#394 follow-up: re-assert the identifier guard at the eval call site

EnvAllowListScrub's blanking loop splices each name into a string
handed to eval ("export ${n}="). That is only safe because every name
reaching _cb633_blank already passed an identifier check in the
enumeration loop -- 20 lines away, in a different loop. Before eval
was introduced a non-conforming name reaching plain `export "$n="`
was inert either way (the quoting neutralized it); eval removed that
safety net, so the enumeration loop's guard became the ONLY thing
standing between a non-identifier string and code execution in the
member's pane, with nothing at the eval site itself defending that
property.

Re-assert the same [A-Za-z_][A-Za-z0-9_]* check immediately before
the eval call, independent of the enumeration loop's own guard (left
untouched, not moved). A name that fails it is counted unblankable
rather than silently dropped, so a bypass of the upstream guard would
leave real evidence in the report.

New test exploits the "junk from multi-line values" gap the
enumeration loop's own comment already documents: a value with an
embedded newline makes `command env`'s text output split into a
spurious extra "name" line that was never a real variable. Runs the
real generated scrubScript() end-to-end under zsh and asserts the
non-conforming fragment is neither blanked nor counted unblankable.
The fragment used is merely non-conforming (contains a dot) --
never command-shaped.

Mutation-verified both guards. Weakening the enumeration guard alone
DOES break the new test (the fragment then reaches the new eval-site
guard and gets counted unblankable, failing the "not unblankable"
assertion). Removing the new eval-site guard alone, with the
enumeration guard intact, does NOT break it: _cb633_blank has exactly
one producer (the enumeration loop), so nothing can reach the eval
site without already having passed the identical check there. That is
expected given the single-source architecture, and it is exactly why
the eval-site guard is defense-in-depth against a future change that
adds a second path into _cb633_blank or decouples the two loops --
not a currently independently-observable divergence.

fleetd/src/main/java/dev/ltms/fleet/Fleetd.java

@@ -584,8 +584,12 @@ public final class Fleetd {
         if (cfg.health() != null && cfg.health().isEnabled()) {
             // CB-580: a member found GONE/NEVER_READY must fail whatever ticket is waiting on it,
             // through the same idempotent target-wide operation CB-516 already uses on release.
+            // fleetd #386: System::nanoTime freezes across a macOS sleep, so the stall check also
+            // gets a wall-clock source to detect and correct for that freeze. Every other decision
+            // in FleetHealthMonitor stays on the monotonic clock, unchanged.
             healthMonitor = new FleetHealthMonitor(agents, sessions::roster, messages, healthScheduler,
-                    System::nanoTime, cfg.health().intervalOrDefault(),
+                    System::nanoTime, () -> TimeUnit.MILLISECONDS.toNanos(System.currentTimeMillis()),
+                    cfg.health().intervalOrDefault(),
                     cfg.health().workingSuspectAfterOrDefault(), messages::abandon);
             String coverage = FleetHealthMonitor.coverage(true,
                     cfg.health().notifications() != null && cfg.health().notifications().configured());

fleetd/src/main/java/dev/ltms/fleet/health/FleetHealthMonitor.java

@@ -38,15 +38,46 @@ public final class FleetHealthMonitor {
      */
     static final long ASK_LAPSE_RECHECK_DELAY_SECONDS = 120;
 
+    /**
+     * fleetd #386: {@code System.nanoTime()} (or whatever {@link #clock} is) does not advance while
+     * macOS sleeps, so a raw {@code nowNanos - lastActivityAtNanos} comparison freezes with the
+     * host and can never cross {@link #workingSuspectAfterNanos}. This is a second, wall-clock
+     * source used ONLY inside the stall check ({@link #stallElapsedNanos}) to detect and correct
+     * for that freeze. Nothing else in this class reads it — every other decision (readiness grace,
+     * the fault classification itself) stays exactly on {@link #clock}, as the ticket requires.
+     */
+    private static final LongSupplier DEFAULT_REALTIME_CLOCK =
+            () -> TimeUnit.MILLISECONDS.toNanos(System.currentTimeMillis());
+
     private final AgentControl agents;
     private final Supplier<List<MemberSession>> roster;
     private final MessageService messages;
     private final ScheduledExecutorService scheduler;
     private final LongSupplier clock;
+    private final LongSupplier realtimeClock;
     private final long intervalSeconds;
+    private final long tickIntervalNanos;
     private final long workingSuspectAfterNanos;
     private final BiConsumer<String, String> failTarget;
     private final Map<String, HealthPrior> priors = new HashMap<>();
+    /**
+     * fleetd #386 clock-drift bookkeeping. {@code haveClockBaseline}/{@code lastTickMonoNanos}/
+     * {@code lastTickRealNanos} track the previous tick's pair of readings so each new tick can
+     * measure how far the two clocks moved apart since then. {@code accumulatedDriftNanos} is the
+     * running total of every such divergence observed since this monitor started (never decreases —
+     * the monotonic clock can only lag real time, never lead it). {@code busyDriftBaselineNanos}/
+     * {@code busyBaselineActivityNanos} record, per target, the value of {@code accumulatedDriftNanos}
+     * at the moment this monitor first saw that target's CURRENT {@code lastActivityAtNanos} while
+     * BUSY — so {@link #stallElapsedNanos} adds back only the drift observed DURING this BUSY span,
+     * never drift from a sleep that happened before the member went busy. All five fields are touched
+     * only from {@code tick()}, like {@link #priors}.
+     */
+    private boolean haveClockBaseline = false;
+    private long lastTickMonoNanos;
+    private long lastTickRealNanos;
+    private long accumulatedDriftNanos = 0;
+    private final Map<String, Long> busyDriftBaselineNanos = new HashMap<>();
+    private final Map<String, Long> busyBaselineActivityNanos = new HashMap<>();
     /**
      * The live classification per member, and the only one of this class's three maps that more
      * than one scheduler task touches. {@code tick} writes it (and prunes it to the roster);
@@ -88,12 +119,29 @@ public final class FleetHealthMonitor {
     public FleetHealthMonitor(AgentControl agents, Supplier<List<MemberSession>> roster, MessageService messages,
                               ScheduledExecutorService scheduler, LongSupplier clock, long intervalSeconds,
                               long workingSuspectAfterSeconds, BiConsumer<String, String> failTarget) {
+        this(agents, roster, messages, scheduler, clock, DEFAULT_REALTIME_CLOCK, intervalSeconds,
+                workingSuspectAfterSeconds, failTarget);
+    }
+
+    /**
+     * @param realtimeClock fleetd #386: a wall-clock nanosecond source (e.g.
+     *                       {@code System.currentTimeMillis()} converted to nanos) that keeps
+     *                       advancing while {@code clock} is frozen by a host sleep. Used only to
+     *                       correct the stall check — see the class-level javadoc on the
+     *                       clock-drift fields.
+     */
+    public FleetHealthMonitor(AgentControl agents, Supplier<List<MemberSession>> roster, MessageService messages,
+                              ScheduledExecutorService scheduler, LongSupplier clock, LongSupplier realtimeClock,
+                              long intervalSeconds, long workingSuspectAfterSeconds,
+                              BiConsumer<String, String> failTarget) {
         this.agents = agents;
         this.roster = roster;
         this.messages = messages;
         this.scheduler = scheduler;
         this.clock = clock;
+        this.realtimeClock = Objects.requireNonNull(realtimeClock, "realtimeClock");
         this.intervalSeconds = intervalSeconds;
+        this.tickIntervalNanos = TimeUnit.SECONDS.toNanos(intervalSeconds);
         this.workingSuspectAfterNanos = TimeUnit.SECONDS.toNanos(workingSuspectAfterSeconds);
         this.failTarget = Objects.requireNonNull(failTarget, "failTarget");
     }
@@ -123,6 +171,7 @@ public final class FleetHealthMonitor {
             for (Agent agent : agentsNow) live.put(agent.terminalId(), agent);
             HashSet<String> current = new HashSet<>();
             long nowNanos = clock.getAsLong();
+            long driftBeforeThisTick = observeClockDrift(nowNanos);
             for (MemberSession session : rosterNow) {
                 current.add(session.terminalId());
                 Agent agent = live.get(session.terminalId());
@@ -133,7 +182,7 @@ public final class FleetHealthMonitor {
                         && session.state() != MemberSession.State.SPAWNING;
                 boolean readinessGraceElapsed = nowNanos - session.spawnedAtNanos() >= READINESS_GRACE_NANOS;
                 boolean stalled = session.state() == MemberSession.State.BUSY
-                        && nowNanos - session.lastActivityAtNanos() >= workingSuspectAfterNanos;
+                        && stallElapsedNanos(session, nowNanos, driftBeforeThisTick) >= workingSuspectAfterNanos;
                 // CB-643: the three message-layer facts CB-640 published. Read them here rather than
                 // leaving them false — that constant is what made 8 of the 9 fault states dead.
                 boolean queuedDelivery = messages.hasQueuedDelivery(session.terminalId());
@@ -151,6 +200,8 @@ public final class FleetHealthMonitor {
             priors.keySet().retainAll(current);
             states.keySet().retainAll(current);
             orphanStreaks.keySet().retainAll(current);
+            busyDriftBaselineNanos.keySet().retainAll(current);
+            busyBaselineActivityNanos.keySet().retainAll(current);
         } catch (Throwable error) {
             // Any unclassified collection failure must never kill the monitor's only scheduler task.
             log.warn("fleet health collection failed; will retry next tick", error);
@@ -175,6 +226,65 @@ public final class FleetHealthMonitor {
         return streak >= ORPHAN_CONFIRM_TICKS;
     }
 
+    /**
+     * fleetd #386: compare this tick's monotonic and real-time readings against the previous
+     * tick's, and fold any positive divergence into {@link #accumulatedDriftNanos} (a ratchet — it
+     * never decreases, since the monotonic clock can only fall behind real time, never ahead of
+     * it). Logs once, at WARN, when that single tick's divergence exceeds one full tick interval —
+     * the signature of a host that slept between the two ticks (a tick literally cannot run while
+     * the process itself is suspended, so the whole sleep duration lands inside one tick's gap).
+     *
+     * @return {@link #accumulatedDriftNanos} as it stood BEFORE this tick's divergence was folded
+     *         in — the baseline {@link #stallElapsedNanos} needs when a target is observed BUSY
+     *         for the first time this tick, so a sleep that happened before this member went busy
+     *         is not attributed to it.
+     */
+    private long observeClockDrift(long nowNanos) {
+        long nowRealNanos = realtimeClock.getAsLong();
+        long driftBeforeThisTick = accumulatedDriftNanos;
+        if (haveClockBaseline) {
+            long monoDelta = nowNanos - lastTickMonoNanos;
+            long realDelta = nowRealNanos - lastTickRealNanos;
+            long tickDrift = realDelta - monoDelta;
+            if (tickDrift > tickIntervalNanos) {
+                log.warn("fleet health: the monotonic clock did not advance for about {}s that the "
+                        + "real clock did since the last tick (host likely slept); the stall "
+                        + "detector could not see that time", TimeUnit.NANOSECONDS.toSeconds(tickDrift));
+            }
+            if (tickDrift > 0) {
+                accumulatedDriftNanos = driftBeforeThisTick + tickDrift;
+            }
+        }
+        lastTickMonoNanos = nowNanos;
+        lastTickRealNanos = nowRealNanos;
+        haveClockBaseline = true;
+        return driftBeforeThisTick;
+    }
+
+    /**
+     * fleetd #386: {@code nowNanos - lastActivityAtNanos} alone freezes across a host sleep, since
+     * both come from the monotonic {@link #clock}. This adds back the real-time drift observed
+     * since this BUSY span started — not the monitor's whole lifetime, so a sleep that happened
+     * before this member went busy never leaks into its stall reading (see the class-level javadoc
+     * on the drift fields). The baseline resets whenever {@code lastActivityAtNanos} changes (a new
+     * turn) or the member is not currently BUSY.
+     */
+    private long stallElapsedNanos(MemberSession session, long nowNanos, long driftBeforeThisTick) {
+        String target = session.terminalId();
+        if (session.state() != MemberSession.State.BUSY) {
+            busyDriftBaselineNanos.remove(target);
+            busyBaselineActivityNanos.remove(target);
+            return nowNanos - session.lastActivityAtNanos();
+        }
+        Long baselineActivity = busyBaselineActivityNanos.get(target);
+        if (baselineActivity == null || baselineActivity != session.lastActivityAtNanos()) {
+            busyBaselineActivityNanos.put(target, session.lastActivityAtNanos());
+            busyDriftBaselineNanos.put(target, driftBeforeThisTick);
+        }
+        long driftSinceBusyStart = accumulatedDriftNanos - busyDriftBaselineNanos.get(target);
+        return (nowNanos - session.lastActivityAtNanos()) + driftSinceBusyStart;
+    }
+
     void reportTransition(String target, HealthState next) {
         HealthState previous = states.put(target, next);
         if (previous == next) return;

fleetd/src/main/java/dev/ltms/fleet/member/EnvAllowListScrub.java

@@ -13,6 +13,7 @@ import java.nio.file.attribute.PosixFilePermissions;
 import java.time.Duration;
 import java.time.Instant;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.stream.Stream;
@@ -28,33 +29,74 @@ import java.util.stream.Stream;
  * control lacked: herdr applies that overlay BEFORE the shell starts, so any sourced file can undo
  * it — and did.
  *
- * <p><b>Which file is last depends on the platform, so the scrub runs from two of them.</b> zsh
+ * <p><b>zsh reads its four startup files under three different conditions, so no single file is
+ * guaranteed to run — the scrub has to cover the gap between them, not just the platforms.</b> zsh
  * reads {@code .zshenv} always, {@code .zprofile} and {@code .zlogin} only for a LOGIN shell, and
- * {@code .zshrc} only for an INTERACTIVE one. herdr does not open the same kind of shell
- * everywhere — measured on herdr 0.8.0: macOS panes run {@code -zsh} (login, so {@code .zlogin}
- * runs), Linux panes run a plain {@code /usr/bin/zsh} (interactive but NOT login, so
- * {@code .zlogin} never runs at all). A scrub in {@code .zlogin} alone is therefore a control that
- * silently does nothing on Linux — the exact failure this class exists to remove, one platform
- * over.
+ * {@code .zshrc} only for an INTERACTIVE one. A pane shell that is at least one of login or
+ * interactive is covered by sourcing the scrub from {@code .zshrc} and {@code .zlogin} (below), but
+ * a pane shell that is NEITHER reads only {@code .zshenv} and stops — fleetd #388, measured: a herdr
+ * pane can be neither login nor interactive, and such a pane read {@code .zshenv}, never reached
+ * {@code scrub.zsh}, and left no report at all. A bare {@code argv[0]} of {@code /usr/bin/zsh}
+ * proves the shell is NOT a login shell; it says nothing about whether it is interactive, so it
+ * must never be read as "therefore interactive" — that wrong inference is what let #388 ship.
  *
- * <p>So both {@code .zshrc} and {@code .zlogin} source the same generated {@code scrub.zsh} after
- * sourcing their {@code $HOME} counterpart. On Linux only the first fires; on macOS both do, and
- * the second pass is deliberate rather than merely harmless — it re-scrubs anything the operator's
- * own {@code ~/.zlogin} exported after {@code .zshrc} had finished. Re-running is idempotent: a
- * name already blank is blanked again, and the report is rewritten with the same counts.
+ * <p>So {@code .zshenv} carries a THIRD pass, guarded by the exact condition that defines the gap:
+ * {@code [[ ! -o login && ! -o interactive ]]}. That guard is why this pass cannot double-scrub a
+ * pane that {@code .zshrc} or {@code .zlogin} will also cover — one of {@code -o login}/
+ * {@code -o interactive} is always true there, so the {@code .zshenv} pass never fires for them, and
+ * their own unconditional sourcing is untouched. The guard also carries a sentinel
+ * ({@value #SCRUB_SENTINEL}) so it fires once per PANE and not once per PROCESS: {@code .zshenv} is
+ * read by every zsh a member's own tooling forks (a plain {@code zsh -c '...'} for a single
+ * command is itself neither login nor interactive), and those children inherit variables their
+ * parent deliberately set for them (git hooks get {@code GIT_DIR}, a venv gets
+ * {@code VIRTUAL_ENV}, a build tool gets {@code NODE_OPTIONS} or {@code JAVA_TOOL_OPTIONS}).
+ * Re-scrubbing every such child would blank all of that, and would also make the pane's own
+ * {@code scrub-report.txt} — rewritten on every pass — describe whichever child exited last
+ * instead of the pane. The sentinel is exported only AFTER {@code scrub.zsh} runs, so the pass
+ * that sets it never sees it and cannot blank it; it must also be on the scrub's own allow-list
+ * (see {@link #generate(Path, Set)}) so a later pass, in the same pane, cannot blank it back to
+ * empty — an exported-but-empty sentinel reads as unset to the {@code -z} guard and would silently
+ * re-enable scrubbing for every subsequent child of that pane.
+ *
+ * <p>So all three of {@code .zshenv} (gap only, guarded), {@code .zshrc}, and {@code .zlogin}
+ * source the same generated {@code scrub.zsh} after sourcing their {@code $HOME} counterpart. A
+ * login-and-interactive pane runs the {@code .zshrc} and {@code .zlogin} passes, and the second is
+ * deliberate rather than merely harmless — it re-scrubs anything the operator's own
+ * {@code ~/.zlogin} exported after {@code .zshrc} had finished. A pane that is neither runs only the
+ * {@code .zshenv} pass. Re-running is idempotent: a name already blank is blanked again, and the
+ * report is rewritten with the same counts.
  *
  * <p>Each generated file sources its {@code $HOME} counterpart FIRST, so {@code PATH} and every
- * toolchain binary still resolve exactly as the operator configured them; only afterwards does
- * {@code .zlogin} run the scrub: every EXPORTED variable not on the derived allow-list is re-exported
+ * toolchain binary still resolve exactly as the operator configured them; only afterwards does the
+ * scrub run: every EXPORTED variable not on the derived allow-list is re-exported
  * blank. Blank, not credential-shaped-pattern-filtered: a pattern list ({@code *TOKEN*}, …) is an
  * enumeration and misses what it did not think of — a username is the other half of a credential and
  * is shaped like none. Credential-SHAPED names among the blanked set go to the WARN log only,
  * never to the control.
  *
  * <p>The scrub also writes {@code scrub-report.txt} into its own directory: one {@code allowed N of
- * M} line (N = exports left untouched, M = exports present when the scrub ran), then the blanked
- * NAMES — never values. The launcher reads this back at teardown and logs it, because a blocked
- * count next to an unknown denominator is not a finding.
+ * M failed F} line (N = exports left untouched, M = exports present when the scrub ran, F = names
+ * the scrub attempted to blank but could not), then the NAMES — blanked ones bare, unblankable ones
+ * {@code !}-prefixed — never values. The launcher reads this back at teardown and logs it, because a
+ * blocked count next to an unknown denominator is not a finding.
+ *
+ * <p><b>fleetd #394:</b> plain {@code export "$n="} is a FATAL error for a zsh read-only or special
+ * parameter (for example {@code UID}) — it aborts the whole sourced file, so every name still to
+ * come is never blanked and the report above is never written at all. The blanking loop instead
+ * routes each attempt through {@code eval}, which contains that error to the single iteration: the
+ * loop always finishes, and a name that could not be blanked is counted as {@code failed} and
+ * listed {@code !}-prefixed rather than silently disappearing. This is deliberately not a skip-list
+ * of known-bad names — every enumerated name is still attempted, so a name nobody has thought of
+ * yet still gets tried and, if it fails, still gets counted.
+ *
+ * <p>The blanking loop also re-asserts, on its own, the same {@code [A-Za-z_][A-Za-z0-9_]*} shape
+ * check the enumeration loop already applied. Before {@code eval} was introduced a non-conforming
+ * name reaching {@code export "$n="} was harmless either way — the quoting made it inert. With
+ * {@code eval}, the name is spliced into a string and interpreted as shell syntax, so the enumeration
+ * loop's check is no longer sufficient on its own to keep that call site safe — it is a guard on a
+ * different loop, and the two must not silently drift apart. Re-checking right before the
+ * {@code eval} keeps that call site safe by its own reading, independent of whatever the enumeration
+ * loop does or stops doing in a later change.
  */
 public final class EnvAllowListScrub {
 
@@ -63,7 +105,11 @@ public final class EnvAllowListScrub {
     /** Name of the report file written into the generated directory by the scrub itself. */
     static final String REPORT_FILE = "scrub-report.txt";
 
-    /** The scrub body, generated once and sourced from both {@code .zshrc} and {@code .zlogin}. */
+    /**
+     * The scrub body, generated once and sourced from {@code .zshrc} and {@code .zlogin}
+     * unconditionally, and from {@code .zshenv} when the pane shell is neither login nor
+     * interactive (fleetd #388) — see the class javadoc.
+     */
     static final String SCRUB_FILE = "scrub.zsh";
 
     /** Prefix of every generated directory — also what {@link #reapOrphans} matches on. */
@@ -79,14 +125,42 @@ public final class EnvAllowListScrub {
     private static final String SOURCE_SCRUB =
             "source \"$ZDOTDIR/" + SCRUB_FILE + "\"\n";
 
+    /**
+     * fleetd #388: marks a pane, not a process, as already scrubbed. Set only by the guarded
+     * {@code .zshenv} pass (see {@link #NEITHER_LOGIN_NOR_INTERACTIVE_SCRUB}) after
+     * {@code scrub.zsh} has run, so it must also be folded into that pass's own allow-list — see
+     * the class javadoc's "must also be on the scrub's own allow-list" paragraph.
+     */
+    static final String SCRUB_SENTINEL = "_CB633_SCRUBBED";
+
+    /**
+     * Appended to {@code .zshenv}, after its {@code $HOME} source: the third pass, guarded on the
+     * exact condition that defines the gap {@code .zshrc}/{@code .zlogin} do not cover — a shell
+     * that is neither login nor interactive. The sentinel export happens only once the scrub has
+     * already run, and only for as long as the current pane's environment has not been rebuilt from
+     * scratch (a fresh {@code env -i} child would not inherit it — that is out of scope here, since
+     * such a child is no longer running under the pane's own environment at all).
+     */
+    private static final String NEITHER_LOGIN_NOR_INTERACTIVE_SCRUB =
+            "if [[ ! -o login && ! -o interactive && -z \"${" + SCRUB_SENTINEL + ":-}\" ]]; then\n"
+            + "  " + SOURCE_SCRUB
+            + "  export " + SCRUB_SENTINEL + "=1\n"
+            + "fi\n";
+
     private EnvAllowListScrub() {
     }
 
     /**
-     * A parsed {@code scrub-report.txt}: how many exported variables existed when the scrub ran,
-     * how many were left untouched (allowed), and the NAMES that were blanked. Values never appear.
+     * A parsed {@code scrub-report.txt}: how many exported variables existed when the scrub ran
+     * ({@code total}), how many were left untouched ({@code allowed}), how many the scrub attempted
+     * to blank but could not ({@code failed} — fleetd #394: a zsh read-only/special parameter such
+     * as {@code UID} fatally errors on plain {@code export NAME=}, so those attempts go through
+     * {@code eval} instead so the loop keeps going and the failure is counted rather than left
+     * invisible), and the NAMES in each of the latter two categories. {@code allowed +
+     * blanked.size() + unblankable.size() == total}, and {@code unblankable.size() == failed}.
+     * Values never appear.
      */
-    record ScrubReport(int allowed, int total, List<String> blanked) {
+    record ScrubReport(int allowed, int total, int failed, List<String> blanked, List<String> unblankable) {
     }
 
     /**
@@ -105,11 +179,16 @@ public final class EnvAllowListScrub {
             reapOrphans(parentDir);
             Path dir = Files.createTempDirectory(parentDir, DIR_PREFIX);
             dir.toFile().deleteOnExit();
-            // The report is written by zsh, after these hooks are registered, so register its path
-            // too — otherwise the directory is non-empty at JVM exit and cannot be removed at all.
-            dir.resolve(REPORT_FILE).toFile().deleteOnExit();
-            write(dir, SCRUB_FILE, scrubScript(allowedNames));
-            write(dir, ".zshenv", homeSourcingFile(".zshenv"));
+            // zsh truncates this pre-created receipt after these hooks are registered. Register its
+            // path too — otherwise the directory is non-empty at JVM exit and cannot be removed.
+            Files.createFile(dir.resolve(REPORT_FILE)).toFile().deleteOnExit();
+            // fleetd #388: scrub.zsh's OWN allow-list must also keep SCRUB_SENTINEL, or a later
+            // pass in the same pane blanks it back to empty and the .zshenv guard below thinks it
+            // was never scrubbed — see the class javadoc.
+            Set<String> namesForScrubScript = new HashSet<>(allowedNames);
+            namesForScrubScript.add(SCRUB_SENTINEL);
+            write(dir, SCRUB_FILE, scrubScript(namesForScrubScript));
+            write(dir, ".zshenv", homeSourcingFile(".zshenv") + NEITHER_LOGIN_NOR_INTERACTIVE_SCRUB);
             write(dir, ".zprofile", homeSourcingFile(".zprofile"));
             write(dir, ".zshrc", homeSourcingFile(".zshrc") + SOURCE_SCRUB);
             write(dir, ".zlogin", homeSourcingFile(".zlogin") + SOURCE_SCRUB);
@@ -147,12 +226,11 @@ public final class EnvAllowListScrub {
      * into it: owner keeps full access, {@code group} gets traverse+read on the directory ({@code
      * rwxr-x---}, so a member process — a login shell reading it via {@code ZDOTDIR}, or another
      * process simply opening a file under it — running under that group can find and read the
-     * files) and read-only on each file ({@code rw-r-----}) — deliberately no group WRITE anywhere,
-     * since a member never needs to add or change what fleetd generated. (For the ZDOTDIR scrub
-     * specifically, this also means the scrub script's own report write inside the pane fails
-     * closed rather than open — see {@code scrub.zsh}'s trailing {@code 2>/dev/null} — which {@link
-     * dev.ltms.fleet.member.HerdrPeerLauncher#releaseZdotdir} already treats as "cannot be
-     * confirmed to have run" rather than success.)
+     * files) and read-only on each file ({@code rw-r-----}), except the pre-created ZDOTDIR
+     * {@code scrub-report.txt}. That receipt gets group write ({@code rw-rw----}), so
+     * {@code scrub.zsh} can truncate and write it without granting group write on the directory.
+     * If its optional permission change fails, the member cannot write a receipt and the launcher
+     * keeps its existing WARN rather than failing the spawn.
      *
      * <p>Package-private and named generically on purpose: fleetd #213 built this for the ZDOTDIR
      * scrub directory, and fleetd #219 reuses it verbatim for {@link
@@ -167,7 +245,15 @@ public final class EnvAllowListScrub {
             setGroupAndPermissions(dir, principal, "rwxr-x---");
             try (Stream<Path> entries = Files.list(dir)) {
                 for (Path file : entries.toList()) {
-                    setGroupAndPermissions(file, principal, "rw-r-----");
+                    if (REPORT_FILE.equals(file.getFileName().toString())) {
+                        try {
+                            setGroupAndPermissions(file, principal, "rw-rw----");
+                        } catch (IOException | UnsupportedOperationException ignored) {
+                            // The receipt is optional. Its absence keeps the existing WARN path.
+                        }
+                    } else {
+                        setGroupAndPermissions(file, principal, "rw-r-----");
+                    }
                 }
             }
         } catch (IOException e) {
@@ -245,11 +331,13 @@ public final class EnvAllowListScrub {
         }
         return """
                 # generated by fleetd (CB-633 memberCredentials policy=allow-list) — do not edit.
-                # Sourced from .zshrc and again from .zlogin, each time AFTER that file has sourced
-                # its $HOME counterpart — so this runs after everything the operator sourced, on a
-                # login shell (macOS panes) and on a plain interactive one (Linux panes) alike.
-                # Running twice is idempotent and deliberate: the second pass catches anything
-                # ~/.zlogin exported after ~/.zshrc had finished.
+                # Sourced unconditionally from .zshrc and again from .zlogin, each time AFTER that
+                # file has sourced its $HOME counterpart — so this runs after everything the
+                # operator sourced, on any pane that is login and/or interactive. Running twice is
+                # idempotent and deliberate: the second pass catches anything ~/.zlogin exported
+                # after ~/.zshrc had finished. Also sourced, once, from a guarded pass in .zshenv
+                # (fleetd #388) when the pane shell is NEITHER login nor interactive — the one gap
+                # those two files do not cover.
 
                 typeset -A _cb633_allowed
                 for _cb633_n in %s; do _cb633_allowed[$_cb633_n]=1; done
@@ -271,15 +359,46 @@ public final class EnvAllowListScrub {
                   _cb633_blank+=("$_cb633_n")
                 done
 
-                { for _cb633_n in "${_cb633_blank[@]}"; do export "$_cb633_n="; done; } 2>/dev/null
+                # fleetd #394: plain `export "$n="` is FATAL for a zsh read-only/special parameter
+                # (e.g. UID) and aborts this whole sourced file — every name still to come is never
+                # blanked, and the report below is never written, silently. `eval` contains that
+                # error to the single iteration instead: it still fails for that one name, but the
+                # loop continues and we can tell allowed / blanked / unblankable apart afterwards.
+                # This is not a skip-list of known-bad names (that would miss the next one nobody
+                # thought of) — every name in _cb633_blank is still attempted, unconditionally.
+                # Every name reaching this loop already passed the identical identifier check in the
+                # enumeration loop above — but that guard is 20 lines away in a different loop, and
+                # this line is about to splice the name into a string handed to `eval`. Before this
+                # fix the name only ever reached `export` quoted ("$n="), which is inert on a
+                # non-identifier string either way; `eval` makes THIS line the only thing standing
+                # between such a string and code execution in the member's pane, so it re-asserts the
+                # same check on its own rather than trusting a guard it does not own. Under normal
+                # operation this can never fire (the enumeration guard already filtered everything
+                # reaching _cb633_blank), so a name caught here is counted as unblankable rather than
+                # silently dropped — it is real evidence that the upstream guard was bypassed.
+                typeset -a _cb633_ok _cb633_unblankable
+                _cb633_ok=()
+                _cb633_unblankable=()
+                for _cb633_n in "${_cb633_blank[@]}"; do
+                  if [[ ! "$_cb633_n" =~ ^[A-Za-z_][A-Za-z0-9_]*$ ]]; then
+                    _cb633_unblankable+=("$_cb633_n")
+                    continue
+                  fi
+                  if eval "export ${_cb633_n}=" 2>/dev/null; then
+                    _cb633_ok+=("$_cb633_n")
+                  else
+                    _cb633_unblankable+=("$_cb633_n")
+                  fi
+                done
 
                 integer _cb633_kept=$(( _cb633_total - ${#_cb633_blank} ))
                 {
-                  print -r -- "allowed $_cb633_kept of $_cb633_total"
-                  for _cb633_n in "${_cb633_blank[@]}"; do print -r -- "$_cb633_n"; done
+                  print -r -- "allowed $_cb633_kept of $_cb633_total failed ${#_cb633_unblankable}"
+                  for _cb633_n in "${_cb633_ok[@]}"; do print -r -- "$_cb633_n"; done
+                  for _cb633_n in "${_cb633_unblankable[@]}"; do print -r -- "!$_cb633_n"; done
                 } > "$ZDOTDIR/%s" 2>/dev/null
 
-                unset _cb633_allowed _cb633_names _cb633_blank _cb633_n _cb633_total _cb633_kept
+                unset _cb633_allowed _cb633_names _cb633_blank _cb633_ok _cb633_unblankable _cb633_n _cb633_total _cb633_kept
                 """.formatted(names, MemberEnvAllowList.zshCasePattern(), REPORT_FILE);
     }
 
@@ -293,6 +412,11 @@ public final class EnvAllowListScrub {
      * Read and parse {@link #REPORT_FILE} out of a generated ZDOTDIR directory. Returns {@code null}
      * when absent or unreadable (the pane may have been torn down before its login shell ever got to
      * the scrub) — callers treat that as "no measurement available", never as success.
+     *
+     * <p>First line is {@code "allowed <N> of <M> failed <F>"} (fleetd #394 added the trailing
+     * {@code failed <F>} — a count of names the scrub attempted to blank but could not, e.g. a zsh
+     * read-only/special parameter). Every following non-blank line is a name: a bare name was
+     * blanked, a {@code !}-prefixed name was attempted and failed. Values never appear on either.
      */
     static ScrubReport readReport(Path zdotdir) {
         Path report = zdotdir.resolve(REPORT_FILE);
@@ -305,17 +429,24 @@ public final class EnvAllowListScrub {
                 return null;
             }
             String[] parts = lines.getFirst().substring("allowed ".length()).trim().split("\\s+");
-            if (parts.length != 3 || !"of".equals(parts[1])) {
+            if (parts.length != 5 || !"of".equals(parts[1]) || !"failed".equals(parts[3])) {
                 return null;
             }
             List<String> blanked = new ArrayList<>();
+            List<String> unblankable = new ArrayList<>();
             for (int i = 1; i < lines.size(); i++) {
-                if (!lines.get(i).isBlank()) {
-                    blanked.add(lines.get(i));
+                String line = lines.get(i);
+                if (line.isBlank()) {
+                    continue;
+                }
+                if (line.startsWith("!")) {
+                    unblankable.add(line.substring(1));
+                } else {
+                    blanked.add(line);
                 }
             }
             return new ScrubReport(Integer.parseInt(parts[0]), Integer.parseInt(parts[2]),
-                    List.copyOf(blanked));
+                    Integer.parseInt(parts[4]), List.copyOf(blanked), List.copyOf(unblankable));
         } catch (IOException | NumberFormatException e) {
             return null;
         }

fleetd/src/main/java/dev/ltms/fleet/member/HerdrPeerLauncher.java

@@ -1643,11 +1643,19 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
             log.warn("memberCredentials allow-list: pane {} left no scrub report in {} — the "
                     + "environment scrub cannot be confirmed to have run. Either the pane ended "
                     + "before its shell finished starting, or its shell never read our generated "
-                    + "startup files, in which case that member saw the full host environment.",
+                    + "startup files. Either way, we cannot tell from here whether the scrub ran, "
+                    + "so we do not know what that member's environment contained.",
                     paneId, dir);
         } else {
             log.info("memberCredentials allow-list: pane {} allowed {} of {} environment variables",
                     paneId, report.allowed(), report.total());
+            if (report.failed() > 0) {
+                log.warn("memberCredentials allow-list: pane {} could not blank {} environment "
+                        + "variable(s) — {} (likely a zsh read-only/special parameter) — those "
+                        + "names were left in the member's environment. Confirm none of them is a "
+                        + "credential.",
+                        paneId, report.failed(), report.unblankable());
+            }
             List<String> shaped = report.blanked().stream()
                     .filter(name -> CREDENTIAL_SHAPED_NAME.matcher(name).matches())
                     .toList();

fleetd/src/test/java/dev/ltms/fleet/health/FleetHealthMonitorTest.java

@@ -30,6 +30,7 @@ import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiConsumer;
 import java.util.function.LongSupplier;
 
@@ -206,6 +207,139 @@ class FleetHealthMonitorTest {
                 .workingSuspectAfterOrDefault());
     }
 
+    // --- fleetd #386: a stall detector whose only clock freezes with a sleeping host is worse
+    // than a silent one — it reports "quiet" for a member that was genuinely busy for hours.
+
+    @Test void monotonicClockFrozenPastThresholdOnRealClockStillReportsStallSuspected() {
+        Logger logger = (Logger) LoggerFactory.getLogger(FleetHealthMonitor.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        logger.addAppender(appender);
+        try {
+            AtomicLong mono = new AtomicLong(0);
+            AtomicLong real = new AtomicLong(0);
+            FakeHerdr herdr = new FakeHerdr().withAgent("busy", "term_busy", "pane_busy", "tab_busy");
+            var scheduler = Executors.newSingleThreadScheduledExecutor();
+            FleetHealthMonitor monitor = monitorWithClocks(herdr,
+                    List.of(member("term_busy", MemberSession.State.BUSY, 0, 0)), scheduler,
+                    mono::get, real::get, 60, 600, (_, _) -> { });
+
+            monitor.tick(); // establishes the clock baseline; nothing has diverged yet
+            assertEquals(0, appender.list.stream().filter(event -> event.getFormattedMessage()
+                    .contains("state=STALL_SUSPECTED")).count());
+
+            // The host "sleeps": the monotonic clock stands completely still while the real clock
+            // keeps moving, past the 600s stall threshold.
+            real.set(TimeUnit.SECONDS.toNanos(700));
+            monitor.tick();
+            monitor.stop();
+
+            assertTrue(appender.list.stream().anyMatch(event -> event.getFormattedMessage()
+                            .contains("member=term_busy state=STALL_SUSPECTED")),
+                    "the real clock crossed the stall threshold even though the monotonic clock never moved");
+        } finally {
+            logger.detachAppender(appender);
+        }
+    }
+
+    @Test void clockDivergenceIsLoggedOnceNotOncePerTick() {
+        Logger logger = (Logger) LoggerFactory.getLogger(FleetHealthMonitor.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        logger.addAppender(appender);
+        try {
+            AtomicLong mono = new AtomicLong(0);
+            AtomicLong real = new AtomicLong(0);
+            var scheduler = Executors.newSingleThreadScheduledExecutor();
+            FleetHealthMonitor monitor = monitorWithClocks(new FakeHerdr(), List.of(), scheduler,
+                    mono::get, real::get, 60, 600, (_, _) -> { });
+
+            monitor.tick(); // baseline: no divergence possible yet
+
+            // One sleep gap: the monotonic clock is frozen while the real clock jumps far past one
+            // tick interval (60s).
+            real.set(TimeUnit.SECONDS.toNanos(700));
+            monitor.tick();
+
+            // The host is awake again: both clocks advance together from here, so no more divergence.
+            mono.set(TimeUnit.SECONDS.toNanos(10));
+            real.set(TimeUnit.SECONDS.toNanos(710));
+            monitor.tick();
+            mono.set(TimeUnit.SECONDS.toNanos(20));
+            real.set(TimeUnit.SECONDS.toNanos(720));
+            monitor.tick();
+            monitor.stop();
+
+            assertEquals(1, appender.list.stream().filter(event -> event.getFormattedMessage()
+                            .contains("the monotonic clock did not advance"))
+                    .count(), "one sleep gap must produce exactly one divergence line, not one per tick");
+        } finally {
+            logger.detachAppender(appender);
+        }
+    }
+
+    /**
+     * fleetd #386 follow-up, added on merge. The fix carries a PER-MEMBER drift baseline, so drift
+     * from a sleep that happened BEFORE a member went busy is never charged to that member. The
+     * two tests shipped with the fix both start with the member already BUSY, so a single global
+     * baseline passes them — this one fails without the per-member map.
+     *
+     * <p>Order matters: the host sleeps while nothing is busy, and only then does a member take a
+     * turn. Its stall clock must start at zero.
+     */
+    @Test void driftFromASleepBeforeAMemberWentBusyIsNotChargedToThatMember() {
+        Logger logger = (Logger) LoggerFactory.getLogger(FleetHealthMonitor.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        logger.addAppender(appender);
+        try {
+            AtomicLong mono = new AtomicLong(0);
+            AtomicLong real = new AtomicLong(0);
+            AtomicReference<List<MemberSession>> roster = new AtomicReference<>(List.of());
+            FakeHerdr herdr = new FakeHerdr().withAgent("busy", "term_busy", "pane_busy", "tab_busy");
+            var scheduler = Executors.newSingleThreadScheduledExecutor();
+            AgentControl agents = new AgentControl(herdr);
+            FleetHealthMonitor monitor = new FleetHealthMonitor(agents, roster::get,
+                    new MessageService(agents, new Injector(agents), new Rendezvous(), new InMemoryReplyInbox()),
+                    scheduler, mono::get, real::get, 60, 600, (_, _) -> { });
+
+            monitor.tick();                                   // baseline, no members yet
+
+            // The host sleeps for 700s with nobody busy: the monotonic clock stands still.
+            real.set(TimeUnit.SECONDS.toNanos(700));
+            monitor.tick();
+
+            // Awake again. Only NOW does a member start a turn, with a fresh activity stamp taken
+            // from the monotonic clock. Both clocks advance together from here.
+            mono.set(TimeUnit.SECONDS.toNanos(10));
+            real.set(TimeUnit.SECONDS.toNanos(710));
+            roster.set(List.of(member("term_busy", MemberSession.State.BUSY,
+                    0, TimeUnit.SECONDS.toNanos(10))));
+            monitor.tick();
+
+            mono.set(TimeUnit.SECONDS.toNanos(20));
+            real.set(TimeUnit.SECONDS.toNanos(720));
+            monitor.tick();
+            monitor.stop();
+
+            assertEquals(0, appender.list.stream().filter(event -> event.getFormattedMessage()
+                            .contains("member=term_busy state=STALL_SUSPECTED")).count(),
+                    "the member has been busy for 10s, not 710s — the earlier sleep is not its stall");
+        } finally {
+            logger.detachAppender(appender);
+        }
+    }
+
+    private static FleetHealthMonitor monitorWithClocks(FakeHerdr herdr, List<MemberSession> roster,
+            java.util.concurrent.ScheduledExecutorService scheduler, LongSupplier clock,
+            LongSupplier realtimeClock, long intervalSeconds, long workingSuspectAfterSeconds,
+            BiConsumer<String, String> failTarget) {
+        AgentControl agents = new AgentControl(herdr);
+        return new FleetHealthMonitor(agents, () -> roster,
+                new MessageService(agents, new Injector(agents), new Rendezvous(), new InMemoryReplyInbox()),
+                scheduler, clock, realtimeClock, intervalSeconds, workingSuspectAfterSeconds, failTarget);
+    }
+
     @Test void goneMemberRecoveryLogsOnceWithoutRefiringTargetFailure() {
         Logger logger = (Logger) LoggerFactory.getLogger(FleetHealthMonitor.class);
         Level previousLevel = logger.getLevel();

fleetd/src/test/java/dev/ltms/fleet/member/EnvAllowListScrubTest.java

@@ -8,6 +8,7 @@ import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -17,6 +18,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -45,6 +47,15 @@ class EnvAllowListScrubTest {
     /** Env var names appearing in command output; anything else (prompts, wrapped lines) is noise. */
     private static final Pattern ENV_NAME = Pattern.compile("^([A-Za-z_][A-Za-z0-9_]*)$");
 
+    /**
+     * fleetd #388: the sentinel name the generated {@code .zshenv} guard uses, kept here as a
+     * literal rather than referencing {@link EnvAllowListScrub#SCRUB_SENTINEL} — the two tests that
+     * use it must still compile and run against the pre-fix production class (which has no such
+     * constant), so the revert-and-prove-it-fails step exercises a real assertion instead of a
+     * compilation error.
+     */
+    private static final String SCRUB_SENTINEL_NAME = "_CB633_SCRUBBED";
+
     /**
      * The equality test. Expected survivors = baseline exports ∩ allowed — i.e. every survivor is
      * allowed AND every allowed name that existed survives. The operator's own secret-store exports
@@ -108,6 +119,156 @@ class EnvAllowListScrubTest {
                 "allowed N of M with N <= M — the denominator is always reported");
     }
 
+    /**
+     * fleetd #394: the actual defect. Plain {@code export "$n="} is FATAL for a zsh read-only or
+     * special parameter (e.g. {@code UID}) and aborts the whole sourced file — every name still to
+     * come is never blanked, and the {@code scrub-report.txt} below is never written at all,
+     * silently ({@code 2>/dev/null} swallows the error). This plants an unblankable, exported,
+     * read-only variable in the MIDDLE of the names the scrub attempts to blank, with two more
+     * names after it, and asserts that both of those later names are STILL blanked and the report
+     * is STILL written with the failure counted — a test that only checked names BEFORE the failure
+     * point would pass today and prove nothing.
+     *
+     * <p>The planted name is a made-up one ({@code FLEETD_TEST_UNBLANKABLE}), not {@code UID} or
+     * any other name a skip-list might already know about — invariant 1 is that the loop survives
+     * ANY unblankable name, not a known one, so the test must not lean on one either.
+     *
+     * <p>Exercises the real artefact: {@link EnvAllowListScrub#scrubScript} is run verbatim under a
+     * real {@code /bin/zsh}, not just asserted on as a Java string. The four planted names are
+     * exported one at a time via {@code typeset -x}/{@code typeset -rx} immediately before the
+     * script runs, in a fixed order — zsh's {@code export}/{@code typeset -x} appends to the
+     * process's environment table in call order (verified empirically: a freshly-exported name
+     * always sorts after every inherited one and after every earlier freshly-exported name in
+     * {@code command env}'s own output), which is what makes the "middle" position deterministic
+     * here, unlike relying on the OS's own inherited-environment order.
+     */
+    @Test
+    void unblankableNameInTheMiddleDoesNotAbortNamesAfterIt(@TempDir Path tmp) throws Exception {
+        assumeTrue(Files.isExecutable(ZSH), "/bin/zsh not present — nothing to prove here");
+
+        // Only ZDOTDIR is allowed — it must survive the scrub itself, since the report is written
+        // to "$ZDOTDIR/..." AFTER the blanking loop runs; if ZDOTDIR were blanked as a side effect,
+        // the report write would silently go to the wrong place instead of testing anything.
+        String script = EnvAllowListScrub.scrubScript(Set.of("ZDOTDIR"));
+        String setup = """
+                typeset -x FLEETD_TEST_BEFORE=1
+                typeset -rx FLEETD_TEST_UNBLANKABLE=1
+                typeset -x FLEETD_TEST_AFTER_A=1
+                typeset -x FLEETD_TEST_AFTER_B=1
+                """;
+
+        ProcessBuilder pb = new ProcessBuilder("/bin/zsh");
+        pb.environment().clear();
+        pb.environment().put("PATH", "/usr/bin:/bin");
+        pb.environment().put("ZDOTDIR", tmp.toAbsolutePath().toString());
+        pb.redirectError(ProcessBuilder.Redirect.DISCARD);
+        Process zsh = pb.start();
+        zsh.getOutputStream().write((setup + script).getBytes(StandardCharsets.UTF_8));
+        zsh.getOutputStream().flush();
+        zsh.getOutputStream().close();
+        assertTrue(zsh.waitFor(60, java.util.concurrent.TimeUnit.SECONDS),
+                "the scrub script did not exit within 60s");
+        assertEquals(0, zsh.exitValue(),
+                "the scrub script itself must never abort — an unblankable name must not kill the "
+                        + "sourced file");
+
+        EnvAllowListScrub.ScrubReport report = EnvAllowListScrub.readReport(tmp);
+        assertNotNull(report, "the report must still be written even though one name could not be "
+                + "blanked — a report that silently never appears is the #394 bug");
+        assertTrue(report.blanked().contains("FLEETD_TEST_BEFORE"),
+                "sanity: the name before the unblankable one must be blanked");
+        assertTrue(report.blanked().contains("FLEETD_TEST_AFTER_A"),
+                "the FIRST name AFTER the unblankable one must still be blanked — before the fix, "
+                        + "the whole loop aborted at the unblankable name and every later name was "
+                        + "silently left untouched");
+        assertTrue(report.blanked().contains("FLEETD_TEST_AFTER_B"),
+                "the SECOND name after the unblankable one must also still be blanked");
+        assertEquals(1, report.failed(),
+                "exactly one attempted name could not be blanked, and that count must be visible "
+                        + "without reading the member's environment");
+        assertEquals(List.of("FLEETD_TEST_UNBLANKABLE"), report.unblankable(),
+                "the unblankable name is reported by name, not silently dropped");
+    }
+
+    /**
+     * fleetd #394 follow-up: the blanking loop's {@code eval "export ${n}="} splices {@code n} into
+     * a string that zsh then interprets as shell syntax. That is only safe because every name
+     * reaching {@code _cb633_blank} already passed an identifier check in the ENUMERATION loop
+     * (20 lines away, in a different loop) — so the fix re-asserts the identical check immediately
+     * before the {@code eval} call, rather than trusting that distant guard to keep holding.
+     *
+     * <p>This test plants a value with an embedded newline, exploiting the exact "junk from
+     * multi-line values" gap the enumeration loop's own comment already documents: {@code command
+     * env}'s text output is read line-by-line, so a value's second line becomes a spurious extra
+     * "name" that was never a real exported variable. The fragment used here ({@code
+     * junk.fragment}) is merely non-conforming (it contains a dot) — never command-shaped; this
+     * test must never demonstrate command execution and plants no command-shaped payload.
+     *
+     * <p>Exercises the real artefact end-to-end: {@link EnvAllowListScrub#scrubScript} runs
+     * verbatim under a real {@code /bin/zsh}, exactly as {@code generate()} would produce it — this
+     * is not a synthetic call into just the blanking loop.
+     */
+    @Test
+    void nonIdentifierJunkFromAMultilineValueIsSkippedNotBlankedOrUnblankable(@TempDir Path tmp)
+            throws Exception {
+        assumeTrue(Files.isExecutable(ZSH), "/bin/zsh not present — nothing to prove here");
+
+        String script = EnvAllowListScrub.scrubScript(Set.of("ZDOTDIR"));
+
+        ProcessBuilder pb = new ProcessBuilder("/bin/zsh");
+        pb.environment().clear();
+        pb.environment().put("PATH", "/usr/bin:/bin");
+        pb.environment().put("ZDOTDIR", tmp.toAbsolutePath().toString());
+        // Embedded newline: `command env`'s own text output splits this into two lines, and the
+        // second ("junk.fragment") has no "=" at all, so `cut -d= -f1` returns it unchanged as a
+        // spurious candidate "name" — it was never an actual exported variable by that name.
+        pb.environment().put("FLEETD_TEST_MULTILINE", "keep\njunk.fragment");
+        pb.redirectError(ProcessBuilder.Redirect.DISCARD);
+        Process zsh = pb.start();
+        zsh.getOutputStream().write(script.getBytes(StandardCharsets.UTF_8));
+        zsh.getOutputStream().flush();
+        zsh.getOutputStream().close();
+        assertTrue(zsh.waitFor(60, java.util.concurrent.TimeUnit.SECONDS),
+                "the scrub script did not exit within 60s");
+        assertEquals(0, zsh.exitValue(), "the scrub script must reach its end");
+
+        EnvAllowListScrub.ScrubReport report = EnvAllowListScrub.readReport(tmp);
+        assertNotNull(report, "the report must still be written");
+        assertTrue(report.blanked().contains("FLEETD_TEST_MULTILINE"),
+                "sanity: the real, identifier-shaped variable must still be blanked normally");
+        assertFalse(report.blanked().contains("junk.fragment"),
+                "a non-identifier fragment is not a real variable and must never be blanked");
+        assertFalse(report.unblankable().contains("junk.fragment"),
+                "a non-identifier fragment must never even become a candidate the blanking loop "
+                        + "attempts — it must be filtered before either guard has to catch it, so "
+                        + "it is neither blanked nor counted as a failed attempt");
+    }
+
+    /** A group-shared ZDOTDIR still lets the member truncate and write its pre-created receipt. */
+    @Test
+    void groupSharedScrubWritesAndReadsItsReport(@TempDir Path tmp) throws Exception {
+        assumeTrue(Files.isExecutable(ZSH), "/bin/zsh not present — nothing to prove here");
+        Set<String> allowed = MemberEnvAllowList.derive(List.of());
+        Path zdotdir = EnvAllowListScrub.generate(tmp, allowed, currentUserGroup());
+
+        Map<String, String> cleanParent = Map.of(
+                "HOME", System.getProperty("user.home"),
+                "PATH", "/usr/bin:/bin",
+                "SHELL", "/bin/zsh");
+        exportedNamesFromCleanParent(cleanParent, zdotdir);
+
+        EnvAllowListScrub.ScrubReport report = EnvAllowListScrub.readReport(zdotdir);
+        assertNotNull(report, "a group-shared completed login shell must leave a report behind");
+        assertTrue(report.allowed() >= 0 && report.total() >= report.allowed(),
+                "allowed N of M with N <= M — the denominator is always reported");
+        assertEquals("rw-rw----", java.nio.file.attribute.PosixFilePermissions.toString(
+                        Files.getPosixFilePermissions(zdotdir.resolve(EnvAllowListScrub.REPORT_FILE))),
+                "the pre-created receipt must be group-writable");
+        assertEquals("rwxr-x---", java.nio.file.attribute.PosixFilePermissions.toString(
+                        Files.getPosixFilePermissions(zdotdir)),
+                "group sharing must not make the ZDOTDIR directory group-writable");
+    }
+
     /** Report parsing is lenient: absent file → null (no measurement), not an exception. */
     @Test
     void readReportReturnsNullForADirectoryWithoutOne(@TempDir Path dir) {
@@ -224,6 +385,140 @@ class EnvAllowListScrubTest {
                         + "shell. A difference here means the scrub is dead on Linux.");
     }
 
+    /**
+     * fleetd #388: the actual gap. zsh reads {@code .zshenv} always, {@code .zprofile}/
+     * {@code .zlogin} only for a LOGIN shell, and {@code .zshrc} only for an INTERACTIVE one — so a
+     * shell that is NEITHER (a bare {@code /bin/zsh} reading a script off a non-tty stdin, no
+     * {@code -l}, no {@code -i}) reads only {@code .zshenv} and stops. Before this fix, that shell
+     * never reached {@code scrub.zsh} at all: the decoy secret below would survive untouched. This
+     * test injects that decoy directly into the process environment (not via a sourced dotfile,
+     * since the whole point of the gap is that {@code .zshenv} is normally close to empty) so the
+     * test does not depend on any real {@code ~/.zshrc} content existing on the host.
+     */
+    @Test
+    void scrubRunsInAShellThatIsNeitherLoginNorInteractive(@TempDir Path tmp) throws Exception {
+        assumeTrue(Files.isExecutable(ZSH), "/bin/zsh not present — nothing to prove here");
+        Set<String> allowed = MemberEnvAllowList.derive(List.of());
+        Path zdotdir = EnvAllowListScrub.generate(tmp, allowed);
+
+        Map<String, String> cleanParent = new HashMap<>(Map.of(
+                "HOME", System.getProperty("user.home"),
+                "PATH", "/usr/bin:/bin",
+                "SHELL", "/bin/zsh",
+                "USER", System.getProperty("user.name", "nobody"),
+                "TMPDIR", tmp.toString()));
+        cleanParent.put("FLEETD_TEST_DECOY_SECRET", "x"); // not on any allow-list; must be blanked
+
+        List<String> neither = List.of(); // no -l, no -i; stdin is a pipe (never a tty) either way
+        Set<String> baseline = exportedNamesFromCleanParent(cleanParent, null, neither);
+        Set<String> scrubbed = exportedNamesFromCleanParent(cleanParent, zdotdir, neither);
+
+        Set<String> expected = new TreeSet<>();
+        for (String name : baseline) {
+            if (MemberEnvAllowList.keeps(allowed, name)) {
+                expected.add(name);
+            }
+        }
+        assertTrue(baseline.contains("FLEETD_TEST_DECOY_SECRET"),
+                "sanity: the decoy must actually reach the un-scrubbed baseline, or this test proves "
+                        + "nothing");
+        expected.add("ZDOTDIR"); // the harness set it and it is infrastructure, so it must survive
+        expected.add(SCRUB_SENTINEL_NAME); // set by the new .zshenv guard once scrubbed
+        assertEquals(expected, scrubbed,
+                "a pane shell that is NEITHER login nor interactive must still be scrubbed — its "
+                        + "surviving exported names must EQUAL baseline ∩ allow-list, plus the "
+                        + "sentinel the guard sets once it has run. FLEETD_TEST_DECOY_SECRET surviving "
+                        + "here means the gap is still open.");
+    }
+
+    /**
+     * fleetd #388 invariants 3 and 4, which a name-set equality cannot show: a member's own tooling
+     * forks plain, non-login, non-interactive zsh processes for a single command (the same shape as
+     * the pane shell itself), and such a child must (a) keep whatever its parent deliberately set
+     * for it, never (b) re-run the scrub and blank it, and never (c) overwrite the pane's own
+     * {@code scrub-report.txt} with a description of itself instead of the pane. All three can only
+     * be shown by actually running a child process from within the scrubbed pane shell.
+     *
+     * <p>The pane and the child both report presence via {@code ${NAME:+present}} — empty when a
+     * name is unset OR blanked (exported empty), {@code present} when it is set and non-empty. No
+     * value is ever printed, only these two shapes and the literal word {@code set}/{@code unset}
+     * for the sentinel.
+     */
+    @Test
+    void neitherShellChildKeepsParentVariablesAndReceiptStillDescribesThePane(@TempDir Path tmp) throws Exception {
+        assumeTrue(Files.isExecutable(ZSH), "/bin/zsh not present — nothing to prove here");
+        Set<String> allowed = MemberEnvAllowList.derive(List.of());
+        Path zdotdir = EnvAllowListScrub.generate(tmp, allowed);
+
+        Map<String, String> paneEnv = new HashMap<>(Map.of(
+                "HOME", System.getProperty("user.home"),
+                "PATH", "/usr/bin:/bin",
+                "SHELL", "/bin/zsh",
+                "USER", System.getProperty("user.name", "nobody"),
+                "TMPDIR", tmp.toString()));
+        paneEnv.put("FLEETD_TEST_DECOY_SECRET", "x"); // not allow-listed; the pane must blank it
+        paneEnv.put("ZDOTDIR", zdotdir.toAbsolutePath().toString());
+
+        // The pane's own script reports what IT sees, then forks a plain non-login, non-interactive
+        // child — the shape a member's own tooling uses — carrying a variable the "parent" (this
+        // pane) deliberately set for it, the way git sets GIT_DIR for a hook.
+        String outerScript = """
+                print -r -- "PANE_SENTINEL=${%1$s:+set}"
+                print -r -- "PANE_DECOY=${FLEETD_TEST_DECOY_SECRET:+present}"
+                FLEETD_TEST_TOOL_VAR=keep /bin/zsh <<'CHILD'
+                print -r -- "CHILD_LOGIN=$([[ -o login ]] && echo yes || echo no)"
+                print -r -- "CHILD_INTERACTIVE=$([[ -o interactive ]] && echo yes || echo no)"
+                print -r -- "CHILD_TOOL_VAR=${FLEETD_TEST_TOOL_VAR:+present}"
+                print -r -- "CHILD_DECOY=${FLEETD_TEST_DECOY_SECRET:+present}"
+                print -r -- "CHILD_SENTINEL=${%1$s:+set}"
+                CHILD
+                exit
+                """.formatted(SCRUB_SENTINEL_NAME);
+
+        ProcessBuilder pb = new ProcessBuilder("/bin/zsh"); // no -l, no -i: the pane's own shape
+        pb.environment().clear();
+        pb.environment().putAll(paneEnv);
+        pb.redirectError(ProcessBuilder.Redirect.DISCARD);
+        Process zsh = pb.start();
+        zsh.getOutputStream().write(outerScript.getBytes(StandardCharsets.UTF_8));
+        zsh.getOutputStream().flush();
+        zsh.getOutputStream().close();
+        String stdout = new String(zsh.getInputStream().readAllBytes(), StandardCharsets.UTF_8);
+        assertTrue(zsh.waitFor(60, java.util.concurrent.TimeUnit.SECONDS),
+                "the pane+child probe did not exit within 60s");
+        assertTrue(zsh.exitValue() == 0, "probe zsh exited non-zero: " + stdout);
+
+        Map<String, String> reported = new HashMap<>();
+        for (String line : stdout.split("\n")) {
+            int eq = line.indexOf('=');
+            if (eq > 0) {
+                reported.put(line.substring(0, eq).trim(), line.substring(eq + 1).trim());
+            }
+        }
+
+        assertEquals("set", reported.get("PANE_SENTINEL"),
+                "the pane itself is neither login nor interactive, so the .zshenv guard must have "
+                        + "run the scrub and exported the sentinel");
+        assertEquals("", reported.get("PANE_DECOY"),
+                "the pane must blank a non-allow-listed name — invariant 1");
+        assertEquals("no", reported.get("CHILD_LOGIN"), "sanity: the child must also be non-login");
+        assertEquals("no", reported.get("CHILD_INTERACTIVE"), "sanity: the child must also be non-interactive");
+        assertEquals("present", reported.get("CHILD_TOOL_VAR"),
+                "invariant 3: a variable the pane deliberately set for its child must survive — a "
+                        + "child that re-ran the scrub would have blanked it");
+        assertEquals("", reported.get("CHILD_DECOY"),
+                "a name already blanked by the pane must stay blanked in the child, never resurrected");
+        assertEquals("set", reported.get("CHILD_SENTINEL"),
+                "the child must inherit the sentinel from the pane's environment, or it would re-scrub");
+
+        EnvAllowListScrub.ScrubReport report = EnvAllowListScrub.readReport(zdotdir);
+        assertNotNull(report, "the pane's own scrub pass must leave a report behind");
+        assertTrue(report.blanked().stream().noneMatch(n -> n.startsWith("FLEETD_TEST_TOOL_VAR")),
+                "invariant 4: the receipt must still describe the PANE, not the child — a child that "
+                        + "re-ran the scrub would have rewritten this file to list its own "
+                        + "FLEETD_TEST_TOOL_VAR as blanked");
+    }
+
     /**
      * Run {@code /bin/zsh -l -i} from a clean parent and return the NAMES it has exported by prompt
      * time. With {@code zdotdir} non-null, {@code ZDOTDIR} points at a generated scrub directory, so