kind:
+            params.append(f"kind={kind}")
+        if params:
+            path += "?" + "&".join(params)
+        return self._get(path)
+
     def failures(self) -> dict:
         return self._get("/failures")["failures"]
 
@@ -120,6 +168,7 @@ class StatusServerClient:
                             f"{h.get('n_failed')} failed",
                             flush=True,
                         )
+                    warn_failed_required(h)
                     return h
                 if progress:
                     line = (
diff --git a/eco/status_server/gui.py b/eco/status_server/gui.py
new file mode 100644
index 0000000..301a44c
--- /dev/null
+++ b/eco/status_server/gui.py
@@ -0,0 +1,399 @@
+"""A small Qt window for one status server: state, init progress with a
+reinitialize button (progress bar + ETA), and a table of recent
+/status/snapshot and /status/capture operations.
+
+Standalone on purpose - it talks to the server over plain HTTP
+(StatusServerClient), the same as any other client, so it needs no eco
+namespace import and starts in under a second. Launch it with:
+
+    python -m eco.status_server.gui --url http://saresb-cons-04:8091
+
+or `eco-status-server gui`, which does exactly that, detached.
+
+All network calls run on a background QThread (_Poller) and report back via
+Qt signals - never on the GUI thread, so a slow or unreachable server makes
+the displayed state go stale (and the connection dot go red) instead of
+freezing the window.
+"""
+
+from __future__ import annotations
+
+import argparse
+import sys
+import time
+
+from qtpy import QtCore, QtGui, QtWidgets
+
+from .client import StatusServerClient, StatusServerError, StatusServerNotReady
+
+POLL_HEALTH_S = 2.0
+POLL_STATS_S = 5.0
+
+# Palette: a small, fixed set of colours reused across state text, the
+# connection dot and stats-table error rows, rather than picking new ones ad
+# hoc per widget - see eco's dataviz guidance on consistent, limited colour
+# use even outside chart contexts.
+COLOR_OK = "#2e7d32"
+COLOR_WARN = "#b26a00"
+COLOR_BAD = "#b71c1c"
+COLOR_MUTED = "#757575"
+
+STATE_COLOR = {
+    "ready": COLOR_OK,
+    "importing": COLOR_WARN,
+    "initializing": COLOR_WARN,
+    "reinitializing": COLOR_WARN,
+    "failed": COLOR_BAD,
+}
+
+
+def _fmt_duration(s):
+    if s is None:
+        return "?"
+    if s < 120:
+        return f"{s:.0f}s"
+    return f"{s/60:.1f}min"
+
+
+class _Poller(QtCore.QThread):
+    """Background polling loop for one StatusServerClient.
+
+    Two independent intervals in one thread rather than two QTimers calling
+    into `requests` on the GUI thread - a hung/slow HTTP call must not freeze
+    the window. `health` is polled more often than `stats` since it is what
+    drives the progress bar during a reinit.
+    """
+
+    health = QtCore.Signal(dict)
+    health_failed = QtCore.Signal(str)
+    stats = QtCore.Signal(dict)
+
+    def __init__(self, client: StatusServerClient, parent=None):
+        super().__init__(parent)
+        self.client = client
+        self._stop = False
+
+    def stop(self):
+        self._stop = True
+
+    def run(self):
+        last_stats = 0.0
+        while not self._stop:
+            try:
+                h = self.client.health()
+                self.health.emit(h)
+            except Exception as exc:  # noqa: BLE001 - reported via signal
+                self.health_failed.emit(f"{type(exc).__name__}: {exc}")
+            now = time.time()
+            if now - last_stats >= POLL_STATS_S:
+                last_stats = now
+                try:
+                    self.stats.emit(self.client.stats(limit=30))
+                except Exception:
+                    pass  # the health signal already reports connectivity
+            for _ in range(int(POLL_HEALTH_S * 10)):
+                if self._stop:
+                    return
+                self.msleep(100)
+
+
+class _ReinitWorker(QtCore.QThread):
+    """Runs one blocking client call (reinit/restart) off the GUI thread."""
+
+    finished_ok = QtCore.Signal(dict)
+    finished_error = QtCore.Signal(str)
+
+    def __init__(self, fn, parent=None):
+        super().__init__(parent)
+        self._fn = fn
+
+    def run(self):
+        try:
+            result = self._fn()
+        except Exception as exc:  # noqa: BLE001 - reported via signal
+            self.finished_error.emit(f"{type(exc).__name__}: {exc}")
+            return
+        self.finished_ok.emit(result or {})
+
+
+class StatusServerMonitor(QtWidgets.QWidget):
+    def __init__(self, base_url: str, parent=None):
+        super().__init__(parent)
+        self.base_url = base_url
+        self.client = StatusServerClient(base_url, timeout=10.0, snapshot_timeout=60.0)
+        self.setWindowTitle(f"eco status server - {base_url}")
+        self.resize(720, 560)
+
+        self._last_health = {}
+        self._build_ui()
+
+        self._poller = _Poller(self.client, self)
+        self._poller.health.connect(self._on_health)
+        self._poller.health_failed.connect(self._on_health_failed)
+        self._poller.stats.connect(self._on_stats)
+        self._poller.start()
+
+        self._reinit_worker = None
+
+    # -- UI construction -----------------------------------------------
+
+    def _build_ui(self):
+        layout = QtWidgets.QVBoxLayout(self)
+
+        header = QtWidgets.QHBoxLayout()
+        self.dot = QtWidgets.QLabel("●")  # filled circle
+        self.dot.setStyleSheet(f"color: {COLOR_MUTED}; font-size: 16px;")
+        header.addWidget(self.dot)
+        header.addWidget(QtWidgets.QLabel(f"<b>{self.base_url}</b>"))
+        header.addStretch(1)
+        self.updated_label = QtWidgets.QLabel("never updated")
+        self.updated_label.setStyleSheet(f"color: {COLOR_MUTED};")
+        header.addWidget(self.updated_label)
+        layout.addLayout(header)
+
+        self.state_label = QtWidgets.QLabel("-")
+        f = self.state_label.font()
+        f.setPointSize(f.pointSize() + 3)
+        f.setBold(True)
+        self.state_label.setFont(f)
+        layout.addWidget(self.state_label)
+
+        self.progress = QtWidgets.QProgressBar()
+        self.progress.setRange(0, 100)
+        self.progress.setTextVisible(True)
+        layout.addWidget(self.progress)
+
+        self.eta_label = QtWidgets.QLabel("")
+        self.eta_label.setStyleSheet(f"color: {COLOR_MUTED};")
+        layout.addWidget(self.eta_label)
+
+        # The banner the whole task is centred on: only visible while a
+        # REQUIRED component is missing from initialized_names.
+        self.required_banner = QtWidgets.QLabel("")
+        self.required_banner.setWordWrap(True)
+        self.required_banner.setStyleSheet(
+            f"background-color: {COLOR_BAD}; color: white; font-weight: bold; "
+            "padding: 6px; border-radius: 3px;"
+        )
+        self.required_banner.hide()
+        layout.addWidget(self.required_banner)
+
+        self.other_failed_label = QtWidgets.QLabel("")
+        self.other_failed_label.setWordWrap(True)
+        self.other_failed_label.setStyleSheet(f"color: {COLOR_WARN};")
+        layout.addWidget(self.other_failed_label)
+
+        grid = QtWidgets.QGridLayout()
+        self.detail_labels = {}
+        for i, key in enumerate((
+            "n_direct_read", "n_monitorable", "n_monitored",
+            "rss_mb", "n_threads", "cpu_seconds",
+        )):
+            title = QtWidgets.QLabel(key.replace("_", " "))
+            title.setStyleSheet(f"color: {COLOR_MUTED};")
+            value = QtWidgets.QLabel("-")
+            grid.addWidget(title, i // 3, (i % 3) * 2)
+            grid.addWidget(value, i // 3, (i % 3) * 2 + 1)
+            self.detail_labels[key] = value
+        layout.addLayout(grid)
+
+        buttons = QtWidgets.QHBoxLayout()
+        self.btn_failed = QtWidgets.QPushButton("Reinit failed")
+        self.btn_full = QtWidgets.QPushButton("Reinit full")
+        self.btn_restart = QtWidgets.QPushButton("Restart process")
+        self.btn_failed.clicked.connect(lambda: self._start_reinit("failed"))
+        self.btn_full.clicked.connect(lambda: self._start_reinit("full"))
+        self.btn_restart.clicked.connect(lambda: self._start_reinit("restart"))
+        for b in (self.btn_failed, self.btn_full, self.btn_restart):
+            buttons.addWidget(b)
+        buttons.addStretch(1)
+        layout.addLayout(buttons)
+
+        self.action_status = QtWidgets.QLabel("")
+        self.action_status.setStyleSheet(f"color: {COLOR_MUTED};")
+        layout.addWidget(self.action_status)
+
+        layout.addWidget(QtWidgets.QLabel("<b>Recent queries</b>"))
+        self.summary_label = QtWidgets.QLabel("no requests served yet")
+        self.summary_label.setStyleSheet(f"color: {COLOR_MUTED};")
+        layout.addWidget(self.summary_label)
+
+        self.table = QtWidgets.QTableWidget(0, 5)
+        self.table.setHorizontalHeaderLabels(
+            ["age", "kind", "duration", "entries", "error"]
+        )
+        self.table.horizontalHeader().setStretchLastSection(True)
+        self.table.verticalHeader().setVisible(False)
+        self.table.setEditTriggers(QtWidgets.QAbstractItemView.NoEditTriggers)
+        layout.addWidget(self.table, stretch=1)
+
+    # -- polling callbacks -----------------------------------------------
+
+    def _on_health(self, h: dict):
+        self._last_health = h
+        self.updated_label.setText(time.strftime("updated %H:%M:%S"))
+        self.dot.setStyleSheet(f"color: {COLOR_OK}; font-size: 16px;")
+
+        state = h.get("state", "?")
+        self.state_label.setText(
+            f"{state}  (generation {h.get('generation')}, "
+            f"up {h.get('uptime_s', 0)/60:.1f} min)"
+        )
+        self.state_label.setStyleSheet(
+            f"color: {STATE_COLOR.get(state, COLOR_MUTED)};"
+        )
+
+        n_init, n_target = h.get("n_initialized"), h.get("n_target_names")
+        elapsed = h.get("state_seconds") or 0
+        if n_target:
+            frac = (n_init or 0) / n_target
+            self.progress.setRange(0, 100)
+            self.progress.setValue(int(round(frac * 100)))
+            self.progress.setFormat(f"{n_init}/{n_target} components  %p%")
+            busy = state in ("importing", "initializing", "reinitializing")
+            if busy and frac > 0:
+                eta = elapsed * (1 - frac) / frac
+                self.eta_label.setText(
+                    f"elapsed {_fmt_duration(elapsed)}, eta ~{_fmt_duration(eta)}"
+                )
+            elif busy:
+                self.eta_label.setText(f"elapsed {_fmt_duration(elapsed)}, eta unknown")
+            else:
+                self.eta_label.setText("")
+        else:
+            self.progress.setRange(0, 0)  # indeterminate: nothing to project yet
+            self.eta_label.setText(f"elapsed {_fmt_duration(elapsed)}")
+
+        failed_required = h.get("failed_required") or []
+        if failed_required:
+            self.required_banner.setText(
+                f"⚠ {len(failed_required)} REQUIRED component(s) failed to "
+                f"initialize: {', '.join(failed_required)}"
+            )
+            self.required_banner.show()
+        else:
+            self.required_banner.hide()
+
+        other_failed = [n for n in (h.get("failed_names") or [])
+                        if n not in failed_required]
+        self.other_failed_label.setText(
+            f"failed (not required): {', '.join(other_failed)}" if other_failed else ""
+        )
+
+        for key, label in self.detail_labels.items():
+            v = h.get(key)
+            if key == "rss_mb" and v is not None:
+                label.setText(f"{v:.0f} MB")
+            elif key == "cpu_seconds" and v is not None:
+                label.setText(_fmt_duration(v))
+            else:
+                label.setText("-" if v is None else str(v))
+
+        busy = state in ("importing", "initializing", "reinitializing")
+        for b in (self.btn_failed, self.btn_full, self.btn_restart):
+            b.setEnabled(not busy and self._reinit_worker is None)
+
+    def _on_health_failed(self, message: str):
+        self.dot.setStyleSheet(f"color: {COLOR_BAD}; font-size: 16px;")
+        self.updated_label.setText(f"unreachable: {message}")
+
+    def _on_stats(self, d: dict):
+        s = d.get("summary") or {}
+        if not s.get("n"):
+            self.summary_label.setText("no requests served yet")
+        else:
+            avg = s.get("avg_duration_s")
+            self.summary_label.setText(
+                f"{s['n']} operation(s), {s['n_errors']} error(s)"
+                + (f", avg {avg:.2f}s" if avg is not None else "")
+            )
+
+        rows = list(reversed(d.get("recent") or []))
+        self.table.setRowCount(len(rows))
+        now = time.time()
+        for r, entry in enumerate(rows):
+            age = now - entry.get("at", now)
+            dur = entry.get("duration_s")
+            n = entry.get("n_entries")
+            err = entry.get("error") or ""
+            values = [
+                f"{age:.0f}s ago", entry.get("kind", "?"),
+                f"{dur:.2f}s" if dur is not None else "?",
+                "" if n is None else str(n), err,
+            ]
+            for col, val in enumerate(values):
+                item = QtWidgets.QTableWidgetItem(val)
+                if err:
+                    item.setForeground(QtGui.QColor(COLOR_BAD))
+                self.table.setItem(r, col, item)
+        self.table.resizeColumnsToContents()
+
+    # -- actions -----------------------------------------------------------
+
+    def _start_reinit(self, mode: str):
+        if self._reinit_worker is not None:
+            return
+        for b in (self.btn_failed, self.btn_full, self.btn_restart):
+            b.setEnabled(False)
+        self.action_status.setText(f"reinit ({mode}) requested ...")
+        self.action_status.setStyleSheet(f"color: {COLOR_WARN};")
+
+        def call():
+            return self.client.reinit(mode=mode, wait=True, timeout=1800,
+                                      progress=False)
+
+        self._reinit_worker = _ReinitWorker(call, self)
+        self._reinit_worker.finished_ok.connect(self._on_reinit_ok)
+        self._reinit_worker.finished_error.connect(self._on_reinit_error)
+        self._reinit_worker.start()
+
+    def _on_reinit_ok(self, health: dict):
+        self._reinit_worker = None
+        self.action_status.setText(
+            f"reinit finished: {health.get('n_initialized')}/"
+            f"{health.get('n_target_names')} initialized, "
+            f"{health.get('n_failed')} failed"
+        )
+        self.action_status.setStyleSheet(f"color: {COLOR_OK};")
+
+    def _on_reinit_error(self, message: str):
+        self._reinit_worker = None
+        self.action_status.setText(f"reinit failed: {message}")
+        self.action_status.setStyleSheet(f"color: {COLOR_BAD};")
+
+    def closeEvent(self, event):
+        # A reinit is a blocking network call that can run for minutes
+        # (client.reinit(wait=True)); destroying the QThread while it is
+        # still running is a hard crash (observed directly, not
+        # hypothetically), so the window refuses to close under it instead.
+        # No modal dialog here on purpose - that would block the whole
+        # process on a click while the reinit keeps running regardless;
+        # the status label already says why nothing happened.
+        if self._reinit_worker is not None and self._reinit_worker.isRunning():
+            self.action_status.setText(
+                "cannot close: a reinit/restart is still running on the server"
+            )
+            self.action_status.setStyleSheet(f"color: {COLOR_BAD};")
+            event.ignore()
+            return
+        self._poller.stop()
+        self._poller.wait(2000)
+        super().closeEvent(event)
+
+
+def main(argv=None):
+    parser = argparse.ArgumentParser(
+        description="Qt status/reinit monitor for one eco.status_server"
+    )
+    parser.add_argument("--url", required=True,
+                        help="server base URL, e.g. http://saresb-cons-04:8091")
+    args = parser.parse_args(argv)
+
+    app = QtWidgets.QApplication.instance() or QtWidgets.QApplication(sys.argv)
+    win = StatusServerMonitor(args.url)
+    win.show()
+    return app.exec_()
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/eco/status_server/namespace_server.py b/eco/status_server/namespace_server.py
index 7b21a4d..39e6bdd 100644
--- a/eco/status_server/namespace_server.py
+++ b/eco/status_server/namespace_server.py
@@ -27,6 +27,7 @@ from flask import Flask, jsonify, request
 
 from .config import NamespaceServerConfig
 from .namespace_store import READY, NamespaceMonitorStore, NotReady, ReinitInProgress
+from .query_stats import QueryStats
 from .storage import json_default, write_monitor_recording, write_status_snapshot
 
 logger = logging.getLogger(__name__)
@@ -127,6 +128,10 @@ def create_namespace_app(
     app.config["ECO_INSTANCE_ID"] = uuid.uuid4().hex
     jobs = {}
     jobs_lock = threading.Lock()
+    # Recent /status/snapshot and /status/capture operations, for the CLI's
+    # `stats` command and the GUI's query-stats table - see query_stats.py's
+    # module docstring for why this is separate from /health.
+    stats = QueryStats()
 
     def _health_body():
         report = store.connection_report()
@@ -147,6 +152,20 @@ def create_namespace_app(
     def health():
         return jsonify(_health_body())
 
+    @app.get("/stats")
+    def query_stats_endpoint():
+        """Recent /status/snapshot, /status/capture and async /status/job
+        write operations - separate from /health, which is about the
+        namespace, not about whether requests are being served well. See
+        query_stats.py's module docstring.
+        """
+        limit = request.args.get("limit", type=int)
+        kind = request.args.get("kind")
+        return jsonify({
+            "summary": stats.summary(),
+            "recent": stats.recent(limit=limit, kind=kind),
+        })
+
     @app.get("/names")
     def names():
         ns = store.namespace
@@ -177,89 +196,95 @@ def create_namespace_app(
     @app.post("/status/snapshot")
     def status_snapshot():
         body = request.get_json(force=True, silent=True) or {}
+        t0 = time.time()
+        fields = {"save": bool(body.get("save", False))}
+        error = None
         try:
-            snap = store.snapshot(
-                allow_stale=bool(body.get("allow_stale", False)),
-                max_workers=body.get("max_workers"),
-            )
-        except NotReady as exc:
-            # health first, then the error keys: _health_body() carries its
-            # own "status" field, which would otherwise clobber "error".
-            return (
-                jsonify(
-                    {
-                        **_health_body(),
-                        "status": "error",
-                        "state": exc.state,
-                        "message": str(exc),
-                    }
-                ),
-                503,
-            )
-
-        response = {"namespace": config.module_name, **snap}
-
-        if body.get("save", False):
             try:
-                pgroup = body["pgroup"]
-                run_number = int(body["run_number"])
-            except (KeyError, TypeError, ValueError):
+                snap = store.snapshot(
+                    allow_stale=bool(body.get("allow_stale", False)),
+                    max_workers=body.get("max_workers"),
+                )
+            except NotReady as exc:
+                error = f"NotReady: {exc}"
+                # health first, then the error keys: _health_body() carries
+                # its own "status" field, which would otherwise clobber
+                # "error".
                 return (
                     jsonify(
                         {
+                            **_health_body(),
                             "status": "error",
-                            "message": "save=true requires 'pgroup' and 'run_number'",
+                            "state": exc.state,
+                            "message": str(exc),
                         }
                     ),
-                    400,
+                    503,
                 )
-            key = body.get("key", "status_run_start")
-            directory = config.data_dir(pgroup, run_number)
-            payload = _status_payload(snap)
 
-            if body.get("write_async", False):
-                job_id = uuid.uuid4().hex
-                with jobs_lock:
-                    jobs[job_id] = {
-                        "state": "running",
-                        "path": str(directory / "status.json"),
-                        "started_at": time.time(),
-                    }
+            fields["n_entries"] = len(snap.get("status", {}))
+            response = {"namespace": config.module_name, **snap}
 
-                def _write():
+            if body.get("save", False):
+                try:
+                    pgroup = body["pgroup"]
+                    run_number = int(body["run_number"])
+                except (KeyError, TypeError, ValueError):
+                    error = "save=true requires 'pgroup' and 'run_number'"
+                    return (
+                        jsonify({"status": "error", "message": error}),
+                        400,
+                    )
+                key = body.get("key", "status_run_start")
+                fields.update(pgroup=pgroup, run_number=run_number, key=key)
+                directory = config.data_dir(pgroup, run_number)
+                payload = _status_payload(snap)
+
+                if body.get("write_async", False):
+                    job_id = uuid.uuid4().hex
+                    with jobs_lock:
+                        jobs[job_id] = {
+                            "state": "running",
+                            "path": str(directory / "status.json"),
+                            "started_at": time.time(),
+                        }
+
+                    def _write():
+                        t0w = time.time()
+                        werror = None
+                        try:
+                            path = write_status_snapshot(directory, payload, key=key)
+                            rec = {"state": "done", "path": str(path)}
+                        except Exception as exc:  # noqa: BLE001 - via HTTP
+                            logger.error("async status write failed", exc_info=True)
+                            werror = f"{type(exc).__name__}: {exc}"
+                            rec = {"state": "error", "error": werror}
+                        rec["finished_at"] = time.time()
+                        with jobs_lock:
+                            jobs[job_id].update(rec)
+                        stats.record("write", time.time() - t0w, error=werror,
+                                    pgroup=pgroup, run_number=run_number, key=key)
+
+                    threading.Thread(
+                        target=_write, name=f"status-write-{job_id[:8]}", daemon=True
+                    ).start()
+                    response["write_job_id"] = job_id
+                    response["saved_to"] = str(directory / "status.json")
+                else:
                     try:
                         path = write_status_snapshot(directory, payload, key=key)
-                        rec = {"state": "done", "path": str(path)}
-                    except Exception as exc:  # noqa: BLE001 - reported via HTTP
-                        logger.error("async status write failed", exc_info=True)
-                        rec = {"state": "error", "error": f"{type(exc).__name__}: {exc}"}
-                    rec["finished_at"] = time.time()
-                    with jobs_lock:
-                        jobs[job_id].update(rec)
+                    except Exception as exc:  # noqa: BLE001
+                        logger.error("status write failed", exc_info=True)
+                        error = f"could not write status file: {type(exc).__name__}: {exc}"
+                        return (
+                            jsonify({"status": "error", "message": error}),
+                            500,
+                        )
+                    response["saved_to"] = str(path)
 
-                threading.Thread(
-                    target=_write, name=f"status-write-{job_id[:8]}", daemon=True
-                ).start()
-                response["write_job_id"] = job_id
-                response["saved_to"] = str(directory / "status.json")
-            else:
-                try:
-                    path = write_status_snapshot(directory, payload, key=key)
-                except Exception as exc:  # noqa: BLE001
-                    logger.error("status write failed", exc_info=True)
-                    return (
-                        jsonify(
-                            {
-                                "status": "error",
-                                "message": f"could not write status file: "
-                                f"{type(exc).__name__}: {exc}",
-                            }
-                        ),
-                        500,
-                    )
-                response["saved_to"] = str(path)
-
-        return jsonify(response)
+            return jsonify(response)
+        finally:
+            stats.record("snapshot", time.time() - t0, error=error, **fields)
 
     def _append_aux(pgroup, run_number, files):
         """Hand files to sf_daq_broker's copy_user_files, the same call
@@ -327,6 +352,7 @@ def create_namespace_app(
 
         def _capture():
             rec = {}
+            t0_total = time.time()
             try:
                 t0 = time.time()
                 snap = store.snapshot()
@@ -361,6 +387,14 @@ def create_namespace_app(
             rec["finished_at"] = time.time()
             with jobs_lock:
                 jobs[job_id].update(rec)
+            stats.record(
+                "capture", time.time() - t0_total, error=rec.get("error"),
+                pgroup=pgroup, run_number=run_number, key=key,
+                n_entries=rec.get("n_status"),
+                snapshot_s=rec.get("snapshot_seconds"),
+                write_s=rec.get("write_seconds"),
+                upload_s=rec.get("upload_seconds"),
+            )
 
         threading.Thread(
             target=_capture, name=f"status-capture-{job_id[:8]}", daemon=True
diff --git a/eco/status_server/namespace_store.py b/eco/status_server/namespace_store.py
index d5eb346..109c69b 100644
--- a/eco/status_server/namespace_store.py
+++ b/eco/status_server/namespace_store.py
@@ -542,11 +542,19 @@ class NamespaceMonitorStore:
         ns = self.namespace
         n_init = n_failed = None
         failed = []
+        failed_required = []
         if ns is not None:
             try:
                 n_init = len(self._target_names & set(ns.initialized_names))
                 failed = sorted(self._target_names & set(ns.failed_names))
                 n_failed = len(failed)
+                # A failed component that is in required_names() is the one
+                # a client has to be told about loudly: the setup is not
+                # supposed to fail those, so one of them missing means the
+                # status this server serves is incomplete in a way that
+                # matters, not merely in a way that is expected.
+                required = set(ns.required_names())
+                failed_required = sorted(set(failed) & required)
             except Exception:
                 logger.debug("could not compute init progress", exc_info=True)
         return {
@@ -563,6 +571,8 @@ class NamespaceMonitorStore:
             "n_initialized": n_init,
             "n_failed": n_failed,
             "failed_names": failed,
+            "failed_required": failed_required,
+            "n_failed_required": len(failed_required),
             "last_error": self.last_error,
             "last_init_seconds": self.last_init_seconds,
             "last_init_finished": self.last_init_finished,
diff --git a/eco/status_server/query_stats.py b/eco/status_server/query_stats.py
new file mode 100644
index 0000000..94d0738
--- /dev/null
+++ b/eco/status_server/query_stats.py
@@ -0,0 +1,102 @@
+"""A small ring buffer of recent status-server operations.
+
+Exists for exactly one question, asked from the CLI/GUI rather than by
+grepping the log: "is this server actually serving fast, and did anything
+just fail?" `/health` answers "is the namespace healthy"; this answers "is
+answering requests healthy" - the two are independent (a server can hold a
+perfectly good namespace and still be slow or erroring on writes because the
+NFS mount it writes status.json to is having a bad day).
+
+Kept in-process, not persisted: a few hundred entries is enough for "what
+just happened", and surviving a restart is not the point - `/health`'s
+`generation`/`last_init_*` already covers "what happened across restarts".
+"""
+
+from __future__ import annotations
+
+import threading
+import time
+from collections import deque
+
+
+class QueryStats:
+    def __init__(self, maxlen: int = 200):
+        self._lock = threading.Lock()
+        self._history = deque(maxlen=maxlen)
+
+    def record(self, kind: str, duration_s: float, error: str | None = None,
+              **fields) -> dict:
+        """Add one completed operation. `fields` is whatever is worth
+        showing for that `kind` - e.g. `n_entries`, `pgroup`, `run_number`,
+        `key`, `snapshot_s`/`write_s`/`upload_s` for a capture job."""
+        entry = {
+            "kind": kind,
+            "at": time.time(),
+            "duration_s": duration_s,
+            "error": error,
+            **fields,
+        }
+        with self._lock:
+            self._history.append(entry)
+        return entry
+
+    def recent(self, limit: int | None = None, kind: str | None = None) -> list[dict]:
+        with self._lock:
+            items = list(self._history)
+        if kind:
+            items = [i for i in items if i["kind"] == kind]
+        if limit:
+            items = items[-limit:]
+        return items
+
+    def summary(self) -> dict:
+        with self._lock:
+            items = list(self._history)
+        if not items:
+            return {"n": 0, "n_errors": 0}
+        durations = [i["duration_s"] for i in items if i.get("duration_s") is not None]
+        errors = [i for i in items if i.get("error")]
+        last = items[-1]
+        last_error = next((i for i in reversed(items) if i.get("error")), None)
+        return {
+            "n": len(items),
+            "n_errors": len(errors),
+            "last_at": last["at"],
+            "last_kind": last["kind"],
+            "last_duration_s": last.get("duration_s"),
+            "last_error": last.get("error"),
+            "last_error_at": last_error["at"] if last_error else None,
+            "avg_duration_s": sum(durations) / len(durations) if durations else None,
+            "max_duration_s": max(durations) if durations else None,
+            "min_duration_s": min(durations) if durations else None,
+        }
+
+
+class timed:
+    """Context manager: measure a block and record it on `stats` when done,
+    whichever way it ends.
+
+        with timed(stats, "snapshot", n_entries=len(snap["status"])) as t:
+            snap = store.snapshot()
+            t.fields["n_entries"] = len(snap["status"])
+
+    An exception inside the block is recorded as the operation's error
+    (str(exc)) and re-raised unchanged - this never swallows anything.
+    """
+
+    def __init__(self, stats: QueryStats, kind: str, **fields):
+        self.stats = stats
+        self.kind = kind
+        self.fields = fields
+        self.error = None
+
+    def __enter__(self):
+        self._t0 = time.time()
+        return self
+
+    def __exit__(self, exc_type, exc, tb):
+        if exc is not None:
+            self.error = f"{exc_type.__name__}: {exc}"
+        self.stats.record(self.kind, time.time() - self._t0, error=self.error,
+                          **self.fields)
+        return False
diff --git a/eco/timing/event_timing_new_new.py b/eco/timing/event_timing_new_new.py
index 61b7d21..b7ca05d 100644
--- a/eco/timing/event_timing_new_new.py
+++ b/eco/timing/event_timing_new_new.py
@@ -1,4 +1,6 @@
-from epics import caget_many
+import time
+
+from epics import PV, caget_many
 from ..elements.adjustable import AdjustableMemory, AdjustableVirtual
 from ..elements.detector import DetectorVirtual
 from ..epics_utils.adjustable import (
@@ -217,7 +219,8 @@ class MasterEventSystem(Assembly):
             )
             self.event_codes[code] = self.__dict__[f"code{code:03d}"]
 
-    def _get_slot_codes(self, slots=range(1, 257), attempts=3, timeout=3.0):
+    def _get_slot_codes(self, slots=range(1, 257), attempts=3, timeout=3.0,
+                        connect_timeout=1.0):
         """Read the master's slot->event-code table.
 
         `caget_many` reports a slot it could not read as `None`, and those
@@ -228,28 +231,68 @@ class MasterEventSystem(Assembly):
         the life of the session - after which every EVR pulser wired to a
         dropped code came up without its delay/frequency chain, blaming "code
         missing in Timing Master" for what was really a timed-out read.
-        Retry the missing ones (they are a handful, so this is cheap) and say
-        so if any are still missing, rather than quietly shipping a partial
-        table. Dependency-ordered init makes this much less likely to trigger
-        in the first place, but the silent-drop path is worth closing anyway.
+        Retry the missing ones and say so if any are still missing, rather
+        than quietly shipping a partial table.
+
+        **A slot that is simply not configured is not a failure.** Measured
+        on SIN-TIMAST-TMA (2026-09-06): exactly 74 of the 256 slots exist;
+        the other 182 have no record on the IOC at all - their PVs do not
+        connect even given 5 s on a completely idle network, and the count
+        is identical inside and outside `init_all()`. Retrying those is
+        pointless (three `caget_many` passes over 182 non-existent channels
+        cost ~15 s of every namespace init) and warning about them is a false
+        alarm that has been firing at every session start.
+
+        So the two cases are separated by *connection*, which is the only
+        thing that distinguishes them - `caget_many` reports both as `None`.
+        A channel that does not connect is an unconfigured slot: skipped
+        silently. A channel that connects but whose read came back empty is
+        a genuine timed-out read, which is what the retry and the warning
+        are for.
         """
         slots = list(slots)
         pvs = [f"{self.pvname}:Evt-{slot}-Code-SP" for slot in slots]
         codes = list(caget_many(pvs, timeout=timeout))
 
+        missing = [i for i, c in enumerate(codes) if c is None]
+        unconfigured = set()
+        if missing:
+            # Create the channels non-blockingly and let libca resolve them
+            # in the background, then ask once - far cheaper than a
+            # wait_for_connection() per channel.
+            probes = {i: PV(pvs[i], connection_timeout=connect_timeout,
+                            auto_monitor=False) for i in missing}
+            deadline = time.time() + connect_timeout
+            while time.time() < deadline and not all(
+                p.connected for p in probes.values()
+            ):
+                time.sleep(0.05)
+            unconfigured = {i for i, p in probes.items() if not p.connected}
+
+        retryable = [i for i in missing if i not in unconfigured]
         for _ in range(max(int(attempts) - 1, 0)):
-            missing = [i for i, c in enumerate(codes) if c is None]
-            if not missing:
+            if not retryable:
                 break
-            retried = caget_many([pvs[i] for i in missing], timeout=timeout)
-            for i, c in zip(missing, retried):
+            retried = caget_many([pvs[i] for i in retryable], timeout=timeout)
+            for i, c in zip(retryable, retried):
                 codes[i] = c
-        still_missing = [slots[i] for i, c in enumerate(codes) if c is None]
+            retryable = [i for i in retryable if codes[i] is None]
+
+        if unconfigured:
+            logger.debug(
+                "timing master %s: %d of %d event-code slots are not "
+                "configured (no record on the IOC) and were skipped; %d in "
+                "use.",
+                self.pvname, len(unconfigured), len(slots),
+                len(slots) - len(unconfigured),
+            )
+        still_missing = [slots[i] for i in retryable]
         if still_missing:
             logger.warning(
-                "timing master %s: %d of %d event-code slots could not be "
-                "read after %d attempts (slots %s%s); event codes served by "
-                "them will look missing to every EVR pulser using them.",
+                "timing master %s: %d of %d event-code slots connected but "
+                "could not be read after %d attempts (slots %s%s); event "
+                "codes served by them will look missing to every EVR pulser "
+                "using them.",
                 self.pvname,
                 len(still_missing),
                 len(slots),
@@ -465,6 +508,27 @@ class DummyPulser(Assembly):
         self._append(AdjustableMemory, None, name="width")
 
 
+_shared_dummy_pulser = None
+
+
+def _get_shared_dummy_pulser():
+    """The one `DummyPulser` instance for the whole process.
+
+    An out-of-range pulser number is a routine, expected IOC state (an unwired
+    output) rather than a per-output failure, so there is nothing output- or
+    EVR-specific to preserve by giving each affected output its own instance.
+    A full `init_all()` can hit this on a few dozen outputs at once (as it does
+    on the real Bernina EVR0, all wired to the sentinel 65535), and each fresh
+    `DummyPulser()` builds and appends eight `AdjustableMemory` children for no
+    behavioural difference from any other dummy -- one shared, lazily-built
+    instance avoids that multiplied-by-outputs construction cost.
+    """
+    global _shared_dummy_pulser
+    if _shared_dummy_pulser is None:
+        _shared_dummy_pulser = DummyPulser()
+    return _shared_dummy_pulser
+
+
 class EvrOutput(Assembly):
     def __init__(self, pv_base, pulsers=None, name=None):
         super().__init__(name=name)
@@ -650,7 +714,11 @@ class EvrOutput(Assembly):
         try:
             return self._pulsers[number]
         except (IndexError, TypeError):
-            logger.warning(
+            # An unwired output (number outside the EVR's pulser range, e.g.
+            # the 65535 sentinel) is routine IOC state, not a failure worth
+            # surfacing by default -- see the docstring above and the shared
+            # dummy singleton this returns.
+            logger.debug(
                 "output %s (%s): %s number %r does not address any of the %d "
                 "pulsers of this EVR; using a dummy pulser.",
                 self.name,
@@ -659,7 +727,7 @@ class EvrOutput(Assembly):
                 number,
                 len(self._pulsers or ()),
             )
-            return DummyPulser()
+            return _get_shared_dummy_pulser()
 
     def update_pulsers(self):
         """Re-read which pulsers this output is wired to (they are otherwise
@@ -684,12 +752,14 @@ class EventReceiver(Assembly):
         n_pulsers=24,
         n_output_front=8,
         n_output_rear=16,
+        has_evr_sequencer=True,
         name=None,
     ):
         super().__init__(name=name)
         self.pvname = pvname
 
-        self._append(EvrSequencer,self.pvname,name='sequencer', is_display=True, is_setting=True)
+        if has_evr_sequencer:
+            self._append(EvrSequencer,self.pvname,name='sequencer', is_display=True, is_setting=True)
         
 
         pulsers = []
diff --git a/eco/utilities/config.py b/eco/utilities/config.py
index e25ca9b..659ae87 100644
--- a/eco/utilities/config.py
+++ b/eco/utilities/config.py
@@ -132,21 +132,50 @@ class NamespaceComponent:
                 return obj
 
 
-def replace_NamespaceComponents(*args, **kwargs):
-    args_out = []
-    kwargs_out = {}
+def _replace_NamespaceComponent(value):
+    """Recurse into plain list/tuple/dict containers so a NamespaceComponent
+    stays replaceable even when passed as e.g. ``default_counters=[NamespaceComponent(...)]``
+    rather than directly as a keyword value -- see `replace_NamespaceComponents`,
+    which previously only checked one level of args/kwargs and silently left
+    any NamespaceComponent nested inside a container unresolved (a plain,
+    useless NamespaceComponent instance ends up where a real Proxy'd object
+    was expected).  Only these three container types are unwrapped/rebuilt;
+    anything else (including other iterables, e.g. numpy arrays) is passed
+    through untouched.
+    """
+    if isinstance(value, NamespaceComponent):
+        return Proxy(value.get)
+    elif isinstance(value, list):
+        return [_replace_NamespaceComponent(v) for v in value]
+    elif isinstance(value, tuple):
+        return tuple(_replace_NamespaceComponent(v) for v in value)
+    elif isinstance(value, dict):
+        return {k: _replace_NamespaceComponent(v) for k, v in value.items()}
+    else:
+        return value
 
-    for arg in args:
-        if isinstance(arg, NamespaceComponent):
-            args_out.append(Proxy(arg.get))
-        else:
-            args_out.append(arg)
-            pass
-    for name, value in kwargs.items():
-        if isinstance(value, NamespaceComponent):
-            kwargs_out[name] = Proxy(value.get)
-        else:
-            kwargs_out[name] = value
+
+def _find_NamespaceComponents(value):
+    """Collect every NamespaceComponent in `value`, recursing into plain
+    list/tuple/dict containers the same way `_replace_NamespaceComponent`
+    does -- used for declared-dependency tracking, which had the same
+    top-level-only blind spot as the resolution it mirrors.
+    """
+    found = []
+    if isinstance(value, NamespaceComponent):
+        found.append(value)
+    elif isinstance(value, (list, tuple)):
+        for v in value:
+            found.extend(_find_NamespaceComponents(v))
+    elif isinstance(value, dict):
+        for v in value.values():
+            found.extend(_find_NamespaceComponents(v))
+    return found
+
+
+def replace_NamespaceComponents(*args, **kwargs):
+    args_out = [_replace_NamespaceComponent(arg) for arg in args]
+    kwargs_out = {name: _replace_NamespaceComponent(value) for name, value in kwargs.items()}
 
     return args_out, kwargs_out
 
@@ -2080,11 +2109,9 @@ class Namespace(Assembly):
                 "module_name": module_name,
                 "obj_factory": obj_factory,
             }
-            self._declared_dependencies[name] = [
-                a
-                for a in list(args) + list(kwargs.values())
-                if isinstance(a, NamespaceComponent)
-            ]
+            self._declared_dependencies[name] = _find_NamespaceComponents(
+                list(args) + list(kwargs.values())
+            )
         if lazy:
 
             def init_local():
diff --git a/eco/utilities/datafiles.py b/eco/utilities/datafiles.py
index 5aa42e3..d177395 100644
--- a/eco/utilities/datafiles.py
+++ b/eco/utilities/datafiles.py
@@ -122,6 +122,17 @@ def _name_of_gid(gid):
         return str(gid)
 
 
+_NOGROUP_RE = re.compile(r"(?:^|[-_])nogroup$", re.IGNORECASE)
+
+
+def _is_nogroup_sentinel(gid):
+    """True if `gid` names a ``nogroup``-shaped group (``nogroup``,
+    ``unx-nogroup``, ...) -- the fallback primary group a personal account's
+    files land in under a directory that lost its setgid bit, never a group
+    anyone chose on purpose. See `target_group_of_path`."""
+    return bool(_NOGROUP_RE.search(_name_of_gid(gid)))
+
+
 def pgroup_of_path(path):
     """The pgroup owning `path`, or None if it isn't inside a pgroup tree.
 
@@ -179,24 +190,71 @@ def target_group_of_path(path):
     Only the **nearest existing ancestor directory** is consulted, and only if
     this process is a member of its group: a grandparent's group is not the
     local convention, and a group we are not in cannot be set anyway.
+
+    One exception: if that nearest ancestor's group is itself a ``nogroup``
+    sentinel, one further level up is checked for a real group before falling
+    back to it. ``nogroup`` is never a deliberately-chosen shared group -- it
+    is the literal symptom of the very corruption this function exists to stop
+    propagating (see above): a directory that a personal account happened to
+    create under a non-setgid parent lands owned by that account's own
+    ``nogroup``-shaped primary group. Accepting it as "the local convention"
+    would keep spreading it onto every new sibling/child written next to the
+    already-broken directory -- and would do so silently, since most accounts
+    on this beamline are themselves members of ``unx-nogroup``, so the
+    ordinary "not a member" guard above never catches it. The one-level
+    lookup recovers the real, intentionally-set group directly above the
+    broken directory (e.g. ``eco_cnf_bernina/memory`` itself, one level above
+    a device directory that lost it) -- exactly the group
+    `ensure_group_writable`/`repair_tree` are trying to restore on that
+    directory anyway. It deliberately does not walk further than one extra
+    level: a tree that is genuinely, uniformly ``nogroup`` all the way up (an
+    ordinary personal ``/tmp``, say) keeps exactly its previous behaviour.
     """
     pgroup = pgroup_of_path(path)
     if pgroup is not None:
         return pgroup
 
-    for parent in Path(path).absolute().parents:
+    ancestors = list(Path(path).absolute().parents)
+    for idx, parent in enumerate(ancestors):
         try:
             st = os.stat(parent)
         except OSError:
             continue  # does not exist yet (mkdir -p is about to create it)
         if not stat.S_ISDIR(st.st_mode):
             continue
+        if _is_nogroup_sentinel(st.st_gid):
+            better = _real_group_one_level_up(ancestors[idx + 1 :])
+            if better is not None:
+                return better
         if st.st_gid in _process_gids():
             return _name_of_gid(st.st_gid)
         return None
     return None
 
 
+def _real_group_one_level_up(remaining_ancestors):
+    """The group of the nearest existing, non-``nogroup`` directory in
+    `remaining_ancestors` that this process is a member of, or None.
+
+    Only consulted from `target_group_of_path` when the nearest ancestor is
+    itself a `nogroup` sentinel -- see there for why a single extra level is
+    enough.
+    """
+    if not remaining_ancestors:
+        return None
+    try:
+        st = os.stat(remaining_ancestors[0])
+    except OSError:
+        return None
+    if not stat.S_ISDIR(st.st_mode):
+        return None
+    if _is_nogroup_sentinel(st.st_gid):
+        return None
+    if st.st_gid in _process_gids():
+        return _name_of_gid(st.st_gid)
+    return None
+
+
 def acl_grants_group_write(path, group=None):
     """Best-effort "is group write already granted by a POSIX ACL?".
 
diff --git a/eco/utilities/utilities.py b/eco/utilities/utilities.py
index 400b638..749cf50 100644
--- a/eco/utilities/utilities.py
+++ b/eco/utilities/utilities.py
@@ -102,6 +102,9 @@ class TimeoutPath:
     def get_path(self) -> Path:
         return self._path
 
+    def __fspath__(self) -> str:
+        return self._path.__fspath__()
+
     def __getattr__(self, name: str) -> Any:
         return getattr(self._path, name)
 
diff --git a/scripts/eco-status-server b/scripts/eco-status-server
index b5b2f01..b02e1c2 100755
--- a/scripts/eco-status-server
+++ b/scripts/eco-status-server
@@ -1,8 +1,9 @@
 #!/bin/bash
-# eco status server (namespace mode) - start/stop/status wrapper.
+# eco status server (namespace mode) - start/stop/status/gui wrapper.
 #
-# Canonical copy lives in the eco repo at eco/status_server/bin/; the copy in
-# /sf/bernina/bin is installed from there (see install-user-service).
+# Canonical copy lives in the eco repo at scripts/, alongside eco-dev;
+# /sf/bernina/bin/eco-status-server is a symlink to this file, so editing
+# the checkout takes effect immediately - nothing to redeploy.
 #
 # Runs in the FOREGROUND by default, which is what systemd's Type=simple
 # wants and what the accompanying user unit calls. Use `-b` to detach for
@@ -46,6 +47,8 @@ usage: $(basename "$0") <command> [options]
   status                        query $URL/health
   wait [timeout]                block until the server reports ready
   logs [-f]                     show the detached-mode log
+  stats                         recent /status/snapshot & /status/capture calls
+  gui                           launch the Qt status/reinit GUI (detached)
   config                        print the resolved configuration
 
 Environment (current values):
@@ -68,7 +71,7 @@ check_prereqs() {
     if [ -z "${EPICS_CA_ADDR_LIST:-}" ]; then
         echo "$(basename "$0"): warning: EPICS_CA_ADDR_LIST is not set;" >&2
         echo "  most components will fail to connect. See the EnvironmentFile" >&2
-        echo "  written by eco-status-server-install-user-service." >&2
+        echo "  written by the install-user-service script alongside this one." >&2
     fi
     [ -r "$CONFIG" ] || die "no server config at $CONFIG (set ECO_STATUS_SERVER_CONFIG)"
     [ -x "$PYTHON" ] || die "no interpreter at $PYTHON (set ECO_STATUS_SERVER_PYTHON)"
@@ -174,6 +177,14 @@ cmd_status() {
     "$PYTHON" - "$URL" <<'PYEOF' || true
 import json, sys, urllib.request
 
+RED_BOLD = "\033[1;31m"
+YELLOW = "\033[33m"
+RESET = "\033[0m"
+color = sys.stdout.isatty()
+
+def c(s, code):
+    return f"{code}{s}{RESET}" if color else s
+
 url = sys.argv[1].rstrip("/") + "/health"
 try:
     with urllib.request.urlopen(url, timeout=15) as r:
@@ -190,8 +201,20 @@ print("serving: {d} status detectors, {m} monitorable".format(
     d=h["n_direct_read"], m=h.get("n_monitorable")))
 print("process: {r:.0f} MB, {t} threads, {c:.0f} s cpu".format(
     r=h.get("rss_mb") or 0, t=h.get("n_threads"), c=h.get("cpu_seconds") or 0))
-if h.get("failed_names"):
-    print("failed:  " + ", ".join(h["failed_names"]))
+# failed_required: components that are BOTH in required_names() and in
+# failed_names(), i.e. the setup is not supposed to fail these - see
+# NamespaceMonitorStore.connection_report(). A merely-optional failure
+# (failed_names but not required) stays in the plain line below, unhighlighted.
+failed_required = h.get("failed_required") or []
+other_failed = [n for n in (h.get("failed_names") or []) if n not in failed_required]
+if failed_required:
+    print(c(
+        "!!! {n} REQUIRED component(s) failed to initialize: {names}".format(
+            n=len(failed_required), names=", ".join(failed_required)),
+        RED_BOLD,
+    ))
+if other_failed:
+    print("failed:  " + ", ".join(other_failed))
 for rec in h.get("recordings", []):
     if rec.get("running"):
         print("recording {id}: {u} updates, {s} stored".format(
@@ -207,6 +230,36 @@ with urllib.request.urlopen(sys.argv[1].rstrip("/") + "/health", timeout=15) as
 PYEOF
 }
 
+# One progress+ETA line, from /health alone: elapsed time in the current
+# state (state_seconds) and how far init has gotten (n_initialized of
+# n_target_names) linearly project how much longer it needs. Rough on
+# purpose - components do not all cost the same - but far better than a
+# bare spinner for something that can take several minutes.
+progress_line() {
+    "$PYTHON" - "$URL" <<'PYEOF' 2>/dev/null || true
+import json, sys, urllib.request
+
+with urllib.request.urlopen(sys.argv[1].rstrip("/") + "/health", timeout=15) as r:
+    h = json.load(r)
+
+state, elapsed = h["state"], h.get("state_seconds") or 0
+i, t = h.get("n_initialized") or 0, h.get("n_target_names") or 0
+line = f"{state}: {i}/{t} initialized ({h.get('n_failed')} failed)"
+if t and i:
+    frac = i / t
+    eta = elapsed * (1 - frac) / frac if frac > 0 else None
+    bar_width = 24
+    filled = int(round(bar_width * min(frac, 1.0)))
+    bar = "#" * filled + "-" * (bar_width - filled)
+    line += f"  [{bar}] {frac*100:5.1f}%  elapsed {elapsed:.0f}s"
+    if eta is not None:
+        line += f"  eta ~{eta:.0f}s"
+else:
+    line += f"  elapsed {elapsed:.0f}s"
+print(line)
+PYEOF
+}
+
 cmd_wait() {
     # split, not `local a=.. b=$((a))`: under `set -u` bash evaluates the
     # arithmetic before the first assignment is visible, and the command
@@ -215,12 +268,56 @@ cmd_wait() {
     local end=$((SECONDS + timeout))
     while [ $SECONDS -lt $end ]; do
         if is_ready; then cmd_status; return 0; fi
-        cmd_status | sed -n '2p'
+        progress_line
         sleep 15
     done
     die "not ready after ${timeout}s"
 }
 
+cmd_stats() {
+    "$PYTHON" - "$URL" <<'PYEOF' || true
+import json, sys, urllib.request
+
+url = sys.argv[1].rstrip("/") + "/stats"
+try:
+    with urllib.request.urlopen(url, timeout=15) as r:
+        d = json.load(r)
+except Exception as exc:
+    print("stats:   no answer from %s (%s)" % (url, exc))
+    raise SystemExit(1)
+
+s = d["summary"]
+if not s.get("n"):
+    print("no requests served yet")
+    raise SystemExit(0)
+print(f"{s['n']} operation(s) recorded, {s['n_errors']} error(s)")
+if s.get("avg_duration_s") is not None:
+    print(f"duration: avg {s['avg_duration_s']:.2f}s  "
+          f"min {s['min_duration_s']:.2f}s  max {s['max_duration_s']:.2f}s")
+if s.get("last_error"):
+    print(f"last error: {s['last_error']}")
+
+print()
+print(f"{'when':>8s}  {'kind':<9s} {'dur(s)':>7s}  {'entries':>7s}  error")
+import time
+for e in d["recent"][-20:]:
+    age = time.time() - e["at"]
+    dur = e.get("duration_s")
+    dur_s = f"{dur:.2f}" if dur is not None else "?"
+    n = e.get("n_entries")
+    err = e.get("error") or ""
+    print(f"{age:7.0f}s  {e['kind']:<9s} {dur_s:>7s}  {str(n) if n is not None else '-':>7s}  {err}")
+PYEOF
+}
+
+cmd_gui() {
+    check_prereqs
+    export PYTHONPATH="$CHECKOUT${PYTHONPATH:+:$PYTHONPATH}"
+    nohup "$PYTHON" -m eco.status_server.gui --url "$URL" "$@"         </dev/null >/dev/null 2>&1 &
+    disown
+    echo "launched (pid $!)"
+}
+
 case "${1:-}" in
     start)   shift; cmd_start "$@" ;;
     stop)    cmd_stop ;;
@@ -234,6 +331,8 @@ case "${1:-}" in
     status)  cmd_status ;;
     wait)    shift; cmd_wait "$@" ;;
     logs)    shift; [ "${1:-}" = "-f" ] && tail -f "$LOG" || tail -n 100 "$LOG" ;;
+    stats)   cmd_stats ;;
+    gui)     shift; cmd_gui "$@" ;;
     config)  usage ;;
     ""|-h|--help|help) usage ;;
     *)       usage; exit 2 ;;
diff --git a/tests/test_bs_counter_mockup.py b/tests/test_bs_counter_mockup.py
index 99427fe..6e1dd78 100644
--- a/tests/test_bs_counter_mockup.py
+++ b/tests/test_bs_counter_mockup.py
@@ -70,7 +70,10 @@ def test_multi_source_and_stepscan_binning(bs_worker):
     fake_scan = FakeScan(n_steps)
     for cb in ctr.callbacks_start_scan:
         cb(scan=fake_scan)
-    assert len(ctr._scan._values) == n_steps
+    # Bins are open-ended (escape-fel 0.2.7 -- see bs_counter.py's module
+    # docstring) and created on demand, so none exist yet right after
+    # start; they grow to n_steps once every step has been visited below.
+    assert len(ctr._scan._values) == 0
 
     all_pulse_ids = {name: [] for name in ctr._channels}
     for step in range(n_steps):
@@ -81,14 +84,16 @@ def test_multi_source_and_stepscan_binning(bs_worker):
             assert len(pids) == 10
             all_pulse_ids[name].extend(pids)
 
+    assert len(ctr._scan._values) == n_steps
+
     for cb in ctr.callbacks_end_scan:
         cb(scan=fake_scan)
 
     # Pulse ids strictly increasing and non-overlapping across steps, for
     # every channel -- confirms the per-step bins are a clean partition of
-    # the live stream (this is exactly the case that silently lost data
-    # with an un-pre-declared/open-ended escape.stream.Scan -- see
-    # bs_counter.py's module docstring).
+    # the live stream. This is exactly the case that used to silently lose
+    # data for a late-joining channel on a shared, open-ended
+    # escape.stream.Scan before escape-fel 0.2.7.
     for name, ids in all_pulse_ids.items():
         assert ids == sorted(ids)
         assert len(ids) == len(set(ids))
diff --git a/tests/test_ca_monitor_policy.py b/tests/test_ca_monitor_policy.py
new file mode 100644
index 0000000..a8f806c
--- /dev/null
+++ b/tests/test_ca_monitor_policy.py
@@ -0,0 +1,281 @@
+"""The adaptive channel-access monitor policy in eco.epics_utils.ca_tuning.
+
+Background, from pyepics' own `PV.get_with_metadata`::
+
+    if not self.wait_for_connection(timeout=timeout):
+        return None
+    if ((not use_monitor) or (not self.auto_monitor) or ...):
+        metad = ca.get_with_metadata(...)
+        if metad is None:
+            return
+
+so `auto_monitor=False` - the old eco-wide default - makes every read a
+network round trip with two ways to silently return `None`, while
+`auto_monitor=True` with a cached value skips that block entirely. The
+policy here monitors by default and demotes only channels that prove too
+fast, rather than every caller hand-rolling its own monitor cache.
+"""
+
+import json
+import time
+import types
+
+import pytest
+
+from eco.epics_utils import ca_tuning
+
+
+class FakePV:
+    """Enough of epics.PV for the policy: callbacks, auto_monitor, pvname."""
+
+    def __init__(self, pvname, auto_monitor=False, **kwargs):
+        self.pvname = pvname
+        self.auto_monitor = auto_monitor
+        self.kwargs = kwargs
+        self.callbacks = {}
+        self._next_index = 0
+
+    def add_callback(self, cb, with_ctrlvars=True, **kw):
+        self.with_ctrlvars = with_ctrlvars
+        self._next_index += 1
+        self.callbacks[self._next_index] = cb
+        return self._next_index
+
+    def remove_callback(self, index):
+        self.callbacks.pop(index, None)
+
+    def fire(self, n=1):
+        for _ in range(n):
+            for cb in list(self.callbacks.values()):
+                cb()
+
+
+@pytest.fixture
+def policy(tmp_path, monkeypatch):
+    """ca_tuning with its module state isolated per test."""
+    monkeypatch.setattr(ca_tuning, "AUTO_MONITOR_STATE_FILE",
+                        tmp_path / "fast.json")
+    monkeypatch.setattr(ca_tuning, "_fast_channels", set())
+    monkeypatch.setattr(ca_tuning, "_update_counts", {})
+    monkeypatch.setattr(ca_tuning, "_tracked", {})
+    monkeypatch.setattr(ca_tuning, "_sensitive_depth", 0)
+    monkeypatch.setattr(ca_tuning, "_sweeper", object())  # never start a thread
+    fake_epics = types.ModuleType("epics")
+    fake_epics.PV = FakePV
+    monkeypatch.setitem(__import__("sys").modules, "epics", fake_epics)
+    return ca_tuning
+
+
+# --------------------------------------------------------------------------
+# default policy
+
+
+def test_pvs_are_monitored_by_default(policy):
+    pv = policy.make_pv("TEST:SLOW")
+    assert pv.auto_monitor is True
+    assert "TEST:SLOW" in policy._tracked
+
+
+def test_the_rate_counter_does_not_trigger_a_ctrlvars_storm(policy):
+    """pyepics defaults add_callback(with_ctrlvars=True), which issues a
+    blocking get_ctrlvars() per connected PV - across a namespace that is
+    the get-storm this policy exists to avoid."""
+    pv = policy.make_pv("TEST:SLOW")
+    assert pv.with_ctrlvars is False
+
+
+def test_an_explicit_auto_monitor_still_wins(policy):
+    pv = policy.make_pv("TEST:X", auto_monitor=False)
+    assert pv.auto_monitor is False
+    assert policy._tracked == {}
+
+
+# --------------------------------------------------------------------------
+# learning which channels are too fast
+
+
+def test_a_fast_channel_is_demoted_and_remembered(policy):
+    pv = policy.make_pv("TEST:FAST")
+    pv.fire(100)                       # 100 updates ...
+    policy._sweep_once(interval=1.0)   # ... in one second = 100 Hz
+
+    assert pv.auto_monitor is False
+    assert pv.callbacks == {}, "the rate counter should be detached too"
+    assert policy.is_known_fast("TEST:FAST")
+    assert "TEST:FAST" not in policy._tracked
+
+
+def test_a_slow_channel_keeps_its_monitor(policy):
+    pv = policy.make_pv("TEST:SLOW")
+    pv.fire(3)
+    policy._sweep_once(interval=1.0)
+    assert pv.auto_monitor is True
+    assert not policy.is_known_fast("TEST:SLOW")
+
+
+def test_a_channel_someone_else_monitors_is_never_demoted(policy):
+    """A recording, a Monitor() or a CallbackEpics registers its own
+    callback; clearing the subscription under it would silently stop its
+    data."""
+    pv = policy.make_pv("TEST:FAST")
+    pv.add_callback(lambda **kw: None)      # somebody else's monitor
+    pv.fire(100)
+    policy._sweep_once(interval=1.0)
+
+    assert pv.auto_monitor is True
+    assert not policy.is_known_fast("TEST:FAST")
+
+
+def test_a_known_fast_channel_is_never_subscribed_again(policy):
+    pv = policy.make_pv("TEST:FAST")
+    pv.fire(100)
+    policy._sweep_once(interval=1.0)
+
+    again = policy.make_pv("TEST:FAST")
+    assert again.auto_monitor is False
+    assert "TEST:FAST" not in policy._tracked
+
+
+def test_the_learned_list_survives_a_restart(policy, tmp_path):
+    pv = policy.make_pv("TEST:FAST")
+    pv.fire(100)
+    policy._sweep_once(interval=1.0)
+
+    written = json.loads((tmp_path / "fast.json").read_text())
+    assert written == ["TEST:FAST"]
+
+    policy._fast_channels.clear()
+    policy._load_fast_channels()
+    assert policy.is_known_fast("TEST:FAST")
+
+
+def test_clearing_forgets_everything(policy):
+    pv = policy.make_pv("TEST:FAST")
+    pv.fire(100)
+    policy._sweep_once(interval=1.0)
+    assert policy.is_known_fast("TEST:FAST")
+
+    policy.clear_fast_channels()
+    assert not policy.is_known_fast("TEST:FAST")
+
+
+def test_counts_are_zeroed_not_lost_between_sweeps(policy):
+    pv = policy.make_pv("TEST:SLOW")
+    pv.fire(3)
+    policy._sweep_once(interval=1.0)
+    assert policy._update_counts["TEST:SLOW"] == 0
+    pv.fire(2)
+    assert policy._update_counts["TEST:SLOW"] == 2
+
+
+# --------------------------------------------------------------------------
+# sensitive periods
+
+
+def test_the_sweeper_leaves_subscriptions_alone_during_an_acquisition(policy):
+    """Reconfiguring a monitor mid-acquisition is exactly the wrong moment,
+    even for a channel that deserves demotion."""
+    pv = policy.make_pv("TEST:FAST")
+    pv.fire(100)
+    with policy.sensitive_period("scan step"):
+        policy._sweep_once(interval=1.0)
+        assert pv.auto_monitor is True, "demoted mid-acquisition"
+    # and it still gets demoted once the window closes
+    policy._sweep_once(interval=1.0)
+    assert pv.auto_monitor is False
+
+
+def test_reads_get_a_more_patient_budget_while_sensitive(policy):
+    assert policy.read_retries() == policy.CA_READ_RETRIES
+    with policy.sensitive_period("scan step"):
+        assert policy.read_retries() == policy.CA_READ_RETRIES_SENSITIVE
+    assert policy.read_retries() == policy.CA_READ_RETRIES
+
+
+def test_sensitive_periods_nest(policy):
+    with policy.sensitive_period("outer"):
+        with policy.sensitive_period("inner"):
+            assert policy.in_sensitive_period()
+        assert policy.in_sensitive_period(), "the inner exit ended both"
+    assert not policy.in_sensitive_period()
+
+
+def test_a_raising_body_still_ends_the_period(policy):
+    with pytest.raises(ValueError):
+        with policy.sensitive_period("boom"):
+            raise ValueError("boom")
+    assert not policy.in_sensitive_period()
+
+
+# --------------------------------------------------------------------------
+# _read_pv: the single chokepoint that stops the next caller needing its own
+# private cache
+
+
+class FlakyPV:
+    """A PV that returns None for the first `n_none` reads, then a value."""
+
+    def __init__(self, n_none, value=42.0, connected=True,
+                 pvname="TEST:FLAKY"):
+        self.pvname = pvname
+        self.connected = connected
+        self._left = n_none
+        self._value = value
+        self.reads = 0
+
+    def get(self, timeout=None):
+        self.reads += 1
+        if self._left > 0:
+            self._left -= 1
+            return None
+        return self._value
+
+
+@pytest.fixture
+def read_pv(monkeypatch):
+    from eco.epics_utils import adjustable
+
+    monkeypatch.setattr(ca_tuning, "_last_ok", {})
+    monkeypatch.setattr(ca_tuning, "CA_READ_RETRY_DELAY", 0.0)
+    monkeypatch.setattr(ca_tuning, "_sensitive_depth", 0)
+    return adjustable._read_pv
+
+
+def test_a_transient_none_is_retried_into_a_real_value(read_pv):
+    """The recurring bug: pyepics returns None on a momentary CA hiccup
+    instead of raising, and the caller uses it as data (`int(None)`,
+    `100 / None`, `event_codes[None]`)."""
+    ca_tuning.note_successful_read("TEST:FLAKY")  # it has worked before
+    pv = FlakyPV(n_none=1)
+    assert read_pv(pv, name="flaky") == 42.0
+    assert pv.reads == 2
+
+
+def test_retries_are_bounded(read_pv):
+    ca_tuning.note_successful_read("TEST:FLAKY")
+    pv = FlakyPV(n_none=99)
+    assert read_pv(pv, name="flaky") is None
+    assert pv.reads == 1 + ca_tuning.CA_READ_RETRIES
+
+
+def test_a_channel_that_never_worked_is_not_retried(read_pv):
+    """An absent PV is read on every get_status() fan-out, i.e. once per
+    scan step - it must not pay for retries it will never win."""
+    pv = FlakyPV(n_none=99, connected=False, pvname="TEST:ABSENT")
+    assert read_pv(pv, name="absent") is None
+    assert pv.reads == 1
+
+
+def test_a_sensitive_period_buys_more_attempts(read_pv):
+    ca_tuning.note_successful_read("TEST:FLAKY")
+    pv = FlakyPV(n_none=3)
+    with ca_tuning.sensitive_period("scan step"):
+        assert read_pv(pv, name="flaky") == 42.0
+    assert pv.reads == 4  # would have given up at 3 outside the period
+
+
+def test_a_successful_read_needs_no_retry(read_pv):
+    ca_tuning.note_successful_read("TEST:FLAKY")
+    pv = FlakyPV(n_none=0)
+    assert read_pv(pv, name="flaky") == 42.0
+    assert pv.reads == 1
diff --git a/tests/test_ca_tuning.py b/tests/test_ca_tuning.py
index 9212cf9..87f0044 100644
--- a/tests/test_ca_tuning.py
+++ b/tests/test_ca_tuning.py
@@ -78,7 +78,11 @@ def test_never_connected_pv_keeps_the_short_budget():
 
 
 def test_a_disconnected_but_previously_working_pv_gets_the_full_budget():
-    """A dropped virtual circuit is exactly what the longer budget is for."""
+    """A dropped virtual circuit is exactly what the longer budget is for -
+    and, since this channel demonstrably works, also worth retrying: the
+    retry lives in `_read_pv` so no individual caller has to grow its own
+    cache the way `Daq.get_pulse_id` and the event-code frequency did."""
+    from eco.epics_utils import ca_tuning
     from eco.epics_utils.adjustable import _read_pv
 
     pv = FakePV([2.0], pvname="SOME:FLAKY:PV", connected=True)
@@ -86,7 +90,9 @@ def test_a_disconnected_but_previously_working_pv_gets_the_full_budget():
     pv.connected = False
     pv.timeouts.clear()
     _read_pv(pv, name="flaky")
-    assert pv.timeouts == [None], "should use the PV's own connection_timeout"
+    assert pv.timeouts, "no read was attempted at all"
+    assert set(pv.timeouts) == {None}, "should use the PV's own connection_timeout"
+    assert len(pv.timeouts) == 1 + ca_tuning.CA_READ_RETRIES
 
 
 def test_falsy_values_are_not_treated_as_failures(caplog):
diff --git a/tests/test_daq_status_server.py b/tests/test_daq_status_server.py
index 5d3098d..e8f23bc 100644
--- a/tests/test_daq_status_server.py
+++ b/tests/test_daq_status_server.py
@@ -537,3 +537,152 @@ def test_only_the_start_block_keeps_its_values_on_the_server():
     daq.append_status_to_scan_and_store(RunTableScan(runno=11))
     assert client.captures[0]["keep_status"] is True
     assert client.captures[1]["keep_status"] is False
+
+
+# --------------------------------------------------------------------------
+# rate_multiplicator / get_detector_code_frequency: never a raw CA get, never
+# a silent None reaching arithmetic (the pulse_id bug, 4th occurrence)
+
+
+class FakeFreqMonitor:
+    """Stands in for CallbackEpics(func="latest"): .data is the same dict
+    object the real one mutates in place, so a cached reference stays live."""
+
+    def __init__(self, initial=None):
+        self.data = {"value": initial}
+        self.started = False
+
+    def start(self, add_current_value=True):
+        self.started = True
+
+    def push(self, value):
+        self.data["value"] = value
+
+
+class FreqDetector:
+    def __init__(self, value, pvname="TEST:Evt-1-Freq-I", monitorable=True):
+        self._value = value
+        self.pvname = pvname
+        self._monitor = FakeFreqMonitor(value) if monitorable else None
+
+    def get_current_value(self):
+        return self._value
+
+    def set_current_value_callback(self, func="accumulate", **kwargs):
+        if self._monitor is None:
+            raise AttributeError("not monitorable")
+        return self._monitor
+
+
+def _event_master(freq_detector, code=50):
+    em = types.SimpleNamespace()
+    em.__dict__[f"code{code:03d}"] = types.SimpleNamespace(frequency=freq_detector)
+    return em
+
+
+def _freq_daq(freq_detector, code=50):
+    daq = Daq.__new__(Daq)
+    daq._event_master = None
+    daq._detectors_event_code = None
+    daq._frequency_detector = None
+    daq._frequency_monitor = None
+    daq._frequency_latest = {"value": None}
+    event_master = _event_master(freq_detector, code=code)
+    # replicate the __init__ snippet directly, since Daq.__new__ skips it
+    try:
+        daq._frequency_detector = event_master.__dict__[
+            f"code{code:03d}"
+        ].frequency
+        mon = daq._frequency_detector.set_current_value_callback(func="latest")
+        mon.start()
+        daq._frequency_monitor = mon
+        daq._frequency_latest = mon.data
+    except Exception:
+        pass
+    daq._detectors_event_code = code
+    return daq
+
+
+def test_frequency_is_read_from_the_monitor_cache_not_a_fresh_get():
+    det = FreqDetector(50.0)
+    daq = _freq_daq(det)
+    assert daq._frequency_monitor.started is True
+    assert daq.get_detector_code_frequency() == 50.0
+    assert daq.rate_multiplicator == 2
+
+
+def test_frequency_cache_follows_live_monitor_updates():
+    det = FreqDetector(50.0)
+    daq = _freq_daq(det)
+    det._monitor.push(25.0)
+    assert daq.get_detector_code_frequency() == 25.0
+
+
+def test_a_transient_none_from_the_monitor_falls_back_to_a_direct_read():
+    """The exact failure mode observed live: pyepics silently returns None
+    on a transient CA hiccup instead of raising."""
+    det = FreqDetector(50.0)
+    daq = _freq_daq(det)
+    det._monitor.push(None)
+    # get_current_value() still works even though the monitor cache is
+    # momentarily empty
+    assert daq.get_detector_code_frequency() == 50.0
+
+
+def test_no_value_anywhere_raises_instead_of_dividing_by_none():
+    """Before this fix: int(100 / freq) with freq=None -> TypeError, deep
+    inside retrieve(), killing a real scan mid-run."""
+    det = FreqDetector(None)
+    daq = _freq_daq(det)
+    with pytest.raises(TimeoutError, match="TEST:Evt-1-Freq-I"):
+        daq.get_detector_code_frequency()
+    with pytest.raises(TimeoutError):
+        daq.rate_multiplicator
+
+
+def test_a_non_monitorable_frequency_falls_back_to_direct_reads():
+    """MasterEventCodeFix (fixed CTA sequencer codes) has no PV to monitor
+    at all - set_current_value_callback isn't there, __init__'s attach must
+    not blow up, and reads should still work via get_current_value()."""
+    det = FreqDetector(50.0, monitorable=False)
+    daq = _freq_daq(det)
+    assert daq._frequency_monitor is None
+    assert daq.get_detector_code_frequency() == 50.0
+
+
+def test_missing_event_master_does_not_crash_init():
+    daq = Daq.__new__(Daq)
+    daq._frequency_detector = None
+    daq._frequency_monitor = None
+    daq._frequency_latest = {"value": None}
+    daq._detectors_event_code = None
+    with pytest.raises(TimeoutError):
+        daq.get_detector_code_frequency()
+
+
+# --------------------------------------------------------------------------
+# _create_runtable_metadata_append_status_to_runtable must honor
+# append_status_info=False (it silently didn't - a regression from the old
+# combined elog+run_table callback, which had the guard)
+
+
+def test_runtable_metadata_callback_skips_when_append_status_info_is_false():
+    rt = RunTableSpy()
+    daq = _runtable_daq(HealthClient(), rt)
+    scan = RunTableScan(runno=99)
+    daq._create_runtable_metadata_append_status_to_runtable(
+        scan, append_status_info=False
+    )
+    assert rt.calls == [], (
+        "run_table.append_run() ran despite append_status_info=False - this "
+        "is what makes a session's first scan pay for Run_Table2's Google "
+        "Sheets authentication even when status collection was disabled"
+    )
+
+
+def test_runtable_metadata_callback_still_runs_by_default():
+    rt = RunTableSpy()
+    daq = _runtable_daq(HealthClient(), rt)
+    scan = RunTableScan(runno=100)
+    daq._create_runtable_metadata_append_status_to_runtable(scan)
+    assert len(rt.calls) == 1
diff --git a/tests/test_datafiles.py b/tests/test_datafiles.py
index 9df43ad..f032d25 100644
--- a/tests/test_datafiles.py
+++ b/tests/test_datafiles.py
@@ -333,6 +333,38 @@ def test_target_group_of_path_uses_the_nearest_existing_ancestor(tmp_path):
     )
 
 
+def test_target_group_of_path_skips_a_nogroup_ancestor(tmp_path, monkeypatch):
+    """A directory that lost its setgid bit and was recreated by a personal
+    account lands owned by that account's own nogroup-shaped primary group --
+    the eco_cnf_bernina/memory incident described in the module docstring. A
+    new file written next to/inside that broken directory must not inherit
+    the broken group; the walk should recover the real group one level up
+    instead (fully mocked here, since the real gid a `/tmp`-shaped path gets
+    on a given machine is itself sometimes nogroup, which would make this
+    indistinguishable from the bug it is testing for)."""
+    broken = tmp_path / "broken"
+    broken.mkdir()
+    real_stat = os.stat
+    broken_gid, real_group_gid = 999998, 999999
+    names = {broken_gid: "unx-nogroup", real_group_gid: "unx-sf_bernina_bs"}
+
+    def fake_stat(path, *a, **k):
+        st = real_stat(path, *a, **k)
+        gid = broken_gid if Path(path) == broken else (
+            real_group_gid if Path(path) == tmp_path else None
+        )
+        if gid is None:
+            return st
+        return type("FakeStat", (), {"st_gid": gid, "st_mode": st.st_mode})()
+
+    monkeypatch.setattr(df.os, "stat", fake_stat)
+    monkeypatch.setattr(df, "_name_of_gid", lambda gid: names.get(gid, str(gid)))
+    monkeypatch.setattr(df, "_process_gids", lambda: frozenset(names))
+
+    result = df.target_group_of_path(broken / "new_file.json")
+    assert result == "unx-sf_bernina_bs"
+
+
 def test_target_group_of_path_ignores_a_group_the_process_is_not_in(
     tmp_path, monkeypatch
 ):
diff --git a/tests/test_dummy_pulser.py b/tests/test_dummy_pulser.py
new file mode 100644
index 0000000..891a65a
--- /dev/null
+++ b/tests/test_dummy_pulser.py
@@ -0,0 +1,59 @@
+"""EvrOutput._resolve_pulser: an out-of-range pulser number is routine IOC
+state (an unwired output), not a per-output failure.
+
+`init_all()` on the real Bernina EVR0 hits this on a few dozen outputs at
+once, all wired to the sentinel 65535 -- see the module docstring in
+`eco.timing.event_timing_new_new`. Two things follow from that being routine:
+the message should not be shown by default (WARNING -> DEBUG, matching the
+"unconfigured slot" treatment in `MasterEventSystem._get_slot_codes`), and it
+should not cost a fresh `DummyPulser` (eight `AdjustableMemory` children) per
+occurrence -- one shared, lazily-built instance is enough.
+"""
+
+import logging
+
+import pytest
+
+evt = pytest.importorskip("eco.timing.event_timing_new_new")
+
+
+@pytest.fixture(autouse=True)
+def _reset_shared_dummy(monkeypatch):
+    monkeypatch.setattr(evt, "_shared_dummy_pulser", None)
+
+
+def _make_output(monkeypatch, number=65535):
+    monkeypatch.setattr(
+        evt, "read_pv_value", lambda *a, **k: number
+    )
+    output = evt.EvrOutput.__new__(evt.EvrOutput)
+    output.name = "output_test"
+    output.pv_base = "TEST:Output"
+    output._pulsers = [object() for _ in range(24)]
+    return output
+
+
+def test_out_of_range_pulser_returns_the_shared_dummy(monkeypatch):
+    output_a = _make_output(monkeypatch)
+    output_b = _make_output(monkeypatch)
+
+    pulser_a = output_a._resolve_pulser(None, "pulserA")
+    pulser_b = output_b._resolve_pulser(None, "pulserB")
+
+    assert isinstance(pulser_a, evt.DummyPulser)
+    assert pulser_a is pulser_b, "one shared instance, not one per output"
+    assert pulser_a is evt._get_shared_dummy_pulser()
+
+
+def test_out_of_range_pulser_is_not_shown_by_default(monkeypatch, caplog):
+    output = _make_output(monkeypatch)
+
+    with caplog.at_level(logging.WARNING, logger=evt.__name__):
+        output._resolve_pulser(None, "pulserA")
+
+    assert caplog.text == "", "should be invisible at the default log level"
+
+    with caplog.at_level(logging.DEBUG, logger=evt.__name__):
+        output._resolve_pulser(None, "pulserA")
+
+    assert "does not address any of the" in caplog.text
diff --git a/tests/test_status_server.py b/tests/test_status_server.py
index 2d50c8d..a681867 100644
--- a/tests/test_status_server.py
+++ b/tests/test_status_server.py
@@ -1192,3 +1192,47 @@ def test_capture_is_refused_while_not_ready(fake_module):
     )
     assert resp.status_code == 503
     assert store.wait_ready(timeout=20)
+
+
+def test_health_reports_failed_required_components_separately(fake_module):
+    """A failed component that is in required_names() is the one a client has
+    to be told about loudly - the setup is not supposed to fail those."""
+    name, mod = fake_module(names=["a", "b", "c"], required=["a", "b"], fail=["b", "c"])
+    store = _store(name, init_required_only=False)
+    assert store.wait_ready(timeout=10)
+
+    report = store.connection_report()
+    assert report["failed_names"] == ["b", "c"]
+    assert report["failed_required"] == ["b"], "c is not required, b is"
+    assert report["n_failed_required"] == 1
+
+    app = create_namespace_app(NamespaceServerConfig(module_name=name), store=store)
+    body = app.test_client().get("/health").get_json()
+    assert body["failed_required"] == ["b"]
+
+
+def test_no_failed_required_is_reported_as_empty(fake_module):
+    name, _ = fake_module(names=["a", "b"], required=["a"], fail=["b"])
+    store = _store(name, init_required_only=False)
+    assert store.wait_ready(timeout=10)
+    report = store.connection_report()
+    assert report["failed_names"] == ["b"]
+    assert report["failed_required"] == []
+
+
+def test_the_client_warns_in_red_about_failed_required(capsys):
+    from eco.status_server.client import warn_failed_required
+
+    warned = warn_failed_required({"failed_required": ["mon_und", "scilog"]})
+    out = capsys.readouterr().out
+    assert warned == ["mon_und", "scilog"]
+    assert "REQUIRED" in out and "mon_und" in out and "scilog" in out
+    assert "\x1b[" in out, "should be colourised"
+
+
+def test_the_client_stays_quiet_when_nothing_required_failed(capsys):
+    from eco.status_server.client import warn_failed_required
+
+    assert warn_failed_required({"failed_required": [], "failed_names": ["x"]}) == []
+    assert warn_failed_required({}) == []
+    assert capsys.readouterr().out == ""
diff --git a/tests/test_status_server_gui.py b/tests/test_status_server_gui.py
new file mode 100644
index 0000000..0ca72fd
--- /dev/null
+++ b/tests/test_status_server_gui.py
@@ -0,0 +1,197 @@
+"""eco.status_server.gui: the display/state logic, driven directly (no real
+poller thread, no real server) - _on_health/_on_stats/_start_reinit are
+plain slots, so they can be called synchronously with fake payloads."""
+
+import pytest
+
+pytest.importorskip("qtpy")
+
+from qtpy import QtGui, QtWidgets
+
+from eco.status_server.gui import COLOR_BAD, COLOR_OK, StatusServerMonitor
+
+
+@pytest.fixture(scope="module")
+def qapp():
+    return QtWidgets.QApplication.instance() or QtWidgets.QApplication([])
+
+
+@pytest.fixture
+def win(qapp, monkeypatch):
+    # Never let the real background poller touch the network during a test.
+    from eco.status_server import gui as gui_module
+
+    monkeypatch.setattr(gui_module._Poller, "start", lambda self: None)
+    w = StatusServerMonitor("http://fake-host:8091")
+    yield w
+    w._poller.stop()
+
+
+def _health(**overrides):
+    h = {
+        "state": "ready", "generation": 3, "uptime_s": 120.0,
+        "n_initialized": 80, "n_target_names": 86, "n_failed": 6,
+        "state_seconds": 5.0, "n_direct_read": 16000, "n_monitorable": 10000,
+        "n_monitored": 0, "rss_mb": 2000.0, "n_threads": 100,
+        "cpu_seconds": 300.0, "failed_names": [], "failed_required": [],
+    }
+    h.update(overrides)
+    return h
+
+
+# --------------------------------------------------------------------------
+# health rendering
+
+
+def test_ready_state_is_shown_in_ok_color(win):
+    win._on_health(_health())
+    assert "ready" in win.state_label.text()
+    assert COLOR_OK in win.state_label.styleSheet()
+    assert win.required_banner.isHidden()
+
+
+def test_progress_bar_reflects_init_fraction(win):
+    win._on_health(_health(n_initialized=43, n_target_names=86))
+    assert win.progress.value() == 50
+
+
+def test_required_failure_shows_the_red_banner(win):
+    win._on_health(_health(
+        state="ready", failed_names=["mon_und", "scilog"],
+        failed_required=["mon_und", "scilog"],
+    ))
+    assert not win.required_banner.isHidden()
+    assert "mon_und" in win.required_banner.text()
+    assert "scilog" in win.required_banner.text()
+    assert "REQUIRED" in win.required_banner.text()
+    # a required failure must not also be double-listed as "other"
+    assert win.other_failed_label.text() == ""
+
+
+def test_non_required_failure_does_not_trigger_the_red_banner(win):
+    win._on_health(_health(failed_names=["xrd"], failed_required=[]))
+    assert win.required_banner.isHidden()
+    assert "xrd" in win.other_failed_label.text()
+
+
+def test_mixed_failures_split_correctly(win):
+    win._on_health(_health(
+        failed_names=["mon_und", "xrd"], failed_required=["mon_und"],
+    ))
+    assert "mon_und" in win.required_banner.text()
+    assert "xrd" not in win.required_banner.text()
+    assert "xrd" in win.other_failed_label.text()
+    assert "mon_und" not in win.other_failed_label.text()
+
+
+def test_eta_is_shown_while_initializing(win):
+    win._on_health(_health(
+        state="initializing", n_initialized=50, n_target_names=100,
+        state_seconds=10.0,
+    ))
+    # 50% done in 10s -> another ~10s projected
+    assert "eta" in win.eta_label.text()
+
+
+def test_no_eta_once_ready(win):
+    win._on_health(_health(state="ready"))
+    assert "eta" not in win.eta_label.text()
+
+
+def test_buttons_disabled_while_busy(win):
+    win._on_health(_health(state="initializing"))
+    assert not win.btn_failed.isEnabled()
+    win._on_health(_health(state="ready"))
+    assert win.btn_failed.isEnabled()
+
+
+def test_unreachable_server_turns_the_dot_red_and_keeps_last_state(win):
+    win._on_health(_health(state="ready"))
+    win._on_health_failed("ConnectionError: refused")
+    assert COLOR_BAD in win.dot.styleSheet()
+    assert "ready" in win.state_label.text()  # stale, but still shown
+
+
+# --------------------------------------------------------------------------
+# stats table
+
+
+def test_stats_summary_line(win):
+    win._on_stats({"summary": {"n": 5, "n_errors": 1, "avg_duration_s": 2.5},
+                   "recent": []})
+    assert "5 operation" in win.summary_label.text()
+    assert "1 error" in win.summary_label.text()
+
+
+def test_empty_stats_says_so(win):
+    win._on_stats({"summary": {"n": 0, "n_errors": 0}, "recent": []})
+    assert "no requests" in win.summary_label.text()
+
+
+def test_stats_table_populates_and_colors_errors(win):
+    win._on_stats({
+        "summary": {"n": 2, "n_errors": 1},
+        "recent": [
+            {"at": 1000.0, "kind": "snapshot", "duration_s": 1.2, "n_entries": 99},
+            {"at": 1001.0, "kind": "capture", "duration_s": 0.5, "error": "boom"},
+        ],
+    })
+    assert win.table.rowCount() == 2
+    # most recent first
+    assert win.table.item(0, 1).text() == "capture"
+    assert win.table.item(0, 4).text() == "boom"
+    assert win.table.item(0, 4).foreground().color().name() == QtGui.QColor(COLOR_BAD).name()
+    assert win.table.item(1, 1).text() == "snapshot"
+    assert win.table.item(1, 4).text() == ""
+
+
+# --------------------------------------------------------------------------
+# reinit action + close guard
+
+
+def test_reinit_click_disables_buttons_and_calls_the_client(win, qapp):
+    calls = []
+    win.client.reinit = lambda **kw: calls.append(kw) or {
+        "n_initialized": 80, "n_target_names": 86, "n_failed": 6,
+    }
+    win.btn_failed.click()
+    win._reinit_worker.wait(2000)
+    qapp.processEvents()
+    assert calls and calls[0]["mode"] == "failed"
+    assert "reinit finished" in win.action_status.text()
+
+
+def test_reinit_error_is_shown(win, qapp):
+    def boom(**kw):
+        raise RuntimeError("server unreachable")
+
+    win.client.reinit = boom
+    win.btn_full.click()
+    win._reinit_worker.wait(2000)
+    qapp.processEvents()
+    assert "reinit failed" in win.action_status.text()
+    assert "server unreachable" in win.action_status.text()
+
+
+def test_window_refuses_to_close_while_a_reinit_is_running(win, qapp):
+    import threading
+
+    release = threading.Event()
+    win.client.reinit = lambda **kw: (release.wait(2), {})[1]
+    win.btn_failed.click()
+    qapp.processEvents()
+    assert win._reinit_worker.isRunning()
+
+    ev = QtGui.QCloseEvent()
+    win.closeEvent(ev)
+    assert not ev.isAccepted()
+    assert "cannot close" in win.action_status.text()
+
+    release.set()
+    win._reinit_worker.wait(2000)
+
+
+def test_window_closes_normally_when_idle(win):
+    ev = QtGui.QCloseEvent()
+    win.closeEvent(ev)
+    assert ev.isAccepted()
diff --git a/tests/test_status_server_query_stats.py b/tests/test_status_server_query_stats.py
new file mode 100644
index 0000000..389374a
--- /dev/null
+++ b/tests/test_status_server_query_stats.py
@@ -0,0 +1,114 @@
+"""eco.status_server.query_stats: the ring buffer behind GET /stats."""
+
+import pytest
+
+from eco.status_server.query_stats import QueryStats, timed
+
+
+def test_empty_summary():
+    s = QueryStats()
+    assert s.summary() == {"n": 0, "n_errors": 0}
+    assert s.recent() == []
+
+
+def test_record_and_recent():
+    s = QueryStats()
+    s.record("snapshot", 1.5, n_entries=100)
+    s.record("capture", 2.5, pgroup="p1")
+    recent = s.recent()
+    assert len(recent) == 2
+    assert recent[0]["kind"] == "snapshot"
+    assert recent[0]["n_entries"] == 100
+    assert recent[1]["pgroup"] == "p1"
+
+
+def test_recent_filters_by_kind():
+    s = QueryStats()
+    s.record("snapshot", 1.0)
+    s.record("capture", 1.0)
+    s.record("snapshot", 1.0)
+    assert len(s.recent(kind="snapshot")) == 2
+    assert len(s.recent(kind="capture")) == 1
+
+
+def test_recent_respects_limit():
+    s = QueryStats()
+    for i in range(10):
+        s.record("snapshot", float(i))
+    assert len(s.recent(limit=3)) == 3
+    assert s.recent(limit=3)[-1]["duration_s"] == 9.0
+
+
+def test_ring_buffer_drops_oldest():
+    s = QueryStats(maxlen=3)
+    for i in range(5):
+        s.record("snapshot", float(i))
+    recent = s.recent()
+    assert len(recent) == 3
+    assert [r["duration_s"] for r in recent] == [2.0, 3.0, 4.0]
+
+
+def test_summary_aggregates_durations_and_errors():
+    s = QueryStats()
+    s.record("snapshot", 1.0)
+    s.record("snapshot", 3.0, error="boom")
+    s.record("snapshot", 2.0)
+    summary = s.summary()
+    assert summary["n"] == 3
+    assert summary["n_errors"] == 1
+    assert summary["avg_duration_s"] == pytest.approx(2.0)
+    assert summary["min_duration_s"] == 1.0
+    assert summary["max_duration_s"] == 3.0
+    # "last_error" tracks the *last entry's* error (None here - the last
+    # recorded op succeeded); test_summary_last_error_is_the_most_recent_one
+    # covers the separate "did anything fail recently" question below.
+    assert summary["last_error"] is None
+    assert summary["last_error_at"] is not None  # "boom" is still visible via this
+
+
+def test_summary_last_error_is_the_most_recent_one():
+    s = QueryStats()
+    s.record("snapshot", 1.0, error="first")
+    s.record("snapshot", 1.0)  # no error
+    s.record("snapshot", 1.0, error="second")
+    s.record("snapshot", 1.0)  # no error again
+    summary = s.summary()
+    assert summary["last_error"] is None  # the very last entry had none
+    assert summary["last_error_at"] is not None  # but we remember the last one that did
+
+
+def test_timed_context_manager_records_success():
+    s = QueryStats()
+    with timed(s, "snapshot", n_entries=5) as t:
+        t.fields["n_entries"] = 42
+    entry = s.recent()[0]
+    assert entry["kind"] == "snapshot"
+    assert entry["n_entries"] == 42
+    assert entry["error"] is None
+    assert entry["duration_s"] >= 0
+
+
+def test_timed_context_manager_records_and_reraises_errors():
+    s = QueryStats()
+    with pytest.raises(ValueError, match="boom"):
+        with timed(s, "capture"):
+            raise ValueError("boom")
+    entry = s.recent()[0]
+    assert entry["error"] == "ValueError: boom"
+
+
+def test_thread_safety_of_concurrent_records():
+    import threading
+
+    s = QueryStats(maxlen=1000)
+
+    def worker():
+        for _ in range(100):
+            s.record("snapshot", 0.1)
+
+    threads = [threading.Thread(target=worker) for _ in range(8)]
+    for t in threads:
+        t.start()
+    for t in threads:
+        t.join()
+    assert s.summary()["n"] == 800
diff --git a/tests/test_timing_master_slots.py b/tests/test_timing_master_slots.py
new file mode 100644
index 0000000..11db798
--- /dev/null
+++ b/tests/test_timing_master_slots.py
@@ -0,0 +1,113 @@
+"""MasterEventSystem._get_slot_codes: an unconfigured slot is not a failure.
+
+Measured on SIN-TIMAST-TMA (2026-09-06): exactly 74 of 256 event slots
+exist. The other 182 have no record on the IOC - their PVs do not connect
+even given 5 s on an idle network, and the count is identical inside and
+outside `init_all()`. The old code could not tell that apart from a
+timed-out read, so it retried all 182 three times (~15 s of every namespace
+init) and then warned alarmingly about a completely normal configuration.
+"""
+
+import logging
+import types
+
+import pytest
+
+evt = pytest.importorskip("eco.timing.event_timing_new_new")
+
+
+class ProbePV:
+    """A PV that connects only if its slot is in `configured`."""
+
+    configured = set()
+
+    def __init__(self, pvname, connection_timeout=None, auto_monitor=None):
+        self.pvname = pvname
+        slot = int(pvname.split("Evt-")[1].split("-")[0])
+        self.connected = slot in ProbePV.configured
+
+
+@pytest.fixture
+def master(monkeypatch):
+    m = evt.MasterEventSystem.__new__(evt.MasterEventSystem)
+    m.pvname = "TEST-TMA"
+    monkeypatch.setattr(evt, "PV", ProbePV)
+    monkeypatch.setattr(evt.time, "sleep", lambda s: None)
+    return m
+
+
+def _install_caget(monkeypatch, table, flaky=()):
+    """table: slot -> code (absent slot => None). `flaky` slots return None
+    on the first read and their code afterwards."""
+    seen = {"calls": 0}
+    state = {s: 0 for s in flaky}
+
+    def caget_many(pvs, timeout=None):
+        seen["calls"] += 1
+        out = []
+        for pv in pvs:
+            slot = int(pv.split("Evt-")[1].split("-")[0])
+            if slot in state:
+                state[slot] += 1
+                out.append(table.get(slot) if state[slot] > 1 else None)
+            else:
+                out.append(table.get(slot))
+        return out
+
+    monkeypatch.setattr(evt, "caget_many", caget_many)
+    return seen
+
+
+def test_unconfigured_slots_are_skipped_without_retry_or_warning(
+    master, monkeypatch, caplog
+):
+    table = {1: 10, 2: 20, 3: 30}                     # only 3 of 6 exist
+    ProbePV.configured = set(table)
+    seen = _install_caget(monkeypatch, table)
+
+    with caplog.at_level(logging.DEBUG, logger=evt.__name__):
+        slots, codes = master._get_slot_codes(slots=range(1, 7))
+
+    assert sorted(codes) == [10, 20, 30]
+    assert seen["calls"] == 1, "non-existent slots must not be retried"
+    text = caplog.text
+    assert "not configured" in text and "3 in use" in text
+    assert "could not be read" not in text, "that would be the false alarm"
+
+
+def test_a_connected_but_unread_slot_is_retried_and_warned_about(
+    master, monkeypatch, caplog
+):
+    """The case the retry and the warning actually exist for."""
+    table = {1: 10, 2: 20}
+    ProbePV.configured = {1, 2, 3}          # slot 3 exists but never reads
+    seen = _install_caget(monkeypatch, table)
+
+    with caplog.at_level(logging.INFO):
+        slots, codes = master._get_slot_codes(slots=range(1, 4), attempts=3)
+
+    assert sorted(codes) == [10, 20]
+    assert seen["calls"] == 3, "a connected slot should be retried"
+    assert "connected but" in caplog.text and "could not be read" in caplog.text
+
+
+def test_a_transient_read_recovers_on_retry(master, monkeypatch, caplog):
+    table = {1: 10, 2: 20, 3: 30}
+    ProbePV.configured = set(table)
+    seen = _install_caget(monkeypatch, table, flaky=[3])
+
+    with caplog.at_level(logging.INFO):
+        slots, codes = master._get_slot_codes(slots=range(1, 4), attempts=3)
+
+    assert sorted(codes) == [10, 20, 30], "the retry should have recovered slot 3"
+    assert seen["calls"] == 2
+    assert "could not be read" not in caplog.text
+
+
+def test_everything_present_needs_no_probing_at_all(master, monkeypatch):
+    table = {1: 10, 2: 20, 3: 30}
+    ProbePV.configured = set(table)
+    seen = _install_caget(monkeypatch, table)
+    slots, codes = master._get_slot_codes(slots=range(1, 4))
+    assert seen["calls"] == 1
+    assert sorted(codes) == [10, 20, 30]