#213: fix ZDOTDIR credential scrub gate + directory under memberHerdrSocket

The memberCredentials.policy: allow-list ZDOTDIR scrub decided zsh-vs-not
using fleetd's own process $SHELL and wrote the generated scrub dir into
fleetd's own java.io.tmpdir. Under memberHerdrSocket: (member panes run as
a different OS user than fleetd's own process) this silently protects
nothing: the wrong shell decides the gate, and the directory can be
unreachable to the member.

- New FleetConfig.memberLoginShell: the member OS user's login shell,
  only ever read when memberHerdrSocket: is configured; fleetd's own
  $SHELL keeps deciding everything when memberHerdrSocket: is absent
  (byte-identical to before).
- HerdrPeerLauncher.applyEnvironmentAllowListPolicy: memberHerdrSocket +
  memberLoginShell not configured/non-zsh falls back to the CB-596
  sentinel overlay (warn loudly, never refuse to spawn). memberHerdrSocket
  + zsh memberLoginShell generates the ZDOTDIR under the configured
  worktreeRoot instead of java.io.tmpdir, shared with the existing
  worktreeGroup (reused, not a new key).
- EnvAllowListScrub: new generate(parentDir, allowedNames, group) overload
  shares the generated directory via pure-Java POSIX group ownership
  (rwxr-x--- dir, rw-r----- files) — no external process spawn.
- fleetd.example.yaml documents memberLoginShell: and worktreeGroup:'s
  reuse for the scrub directory (the live fleetd.yaml is gitignored).

4 new tests in HerdrPeerLauncherAllowListWiringTest cover the acceptance
criteria; 3 of the 4 were watched failing against the pre-fix code.

fleetd/fleetd.example.yaml

@@ -117,6 +117,15 @@ herdrSocket: ~/.config/herdr/herdr.sock
 # Optional socket for member panes. Omit this to use herdrSocket for both leads and members.
 # memberHerdrSocket: /Users/member/.config/herdr/herdr.sock
 
+# fleetd #213: the login shell the member OS user (memberHerdrSocket above) actually runs. ONLY
+# read when memberHerdrSocket is set — fleetd's own $SHELL says nothing about a pane running
+# under a different OS user, and there is no channel to ask herdr for that user's shell, so this
+# must be told rather than guessed. Absent, blank, or anything not ending in "zsh" is treated the
+# same as "not zsh": the memberCredentials.policy: allow-list ZDOTDIR scrub (see worktreeGroup
+# below) is skipped in favour of the weaker CB-596 sentinel overlay — a degraded control, never a
+# refusal to spawn. When memberHerdrSocket is absent this key is never consulted at all.
+# memberLoginShell: /bin/zsh
+
 # How member sessions are spawned. Define one or more named profiles (backends) under
 # `profiles`; each key is the profile name (also the ccs profile). A profile says only WHICH
 # BACKEND — model, CLI adapter, credentials, cost. It says nothing about what a member spawned on
@@ -634,6 +643,24 @@ guard:
 # to a sibling directory of the repo root.
 # worktreeRoot: /Users/me/src/.bridged-worktrees
 
+# Worktree group sharing (fleetd #185 stage 3). OPTIONAL, off by default. Names an OS group
+# that a provisioned worktree's repo is made group-writable for (git config
+# core.sharedRepository group, plus a one-time chgrp/chmod/setgid fix-up), so a member spawned
+# under a DIFFERENT OS user (see memberHerdrSocket) can write its own worktree, its
+# per-worktree git metadata, and its own commit objects — without it, every file GitWorktrees
+# creates is owned by fleetd's own uid and unwritable by another user.
+# CAUTION: this isolates credentials, not the repository — a member in the group can still
+# write the operator's git objects and refs in the shared repo. The operator running fleetd
+# must already be a member of the named group, or every provisioning spawn fails loudly.
+#
+# fleetd #213: this is also the ONE group the memberCredentials.policy: allow-list ZDOTDIR scrub
+# reuses when memberHerdrSocket is set — deliberately not a second config key. Under
+# memberHerdrSocket, the scrub directory is generated under worktreeRoot (never java.io.tmpdir,
+# which the member OS user cannot reach) and shared read-only with this group. If worktreeGroup
+# is unset while memberHerdrSocket is set, the scrub cannot be guaranteed reachable by the member,
+# so fleetd falls back to the weaker CB-596 sentinel overlay instead (a WARN names the gap).
+# worktreeGroup: fleet-workers
+
 # Session lifecycle limits (CB-303). All knobs are opt-in; omit or set to null to keep
 # the feature disabled. By default the daemon never reaps, caps, or drains sessions.
 #   idleTtlSeconds     → reap READY/DONE sessions idle longer than this (never BUSY/SPAWNING)

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

@@ -224,7 +224,7 @@ public final class Fleetd {
             contextCap = cfg.lifecycle().contextCap();
         }
         boolean clearAfterTurn = cfg.lifecycle() != null && cfg.lifecycle().clearAfterTurn();
-        SessionManager sessions = new SessionManager(workers, new GitWorktrees(cfg.worktreeRoot()),
+        SessionManager sessions = new SessionManager(workers, new GitWorktrees(cfg.worktreeRoot(), cfg.worktreeGroup()),
                 System::nanoTime, contextCap, clearAfterTurn);
         liveCountRef.set(profileName -> (int) sessions.roster().stream()
                 .filter(s -> profileName.equals(s.profile()))

fleetd/src/main/java/dev/ltms/fleet/config/FleetConfig.java

@@ -76,6 +76,26 @@ import java.util.Set;
  *                      stay on {@code broker}'s vhost). {@code null} → no lead mailbox is opened.
  *                      Config parsing + accessors only — nothing here wires it into a live
  *                      {@code LeadMailbox}; that is a separate ticket. See {@link Coordinator}.
+ * @param worktreeGroup optional OS group name (fleetd #185 stage 3) that makes a provisioned
+ *                      worktree's repo group-shared, so a member running as a different OS user
+ *                      (see {@code memberHerdrSocket}) can write its own worktree, its per-worktree
+ *                      git metadata, and its own commit objects. {@code null}/blank/empty ⇒ off,
+ *                      today's behaviour unchanged (every file stays owned by fleetd's own uid).
+ *                      <strong>This isolates credentials, not the repository</strong>: a member in
+ *                      the group can still write the operator's git objects and refs in the shared
+ *                      repo. See {@link dev.ltms.fleet.session.Worktrees#shareWithGroup}.
+ * @param memberLoginShell fleetd #213: the login shell the member's OS user actually runs, ONLY
+ *                      meaningful (and only ever read) when {@code memberHerdrSocket} is
+ *                      configured — that mode spawns member panes under a different OS user than
+ *                      fleetd's own process, so fleetd's own {@code $SHELL} says nothing about what
+ *                      that pane runs. There is no channel to ask herdr for another user's shell, so
+ *                      this must be told, never guessed. {@code null}/blank (or a value not ending
+ *                      in {@code zsh}) is treated the same as "not zsh": the {@code
+ *                      memberCredentials.policy: allow-list} ZDOTDIR scrub is skipped in favour of
+ *                      the CB-596 sentinel overlay — a degraded control, never a refusal to spawn.
+ *                      When {@code memberHerdrSocket} is NOT configured this field is never
+ *                      consulted at all; fleetd keeps reading its own {@code $SHELL}, exactly as
+ *                      before this field existed.
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record FleetConfig(
@@ -98,7 +118,33 @@ public record FleetConfig(
         ConfigReload configReload,
         Integer quarantineCooldownSeconds,
         MemberCredentials memberCredentials,
-        Coordinator coordinator) {
+        Coordinator coordinator,
+        String worktreeGroup,
+        String memberLoginShell) {
+
+    /** Back-compat form before the {@code memberLoginShell} key was added. */
+    public FleetConfig(Bind bind, String herdrSocket, String memberHerdrSocket, Map<String, Profile> profiles,
+                         Guard guard, String worktreeRoot, Lifecycle lifecycle, Integer spawnReadyTimeoutMs,
+                         Integer spawnReadyPollMs, Broker broker, Primary primary, Fleet fleet,
+                         LeadHeartbeat leadHeartbeat, Health health, String placement, Auth auth,
+                         ConfigReload configReload, Integer quarantineCooldownSeconds,
+                         MemberCredentials memberCredentials, Coordinator coordinator, String worktreeGroup) {
+        this(bind, herdrSocket, memberHerdrSocket, profiles, guard, worktreeRoot, lifecycle, spawnReadyTimeoutMs,
+                spawnReadyPollMs, broker, primary, fleet, leadHeartbeat, health, placement, auth,
+                configReload, quarantineCooldownSeconds, memberCredentials, coordinator, worktreeGroup, null);
+    }
+
+    /** Back-compat form before the {@code worktreeGroup} key was added. */
+    public FleetConfig(Bind bind, String herdrSocket, String memberHerdrSocket, Map<String, Profile> profiles,
+                         Guard guard, String worktreeRoot, Lifecycle lifecycle, Integer spawnReadyTimeoutMs,
+                         Integer spawnReadyPollMs, Broker broker, Primary primary, Fleet fleet,
+                         LeadHeartbeat leadHeartbeat, Health health, String placement, Auth auth,
+                         ConfigReload configReload, Integer quarantineCooldownSeconds,
+                         MemberCredentials memberCredentials, Coordinator coordinator) {
+        this(bind, herdrSocket, memberHerdrSocket, profiles, guard, worktreeRoot, lifecycle, spawnReadyTimeoutMs,
+                spawnReadyPollMs, broker, primary, fleet, leadHeartbeat, health, placement, auth,
+                configReload, quarantineCooldownSeconds, memberCredentials, coordinator, null, null);
+    }
 
     /** Back-compat form before the {@code coordinator:} block was added. */
     public FleetConfig(Bind bind, String herdrSocket, Map<String, Profile> profiles, Guard guard,
@@ -109,7 +155,7 @@ public record FleetConfig(
                          MemberCredentials memberCredentials) {
         this(bind, herdrSocket, null, profiles, guard, worktreeRoot, lifecycle, spawnReadyTimeoutMs,
                 spawnReadyPollMs, broker, primary, fleet, leadHeartbeat, health, placement, auth,
-                configReload, quarantineCooldownSeconds, memberCredentials, null);
+                configReload, quarantineCooldownSeconds, memberCredentials, null, null);
     }
 
     /** Back-compat form before the CB-596 {@code memberCredentials:} block was added. */
@@ -1325,7 +1371,7 @@ public record FleetConfig(
             "bind", "herdrSocket", "memberHerdrSocket", "profiles", "guard", "worktreeRoot",
             "lifecycle", "spawnReadyTimeoutMs", "spawnReadyPollMs", "broker", "primary", "fleet",
             "leadHeartbeat", "health", "placement", "auth", "configReload", "quarantineCooldownSeconds",
-            "memberCredentials", "coordinator");
+            "memberCredentials", "coordinator", "worktreeGroup", "memberLoginShell");
 
     /** Load and validate config from {@code path}. */
     public static FleetConfig load(Path path) {
@@ -1943,9 +1989,14 @@ public record FleetConfig(
                 : new MemberCredentials(null, List.of(), List.of());
         // coordinator is left as-is, like broker/primary above: null keeps no LeadMailbox opened,
         // and this ticket's Coordinator is config-only anyway (nothing yet reads it at startup).
+        // worktreeGroup is left as-is (fleetd #185 stage 3): null/blank is "off", and there is no
+        // sane non-null default — an OS group name is operator-specific.
+        // memberLoginShell is left as-is (fleetd #213), like worktreeGroup: null/blank is "not
+        // configured", and there is no sane non-null default — a member's login shell is
+        // operator-specific and only meaningful when memberHerdrSocket is also set.
         return new FleetConfig(b, herdrSocket, memberHerdrSocket, profiles, g, worktreeRoot, l, timeout, pollMs,
                 broker, primary, f, leadHeartbeat, health, placementOrDefault, a, configReload,
-                quarantineCooldown, mc, coordinator);
+                quarantineCooldown, mc, coordinator, worktreeGroup, memberLoginShell);
     }
 
     /**

fleetd/src/main/java/dev/ltms/fleet/mcp/FleetMcp.java

@@ -951,7 +951,10 @@ public final class FleetMcp {
                     .sorted(Map.Entry.comparingByValue())
                     .map(e -> leadView(e.getKey(), e.getValue(), live.get(e.getKey()), selfTerm))
                     .toList();
-            List<MemberSession> roster = sessions.roster();
+            // fleetd #209: this is the caller-driven fleet_list read that actually reports
+            // agentSessionId (via memberCapacityView -> SessionManager.rosterView), so it uses the
+            // resolving roster; the heartbeat/health/metrics timers stay on the plain sessions.roster().
+            List<MemberSession> roster = sessions.rosterResolved();
             List<Map<String, Object>> out = roster.stream()
                     .map(s -> memberCapacityView(s, live.get(s.terminalId()), messages, capacity.clock().getAsLong()))
                     .toList();

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

@@ -7,6 +7,9 @@ import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.attribute.GroupPrincipal;
+import java.nio.file.attribute.PosixFileAttributeView;
+import java.nio.file.attribute.PosixFilePermissions;
 import java.time.Duration;
 import java.time.Instant;
 import java.util.ArrayList;
@@ -116,6 +119,70 @@ public final class EnvAllowListScrub {
         }
     }
 
+    /**
+     * fleetd #213: as {@link #generate(Path, Set)}, plus share the generated directory with
+     * {@code group} — the member OS user's group (the operator's existing {@code worktreeGroup:}
+     * name, reused rather than inventing a second one) — so a member running under a different OS
+     * user than fleetd's own process can still read what it needs from a directory placed outside
+     * {@code java.io.tmpdir}. {@code group} null/blank ⇒ identical to {@link #generate(Path, Set)};
+     * this is the single-daemon (no {@code memberHerdrSocket}) shape, where the pane is fleetd's own
+     * uid and no group sharing is needed.
+     *
+     * @throws UncheckedIOException also when {@code group} does not resolve on this host, or a
+     *                              group-ownership/permission call is refused — the same "fail
+     *                              loudly rather than start unprotected" contract as above: a scrub
+     *                              the configured member user cannot even read is not a working
+     *                              control.
+     */
+    public static Path generate(Path parentDir, Set<String> allowedNames, String group) {
+        Path dir = generate(parentDir, allowedNames);
+        if (group != null && !group.isBlank()) {
+            shareWithGroup(dir, group);
+        }
+        return dir;
+    }
+
+    /**
+     * chgrp/chmod-equivalent over the freshly generated directory and the startup files already
+     * written into it: owner keeps full access, {@code group} gets traverse+read on the directory
+     * ({@code rwxr-x---}, so a login shell under that group can find and source 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 fleetd's own generated scrub. (The scrub script's own
+     * report write inside the pane consequently 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.)
+     */
+    private static void shareWithGroup(Path dir, String group) {
+        try {
+            GroupPrincipal principal = dir.getFileSystem().getUserPrincipalLookupService()
+                    .lookupPrincipalByGroupName(group);
+            setGroupAndPermissions(dir, principal, "rwxr-x---");
+            try (Stream<Path> entries = Files.list(dir)) {
+                for (Path file : entries.toList()) {
+                    setGroupAndPermissions(file, principal, "rw-r-----");
+                }
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException("cannot share generated ZDOTDIR " + dir + " with group '"
+                    + group + "' — the group must exist, and the fleetd operator ("
+                    + System.getProperty("user.name") + ") must be a member of it", e);
+        } catch (UnsupportedOperationException e) {
+            throw new UncheckedIOException("cannot share generated ZDOTDIR " + dir + " with group '"
+                    + group + "' — this filesystem does not support POSIX group ownership",
+                    new IOException(e));
+        }
+    }
+
+    private static void setGroupAndPermissions(Path path, GroupPrincipal group, String perms) throws IOException {
+        PosixFileAttributeView view = Files.getFileAttributeView(path, PosixFileAttributeView.class);
+        if (view == null) {
+            throw new IOException("POSIX file attributes are not supported for " + path);
+        }
+        view.setGroup(group);
+        Files.setPosixFilePermissions(path, PosixFilePermissions.fromString(perms));
+    }
+
     /** One operator-sourcing startup file: source the {@code $HOME} counterpart, change nothing else. */
     private static String homeSourcingFile(String name) {
         return """

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

@@ -112,6 +112,12 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
      * daemon's own process is started the same way (a login shell sourcing the same secret store —
      * see CB-592's investigation of {@code secrets.sh}), so on a single-host deployment its env
      * mirrors what the pane's login shell is about to export.
+     *
+     * <p>fleetd #185 stage 2: that mirroring assumption holds only while the member pane runs under
+     * the SAME OS user as the daemon. When {@code memberHerdrSocket:} is configured, member panes
+     * run on a second herdr owned by a different user — different {@code $HOME}, different {@code
+     * secrets.sh}, different environment entirely — so this field's data no longer describes what a
+     * member pane inherits. See {@link #logCredentialGap} for how that mode is handled.
      */
     private final Supplier<Set<String>> hostEnvNames;
 
@@ -1071,6 +1077,29 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
      * name. It stays a one-off decision because it is a live handle to the operator's ssh-agent, not
      * a value — a member holding it can sign with every key the agent holds, so letting it ride in
      * on the generic {@code allow:} list would hand that out for an unrelated reason.
+     *
+     * <p>fleetd #213: which shell decides the zsh gate, and where the generated directory lives,
+     * both depend on whether {@code memberHerdrSocket:} is configured — see {@link
+     * #memberHerdrSocketConfigured()}'s javadoc for why fleetd's own {@code $SHELL} and {@code
+     * java.io.tmpdir} describe the wrong process once member panes run under a different OS user.
+     * <ul>
+     *   <li>{@code memberHerdrSocket} ABSENT (today's only mode): byte-identical to before this
+     *       fix — fleetd's own {@code $SHELL} decides zsh, and the directory is generated under
+     *       {@code java.io.tmpdir}.</li>
+     *   <li>{@code memberHerdrSocket} PRESENT: the configured {@code memberLoginShell:} decides
+     *       zsh instead — fleetd's own {@code $SHELL} is never consulted, since it names a
+     *       different user's shell, not the member's. Absent/non-zsh falls back exactly like the
+     *       non-zsh case below. When it IS zsh, the directory still cannot go under {@code
+     *       java.io.tmpdir} (mode 0700, unreadable by another uid — the exact gap fleetd #213
+     *       exists to close), so it is generated under {@code worktreeRoot} instead and shared
+     *       read-only with {@code worktreeGroup} — the same group {@link
+     *       dev.ltms.fleet.session.Worktrees#shareWithGroup} already uses, reused rather than
+     *       inventing a second group key. Either one missing means the scrub cannot be guaranteed
+     *       reachable by the member, which is the same "cannot guarantee the scrub runs" case as a
+     *       non-zsh shell, so it gets the identical fallback.</li>
+     * </ul>
+     * In every branch: never refuse to spawn. A degraded credential control must not become an
+     * outage for an opt-in feature.
      */
     private Path applyEnvironmentAllowListPolicy(FleetConfig.Profile cfg, Launch launch) {
         FleetConfig.MemberCredentials creds = memberCredentials == null ? null : memberCredentials.get();
@@ -1078,8 +1107,14 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
             return null;
         }
         Set<String> allowed = derivedAllowedNames(creds, launch);
-        String loginShell = resolveEnv("SHELL");
-        boolean zsh = loginShell != null && (loginShell.endsWith("/zsh") || loginShell.equals("zsh"));
+        boolean memberHerdrSocket = memberHerdrSocketConfigured();
+        // fleetd #213 defect 1: under memberHerdrSocket the member pane runs as a DIFFERENT OS
+        // user, so fleetd's own $SHELL says nothing about what that pane runs — resolveEnv("SHELL")
+        // must not even be called on this path, only the explicit memberLoginShell: config can
+        // answer it. With memberHerdrSocket absent, nothing here changes: fleetd's own $SHELL is
+        // still the input, exactly as before this fix.
+        String loginShell = memberHerdrSocket ? configuredMemberLoginShell() : resolveEnv("SHELL");
+        boolean zsh = isZshShell(loginShell);
         if (!zsh) {
             // A non-zsh login shell ignores ZDOTDIR entirely: NO scrub would run, so pretending
             // otherwise would be worse than saying so. Warn loudly and fall back to the CB-596
@@ -1093,13 +1128,35 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
             logCredentialGap(creds, null);
             return null;
         }
+        Path parentDir;
+        String group = null;
+        if (memberHerdrSocket) {
+            // fleetd #213 defect 2: java.io.tmpdir is fleetd's own per-user temp dir (mode 0700 on
+            // macOS) — a member running as a different uid cannot even traverse it, let alone read
+            // the generated files. worktreeRoot is the only configured location a different-uid
+            // member can be given access to, and only WITH worktreeGroup to grant that access —
+            // absent either, the scrub cannot be guaranteed reachable, so this falls back exactly
+            // like the non-zsh case above rather than generating a directory nothing can read.
+            parentDir = memberScrubParentDir();
+            group = memberGroup();
+            if (parentDir == null || group == null) {
+                warnCannotShareScrubDirectory();
+                overlayBlockedCredentials(launch.env(), creds);
+                logCredentialGap(creds, null);
+                return null;
+            }
+        } else {
+            parentDir = Path.of(System.getProperty("java.io.tmpdir"));
+        }
         // Only reached when the scrub is actually about to run — the count below describes that
         // scrub, so it must not be logged before this gate (see the non-zsh branch above). Same
         // reasoning gates logCredentialGap's wording: passing the derived `allowed` set (non-null)
         // here, and ONLY here, is what tells it the scrub will really blank an unkept name — #192.
         logAllowListCoverage(allowed);
         logCredentialGap(creds, allowed);
-        Path dir = EnvAllowListScrub.generate(Path.of(System.getProperty("java.io.tmpdir")), allowed);
+        Path dir = memberHerdrSocket
+                ? EnvAllowListScrub.generate(parentDir, allowed, group)
+                : EnvAllowListScrub.generate(parentDir, allowed);
         launch.env().put("ZDOTDIR", dir.toAbsolutePath().toString());
         log.info("memberCredentials policy=allow-list: profile={} generated ZDOTDIR {} — derived "
                         + "allow-list holds {} name(s); the pane reports allowed N of M at release",
@@ -1107,6 +1164,55 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
         return dir;
     }
 
+    /** True when {@code shell} is a zsh login shell path or bare name — the ZDOTDIR gate. */
+    private static boolean isZshShell(String shell) {
+        return shell != null && (shell.endsWith("/zsh") || shell.equals("zsh"));
+    }
+
+    /**
+     * fleetd #213: the configured {@code memberLoginShell:}, or {@code null} when unconfigured.
+     * Called ONLY from the {@code memberHerdrSocket}-configured branch of {@link
+     * #applyEnvironmentAllowListPolicy} — fleetd's own {@code $SHELL} is never read on that path.
+     * {@link #config} being {@code null} (an older test call site, or a launcher that never
+     * threaded the full config through) is treated the same as "not configured".
+     */
+    private String configuredMemberLoginShell() {
+        FleetConfig cfg = config == null ? null : config.get();
+        return cfg == null ? null : cfg.memberLoginShell();
+    }
+
+    /**
+     * fleetd #213: {@code worktreeRoot}, as the ZDOTDIR scrub's parent directory under {@code
+     * memberHerdrSocket}, or {@code null} when unconfigured — the same "cannot guarantee the scrub
+     * runs" gap as {@link #memberGroup()} being unset (see {@link
+     * #applyEnvironmentAllowListPolicy}). Deliberately no sibling-of-repo-root default here, unlike
+     * {@code GitWorktrees}' own {@code worktreeRoot} resolution: that default is a convenience for
+     * provisioning a worktree that will exist regardless, whereas an unconfigured value here means
+     * fleetd has no operator-endorsed location to put a credential-bearing directory a different OS
+     * user must reach, so falling back to the overlay is the honest answer, not a guess.
+     */
+    private Path memberScrubParentDir() {
+        FleetConfig cfg = config == null ? null : config.get();
+        if (cfg == null || cfg.worktreeRoot() == null || cfg.worktreeRoot().isBlank()) {
+            return null;
+        }
+        return Path.of(cfg.worktreeRoot());
+    }
+
+    /**
+     * fleetd #213: the configured {@code worktreeGroup:}, or {@code null} when unset/blank. Reuses
+     * the group {@link dev.ltms.fleet.session.Worktrees#shareWithGroup} already establishes for
+     * provisioned worktrees, rather than a second group key — see {@link
+     * #applyEnvironmentAllowListPolicy}.
+     */
+    private String memberGroup() {
+        FleetConfig cfg = config == null ? null : config.get();
+        if (cfg == null || cfg.worktreeGroup() == null || cfg.worktreeGroup().isBlank()) {
+            return null;
+        }
+        return cfg.worktreeGroup();
+    }
+
     /**
      * The full kept-name set for this spawn: the profile-derived names, unioned with {@code
      * memberCredentials.allow:} (CB-633 follow-up — previously ignored by this whole policy), the
@@ -1164,6 +1270,30 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
         }
     }
 
+    /** Guards {@link #warnCannotShareScrubDirectory} to one WARN per launcher instance. */
+    private final AtomicBoolean cannotShareScrubDirWarned = new AtomicBoolean();
+
+    /**
+     * fleetd #213: {@code memberHerdrSocket} is configured and the member login shell IS zsh, but
+     * {@code worktreeRoot} and/or {@code worktreeGroup} is missing, so the generated ZDOTDIR cannot
+     * be placed anywhere the member's OS user can reach — {@code java.io.tmpdir} is fleetd's own
+     * 0700 temp dir, unreadable by another uid, which is the exact gap this ticket exists to close.
+     * Say so once per launcher instance, instead of either generating a directory nothing can read
+     * (protection theatre) or refusing to spawn (turning a degraded credential control into an
+     * outage for an opt-in feature).
+     */
+    private void warnCannotShareScrubDirectory() {
+        if (cannotShareScrubDirWarned.compareAndSet(false, true)) {
+            log.warn("memberCredentials policy=allow-list: memberHerdrSocket is configured and the "
+                    + "member login shell is zsh, but worktreeRoot and/or worktreeGroup is not "
+                    + "configured — the generated ZDOTDIR cannot be placed where the member's OS "
+                    + "user can read it (java.io.tmpdir is fleetd's own, unreadable by another uid), "
+                    + "so the scrub cannot be guaranteed to run. Falling back to the CB-596 sentinel "
+                    + "overlay. Configure both worktreeRoot and worktreeGroup to enable the "
+                    + "allow-list scrub under memberHerdrSocket.");
+        }
+    }
+
     /**
      * CB-633 teardown half: read the pane's scrub report (the denominator report the generated
      * scrub wrote) and delete the directory. Called from {@link #stop}, which is the one funnel
@@ -1230,6 +1360,67 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
      */
     private final AtomicBoolean allowListGapLogged = new AtomicBoolean();
 
+    /**
+     * fleetd #185 stage 2: guards {@link #warnUnknownMemberEnvironment} to one WARN per launcher
+     * instance, not one per spawn — the same one-per-instance shape as {@link #unprotectedGapLogged}
+     * and {@link #allowListGapLogged}, kept as its own flag for the same reason those two are split:
+     * this mode is orthogonal to which of the other two branches would otherwise have fired.
+     */
+    private final AtomicBoolean unknownMemberEnvironmentWarned = new AtomicBoolean();
+
+    /**
+     * fleetd #185 stage 2: whether {@code memberHerdrSocket:} is configured, i.e. member panes run
+     * on a second herdr owned by a different OS user than the daemon's own process. Re-read from the
+     * live config on every call (same hot-reload shape as {@link #memberCredentials}), never cached,
+     * so a config reload takes effect on the next spawn without a restart.
+     *
+     * <p>{@link #config} is {@code null} on any call site that never threaded the full config
+     * through (every production {@code HerdrPeerLauncher} does; a handful of older tests do not) —
+     * treated the same as "not configured", which is the correct, permissive default: it is exactly
+     * today's single-daemon behaviour.
+     */
+    private boolean memberHerdrSocketConfigured() {
+        if (config == null) {
+            return false;
+        }
+        FleetConfig cfg = config.get();
+        return cfg != null && cfg.memberHerdrSocket() != null && !cfg.memberHerdrSocket().isBlank();
+    }
+
+    /**
+     * fleetd #185 stage 2: the single replacement WARN for {@link #logCredentialGap}'s usual
+     * conclusions when {@code memberHerdrSocket:} is configured. {@link #hostEnvNames} (and
+     * everything derived from it — {@code known}/{@code allow} coverage, the allow-list scrub's
+     * derived set) describes the DAEMON's own environment; under this config key member panes run as
+     * a different OS user with a different environment entirely, so neither "every member pane
+     * inherits them UNBLOCKED" nor "the scrub blanks them" is evidence-backed here — both would be
+     * reporting on the wrong process. Logged once, names the config key, and states the honest
+     * conclusion: the gap for member panes is UNKNOWN, not clean, so {@code memberCredentials} cannot
+     * be verified from this daemon. The one count it does report is scoped explicitly to fleetd's own
+     * environment, never presented as if it said anything about the member's — see {@link
+     * #logCredentialGap}'s javadoc for why this branch exists.
+     */
+    private void warnUnknownMemberEnvironment(FleetConfig.MemberCredentials creds) {
+        if (!unknownMemberEnvironmentWarned.compareAndSet(false, true)) {
+            return;
+        }
+        Set<String> covered = new HashSet<>(creds.known());
+        covered.addAll(creds.allow());
+        Set<String> hostNames = hostEnvNames.get();
+        long gapInFleetdsOwnEnv = hostNames.stream()
+                .filter(name -> CREDENTIAL_SHAPED_NAME.matcher(name).matches())
+                .filter(name -> !covered.contains(name))
+                .count();
+        log.warn("memberCredentials gap: memberHerdrSocket is configured, so member panes run under "
+                        + "a different OS user than fleetd's own process, with a different environment "
+                        + "entirely — fleetd has no channel to read that user's environment. {} of the "
+                        + "{} names in fleetd's OWN environment are credential-shaped and not on "
+                        + "known:/allow:, but that count describes fleetd's process, not the member "
+                        + "herdr's. The credential gap for member panes is UNKNOWN, not clean, and "
+                        + "memberCredentials cannot be verified from here.",
+                gapInFleetdsOwnEnv, hostNames.size());
+    }
+
     /**
      * CB-596 criterion 4: a credential-shaped host env var name on neither {@code known} nor
      * {@code allow} is not silently allowed — it is reported. {@link #hostEnvNames} enumerates the
@@ -1258,8 +1449,22 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
      * (same severity, and same guard, as the deny-by-default case — a name genuinely reaching a
      * member unprotected is equally serious whichever path put it there), and the names it says are
      * blanked keep the INFO.
+     *
+     * <p>fleetd #185 stage 2: everything above assumes the member pane runs under the same OS user
+     * as the daemon, so {@link #hostEnvNames} mirrors what the pane inherits — see that field's
+     * javadoc. When {@code memberHerdrSocket:} is configured that assumption is false: the member
+     * pane runs on a second herdr owned by a <em>different</em> user, and neither conclusion below
+     * ("inherits them UNBLOCKED" / "the scrub blanks them") is backed by evidence about that user's
+     * environment. So this method checks that first and, when configured, reports the honest
+     * "unknown, not clean" conclusion instead — see {@link #warnUnknownMemberEnvironment}. When
+     * {@code memberHerdrSocket:} is absent (the default, and the only mode this host runs) this
+     * branch is never taken and every line below is unchanged.
      */
     private void logCredentialGap(FleetConfig.MemberCredentials creds, Set<String> effectiveAllowed) {
+        if (memberHerdrSocketConfigured()) {
+            warnUnknownMemberEnvironment(creds);
+            return;
+        }
         Set<String> covered = new HashSet<>(creds.known());
         covered.addAll(creds.allow());
         List<String> gap = hostEnvNames.get().stream()

fleetd/src/main/java/dev/ltms/fleet/msg/MessageService.java

@@ -9,6 +9,7 @@ import dev.ltms.fleet.metrics.Metrics;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
@@ -167,6 +168,12 @@ public final class MessageService {
     private static final class Task {
         private final String ticket;
         private final String target;
+        /**
+         * When this task was created (#137 fix): the tiebreaker for which of several open tasks on
+         * one target gets a recovered reply in {@link #abandon} — the oldest, since it is the one
+         * that has been waiting longest.
+         */
+        private final long createdNanos;
         private final CompletableFuture<Reply> future = new CompletableFuture<>();
         /**
          * When {@link #future} resolved, or {@code null} while it is still pending — the clock
@@ -184,6 +191,7 @@ public final class MessageService {
         private Task(String ticket, String target, LongSupplier nowNanos) {
             this.ticket = ticket;
             this.target = target;
+            this.createdNanos = nowNanos.getAsLong();
             future.whenComplete((reply, ex) -> completedNanos = nowNanos.getAsLong());
         }
     }
@@ -375,6 +383,19 @@ public final class MessageService {
      * {@link Rendezvous#resolveQuestion} must keep today's {@code NO_WAITER} behaviour — questions
      * are interactive and must never be queued.
      *
+     * <p><strong>Ambiguous match also falls to the inbox.</strong> {@link #askAnsweredAsyncTasks}
+     * cannot actually return more than one entry today (see its own javadoc for why — in short,
+     * {@link #hasAsyncQuestion} keeps a target BUSY, so no second task can reach this state, for as
+     * long as an earlier one's {@code turnId} is still stamped). That is an emergent guarantee from
+     * two other facts, not one this method enforces, so this branch stays in as defence in depth
+     * rather than being removed as dead code: if it ever weakens, returning whichever candidate a
+     * {@code ConcurrentHashMap} iteration reaches first would let a genuine reply complete the
+     * <em>wrong</em> ticket — silently handing the lead something that reads like a correct answer to
+     * a delegation the worker never touched, which is worse than a failure because the lead acts on
+     * it. When more than one candidate exists, guessing is not safe: fall back to the inbox exactly
+     * as the zero-candidate case does, and let {@link #abandon} apply the eventual recovery
+     * deterministically instead.
+     *
      * @return always {@code true} — the reply resolved a live send, completed a parked ticket, or
      *         was queued
      */
@@ -392,13 +413,21 @@ public final class MessageService {
         // FAILED with a misleading "session released before it replied" reason, even though the reply
         // had, in fact, arrived. Completing the matching ticket directly here means fleet_poll{ticket}
         // sees the real reply instead.
-        Task orphan = askAnsweredAsyncTask(session);
-        if (orphan != null && orphan.future.complete(new Reply(Outcome.REPLIED, content))) {
-            if (orphan.turnId != null) {
-                asyncTasksByTurn.remove(orphan.turnId, orphan);
+        List<Task> candidates = askAnsweredAsyncTasks(session);
+        if (candidates.size() == 1) {
+            Task orphan = candidates.get(0);
+            if (orphan.future.complete(new Reply(Outcome.REPLIED, content))) {
+                if (orphan.turnId != null) {
+                    asyncTasksByTurn.remove(orphan.turnId, orphan);
+                }
+                count(FleetMetrics.REPLIES, "path", "async-recovered");
+                return true;                   // the ticket itself took it — no inbox stranding at all
             }
-            count(FleetMetrics.REPLIES, "path", "async-recovered");
-            return true;                       // the ticket itself took it — no inbox stranding at all
+        } else if (candidates.size() > 1) {
+            List<String> tickets = candidates.stream().map(t -> t.ticket).toList();
+            log.warn("reply from {} matches {} open async tickets {} — cannot tell which one it "
+                    + "answers, queuing to the inbox instead of guessing", session, candidates.size(),
+                    tickets);
         }
         inbox.publish(session, UUID.randomUUID().toString(), content);
         // CB-640: record the stranding itself (not just the reply text) so fleet health can see a
@@ -414,21 +443,38 @@ public final class MessageService {
     }
 
     /**
-     * The still-open async task on {@code target} whose {@code fleet_ask} was already answered — its
-     * {@link Task#turnId} is stamped but its {@link Task#question} was cleared by {@link #answer} —
-     * yet whose future is not resolved yet (#137). {@code null} if no such task exists, including the
+     * Every still-open async task on {@code target} whose {@code fleet_ask} was already answered —
+     * its {@link Task#turnId} is stamped but its {@link Task#question} was cleared by {@link #answer}
+     * — yet whose future is not resolved yet (#137). Empty if no such task exists, including the
      * common case where {@code target}'s worker never used {@code fleet_ask} at all (a task that was
      * never asked has {@code turnId == null}, so it can never match here and only ever completes
      * through the ordinary rendezvous fast path in {@link #reply}).
+     *
+     * <p><strong>Returns at most one entry today — verified, not assumed.</strong> {@link #send}
+     * refuses to open a waiter on {@code target} while {@link #hasAsyncQuestion} is true, and that
+     * check matches ANY task whose {@code turnId} is still stamped in {@code asyncTasksByTurn} —
+     * not only while its question is still open. {@link #answer} deliberately leaves that stamp in
+     * place ({@code clearAsyncQuestion(turnId, false)}) until the resumed turn's own future actually
+     * resolves, at which point {@link #finishAsyncTask} both removes the stamp AND completes that
+     * task's future in the same call. So a second task can never reach "{@code turnId} stamped, future
+     * still open" — the exact pair this method matches on — while a first one already holds it: by
+     * the time the stamp is gone, so is the eligibility. This is an emergent property of those two
+     * facts holding together, not something this method (or its callers) enforces on its own — flip
+     * {@code forgetTurn} to {@code true} in that one {@link #answer} call and it silently stops being
+     * true, with nothing left to fail loudly. The callers below still handle "more than one" as
+     * defence in depth against exactly that, not because they exercise it today: {@link #reply}
+     * treats it as unresolvable and falls back to the inbox; {@link #abandon} would pick the oldest
+     * deterministically (its own {@code matching} list has no such guarantee — see its javadoc).
      */
-    private Task askAnsweredAsyncTask(String target) {
+    private List<Task> askAnsweredAsyncTasks(String target) {
+        List<Task> candidates = new ArrayList<>();
         for (Task task : tasks.values()) {
             if (target.equals(task.target) && task.question == null && task.turnId != null
                     && !task.future.isDone()) {
-                return task;
+                candidates.add(task);
             }
         }
-        return null;
+        return candidates;
     }
 
     /** Record a counter sample when a registry is wired; a no-op in unit tests. */
@@ -473,16 +519,63 @@ public final class MessageService {
      * outcome is counted, so a torn-down delegation stops being invisible to {@code /metrics}.
      *
      * <p><strong>#137 defence in depth.</strong> {@link #reply} already hands a worker's real
-     * {@code fleet_reply} straight to the async ticket it belongs to whenever one is still parked
-     * waiting for it (see {@link #askAnsweredAsyncTask}), so by the time a session is released its
-     * tasks are normally already resolved — this loop's {@code complete} calls are then harmless
-     * no-ops (a {@link CompletableFuture} can only resolve once). But should some other path someday
-     * strand a reply in the inbox without completing its ticket, checking
+     * {@code fleet_reply} straight to the async ticket it belongs to whenever exactly one is still
+     * parked waiting for it (see {@link #askAnsweredAsyncTasks}), so by the time a session is
+     * released its tasks are normally already resolved — this loop's {@code complete} calls are then
+     * harmless no-ops (a {@link CompletableFuture} can only resolve once). But should some other path
+     * someday strand a reply in the inbox without completing its ticket, checking
      * {@link #hasStrandedReply(String)} here — before ever writing a failure — means a torn-down
      * session whose worker in fact replied is still reported {@code REPLIED} with that reply's own
      * text, never the misleading "the worker session was released before it replied" (which also
      * means the snapshot/worktree recovery hint that follows it never prints once a reply exists).
      *
+     * <p><strong>At most one task gets the recovered reply — and here, unlike {@link #reply}'s
+     * {@link #askAnsweredAsyncTasks}, {@code matching.size() >= 2} alone is reachable today.</strong>
+     * This method's {@code matching} filter has no {@code turnId != null} requirement, so it matches
+     * any plain (never-asked) open task too — and {@link #sendAsync} does not limit a target to one
+     * of those: a second {@code fleet_send{wait:false}} at a target that is still busy returns its own
+     * ticket immediately and simply parks its {@link #send} behind the target's session lock for up
+     * to {@link #ASYNC_TIMEOUT_MS}, exactly as {@code abandonFailsEveryPendingAsyncTicketForTheReleasedTarget}
+     * already proves. Before this fix, the loop below drained the strand once and then reused that
+     * same {@code Reply} for <em>every</em> task it walked past — so two open tasks really did both
+     * complete {@code REPLIED} with the same text (see the pre-fix loop in commit 97f6c33's parent).
+     * A stranded reply is one worker answer, so it can settle at most one open task on this target —
+     * never every open task, and never a guess. When more than one task is still open here, the
+     * recovered reply goes to the <em>oldest</em> (lowest {@link Task#createdNanos}) — it has been
+     * waiting longest, so it is the one most likely to be what the reply actually answers. Every
+     * other open task keeps the ordinary {@code WORKER_FAILED} path it would take without a stranded
+     * reply at all.
+     *
+     * <p><strong>{@code matching.size() >= 2} together with {@code hadStrandedReply} is a different
+     * question, and today it is defence in depth rather than a path this codebase's public API can
+     * drive.</strong> This class has exactly two sites that ever acquire a target's entry in
+     * {@code sessionLocks} — {@link #send} and {@link #answer} — and both open a {@link Rendezvous}
+     * waiter for that same target as the very first thing they do after acquiring the lock, then hold
+     * lock and waiter together for the rest of their critical section ({@link #send} also clears
+     * {@link #strandedReplies} right there, the instant it opens its waiter — before it ever enqueues
+     * delivery). So "the session lock is held" and "a live waiter is open for it" are the same fact
+     * throughout this class, and {@link #reply}'s fast path always resolves a currently-open waiter
+     * directly rather than stranding. The two facts this method wants therefore cannot be produced
+     * side by side: while the lock is held, a real reply resolves the open waiter directly and never
+     * reaches {@link #strandedReplies}; the instant the lock is free, any parked matching task's own
+     * {@link #send} that is scheduled next wins it and, by opening its waiter, clears the strand again
+     * before this method ever runs. There is no way to hold that lock open-but-unaccepted from outside
+     * {@link #send}/{@link #answer} to freeze a window in between. Constructing both facts at once
+     * through {@code sendAsync}/{@code reply}/{@code ask}/{@code answer} would need a race against
+     * virtual-thread scheduling, not a deterministic sequence — so the oldest-wins code below stays as
+     * defence in depth against a regression to that mechanism (e.g. clearing {@link #strandedReplies}
+     * on a narrower condition than "any acceptance"), not because today's test suite exercises the
+     * conjunction. {@code matching.size() >= 2} alone, without a strand, is exactly what
+     * {@code abandonFailsEveryPendingAsyncTicketForTheReleasedTarget} already covers.
+     *
+     * <p><strong>Do not "fix" that gap with a test that reaches past this class.</strong> A test can
+     * build both facts by calling {@link Rendezvous#close} itself on the waiter an accepted
+     * {@link #send} is still blocked on: the send keeps the lock, no waiter is registered any more, a
+     * second parked task stays open, and the next {@link #reply} then strands. That was checked, and
+     * such a test does go red against the pre-fix loop. But it only goes red because it broke the
+     * lock-and-waiter invariant above from outside — no caller of this class ever does that — so it
+     * pins a state production cannot reach, and would read to the next person as if it could.
+     *
      * @return true if a live waiter or an async task was failed (never true for one recovered as a
      *         reply — see the note above)
      */
@@ -494,21 +587,39 @@ public final class MessageService {
         CompletableFuture<Rendezvous.Resolution> waiter = rendezvous.currentWaiter(target);
         boolean failed = waiter != null && !waiter.isDone() && rendezvous.resolveFailure(waiter, reason);
         boolean asyncFailed = false;
-        Reply recovered = null; // lazily drained at most once, only if a task actually needs it
+
+        List<Task> matching = new ArrayList<>();
         for (Task task : tasks.values()) {
-            if (!target.equals(task.target) || task.question != null || task.future.isDone()) {
-                continue;
+            if (target.equals(task.target) && task.question == null && !task.future.isDone()) {
+                matching.add(task);
             }
-            if (hadStrandedReply && recovered == null) {
-                recovered = recoverStrandedReply(target);
+        }
+        Task recoveryTask = null;
+        if (hadStrandedReply && !matching.isEmpty()) {
+            recoveryTask = matching.get(0);
+            for (Task candidate : matching) {
+                if (candidate.createdNanos < recoveryTask.createdNanos) {
+                    recoveryTask = candidate;
+                }
             }
-            Reply outcome = recovered != null ? recovered : new Reply(Outcome.WORKER_FAILED, reason);
+        }
+        Reply recovered = recoveryTask != null ? recoverStrandedReply(target) : null;
+        for (Task task : matching) {
+            boolean isRecovery = task == recoveryTask && recovered != null;
+            Reply outcome = isRecovery ? recovered : new Reply(Outcome.WORKER_FAILED, reason);
             if (task.future.complete(outcome)) {
                 if (outcome.outcome() == Outcome.WORKER_FAILED) {
                     asyncFailed = true;
                 } else if (task.turnId != null) {
                     asyncTasksByTurn.remove(task.turnId, task);
                 }
+            } else if (isRecovery) {
+                // The recovered reply was already drained out of the inbox, but this task resolved
+                // through another path (e.g. a concurrent reply() or a second abandon() racing this
+                // one) between us choosing it and completing it here. Put the reply back rather than
+                // lose it silently — it may still belong to some other still-open task, or the next
+                // caller that drains this target's inbox.
+                inbox.publish(target, UUID.randomUUID().toString(), recovered.text());
             }
         }
         if (failed) {
@@ -523,6 +634,10 @@ public final class MessageService {
      * stranding fact raced away, e.g. a lead's own {@code fleet_poll} on the raw session already
      * drained it first). When more than one message is queued, only the newest is the worker's actual
      * final answer ({@link #drainReplies} returns them oldest-first).
+     *
+     * <p>This does drain (removes the messages from the inbox) before the caller knows whether the
+     * task it is recovering for will actually accept them — {@link #abandon} is the one that puts a
+     * reply back if its {@code complete} call turns out to lose the race.
      */
     private Reply recoverStrandedReply(String target) {
         var messages = drainReplies(target);

fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java

@@ -315,10 +315,18 @@ public final class FleetApp {
                 .map(Agent.class::cast)
                 .filter(a -> a.terminalId() != null)
                 .collect(Collectors.toMap(Agent::terminalId, Function.identity(), (_, b) -> b));
-        List<Map<String, Object>> out = sessions.roster().stream()
+        // fleetd #209: this REST roster reports agentSessionId via SessionManager.rosterView, so it
+        // uses the resolving roster read (caller-driven, not a timer) rather than the plain one.
+        List<Map<String, Object>> out = sessions.rosterResolved().stream()
                 .map(s -> SessionManager.rosterView(s, live.get(s.terminalId())))
                 .toList();
         Map<String, Object> body = new LinkedHashMap<>();
+        // fleetd #199: the endpoint became /members in the CB-634 rename but the body key stayed
+        // "workers", so a caller that read "members" saw an empty fleet and reported no members at
+        // all. "members" is the canonical key; "workers" stays as a deprecated alias so an existing
+        // REST consumer keeps working — the out-of-band path a lead falls back to when its MCP mount
+        // drops reads this endpoint. Drop the alias once nothing reads it.
+        body.put("members", out);
         body.put("workers", out);
         // CB-586: operator visibility for the refs/wip snapshot store without shelling into the
         // repo — how many snapshot refs exist and roughly what they cost. Present only once a

fleetd/src/main/java/dev/ltms/fleet/session/GitWorktrees.java

@@ -23,6 +23,7 @@ import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 
 /**
@@ -88,24 +89,64 @@ public final class GitWorktrees implements Worktrees {
     );
 
     private final String configuredRoot;
+    /** OS group name for {@link #shareWithGroup} (fleetd #185 stage 3); {@code null} ⇒ feature off. */
+    private final String group;
     private final Consumer<String> afterWorktreeAdded;
+    /** How {@link #shareWithGroup}'s processes (git config / chgrp / chmod / find) actually run.
+     *  Defaults to the real {@link #exec(String...)}. Package-private test seam so a unit test can
+     *  prove "no group configured ⇒ zero processes spawned" and inspect exactly what a configured
+     *  group runs, without a real second OS user or OS group on this host. */
+    private final Function<String[], String> shareGroupRunner;
     private final SecureRandom random = new SecureRandom();
     private final AtomicLong seq = new AtomicLong();
 
     /** Default constructor: worktree root is derived per-repo as {@code <repoRoot>/../.bridged-worktrees}. */
     public GitWorktrees() {
-        this(null);
+        this(null, (String) null);
     }
 
-    /** @param configuredRoot nullable absolute or relative path; null/blank derives a sibling of the repo root. */
+    /**
+     * @param configuredRoot nullable absolute or relative path; null/blank derives a sibling of
+     *                       the repo root. No {@code worktreeGroup} configured — {@link #shareWithGroup}
+     *                       is a no-op.
+     */
     public GitWorktrees(String configuredRoot) {
-        this(configuredRoot, _ -> {});
+        this(configuredRoot, (String) null);
+    }
+
+    /**
+     * @param configuredRoot nullable absolute or relative path; null/blank derives a sibling of
+     *                       the repo root.
+     * @param group          optional OS group name (fleetd #185 stage 3, {@code worktreeGroup:} in
+     *                       config); null/blank ⇒ {@link #shareWithGroup} is a no-op.
+     */
+    public GitWorktrees(String configuredRoot, String group) {
+        this(configuredRoot, group, _ -> {});
     }
 
     /** Test seam for changing a real worktree between its creation and its security check. */
     GitWorktrees(String configuredRoot, Consumer<String> afterWorktreeAdded) {
+        this(configuredRoot, null, afterWorktreeAdded);
+    }
+
+    /** Test seam combining a configurable {@code group} with {@link #afterWorktreeAdded}. */
+    GitWorktrees(String configuredRoot, String group, Consumer<String> afterWorktreeAdded) {
+        this(configuredRoot, group, afterWorktreeAdded, null);
+    }
+
+    /**
+     * Full test seam: also overrides how {@link #shareWithGroup}'s processes run (fleetd #185
+     * stage 3), so a unit test can prove "no group configured ⇒ no process spawned" and inspect
+     * exactly what commands a configured group runs, without a real second OS user/group.
+     *
+     * @param shareGroupRunner {@code null} ⇒ the real {@link #exec(String...)}.
+     */
+    GitWorktrees(String configuredRoot, String group, Consumer<String> afterWorktreeAdded,
+                 Function<String[], String> shareGroupRunner) {
         this.configuredRoot = configuredRoot;
+        this.group = (group == null || group.isBlank()) ? null : group;
         this.afterWorktreeAdded = afterWorktreeAdded == null ? _ -> {} : afterWorktreeAdded;
+        this.shareGroupRunner = shareGroupRunner != null ? shareGroupRunner : this::exec;
     }
 
     @Override
@@ -607,6 +648,126 @@ public final class GitWorktrees implements Worktrees {
         return deleted;
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * <p>fleetd #185 stage 3. No-op — no process spawned, nothing logged — when {@link #group} is
+     * null/blank. Otherwise:
+     * <ol>
+     *   <li>{@code git -C repoRoot config core.sharedRepository group} so every future write by
+     *       either uid stays group-writable;</li>
+     *   <li>a one-time {@code chgrp}/{@code chmod g+rwX} fix-up over the worktree directory and,
+     *       under the repo's <em>common</em> git directory, {@code objects}, {@code refs},
+     *       {@code logs}, {@code worktrees} and {@code packed-refs} — with setgid
+     *       ({@code chmod g+s}) applied only to the directories among them, so files created later
+     *       inherit the group;</li>
+     *   <li>one INFO line naming the group and the paths touched.</li>
+     * </ol>
+     *
+     * <p><b>Every path is skipped when it does not exist.</b> {@code .git/logs} is absent in a repo
+     * with {@code core.logAllRefUpdates=false} or one that has had no ref update yet, and
+     * {@code packed-refs} is absent until refs are packed. Passing a missing path to {@code chgrp}
+     * exits non-zero, which would fail <em>every</em> provisioning spawn with a message blaming a
+     * group that is in fact fine.
+     *
+     * <p><b>The git directory is resolved, not assumed.</b> {@code <repoRoot>/.git} is a
+     * <em>file</em>, not a directory, when the checkout is itself a linked worktree — the very
+     * thing this class creates for every member. {@code git rev-parse --git-common-dir} gives the
+     * real shared store, and it may answer relatively, so it is resolved against {@code repoRoot}.
+     *
+     * <p><b>The fix-up re-runs on every spawn, by design.</b> {@code core.sharedRepository=group}
+     * governs only what git writes <em>after</em> it is set; the walk is what covers everything
+     * already on disk. It is not redundant work to optimise away — dropping it silently leaves
+     * pre-existing objects unreadable to the member. It costs three walks of the object store per
+     * spawn (about 3000 files in this repo, well under a second, but it grows with the repo).
+     *
+     * <p>This only fixes up file ownership/permissions on the operator's shared repo so a
+     * different-uid member can write to it — it isolates credentials, not the repository. A member
+     * in the group can still write the operator's git objects and refs.
+     *
+     * <p>Fails loudly: a missing group, or a {@code chgrp}/{@code chmod} refused because the
+     * operator is not a member of it, becomes a {@link WorktreeException} naming the group — never
+     * a silent skip that leaves a member unable to work with nothing in the log to explain why.
+     */
+    @Override
+    public void shareWithGroup(String repoRoot, String worktreePath) {
+        if (group == null) {
+            return;
+        }
+        List<String> touched = new ArrayList<>();
+        try {
+            shareGroupRunner.apply(new String[]{"git", "-C", repoRoot, "config", "core.sharedRepository", "group"});
+            String commonDir = gitCommonDir(repoRoot);
+            shareGroupPathIfPresent(worktreePath, true, touched);
+            for (String name : List.of("objects", "refs", "logs", "worktrees")) {
+                shareGroupPathIfPresent(commonDir + "/" + name, true, touched);
+            }
+            shareGroupPathIfPresent(commonDir + "/packed-refs", false, touched);
+        } catch (WorktreeException e) {
+            throw new WorktreeException("cannot share worktree with group '" + group + "': "
+                    + e.getMessage() + " — the group must exist, and the fleetd operator ("
+                    + System.getProperty("user.name") + ") must be a member of it", e);
+        }
+        log.info("worktreeGroup={} shared repoRoot={} worktreePath={} paths={}",
+                group, repoRoot, worktreePath, touched);
+    }
+
+    /**
+     * The repo's <em>common</em> git directory as an absolute path — where {@code objects},
+     * {@code refs} and {@code worktrees} actually live. {@code git rev-parse --git-common-dir}
+     * answers relative to {@code repoRoot} in the ordinary case ({@code .git}) and absolutely for a
+     * linked worktree, so the answer is resolved against {@code repoRoot} either way. Never
+     * hardcode {@code repoRoot + "/.git"}: that is a FILE when the checkout is itself a linked
+     * worktree.
+     */
+    private String gitCommonDir(String repoRoot) {
+        String answer = shareGroupRunner.apply(
+                new String[]{"git", "-C", repoRoot, "rev-parse", "--git-common-dir"});
+        String trimmed = answer == null ? "" : answer.trim();
+        if (trimmed.isEmpty()) {
+            trimmed = ".git";
+        }
+        return Path.of(repoRoot).resolve(trimmed).normalize().toString();
+    }
+
+    /**
+     * {@link #shareGroupPath} when {@code path} exists, recording it in {@code touched}; otherwise
+     * nothing at all. A missing path is normal, not an error — see {@link #shareWithGroup}'s
+     * javadoc for which ones are routinely absent and why passing them to {@code chgrp} would fail
+     * every spawn.
+     */
+    private void shareGroupPathIfPresent(String path, boolean recursive, List<String> touched) {
+        if (!Files.exists(Path.of(path))) {
+            return;
+        }
+        shareGroupPath(path, recursive);
+        touched.add(path);
+    }
+
+    /**
+     * {@code chgrp}/{@code chmod g+rwX} {@code path} to {@link #group}. When {@code recursive},
+     * also walks the directories under {@code path} (including {@code path} itself, when it is a
+     * directory) and sets setgid on each — directories only, per the javadoc on
+     * {@link #shareWithGroup}.
+     */
+    private void shareGroupPath(String path, boolean recursive) {
+        List<String> chgrp = new ArrayList<>(List.of("chgrp"));
+        if (recursive) chgrp.add("-R");
+        chgrp.add(group);
+        chgrp.add(path);
+        shareGroupRunner.apply(chgrp.toArray(new String[0]));
+
+        List<String> chmod = new ArrayList<>(List.of("chmod"));
+        if (recursive) chmod.add("-R");
+        chmod.add("g+rwX");
+        chmod.add(path);
+        shareGroupRunner.apply(chmod.toArray(new String[0]));
+
+        if (recursive) {
+            shareGroupRunner.apply(new String[]{"find", path, "-type", "d", "-exec", "chmod", "g+s", "{}", "+"});
+        }
+    }
+
     /**
      * Every {@code refs/wip/*} ref (see {@link WipRef}). The committer date is read as a unix
      * count of seconds and converted to millis. {@code %00} (NUL) separates the fields because a

fleetd/src/main/java/dev/ltms/fleet/session/MemberSession.java

@@ -89,4 +89,15 @@ public record MemberSession(
         return new MemberSession(paneId, terminalId, profile, role, cwd, ownerTerminal, spawnedAtNanos,
                 nowNanos, turnCount + 1, state, worktree, branch, charterReceipt, agentSessionId);
     }
+
+    /**
+     * Return a copy with {@code agentSessionId} resolved to a non-null value (fleetd #209). Some
+     * adapters (opencode) cannot answer {@link dev.ltms.fleet.peer.PeerHandle#agentSessionId()} at
+     * spawn time — the peer has not persisted its session record yet — so the id is discovered on
+     * a later poll and swapped into the otherwise-immutable session via this wither.
+     */
+    public MemberSession withAgentSessionId(String agentSessionId) {
+        return new MemberSession(paneId, terminalId, profile, role, cwd, ownerTerminal, spawnedAtNanos,
+                lastActivityAtNanos, turnCount, state, worktree, branch, charterReceipt, agentSessionId);
+    }
 }

fleetd/src/main/java/dev/ltms/fleet/session/SessionManager.java

@@ -46,6 +46,15 @@ public final class SessionManager implements TurnListener {
     private final PeerLauncher launcher;
     private final Worktrees worktrees;
     private final ConcurrentHashMap<String /*paneId*/, MemberSession> registry = new ConcurrentHashMap<>();
+    /**
+     * fleetd #209: the live {@link PeerHandle} for every registered pane, retained solely so
+     * {@link #resolveAgentSessionId} can re-poll {@link PeerHandle#agentSessionId()} after spawn.
+     * The handle used to go out of scope at the end of the spawn method, so a launcher that answers
+     * the id lazily (opencode — the on-disk session row is written after the pane is created) could
+     * never be re-asked, and {@code fleet_list}/{@code fleet_spawn resumeSessionId} never saw it.
+     * Populated on every spawn path, removed on {@link #release}.
+     */
+    private final ConcurrentHashMap<String /*paneId*/, PeerHandle> handles = new ConcurrentHashMap<>();
     private final MemberPresence presence;
     private final SecureRandom nonceRandom = new SecureRandom();
     private final AtomicLong nonceSeq = new AtomicLong();
@@ -205,6 +214,7 @@ public final class SessionManager implements TurnListener {
                     handle.charterReceipt(),
                     handle.agentSessionId());
             registry.put(handle.id(), session);
+            handles.put(handle.id(), handle);
             memberLifecycle.acquired(session.role(), session.profile(), session.terminalId());
             log.debug("acquired session id={} terminal={} profile={} owner={}",
                     handle.id(), handle.terminalId(), session.profile(), session.ownerTerminal());
@@ -257,6 +267,10 @@ public final class SessionManager implements TurnListener {
      */
     private void release(String paneId, ReleaseCause cause) {
         MemberSession removed = registry.remove(paneId);
+        // fleetd #209: remove right alongside the registry entry so a released session's handle is
+        // never leaked — but keep the local reference below, so the id can still be resolved for
+        // the ReleaseDetail this teardown notifies with.
+        PeerHandle removedHandle = handles.remove(paneId);
         boolean preserveWorktree = cause == ReleaseCause.SHUTDOWN;
         String snapshotRef = null;
         if (removed != null) {
@@ -303,8 +317,11 @@ public final class SessionManager implements TurnListener {
                 // too, so a failed ticket's detail can point a lead at the same tree to re-dispatch.
                 // CB-584 (issue #65 criterion 5): carry agentSessionId alongside them, so a lead can
                 // also resume the member's conversation, not just re-dispatch onto its files.
-                notifyReleased(new ReleaseDetail(removed.terminalId(), removed.worktree(),
-                        removed.branch(), snapshotRef, removed.agentSessionId()));
+                // fleetd #209: a late-resolving adapter (opencode) may only now have an id — resolve
+                // one last time so a released member's detail carries the id it now has.
+                MemberSession resolved = resolveAgentSessionId(removed, removedHandle);
+                notifyReleased(new ReleaseDetail(resolved.terminalId(), resolved.worktree(),
+                        resolved.branch(), snapshotRef, resolved.agentSessionId()));
             }
         }
         // CB-581: the pane must always stop, even if the dirty check above threw. A session removed
@@ -472,6 +489,10 @@ public final class SessionManager implements TurnListener {
         try {
             path = worktrees.add(repoRoot, branch, wt.baseRef());
             worktrees.overlayParity(repoRoot, path, launcher.parityOverlay(preResolvedProfile));
+            // fleetd #185 stage 3: MUST run after overlayParity, not folded into add() — overlayParity
+            // copies more files into the worktree after add() returns, so sharing the group any earlier
+            // leaves those overlay files operator-owned and read-only for a different-uid member.
+            worktrees.shareWithGroup(repoRoot, path);
             handle = launcher.spawn(new SpawnRequest(profile, path, callerCwd, sessionName, resumeSessionId, memberRole));
         } catch (RuntimeException e) {
             log.warn("spawn failed for profile={} role={} branch={} path={}: {}",
@@ -504,6 +525,7 @@ public final class SessionManager implements TurnListener {
                 handle.charterReceipt(),
                 handle.agentSessionId());
         registry.put(handle.id(), session);
+        handles.put(handle.id(), handle);
         memberLifecycle.acquired(session.role(), session.profile(), session.terminalId());
         log.debug("acquired worktree session id={} terminal={} profile={} branch={} path={}",
                 handle.id(), handle.terminalId(), session.profile(), session.branch(), session.worktree());
@@ -535,16 +557,73 @@ public final class SessionManager implements TurnListener {
         return launcher.defaultProfile();
     }
 
-    /** The session for {@code paneId}, if it is still registered and not released. */
+    /**
+     * The session for {@code paneId}, if it is still registered and not released. fleetd #209:
+     * resolves a still-unknown {@code agentSessionId} against the retained handle before returning,
+     * so {@code fleet_status} sees an id a lazy-resolving adapter has since written.
+     */
     public Optional<MemberSession> get(String paneId) {
-        return Optional.ofNullable(registry.get(paneId));
+        return Optional.ofNullable(registry.get(paneId)).map(this::resolveAgentSessionId);
     }
 
-    /** Fleet-owned roster: all registered sessions (acquired minus released). */
+    /**
+     * Fleet-owned roster: all registered sessions (acquired minus released). Deliberately does
+     * <strong>not</strong> resolve {@code agentSessionId} (fleetd #209 follow-up) — this is the
+     * roster supplier on the heartbeat and health-tick timers ({@code LeadHeartbeatLoop},
+     * {@code FleetHealthMonitor} in {@code Fleetd}), on the placement/exhaustion paths, and on the
+     * metrics scrape ({@code FleetMetrics}), all called far more often than any caller actually
+     * reads {@code agentSessionId}. Resolving here would mean every tick opens a lazy-resolving
+     * adapter's (opencode's) on-disk session store once per member whose id is still unknown — and
+     * for a member whose id never appears, that cost never stops, for the life of the process. Use
+     * {@link #rosterResolved()} instead wherever the id must be current.
+     */
     public List<MemberSession> roster() {
         return List.copyOf(registry.values());
     }
 
+    /**
+     * {@link #roster()}, with each session's still-unknown {@code agentSessionId} re-resolved
+     * against its retained handle (fleetd #209) — so a caller that actually reports the id (
+     * {@code fleet_list}, the REST roster) sees one a lazy-resolving adapter (opencode) has since
+     * written, rather than the null frozen in at spawn time. Reserved for caller-driven reads, not
+     * timers: see {@link #roster()}'s javadoc for why the plain roster must stay non-resolving.
+     */
+    public List<MemberSession> rosterResolved() {
+        return registry.values().stream().map(this::resolveAgentSessionId).toList();
+    }
+
+    /**
+     * Resolve {@code session}'s {@code agentSessionId} if still unknown, re-polling the retained
+     * {@link PeerHandle} for this pane (fleetd #209). A no-op — returning {@code session} unchanged
+     * — once the id is already known, once no handle is retained for this pane (never spawned, or
+     * already released), or if the handle throws while answering. A resolved id is best-effort
+     * CAS-swapped into the registry via {@link #replace}; a lost race just means another caller
+     * already applied the same update, so the resolved value is returned either way.
+     */
+    private MemberSession resolveAgentSessionId(MemberSession session) {
+        return resolveAgentSessionId(session, handles.get(session.paneId()));
+    }
+
+    private MemberSession resolveAgentSessionId(MemberSession session, PeerHandle handle) {
+        if (session.agentSessionId() != null || handle == null) {
+            return session;
+        }
+        String resolved;
+        try {
+            resolved = handle.agentSessionId();
+        } catch (RuntimeException e) {
+            log.debug("agentSessionId lookup failed for pane={} terminal={}: {}",
+                    session.paneId(), session.terminalId(), e.toString());
+            return session;
+        }
+        if (resolved == null) {
+            return session;
+        }
+        MemberSession updated = session.withAgentSessionId(resolved);
+        replace(session, updated); // best-effort; a lost CAS just means the resolved value stands anyway
+        return updated;
+    }
+
     /**
      * CB-304 merged roster+live view. The registry is authoritative for worktree, branch,
      * profile, owner, and state; the optional live agent supplies the herdr-reported status.

fleetd/src/main/java/dev/ltms/fleet/session/Worktrees.java

@@ -98,4 +98,21 @@ public interface Worktrees {
     /** CB-586: the operator-visible census of {@code refs/wip/*} in one repository. */
     record WipRefStats(int count, long costBytes) {
     }
+
+    /**
+     * Make {@code repoRoot}'s git store and {@code worktreePath} writable by the configured group
+     * (fleetd #185 stage 3), so a member spawned as a different OS user (see
+     * {@code memberHerdrSocket}) can write its own worktree, its per-worktree git metadata, and
+     * its own commit objects. No-op when no group is configured.
+     *
+     * <p><strong>This isolates credentials, not the repository.</strong> A member in the group can
+     * still write the operator's git objects and refs in the shared repo — this only fixes file
+     * ownership/permissions so a different-uid member can work at all, it grants no narrower access
+     * than that.
+     *
+     * @param repoRoot     the repository whose git store ({@code .git/objects}, {@code refs},
+     *                     {@code logs}, {@code worktrees}, {@code packed-refs}) needs sharing
+     * @param worktreePath the linked worktree's own directory
+     */
+    void shareWithGroup(String repoRoot, String worktreePath);
 }

fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigTest.java

@@ -1036,6 +1036,35 @@ class FleetConfigTest {
         assertEquals(LeadMailbox.DEFAULT_PREFETCH, noEnv.prefetchOrDefault());
     }
 
+    @Test
+    void absentWorktreeGroupLeavesItNull(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("no-worktree-group.yaml");
+        Files.writeString(f, "bind:\n  port: 8080\n");
+
+        FleetConfig cfg = FleetConfig.load(f);
+        assertNull(cfg.worktreeGroup(), "no worktreeGroup: key → null → GitWorktrees.shareWithGroup is a no-op");
+    }
+
+    @Test
+    void worktreeGroupKeyParses(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("worktree-group.yaml");
+        Files.writeString(f, "bind:\n  port: 8080\nworktreeGroup: fleet-workers\n");
+
+        FleetConfig cfg = FleetConfig.load(f);
+        assertEquals("fleet-workers", cfg.worktreeGroup());
+    }
+
+    @Test
+    void absentWorktreeGroupSurvivesTheBackCompatConstructorChain() {
+        // fleetd #185 stage 3: withDefaults() (and every pre-existing call site) must not silently
+        // drop a live worktreeGroup by routing through a back-compat constructor that defaults it
+        // to null.
+        FleetConfig cfg = new FleetConfig(null, null, null, Map.of(), null, null, null, null, null,
+                null, null, null, null, null, null, null, null, null, null, null, "fleet-workers");
+        assertEquals("fleet-workers", cfg.withDefaults().worktreeGroup(),
+                "withDefaults() must carry a configured worktreeGroup through unchanged");
+    }
+
     @Test
     void absentPrimaryBlockLeavesPrimaryNull(@TempDir Path dir) throws Exception {
         Path f = dir.resolve("no-primary.yaml");

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

@@ -12,20 +12,26 @@ import dev.ltms.fleet.peer.Capability;
 import dev.ltms.fleet.peer.MemberRole;
 import dev.ltms.fleet.peer.SpawnRequest;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 import org.slf4j.LoggerFactory;
 
+import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.attribute.PosixFileAttributeView;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Function;
 import java.util.function.Supplier;
 
 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.assertTrue;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
 /**
  * CB-633: proves the allow-list scrub is actually WIRED INTO the spawn path — not merely that its
@@ -119,6 +125,18 @@ class HerdrPeerLauncherAllowListWiringTest {
                 FleetConfig.MemberCredentials.POLICY_ALLOW_LIST, allow, List.of(), null);
     }
 
+    /**
+     * Same as {@link #allowList()} but with an operator-configured {@code known:} list, so the
+     * fallback overlay (the non-zsh / no-memberLoginShell path) has something visible to shadow —
+     * {@link FleetConfig.MemberCredentials#blockedSet()} is {@code known - allow}, so an empty
+     * {@code known} (what {@link #allowList()} uses) blocks nothing and a fallback test would have
+     * no sentinel entry to assert on.
+     */
+    private static Supplier<FleetConfig.MemberCredentials> allowListWithKnown(List<String> known) {
+        return () -> new FleetConfig.MemberCredentials(
+                FleetConfig.MemberCredentials.POLICY_ALLOW_LIST, List.of(), known, null);
+    }
+
     /**
      * CB-633 follow-up: a name that lives ONLY in {@code memberCredentials.allow:} — no profile
      * mentions it — must survive the scrub the real spawn path generates. Calling {@code
@@ -257,6 +275,268 @@ class HerdrPeerLauncherAllowListWiringTest {
                         + appender.list.stream().map(ILoggingEvent::getFormattedMessage).toList());
     }
 
+    /**
+     * fleetd #185 stage 2 pin: with {@code memberHerdrSocket:} absent (today's only mode, and the
+     * default — this host runs no other), the gap detector's WARN/INFO conclusions read exactly as
+     * they did before this fix. Real path: {@code FLEETD_WORKER_TOKEN} (the test profile's own
+     * {@code tokenEnv}) is a name the derived allow-list keeps, so it gets the "UNBLOCKED" WARN;
+     * {@code SOME_UNKNOWN_SECRET_TOKEN} is not derived from anywhere, so it gets the "scrub blanks
+     * them" INFO. This is the exact shape #185 stage 2 must not touch on this path.
+     */
+    @Test
+    void gapConclusionsAreByteIdenticalWhenMemberHerdrSocketIsAbsent() {
+        FakeHerdr herdr = new FakeHerdr();
+        Set<String> hostEnvNames = Set.of("FLEETD_WORKER_TOKEN", "SOME_UNKNOWN_SECRET_TOKEN");
+        WiringLauncher launcher = new WiringLauncher(herdr, allowList(), "/bin/zsh", () -> hostEnvNames,
+                () -> config(null));
+
+        List<String> messages = spawnAndCaptureLogs(launcher);
+
+        assertTrue(messages.contains("memberCredentials gap: 1 credential-shaped env var name(s) are on "
+                        + "neither known: nor allow: — the derived allow-list keeps them anyway (a "
+                        + "profile's gitTokenEnv/gitHostEnv/tokenEnv/env: names one, or this spawn "
+                        + "injects it), so every member pane inherits them UNBLOCKED — [FLEETD_WORKER_TOKEN]. "
+                        + "Add each to memberCredentials.known (or .allow if a member legitimately needs "
+                        + "it), or remove it from whatever profile setting derives it in."),
+                "expected the pre-existing UNBLOCKED WARN unchanged, got: " + messages);
+        assertTrue(messages.contains("memberCredentials gap: 1 credential-shaped env var name(s) are on "
+                        + "neither known: nor allow: — [SOME_UNKNOWN_SECRET_TOKEN]. The allow-list scrub "
+                        + "blanks them anyway (they are not on the derived allow-list), so no member pane "
+                        + "keeps them; add each to memberCredentials.known or .allow to make that explicit."),
+                "expected the pre-existing 'scrub blanks them' INFO unchanged, got: " + messages);
+    }
+
+    /**
+     * fleetd #185 stage 2: with {@code memberHerdrSocket:} configured, member panes run under a
+     * different OS user — {@link HerdrPeerLauncher#hostEnvNames} describes fleetd's own process, not
+     * that user's. Neither "inherits them UNBLOCKED" nor "scrub blanks them" is evidence-backed
+     * there, so neither may print; the single unknown-environment WARN must, naming the config key.
+     */
+    @Test
+    void gapDetectorReportsUnknownInsteadOfAConclusionWhenMemberHerdrSocketIsConfigured() {
+        FakeHerdr herdr = new FakeHerdr();
+        Set<String> hostEnvNames = Set.of("FLEETD_WORKER_TOKEN", "SOME_UNKNOWN_SECRET_TOKEN");
+        WiringLauncher launcher = new WiringLauncher(herdr, allowList(), "/bin/zsh", () -> hostEnvNames,
+                () -> configWithMemberHerdrSocket("/tmp/other-user-herdr.sock"));
+
+        List<String> messages = spawnAndCaptureLogs(launcher);
+
+        assertTrue(messages.stream().anyMatch(m -> m.contains("memberHerdrSocket")
+                        && m.contains("UNKNOWN") && m.contains("cannot be verified")),
+                "expected the unknown-member-environment WARN naming memberHerdrSocket, got: " + messages);
+        assertFalse(messages.stream().anyMatch(m -> m.contains("UNBLOCKED")),
+                "the 'inherits them UNBLOCKED' conclusion must not print once the evidence is about "
+                        + "the wrong (daemon's own) environment — got: " + messages);
+        assertFalse(messages.stream().anyMatch(m -> m.contains("scrub blanks them")),
+                "the 'scrub blanks them' conclusion must not print once the evidence is about the "
+                        + "wrong (daemon's own) environment — got: " + messages);
+    }
+
+    /**
+     * fleetd #185 stage 2: the unknown-environment WARN is a standing fact about this launcher's
+     * configuration, not per-spawn news — it must fire once per launcher instance, the same shape as
+     * every other one-time WARN in this class (e.g. {@code warnNonZsh}).
+     */
+    @Test
+    void theUnknownEnvironmentWarnFiresOnceNotOncePerSpawn() {
+        FakeHerdr herdr = new FakeHerdr();
+        Set<String> hostEnvNames = Set.of("FLEETD_WORKER_TOKEN", "SOME_UNKNOWN_SECRET_TOKEN");
+        WiringLauncher launcher = new WiringLauncher(herdr, allowList(), "/bin/zsh", () -> hostEnvNames,
+                () -> configWithMemberHerdrSocket("/tmp/other-user-herdr.sock"));
+
+        Logger logger = (Logger) LoggerFactory.getLogger(HerdrPeerLauncher.class);
+        Level original = logger.getLevel();
+        logger.setLevel(Level.WARN);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        logger.addAppender(appender);
+        try {
+            launcher.spawn(new SpawnRequest("test", null, null, null, null, MemberRole.DEV));
+            launcher.spawn(new SpawnRequest("test", null, null, null, null, MemberRole.DEV));
+        } finally {
+            logger.detachAppender(appender);
+            logger.setLevel(original);
+        }
+
+        long count = appender.list.stream()
+                .filter(e -> e.getFormattedMessage().contains("cannot be verified from here"))
+                .count();
+        assertEquals(1, count, "the unknown-member-environment WARN must fire once per launcher "
+                + "instance, not once per spawn — got " + count + " occurrence(s) among: "
+                + appender.list.stream().map(ILoggingEvent::getFormattedMessage).toList());
+    }
+
+    /**
+     * Hard constraint: the gap detector must never log an env var VALUE, only its NAME. {@code
+     * SOME_UNKNOWN_SECRET_TOKEN} resolves to a distinctive canary value through the same {@code env}
+     * lookup the launcher uses elsewhere (SHELL, PATH, token resolution) — proving the value IS
+     * resolvable does not mean the detector reads it, since {@link HerdrPeerLauncher#hostEnvNames}
+     * (names only) is its data source, never {@code env.apply(name)} for those names.
+     */
+    @Test
+    void theGapDetectorNeverLogsAnEnvVarValueOnlyItsName() {
+        FakeHerdr herdr = new FakeHerdr();
+        String canary = "sekrit-value-CANARY-9f3a1b7c";
+        Set<String> hostEnvNames = Set.of("FLEETD_WORKER_TOKEN", "SOME_UNKNOWN_SECRET_TOKEN");
+        WiringLauncher launcher = new WiringLauncher(herdr, allowList(), "/bin/zsh", () -> hostEnvNames,
+                () -> config(null), Map.of("SOME_UNKNOWN_SECRET_TOKEN", canary));
+
+        List<String> messages = spawnAndCaptureLogs(launcher);
+
+        assertTrue(messages.stream().anyMatch(m -> m.contains("SOME_UNKNOWN_SECRET_TOKEN")),
+                "expected the credential-shaped NAME to appear in the log, got: " + messages);
+        assertFalse(messages.stream().anyMatch(m -> m.contains(canary)),
+                "the log must never contain an env var VALUE, only its NAME — got: " + messages);
+    }
+
+    /**
+     * fleetd #213 defect 1, acceptance criterion 1: {@code memberHerdrSocket} configured and {@code
+     * memberLoginShell} configured as non-zsh must fall back to the sentinel overlay exactly like a
+     * non-zsh {@code $SHELL} does today — and the "generated ZDOTDIR" INFO must not appear, since no
+     * scrub actually runs. The WiringLauncher's own {@code env("SHELL")} is deliberately set to
+     * {@code /bin/zsh} — the OPPOSITE of what {@code memberLoginShell} says — so a launcher that
+     * (incorrectly) fell back to fleetd's own {@code $SHELL} here would wrongly pass the gate and
+     * fail this test.
+     */
+    @Test
+    void memberHerdrSocketWithNonZshMemberLoginShellFallsBackToTheOverlay() {
+        FakeHerdr herdr = new FakeHerdr();
+        WiringLauncher launcher = new WiringLauncher(herdr, allowListWithKnown(List.of("SOME_TOKEN")),
+                "/bin/zsh", null,
+                () -> configWithMemberHerdrSocket("/tmp/other-user-herdr.sock", "/bin/bash"));
+
+        List<String> messages = spawnAndCaptureLogs(launcher);
+
+        assertEquals("blocked-by-fleetd-cb596-see-gitea-issue-82", launcher.env.get("SOME_TOKEN"),
+                "a non-zsh memberLoginShell must fall back to the CB-596 sentinel overlay, exactly "
+                        + "like a non-zsh $SHELL does when memberHerdrSocket is absent");
+        assertFalse(launcher.env.containsKey("ZDOTDIR"),
+                "no scrub directory may be generated when the configured member login shell is not zsh");
+        assertFalse(messages.stream().anyMatch(m -> m.contains("generated ZDOTDIR")),
+                "the 'generated ZDOTDIR' INFO must not appear when the scrub never runs — got: " + messages);
+    }
+
+    /**
+     * fleetd #213 defect 1, acceptance criterion 2: {@code memberHerdrSocket} configured and NO
+     * {@code memberLoginShell} configured must fall back exactly like criterion 1 above — AND
+     * fleetd's own {@code $SHELL} must never even be consulted (not merely "not decisive"). The
+     * fixture's {@code env} function reports {@code /bin/zsh} for {@code SHELL} — a value that would
+     * WRONGLY pass the zsh gate if the fix regressed to reading it — while flagging whether it was
+     * ever asked for at all, so this test fails loudly on either kind of regression.
+     */
+    @Test
+    void memberHerdrSocketWithNoMemberLoginShellFallsBackAndNeverConsultsFleetdsOwnShell() {
+        FakeHerdr herdr = new FakeHerdr();
+        AtomicBoolean shellQueried = new AtomicBoolean(false);
+        Function<String, String> env = name -> {
+            if ("SHELL".equals(name)) {
+                shellQueried.set(true);
+                return "/bin/zsh"; // would wrongly pass the zsh gate if this ever leaked through
+            }
+            return null;
+        };
+        WiringLauncher launcher = new WiringLauncher(herdr, allowListWithKnown(List.of("SOME_TOKEN")), env,
+                () -> configWithMemberHerdrSocket("/tmp/other-user-herdr.sock", null));
+
+        List<String> messages = spawnAndCaptureLogs(launcher);
+
+        assertFalse(shellQueried.get(), "fleetd's own $SHELL must never be consulted once "
+                + "memberHerdrSocket is configured — only memberLoginShell: may decide the gate");
+        assertEquals("blocked-by-fleetd-cb596-see-gitea-issue-82", launcher.env.get("SOME_TOKEN"),
+                "no memberLoginShell configured must fall back to the sentinel overlay, same as a "
+                        + "configured non-zsh shell");
+        assertFalse(messages.stream().anyMatch(m -> m.contains("generated ZDOTDIR")),
+                "no scrub may run without a configured memberLoginShell — got: " + messages);
+    }
+
+    /**
+     * fleetd #213 defect 2, acceptance criterion 3: with {@code memberHerdrSocket} configured, a
+     * zsh {@code memberLoginShell}, and {@code worktreeRoot}/{@code worktreeGroup} both configured,
+     * the generated scrub directory must live under {@code worktreeRoot} — NEVER under {@code
+     * java.io.tmpdir}, which is fleetd's own 0700 temp dir and unreadable by the member's different
+     * OS user. {@code worktreeGroup} is set to the CURRENT process's own primary group so {@code
+     * EnvAllowListScrub}'s group-sharing step resolves on whatever host runs this test, rather than
+     * hardcoding a group name that may not exist here.
+     */
+    @Test
+    void memberHerdrSocketWithZshMemberLoginShellPutsTheScrubOutsideJavaIoTmpdir(@TempDir Path worktreeRoot)
+            throws IOException {
+        String group = currentUserGroup();
+        FakeHerdr herdr = new FakeHerdr();
+        WiringLauncher launcher = new WiringLauncher(herdr, allowList(), "/bin/bash-should-be-ignored", null,
+                () -> configWithMemberHerdrSocketRootAndGroup("/tmp/other-user-herdr.sock", "/bin/zsh",
+                        worktreeRoot.toString(), group));
+
+        launcher.spawn(new SpawnRequest("test", null, null, null, null, MemberRole.DEV));
+
+        String zdotdir = launcher.env.get("ZDOTDIR");
+        assertNotNull(zdotdir, "a zsh memberLoginShell with worktreeRoot+worktreeGroup configured "
+                + "must still generate a ZDOTDIR");
+        Path dir = Path.of(zdotdir);
+        // The immediate PARENT is asserted (not merely startsWith(java.io.tmpdir)), because a
+        // JUnit @TempDir is itself carved out of the JVM's java.io.tmpdir — startsWith alone would
+        // pass by coincidence of the test fixture, not because the launcher used worktreeRoot.
+        assertEquals(worktreeRoot.toAbsolutePath().normalize(), dir.getParent(),
+                "the generated scrub directory's parent must be the configured worktreeRoot, not "
+                        + "System.getProperty(\"java.io.tmpdir\") — got parent " + dir.getParent());
+    }
+
+    /**
+     * fleetd #213, acceptance criterion 4: with {@code memberHerdrSocket} absent (today's only
+     * mode), behaviour must be byte-identical to before this fix — fleetd's own {@code $SHELL}
+     * still decides the gate (proven here, not merely assumed, by flagging the lookup), and the
+     * scrub still lands under {@code java.io.tmpdir}.
+     */
+    @Test
+    void memberHerdrSocketAbsentStillConsultsFleetdsOwnShellAndBehavesAsBefore() {
+        FakeHerdr herdr = new FakeHerdr();
+        AtomicBoolean shellQueried = new AtomicBoolean(false);
+        Function<String, String> env = name -> {
+            if ("SHELL".equals(name)) {
+                shellQueried.set(true);
+                return "/bin/zsh";
+            }
+            return null;
+        };
+        WiringLauncher launcher = new WiringLauncher(herdr, allowList(), env, null); // memberHerdrSocket absent
+
+        launcher.spawn(new SpawnRequest("test", null, null, null, null, MemberRole.DEV));
+
+        assertTrue(shellQueried.get(), "with memberHerdrSocket absent, fleetd's own $SHELL must "
+                + "still decide the zsh gate, unchanged from before this fix");
+        String zdotdir = launcher.env.get("ZDOTDIR");
+        assertNotNull(zdotdir, "SHELL=/bin/zsh with memberHerdrSocket absent must still generate a "
+                + "ZDOTDIR, as before this fix");
+        Path dir = Path.of(zdotdir);
+        assertTrue(dir.startsWith(Path.of(System.getProperty("java.io.tmpdir"))),
+                "with memberHerdrSocket absent the scrub directory must still be generated under "
+                        + "java.io.tmpdir, unchanged from before this fix: " + dir);
+    }
+
+    /** The current process's own primary group — resolvable on whatever host runs this test. */
+    private static String currentUserGroup() throws IOException {
+        PosixFileAttributeView view = Files.getFileAttributeView(Path.of("."), PosixFileAttributeView.class);
+        assumeTrue(view != null, "this host's filesystem does not support POSIX group ownership");
+        return view.readAttributes().group().getName();
+    }
+
+    /** Spawn once through the real launcher path, capturing every INFO+ line this class logs. */
+    private static List<String> spawnAndCaptureLogs(HerdrPeerLauncher launcher) {
+        Logger logger = (Logger) LoggerFactory.getLogger(HerdrPeerLauncher.class);
+        Level original = logger.getLevel();
+        logger.setLevel(Level.INFO);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        logger.addAppender(appender);
+        try {
+            launcher.spawn(new SpawnRequest("test", null, null, null, null, MemberRole.DEV));
+        } finally {
+            logger.detachAppender(appender);
+            logger.setLevel(original);
+        }
+        return appender.list.stream().map(ILoggingEvent::getFormattedMessage).toList();
+    }
+
     private static String readAll(Path p) {
         try {
             return Files.readString(p);
@@ -294,12 +574,40 @@ class HerdrPeerLauncherAllowListWiringTest {
 
         WiringLauncher(FakeHerdr herdr, Supplier<FleetConfig.MemberCredentials> creds, String shell,
                        Supplier<Set<String>> hostEnvNames, Supplier<FleetConfig> config) {
+            this(herdr, creds, shell, hostEnvNames, config, Map.of());
+        }
+
+        /**
+         * Plus a host-env value map (name → value), resolved through the same {@code env} lookup
+         * every adapter uses for {@code SHELL}/{@code PATH}/token resolution — fleetd #185 stage 2's
+         * "the gap detector never logs a value" tests use this to prove a value that IS resolvable
+         * for a credential-shaped name never reaches the log, since the detector only ever reads
+         * {@code hostEnvNames} (names), never {@code env.apply(name)} (values), for those names.
+         */
+        WiringLauncher(FakeHerdr herdr, Supplier<FleetConfig.MemberCredentials> creds, String shell,
+                       Supplier<Set<String>> hostEnvNames, Supplier<FleetConfig> config,
+                       Map<String, String> extraEnvValues) {
             super("test", new AgentControl(herdr), new WorkspaceControl(herdr),
                     Map.of("test", profile()), "test",
-                    name -> "SHELL".equals(name) ? shell : null,
+                    name -> "SHELL".equals(name) ? shell
+                            : (extraEnvValues != null && extraEnvValues.containsKey(name))
+                                    ? extraEnvValues.get(name) : null,
                     0, () -> 0L, () -> { }, null, creds, hostEnvNames, config);
         }
 
+        /**
+         * Full control over the {@code env} lookup, bypassing the {@code shell}/{@code
+         * extraEnvValues} convenience above entirely — fleetd #213's "fleetd's own $SHELL must
+         * never be consulted" tests need to OBSERVE whether {@code SHELL} was ever looked up, which
+         * a plain value substitution cannot do.
+         */
+        WiringLauncher(FakeHerdr herdr, Supplier<FleetConfig.MemberCredentials> creds,
+                       Function<String, String> env, Supplier<FleetConfig> config) {
+            super("test", new AgentControl(herdr), new WorkspaceControl(herdr),
+                    Map.of("test", profile()), "test",
+                    env, 0, () -> 0L, () -> { }, null, creds, null, config);
+        }
+
         @Override
         protected Launch buildLaunch(FleetConfig.Profile cfg, LaunchSpec spec) {
             Map<String, String> launchEnv = baseEnv(cfg);
@@ -321,6 +629,82 @@ class HerdrPeerLauncherAllowListWiringTest {
                 null, null, null, null, null).withDefaults();
     }
 
+    /**
+     * fleetd #185 stage 2: a config with {@code memberHerdrSocket:} set — member panes run on a
+     * second herdr owned by a different OS user, so {@link HerdrPeerLauncher#hostEnvNames} no
+     * longer describes what a member pane inherits.
+     */
+    private static FleetConfig configWithMemberHerdrSocket(String memberHerdrSocket) {
+        return new FleetConfig(null, null, memberHerdrSocket, Map.of(), null, null, null, null, null,
+                null, null, null, null, null, null, null, null, null, null, null).withDefaults();
+    }
+
+    /**
+     * fleetd #213: as {@link #configWithMemberHerdrSocket(String)}, plus the {@code
+     * memberLoginShell:} the member's OS user actually runs — the config key {@link
+     * HerdrPeerLauncher#applyEnvironmentAllowListPolicy} must consult instead of fleetd's own
+     * {@code $SHELL} once {@code memberHerdrSocket} is configured.
+     */
+    private static FleetConfig configWithMemberHerdrSocket(String memberHerdrSocket, String memberLoginShell) {
+        return new FleetConfig(
+                null,               // bind
+                null,               // herdrSocket
+                memberHerdrSocket,  // memberHerdrSocket
+                Map.of(),           // profiles
+                null,               // guard
+                null,               // worktreeRoot
+                null,               // lifecycle
+                null,               // spawnReadyTimeoutMs
+                null,               // spawnReadyPollMs
+                null,               // broker
+                null,               // primary
+                null,               // fleet
+                null,               // leadHeartbeat
+                null,               // health
+                null,               // placement
+                null,               // auth
+                null,               // configReload
+                null,               // quarantineCooldownSeconds
+                null,               // memberCredentials
+                null,               // coordinator
+                null,               // worktreeGroup
+                memberLoginShell    // memberLoginShell
+        ).withDefaults();
+    }
+
+    /**
+     * fleetd #213: as above, plus {@code worktreeRoot:}/{@code worktreeGroup:} — both required for
+     * the ZDOTDIR scrub to run at all once {@code memberHerdrSocket} is configured; either missing
+     * falls back to the sentinel overlay, same as a non-zsh {@code memberLoginShell}.
+     */
+    private static FleetConfig configWithMemberHerdrSocketRootAndGroup(String memberHerdrSocket,
+            String memberLoginShell, String worktreeRoot, String worktreeGroup) {
+        return new FleetConfig(
+                null,               // bind
+                null,               // herdrSocket
+                memberHerdrSocket,  // memberHerdrSocket
+                Map.of(),           // profiles
+                null,               // guard
+                worktreeRoot,       // worktreeRoot
+                null,               // lifecycle
+                null,               // spawnReadyTimeoutMs
+                null,               // spawnReadyPollMs
+                null,               // broker
+                null,               // primary
+                null,               // fleet
+                null,               // leadHeartbeat
+                null,               // health
+                null,               // placement
+                null,               // auth
+                null,               // configReload
+                null,               // quarantineCooldownSeconds
+                null,               // memberCredentials
+                null,               // coordinator
+                worktreeGroup,      // worktreeGroup
+                memberLoginShell    // memberLoginShell
+        ).withDefaults();
+    }
+
     /** The generated directory is a temp directory; make sure the test does not leave a pile. */
     @Test
     void theGeneratedDirectoryIsRemovedWhenThePaneIsStopped() {

fleetd/src/test/java/dev/ltms/fleet/msg/MessageServiceTest.java

@@ -688,6 +688,32 @@ class MessageServiceTest {
         assertFailedTicket(third, "agent target term_a not found");
     }
 
+    // --- #137 follow-up: abandon() must not guess when more than one task is open ---------------
+    //
+    // A test combining a genuine stranded reply (hasStrandedReply(T)==true) with two simultaneously
+    // open matching tasks was attempted here and removed after investigation showed the combination
+    // is not reachable through the public API today, not merely hard to time right:
+    //
+    // This class has exactly two call sites that ever hold a target's entry in the session-lock map
+    // (send() and answer()), and both open a Rendezvous waiter for that same target as the first thing
+    // they do after acquiring the lock, holding lock and waiter together for their whole critical
+    // section. So "the lock is held" and "a live waiter is open" are the same fact throughout this
+    // class. reply()'s fast path always resolves a currently-open waiter directly instead of
+    // stranding — so a strand can only be created while NO task is accepted (lock free), and the
+    // instant the lock is next taken (by any parked matching task's own send(), the moment it is
+    // scheduled), that acceptance clears strandedReplies again (see send()'s CB-640 comment) before
+    // abandon() can ever observe both facts together. Confirmed empirically too: an earlier version of
+    // this test stranded a reply, then created an "accepted" task (awaitWaiting()) followed by a
+    // "parked" one — and the accepted task's own acceptance silently cleared the strand it was
+    // supposed to be racing against, so the parked task came back WORKER_FAILED instead of DONE, not
+    // because the fix was missing but because the test's premise could not be constructed.
+    //
+    // The reachable half — matching.size() >= 2 alone, no strand — is exactly what
+    // abandonFailsEveryPendingAsyncTicketForTheReleasedTarget already covers (all fail, none guess).
+    // The oldest-wins code in abandon() stays as defence in depth (see its own javadoc) against a
+    // regression that would make the conjunction reachable, e.g. clearing strandedReplies on a
+    // narrower condition than "any acceptance" — not because this suite exercises it today.
+
     @Test
     void abandonDoesNotFailAnAsyncTicketWaitingForAnAnswer() throws Exception {
         String ticket = messages.sendAsync(T, "task that asks");

fleetd/src/test/java/dev/ltms/fleet/rest/FleetAppTest.java

@@ -218,9 +218,17 @@ class FleetAppTest {
 
         HttpResponse<String> res = req(port, "GET", "/members");
         assertEquals(200, res.statusCode());
-        JsonNode workers = mapper.readTree(res.body()).get("workers");
-        assertEquals(1, workers.size());
-        JsonNode w = workers.get(0);
+        JsonNode body = mapper.readTree(res.body());
+        // fleetd #199: "members" is the canonical key. The endpoint is /members, so a caller that
+        // reads "members" must not see an empty fleet. "workers" is kept only as a deprecated alias
+        // and must carry the same rows — assert both, or the alias can silently drift.
+        JsonNode members = body.get("members");
+        assertNotNull(members, "GET /members must return its rows under \"members\"");
+        assertEquals(1, members.size());
+        JsonNode workers = body.get("workers");
+        assertNotNull(workers, "the deprecated \"workers\" alias is still emitted");
+        assertEquals(members, workers, "the alias must carry the same rows as \"members\"");
+        JsonNode w = members.get(0);
         assertEquals(spawned.get("terminalId").asText(), w.get("sessionId").asText());
         assertEquals(paneId, w.get("paneId").asText());
         assertEquals("ltms-local", w.get("profile").asText());

fleetd/src/test/java/dev/ltms/fleet/session/FakeWorktrees.java

@@ -30,12 +30,19 @@ public final class FakeWorktrees implements Worktrees {
     public record PruneCall(String repoRoot, long minAgeMillis) {
     }
 
+    public record ShareCall(String repoRoot, String worktreePath) {
+    }
+
     private final List<AddCall> addCalls = new CopyOnWriteArrayList<>();
     private final List<RemoveCall> removeCalls = new CopyOnWriteArrayList<>();
     private final List<OverlayCall> overlayCalls = new CopyOnWriteArrayList<>();
     private final List<RepoRootCall> repoRootCalls = new CopyOnWriteArrayList<>();
     private final List<SnapshotCall> snapshotCalls = new CopyOnWriteArrayList<>();
     private final List<PruneCall> pruneCalls = new CopyOnWriteArrayList<>();
+    private final List<ShareCall> shareCalls = new CopyOnWriteArrayList<>();
+    /** Tags every {@code overlayParity}/{@code shareWithGroup} call in call order, so a test can
+     *  pin that sharing runs after the overlay copy (fleetd #185 stage 3). */
+    private final List<String> overlayShareOrder = new CopyOnWriteArrayList<>();
     private final Set<String> existingPaths = ConcurrentHashMap.newKeySet();
     private final Set<String> trackedPaths = ConcurrentHashMap.newKeySet();
     private final AtomicLong snapshotSeq = new AtomicLong();
@@ -136,6 +143,13 @@ public final class FakeWorktrees implements Worktrees {
         }
         overlayCalls.add(new OverlayCall(repoRoot, worktreePath, List.copyOf(overlay),
                 List.copyOf(copied), List.copyOf(skipped)));
+        overlayShareOrder.add("overlay:" + worktreePath);
+    }
+
+    @Override
+    public void shareWithGroup(String repoRoot, String worktreePath) {
+        shareCalls.add(new ShareCall(repoRoot, worktreePath));
+        overlayShareOrder.add("share:" + worktreePath);
     }
 
     @Override
@@ -203,4 +217,17 @@ public final class FakeWorktrees implements Worktrees {
     public SnapshotCall lastSnapshot() {
         return snapshotCalls.isEmpty() ? null : snapshotCalls.getLast();
     }
+
+    public List<ShareCall> shareCalls() {
+        return List.copyOf(shareCalls);
+    }
+
+    public ShareCall lastShare() {
+        return shareCalls.isEmpty() ? null : shareCalls.getLast();
+    }
+
+    /** Call-order tags ({@code "overlay:<path>"}/{@code "share:<path>"}) — see field javadoc. */
+    public List<String> overlayShareOrder() {
+        return List.copyOf(overlayShareOrder);
+    }
 }

fleetd/src/test/java/dev/ltms/fleet/session/GitWorktreesTest.java

@@ -924,4 +924,179 @@ class GitWorktreesTest {
         assertEquals(2, stats.count(), "two snapshot refs are reported");
         assertTrue(stats.costBytes() > 0, "the cost of the snapshots is a positive byte count");
     }
+
+    /**
+     * fleetd #185 stage 3: a recording {@link java.util.function.Function} test seam stands in for
+     * every process {@link GitWorktrees#shareWithGroup} would run — no real second OS user/group
+     * exists on this host, so these are unit tests against that seam, not a live-group integration
+     * test (out of scope per the ticket).
+     */
+    private static List<String> joined(String[] command) {
+        return List.of(command);
+    }
+
+    /** Remove {@code path} and anything under it. Tolerates an already-absent path. */
+    private static void deleteRecursively(Path path) throws Exception {
+        if (!Files.exists(path)) {
+            return;
+        }
+        if (Files.isDirectory(path)) {
+            try (java.util.stream.Stream<Path> children = Files.list(path)) {
+                for (Path child : children.toList()) {
+                    deleteRecursively(child);
+                }
+            }
+        }
+        Files.delete(path);
+    }
+
+    /** {@code worktreeGroup} absent ⇒ zero processes spawned and no git config written. */
+    @Test
+    void shareWithGroupIsNoopWhenNoGroupConfigured(@TempDir Path tmp) throws Exception {
+        Path repo = initRepo(tmp.resolve("repo"));
+        List<List<String>> recorded = new java.util.ArrayList<>();
+        java.util.function.Function<String[], String> recordingRunner = cmd -> {
+            recorded.add(joined(cmd));
+            return "";
+        };
+        GitWorktrees gitWorktrees = new GitWorktrees(tmp.resolve("wts").toString(), null, _ -> {}, recordingRunner);
+
+        gitWorktrees.shareWithGroup(repo.toString(), repo.resolve("some-worktree").toString());
+
+        assertTrue(recorded.isEmpty(), "no group configured must spawn no process at all: " + recorded);
+    }
+
+    /** A configured group runs {@code git config core.sharedRepository group} first, then
+     *  chgrp/chmod/setgid over every path {@link GitWorktrees#shareWithGroup} documents. */
+    @Test
+    void shareWithGroupRunsConfigThenChgrpChmodSetgidPerPath(@TempDir Path tmp) throws Exception {
+        Path repo = initRepo(tmp.resolve("repo"));
+        String repoRoot = repo.toString();
+        Path worktree = Files.createDirectories(repo.resolve("some-worktree"));
+        String worktreePath = worktree.toString();
+        Files.createDirectories(repo.resolve(".git/worktrees"));
+        List<List<String>> recorded = new java.util.ArrayList<>();
+        java.util.function.Function<String[], String> recordingRunner = cmd -> {
+            recorded.add(joined(cmd));
+            // What real git answers for an ordinary (non-linked) checkout: relative to repoRoot.
+            return List.of(cmd).contains("--git-common-dir") ? ".git\n" : "";
+        };
+        GitWorktrees gitWorktrees =
+                new GitWorktrees(tmp.resolve("wts").toString(), "devteam", _ -> {}, recordingRunner);
+
+        gitWorktrees.shareWithGroup(repoRoot, worktreePath);
+
+        assertEquals(List.of("git", "-C", repoRoot, "config", "core.sharedRepository", "group"), recorded.get(0),
+                "core.sharedRepository must be set first, so it keeps working after the one-time fix-up");
+        assertTrue(recorded.contains(List.of("git", "-C", repoRoot, "rev-parse", "--git-common-dir")),
+                "the git dir must be asked for, never hardcoded as <repoRoot>/.git — that is a FILE "
+                        + "when the checkout is itself a linked worktree: " + recorded);
+
+        for (String dir : List.of(worktreePath, repoRoot + "/.git/objects", repoRoot + "/.git/refs",
+                repoRoot + "/.git/logs", repoRoot + "/.git/worktrees")) {
+            assertTrue(recorded.contains(List.of("chgrp", "-R", "devteam", dir)), "missing chgrp -R for " + dir);
+            assertTrue(recorded.contains(List.of("chmod", "-R", "g+rwX", dir)), "missing chmod -R for " + dir);
+            assertTrue(recorded.contains(List.of("find", dir, "-type", "d", "-exec", "chmod", "g+s", "{}", "+")),
+                    "missing setgid find pass for " + dir);
+        }
+        // packed-refs does not exist in a freshly-init'd repo (only git gc / pack-refs creates it) —
+        // tolerated absence, so it must not appear at all: no recursive/-R treatment for a plain file.
+        String packedRefs = repoRoot + "/.git/packed-refs";
+        assertTrue(recorded.stream().noneMatch(c -> c.contains(packedRefs)),
+                "packed-refs is absent here and must be skipped, not chgrp'd: " + recorded);
+    }
+
+    /**
+     * A path that does not exist is skipped, never handed to {@code chgrp}. {@code .git/logs} is
+     * absent whenever {@code core.logAllRefUpdates} is false or no ref has been updated yet, and
+     * {@code chgrp} on a missing path exits non-zero — which would fail EVERY provisioning spawn
+     * with a message blaming a group that is in fact fine.
+     */
+    @Test
+    void shareWithGroupSkipsPathsThatDoNotExist(@TempDir Path tmp) throws Exception {
+        Path repo = initRepo(tmp.resolve("repo"));
+        String repoRoot = repo.toString();
+        deleteRecursively(repo.resolve(".git/logs"));
+        assertFalse(Files.exists(repo.resolve(".git/logs")), "fixture: .git/logs must be gone");
+        List<List<String>> recorded = new java.util.ArrayList<>();
+        java.util.function.Function<String[], String> recordingRunner = cmd -> {
+            recorded.add(joined(cmd));
+            return List.of(cmd).contains("--git-common-dir") ? ".git\n" : "";
+        };
+        GitWorktrees gitWorktrees =
+                new GitWorktrees(tmp.resolve("wts").toString(), "devteam", _ -> {}, recordingRunner);
+
+        gitWorktrees.shareWithGroup(repoRoot, repo.resolve("no-such-worktree").toString());
+
+        String logs = repoRoot + "/.git/logs";
+        assertTrue(recorded.stream().noneMatch(c -> c.contains(logs)),
+                "a missing .git/logs must be skipped, not chgrp'd: " + recorded);
+        assertTrue(recorded.stream().noneMatch(c -> c.contains(repo.resolve("no-such-worktree").toString())),
+                "a missing worktree path must be skipped too: " + recorded);
+        assertTrue(recorded.contains(List.of("chgrp", "-R", "devteam", repoRoot + "/.git/objects")),
+                "paths that DO exist are still shared: " + recorded);
+    }
+
+    /**
+     * The git store is located by {@code rev-parse --git-common-dir}, not by appending
+     * {@code /.git}. When git answers with an absolute path — what it does for a linked worktree,
+     * where {@code <repoRoot>/.git} is a file — every shared path must follow that answer.
+     */
+    @Test
+    void shareWithGroupFollowsAnAbsoluteGitCommonDir(@TempDir Path tmp) throws Exception {
+        Path repo = initRepo(tmp.resolve("repo"));
+        Path realGitDir = repo.resolve(".git");
+        List<List<String>> recorded = new java.util.ArrayList<>();
+        java.util.function.Function<String[], String> recordingRunner = cmd -> {
+            recorded.add(joined(cmd));
+            return List.of(cmd).contains("--git-common-dir") ? realGitDir + "\n" : "";
+        };
+        GitWorktrees gitWorktrees =
+                new GitWorktrees(tmp.resolve("wts").toString(), "devteam", _ -> {}, recordingRunner);
+
+        gitWorktrees.shareWithGroup(tmp.resolve("some/linked/worktree").toString(),
+                repo.resolve("wt").toString());
+
+        assertTrue(recorded.contains(List.of("chgrp", "-R", "devteam", realGitDir + "/objects")),
+                "objects must be taken from the reported common dir, not <repoRoot>/.git: " + recorded);
+    }
+
+    /** {@code packed-refs}, when present, is chgrp/chmod'd but never setgid'd (it is a file, not a dir). */
+    @Test
+    void shareWithGroupIncludesPackedRefsWhenPresent(@TempDir Path tmp) throws Exception {
+        Path repo = initRepo(tmp.resolve("repo"));
+        String repoRoot = repo.toString();
+        Path packedRefsPath = repo.resolve(".git/packed-refs");
+        Files.writeString(packedRefsPath, "");
+        List<List<String>> recorded = new java.util.ArrayList<>();
+        java.util.function.Function<String[], String> recordingRunner = cmd -> {
+            recorded.add(joined(cmd));
+            return "";
+        };
+        GitWorktrees gitWorktrees =
+                new GitWorktrees(tmp.resolve("wts").toString(), "devteam", _ -> {}, recordingRunner);
+
+        gitWorktrees.shareWithGroup(repoRoot, repo.resolve("some-worktree").toString());
+
+        String packedRefs = packedRefsPath.toString();
+        assertTrue(recorded.contains(List.of("chgrp", "devteam", packedRefs)),
+                "packed-refs must be chgrp'd non-recursively when present: " + recorded);
+        assertTrue(recorded.contains(List.of("chmod", "g+rwX", packedRefs)),
+                "packed-refs must be chmod'd non-recursively when present: " + recorded);
+        assertTrue(recorded.stream().noneMatch(c -> c.contains("find") && c.contains(packedRefs)),
+                "packed-refs (a file) must never get the recursive setgid pass: " + recorded);
+    }
+
+    /** A group that does not exist (or that the operator is not a member of) fails loudly, naming it. */
+    @Test
+    void shareWithGroupThrowsNamingTheGroupWhenChgrpFails(@TempDir Path tmp) throws Exception {
+        Path repo = initRepo(tmp.resolve("repo"));
+        GitWorktrees gitWorktrees = new GitWorktrees(tmp.resolve("wts").toString(), "cb185-nonexistent-group-zz");
+        String wt = new GitWorktrees(tmp.resolve("wts").toString()).add(repo.toString(), "cb-185-share", "HEAD");
+
+        WorktreeException e = assertThrows(WorktreeException.class,
+                () -> gitWorktrees.shareWithGroup(repo.toString(), wt));
+        assertTrue(e.getMessage().contains("cb185-nonexistent-group-zz"),
+                "exception must name the missing/refused group: " + e.getMessage());
+    }
 }

fleetd/src/test/java/dev/ltms/fleet/session/SessionManagerTest.java

@@ -148,6 +148,10 @@ class SessionManagerTest {
             return 0;
         }
 
+        @Override
+        public void shareWithGroup(String repoRoot, String worktreePath) {
+        }
+
         List<String> removeCalls() {
             return List.copyOf(removeCalls);
         }
@@ -927,4 +931,235 @@ class SessionManagerTest {
         assertTrue(e.getMessage().contains("SESSION_RESUME"), e.getMessage());
         assertTrue(e.getMessage().contains("stub-profile"), e.getMessage());
     }
+
+    // ── fleetd #209: agentSessionId resolved lazily against the retained handle ─────────────────
+    //
+    // The opencode adapter cannot answer PeerHandle.agentSessionId() at spawn time — the on-disk
+    // session row is written only after the pane is live — so the id must be re-polled on a LATER
+    // call, against the SAME handle instance the launcher returned at spawn. SessionManager used
+    // to let that handle go out of scope at the end of the spawn method, so no caller ever re-asked
+    // it and fleet_list/fleet_status never saw the id. LazyIdHandle below reproduces exactly that
+    // shape: null on the first N calls (the spawn-time call included), a real id after.
+
+    /**
+     * A {@link PeerHandle} whose {@link #agentSessionId()} answers {@code null} for its first
+     * {@code nullCalls} invocations, then either a fixed id or a configured throw on every call
+     * after that — the shape of the opencode bug (fleetd #209): the session row is not written
+     * until after the pane is live, so early polls come back empty and a later one finds it.
+     */
+    private static final class LazyIdHandle implements PeerHandle {
+        private final String id;
+        private final String terminalId;
+        private final int nullCalls;
+        private final String resolvedId;
+        private final java.util.concurrent.atomic.AtomicInteger calls =
+                new java.util.concurrent.atomic.AtomicInteger();
+        private volatile RuntimeException throwAfter;
+
+        LazyIdHandle(String id, String terminalId, int nullCalls, String resolvedId) {
+            this.id = id;
+            this.terminalId = terminalId;
+            this.nullCalls = nullCalls;
+            this.resolvedId = resolvedId;
+        }
+
+        /** After the null calls are exhausted, throw instead of answering the resolved id. */
+        LazyIdHandle throwing(RuntimeException e) {
+            this.throwAfter = e;
+            return this;
+        }
+
+        @Override
+        public String id() {
+            return id;
+        }
+
+        @Override
+        public String terminalId() {
+            return terminalId;
+        }
+
+        @Override
+        public String agentSessionId() {
+            int n = calls.incrementAndGet();
+            if (n <= nullCalls) {
+                return null;
+            }
+            if (throwAfter != null) {
+                throw throwAfter;
+            }
+            return resolvedId;
+        }
+
+        @Override
+        public CharterReceipt charterReceipt() {
+            return null;
+        }
+
+        int callCount() {
+            return calls.get();
+        }
+    }
+
+    /** A minimal {@link PeerLauncher} that hands out pre-built {@link LazyIdHandle}s, one per spawn. */
+    private static final class LazyIdLauncher implements PeerLauncher {
+        private final java.util.Deque<LazyIdHandle> queued = new java.util.ArrayDeque<>();
+
+        LazyIdLauncher queue(LazyIdHandle handle) {
+            queued.add(handle);
+            return this;
+        }
+
+        @Override
+        public Set<Capability> capabilities() {
+            return Set.of(Capability.WORKTREE, Capability.SESSION_RESUME);
+        }
+
+        @Override
+        public Set<Capability> capabilitiesFor(String profileName) {
+            return capabilities();
+        }
+
+        @Override
+        public PeerHandle spawn(SpawnRequest req) {
+            LazyIdHandle handle = queued.poll();
+            if (handle == null) {
+                throw new IllegalStateException("no queued LazyIdHandle for this spawn");
+            }
+            return handle;
+        }
+
+        @Override
+        public Set<String> profiles() {
+            return Set.of("lazy");
+        }
+
+        @Override
+        public String defaultProfile() {
+            return "lazy";
+        }
+
+        @Override
+        public String effectiveCwd(SpawnRequest req) {
+            return "/cwd";
+        }
+
+        @Override
+        public List<String> parityOverlay(String profileName) {
+            return List.of();
+        }
+
+        @Override
+        public List<?> list() {
+            return List.of();
+        }
+
+        @Override
+        public int reapOrphanWorkers() {
+            return 0;
+        }
+
+        @Override
+        public void stop(String id) {
+        }
+
+        @Override
+        public boolean clearContext(String id) {
+            return false;
+        }
+    }
+
+    @Test
+    void plainRosterDoesNotResolveAgentSessionId() {
+        // fleetd #209 follow-up: roster() sits on the heartbeat/health-tick timers (and the metrics
+        // scrape), so it must never trigger the resolve lookup — for opencode that lookup opens an
+        // on-disk session database, and a member whose id never appears would pay that cost forever.
+        // rosterResolved() is the one to use when a caller actually reports the id.
+        LazyIdHandle handle = new LazyIdHandle("p0", "t0", 1, "oc-session-0");
+        SessionManager sessions = new SessionManager(new LazyIdLauncher().queue(handle));
+        MemberSession acquired = sessions.acquire("lazy", "/cwd", "/caller", null);
+        assertEquals(1, handle.callCount(), "sanity: only the spawn-time call happened so far");
+
+        List<MemberSession> roster = sessions.roster();
+
+        assertEquals(1, roster.size());
+        assertEquals(acquired.paneId(), roster.getFirst().paneId());
+        assertNull(roster.getFirst().agentSessionId(), "the plain roster must not resolve the id");
+        assertEquals(1, handle.callCount(),
+                "roster() must never call agentSessionId() again — it sits on the heartbeat/health timers");
+    }
+
+    @Test
+    void rosterResolvedResolvesALateAgentSessionIdFromTheRetainedHandle() {
+        LazyIdHandle handle = new LazyIdHandle("p1", "t1", 1, "oc-session-1");
+        SessionManager sessions = new SessionManager(new LazyIdLauncher().queue(handle));
+
+        MemberSession acquired = sessions.acquire("lazy", "/cwd", "/caller", null);
+        assertNull(acquired.agentSessionId(),
+                "opencode has not written its session row yet at spawn time");
+
+        List<MemberSession> roster = sessions.rosterResolved();
+        assertEquals(1, roster.size());
+        assertEquals("oc-session-1", roster.getFirst().agentSessionId(),
+                "fleet_list must see the id once the adapter can answer it");
+
+        Map<String, Object> view = SessionManager.rosterView(roster.getFirst(), null);
+        assertEquals("oc-session-1", view.get("agentSessionId"),
+                "rosterView renders whatever rosterResolved() resolved");
+    }
+
+    @Test
+    void getResolvesALateAgentSessionIdFromTheRetainedHandle() {
+        LazyIdHandle handle = new LazyIdHandle("p2", "t2", 1, "oc-session-2");
+        SessionManager sessions = new SessionManager(new LazyIdLauncher().queue(handle));
+        MemberSession acquired = sessions.acquire("lazy", "/cwd", "/caller", null);
+
+        MemberSession resolved = sessions.get(acquired.paneId()).orElseThrow();
+
+        assertEquals("oc-session-2", resolved.agentSessionId(),
+                "fleet_status (single-session lookup) must also see the late-resolved id");
+    }
+
+    @Test
+    void releaseCarriesALateResolvedAgentSessionIdIntoTheReleaseDetail() {
+        LazyIdHandle handle = new LazyIdHandle("p3", "t3", 1, "oc-session-3");
+        SessionManager sessions = new SessionManager(new LazyIdLauncher().queue(handle));
+        MemberSession acquired = sessions.acquire("lazy", "/cwd", "/caller", null);
+        java.util.List<String> released = new java.util.concurrent.CopyOnWriteArrayList<>();
+        sessions.onRelease(detail -> released.add(detail.agentSessionId()));
+
+        sessions.release(acquired.paneId());
+
+        assertEquals(java.util.List.of("oc-session-3"), released,
+                "a released member's detail carries the id it has since resolved, not the null "
+                        + "frozen in at spawn time");
+    }
+
+    @Test
+    void aThrowingHandleDoesNotBreakRosterResolved() {
+        LazyIdHandle handle = new LazyIdHandle("p4", "t4", 1, "oc-session-4")
+                .throwing(new RuntimeException("sqlite locked"));
+        SessionManager sessions = new SessionManager(new LazyIdLauncher().queue(handle));
+        sessions.acquire("lazy", "/cwd", "/caller", null);
+
+        List<MemberSession> roster = assertDoesNotThrow(sessions::rosterResolved,
+                "a handle that throws resolving its id must not break the roster read");
+
+        assertEquals(1, roster.size());
+        assertNull(roster.getFirst().agentSessionId(), "the id stays unresolved when the lookup throws");
+    }
+
+    @Test
+    void aResolvedAgentSessionIdIsNotLookedUpAgain() {
+        LazyIdHandle handle = new LazyIdHandle("p5", "t5", 1, "oc-session-5");
+        SessionManager sessions = new SessionManager(new LazyIdLauncher().queue(handle));
+        sessions.acquire("lazy", "/cwd", "/caller", null);
+        assertEquals(1, handle.callCount(), "sanity: only the spawn-time call happened so far");
+
+        sessions.rosterResolved();
+        assertEquals(2, handle.callCount(), "the first rosterResolved() read resolves the id");
+
+        sessions.rosterResolved();
+        assertEquals(2, handle.callCount(), "once resolved, the id must not be looked up again");
+    }
 }

fleetd/src/test/java/dev/ltms/fleet/session/WorktreeSessionManagerTest.java

@@ -163,6 +163,37 @@ class WorktreeSessionManagerTest {
                 "tracked copied paths are --skip-worktree'd");
     }
 
+    /**
+     * fleetd #185 stage 3, THE TRAP: {@code overlayParity} copies more files into the worktree
+     * AFTER {@code add} returns, so {@code shareWithGroup} must run after it, not folded into
+     * {@code add()} — otherwise every overlay file lands operator-owned and unwritable for a
+     * different-uid member, with a green test suite hiding it.
+     */
+    @Test
+    void shareWithGroupRunsAfterOverlayParityNotBeforeIt() {
+        FakeHerdr herdr = new FakeHerdr();
+        FakeWorktrees worktrees = new FakeWorktrees().withRepoRoot("/repo").withPrefix("/wt")
+                .track(".envrc");
+        SessionManager sessions = new SessionManager(workerService(herdr), worktrees);
+
+        MemberSession s = sessions.acquire("ltms-local", null, "/caller/proj", null,
+                new WorktreeRequest("cb-185", null));
+
+        assertEquals(1, worktrees.overlayCalls().size(), "overlayParity ran exactly once");
+        assertEquals(1, worktrees.shareCalls().size(), "shareWithGroup ran exactly once");
+        FakeWorktrees.OverlayCall overlay = worktrees.lastOverlay();
+        FakeWorktrees.ShareCall share = worktrees.lastShare();
+        assertEquals(s.worktree(), overlay.worktreePath());
+        assertEquals(s.worktree(), share.worktreePath());
+
+        List<String> order = worktrees.overlayShareOrder();
+        int overlayIndex = order.indexOf("overlay:" + s.worktree());
+        int shareIndex = order.indexOf("share:" + s.worktree());
+        assertTrue(overlayIndex >= 0 && shareIndex >= 0, "both calls must be recorded: " + order);
+        assertTrue(overlayIndex < shareIndex,
+                "shareWithGroup MUST run after overlayParity, not before/inside add(): " + order);
+    }
+
     @Test
     void releaseRemovesWorktreeButDoesNotDeleteBranch() {
         FakeHerdr herdr = new FakeHerdr();