fleetd #422 follow-up: make the model gate's own state observable

PeerLauncher.disabledModels() reported an empty set both when no
models: block exists and when a block exists with nothing off, so
fleet_profiles/GET /profiles and the startup log could not tell an
inert gate from an armed one reporting zero. Add
PeerLauncher.ModelGateState (configured + off), a modelGateState()
default method disabledModels() now delegates to, and a
CompositePeerLauncher override that reads models0() once and
distinguishes the null-supplier case (no models: block) from a real,
config-supplied block via identity against the NO_MODELS_CONFIGURED
sentinel — reusing the exact accessor the spawn gate itself reads, per
the fleetd #404 lesson.

Wires the state into a new startup log line (Fleetd.modelGateCoverageLine)
and a new modelGateArmed field in FleetMcp.profilesView, reported
unconditionally alongside the existing modelsOff set.

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

@@ -69,6 +69,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import java.util.TreeSet;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
@@ -231,6 +232,13 @@ public final class Fleetd {
                 profileName -> liveCountRef.get().apply(profileName),
                 quarantine,
                 outagePolicy);
+        // fleetd #422 follow-up: say which of the three model-gate states the daemon booted into —
+        // no models: block at all, a block armed with nothing off, or a block with N off — the same
+        // way exhaustedPatternCoverageLine/errorPatternCoverageLine report CB-578 stage A/fleetd
+        // #201 Unit 5 coverage just below. Read from workers.modelGateState() (never a separate
+        // config.get().models() here) so this line and fleet_profiles' modelGateArmed can never
+        // disagree about what CompositePeerLauncher's spawn gate actually enforces.
+        log.info("model gate (fleetd #422): {}", modelGateCoverageLine(workers.modelGateState()));
         // CB-504: under supervision (launchd/systemd) fleetd can start before herdr's socket
         // exists. The client itself is lazy — it connects per call — but the orphan reap below is
         // the first thing that actually talks to herdr, so without this wait a boot-order race
@@ -352,7 +360,11 @@ public final class Fleetd {
         // pane resolves to an architect until the later spawn lifecycle binds one. The registry is
         // what CallerResolver resolves against and what that lifecycle will read profiles from;
         // nothing here spawns a slot.
-        MemberRegistry members = new MemberRegistry(cfg.fleet());
+        // fleetd #424: MemberRegistry.live re-reads fleet.architects through `config` on every
+        // reserve/requireSlotFor call, so a reload that removes or adds an architect slot governs
+        // the next spawn with no restart — the frozen `new MemberRegistry(cfg.fleet())` this used
+        // to be let a "revoked" slot keep granting new architect spawns forever.
+        MemberRegistry members = MemberRegistry.live(() -> config.get().fleet());
         sessions.setMemberLifecycle(members);
         if (!members.slots().isEmpty()) {
             log.info("member slots: {} configured {} — none bound yet (a slot is idle until the "
@@ -380,8 +392,7 @@ public final class Fleetd {
                 .map(session -> exhaustedPatternsByProfile.get(session.profile()))
                 .orElse(null);
         log.info("backend-exhausted classification (CB-578 stage A): {}",
-                CompletionResolver.coverage("exhaustedPattern", cfg.profiles().keySet(),
-                        exhaustedPatternsByProfile.keySet()));
+                exhaustedPatternCoverageLine(cfg.profiles().keySet(), exhaustedPatternsByProfile.keySet()));
         // fleetd #201 Unit 5: classify a completion-fallback scrape that matches a profile's
         // configured backend-error refusal (a credential outage, a provider 5xx) as a backend error
         // rather than handing it back as a real answer. Compiled once at startup, keyed by profile
@@ -401,8 +412,7 @@ public final class Fleetd {
         BackendErrorPatternLookup backendErrorPatterns = backendErrorPatternLookup(sessions::roster,
                 errorPatternsByProfile);
         log.info("backend-error classification (fleetd #201 Unit 5): {}",
-                CompletionResolver.coverage("errorPattern", cfg.profiles().keySet(),
-                        errorPatternsByProfile.keySet()));
+                errorPatternCoverageLine(cfg.profiles().keySet(), errorPatternsByProfile.keySet()));
         // CB-578 stage B: on a classification that actually wins, quarantine the exhausted profile's
         // CREDENTIAL — not the profile name — so a profile sharing that credential (e.g. two models
         // on one OpenAI account) is refused too, not just the one that happened to report it. Reads
@@ -807,6 +817,66 @@ public final class Fleetd {
         }, quarantine, profile -> startupExhaustedPatterns.containsKey(profile));
     }
 
+    /**
+     * fleetd #415 (review follow-up): package-private factory for the CB-578 stage A {@code
+     * exhaustedPattern} startup coverage line, paired explicitly with {@link
+     * CompletionResolver.UnsetMeaning#OFF} — {@code exhaustedPattern} has no fallback, so a
+     * profile with none configured really does have the classification off.
+     *
+     * <p>Extracted out of {@code main} for the same reason {@link #capacitySource} and {@link
+     * #worktreeBranchLookup} were: {@code coverage()}'s own tests ({@code CompletionResolverTest})
+     * prove it words {@code OFF} and {@link CompletionResolver.UnsetMeaning#BUILT_IN_DEFAULT}
+     * correctly when a test supplies the meaning itself — they cannot prove {@code main} pairs the
+     * right meaning with the right key, which is the actual fleetd #415 defect. <b>Measured:</b>
+     * swapping the {@code UnsetMeaning} arguments between this method and {@link
+     * #errorPatternCoverageLine} — recreating #415's defect with the two keys exchanged — compiled
+     * with 0 errors and left all 1506 existing tests green before {@code
+     * FleetdPatternCoverageLineTest} was added to catch exactly that swap.
+     */
+    static String exhaustedPatternCoverageLine(Set<String> allProfiles, Set<String> configuredProfiles) {
+        return CompletionResolver.coverage("exhaustedPattern", CompletionResolver.UnsetMeaning.OFF,
+                allProfiles, configuredProfiles);
+    }
+
+    /**
+     * fleetd #415 (review follow-up): the {@code errorPattern} counterpart of {@link
+     * #exhaustedPatternCoverageLine}, paired explicitly with {@link
+     * CompletionResolver.UnsetMeaning#BUILT_IN_DEFAULT} — an unset {@code errorPattern} still runs
+     * backend-error classification against {@code CompletionResolver}'s built-in {@code
+     * BACKEND_ERROR} pattern, so the empty case is not "off". See {@link
+     * #exhaustedPatternCoverageLine}'s javadoc for the measured swap mutation this pairing guards
+     * against.
+     */
+    static String errorPatternCoverageLine(Set<String> allProfiles, Set<String> configuredProfiles) {
+        return CompletionResolver.coverage("errorPattern", CompletionResolver.UnsetMeaning.BUILT_IN_DEFAULT,
+                allProfiles, configuredProfiles);
+    }
+
+    /**
+     * fleetd #422 follow-up: package-private factory for the startup line reporting which of the
+     * three central {@code models.allow:} gate states the daemon booted into. Extracted the same
+     * way {@link #exhaustedPatternCoverageLine}/{@link #errorPatternCoverageLine} are, so a
+     * dedicated test can call it directly rather than parsing log output, and so {@code main}'s
+     * only source for this line is {@link PeerLauncher#modelGateState()} — never a second,
+     * independently-derived read of {@code cfg.models()} that could disagree with what {@code
+     * CompositePeerLauncher}'s spawn gate actually enforces (the fleetd #404 lesson).
+     *
+     * <p>Unlike the two pattern-key lines above, there is no {@code UnsetMeaning} choice to make
+     * here: {@link PeerLauncher.ModelGateState#configured()} already states, unambiguously, whether
+     * an empty {@link PeerLauncher.ModelGateState#off()} means "no {@code models:} block to gate
+     * with" or "a block armed and currently reporting zero off" — the exact two states a bare
+     * {@code disabledModels()} read could not tell apart before this ticket.
+     */
+    static String modelGateCoverageLine(PeerLauncher.ModelGateState state) {
+        if (!state.configured()) {
+            return "not configured (no models: block — nothing is gated, and nothing can be)";
+        }
+        Set<String> off = state.off();
+        return off.isEmpty()
+                ? "armed (models: block present; 0 models currently turned off)"
+                : "armed (" + off.size() + " model(s) turned off: " + new TreeSet<>(off) + ")";
+    }
+
     /**
      * fleetd #416: production source for {@code fleet_list}'s per-profile capacity facts.
      *

fleetd/src/main/java/dev/ltms/fleet/auth/MemberRegistry.java

@@ -11,6 +11,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.function.Supplier;
 
 /**
  * The architect-slot registry (CB-548): every gateway-local architect name and the strong-model
@@ -19,16 +20,43 @@ import java.util.Objects;
  *
  * <p>Two halves, split by who owns each:
  * <ul>
- *   <li><b>slots</b> — configured once, keyed by the gateway-local unique name; each carries the
- *       {@code profile} reference the spawn lifecycle reads when it stands the slot up. A read-only
- *       snapshot taken at construction.</li>
- *   <li><b>terminal bindings</b> — owned by this registry and initially <em>empty</em>. Config
- *       declares no architect terminal, so at startup every slot is idle and nothing resolves to an
- *       architect; a session only becomes one when the spawn lifecycle {@linkplain #bind(String,
- *       String) binds} its terminal to a slot. {@link CallerResolver} reads this through
- *       {@link #snapshot()} to turn a pane into an {@link Role#ARCHITECT}.</li>
+ *   <li><b>slots</b> — read from {@code fleet.architects}/{@code developers}/{@code reviewers}
+ *       (see {@link #slots()}), each carrying the {@code profile} reference the spawn lifecycle
+ *       reads when it stands the slot up. <strong>Live, since fleetd #424</strong>: {@link #live}
+ *       re-reads {@code fleet:} on every call, through a supplier the same shape as
+ *       {@code CompositePeerLauncher}'s (see {@code ConfigRef}'s class doc) — so a config reload
+ *       that removes or adds an architect slot governs the <em>next</em> spawn with no restart.
+ *       Only {@link #MemberRegistry(FleetConfig.Fleet)} freezes the pool at construction, and that
+ *       constructor exists for tests and for the (rare) case of wiring a fixed, code-built config.</li>
+ *   <li><b>terminal bindings</b> — owned by this registry, initially <em>empty</em>, and
+ *       <strong>never</strong> touched by a reload. Config declares no architect terminal, so at
+ *       startup every slot is idle and nothing resolves to an architect; a session only becomes one
+ *       when the spawn lifecycle {@linkplain #bind(String, String) binds} its terminal to a slot.
+ *       {@link CallerResolver} reads this through {@link #snapshot()} to turn a pane into an
+ *       {@link Role#ARCHITECT}.</li>
  * </ul>
  *
+ * <p><strong>The binding rule (fleetd #424): config governs what a bound slot still grants, as
+ * well as what may be bound next.</strong> Removing a slot from config revokes it — that is the
+ * ticket's entire point ("Revoking an architect slot does not revoke it"). Revoking it means an
+ * architect already bound to that slot loses the ARCHITECT privilege on its very next request:
+ * {@link #roleForSlot} and {@link #nameForSlot} read {@link #slots()} directly, with no cache, so
+ * the moment a slot drops out of config, {@link CallerResolver#resolve} (which calls both on every
+ * request from a bound pane, {@code CallerResolver.java:220}) can no longer confirm the pane's slot
+ * is an architect slot, and the pane falls through to {@code Principal.worker(...)}. What does
+ * <em>not</em> change is the {@code terminalToSlot} <em>occupancy</em> — the binding created by
+ * {@link #bind} is untouched by a reload, on purpose: unbinding it here would double-book the slot
+ * key (a second terminal could then bind to the "freed" key while the first is still the terminal
+ * the operator actually meant to demote) and would silently break {@link #unbind}'s compare-safe
+ * contract, which needs the original {@code terminal → slot} pair intact to remove it cleanly. So
+ * the demoted session keeps occupying its slot — {@link #slotForTerminal} and {@link #snapshot()}
+ * still name it — it just no longer resolves as an architect through that occupancy, and a fresh
+ * spawn still cannot bind to the same key while it is occupied ({@link #reserve}/
+ * {@link #requireSlotFor} refuse it anyway, since it is gone from {@link #slots()}). The demoted
+ * session's own turn is unaffected: {@code fleet_reply}'s authorization
+ * ({@code Authz.Action.REPLY}) is {@code caller.ownsSession(targetSession)} — identity by terminal,
+ * not by role — so a demoted architect can still end its own turn normally.
+ *
  * <p>Spawning/lifecycle is deliberately a separate unit: this class only owns the bindings and
  * exposes the map the resolver resolves against plus the profile lookup lifecycle will call.
  * Nothing here creates or manages an architect session.
@@ -55,14 +83,42 @@ public final class MemberRegistry implements MemberLifecycle {
         }
     }
 
-    private final Map<String, Entry> slots;
+    private final Supplier<FleetConfig.Fleet> fleet;
     /** Live {@code terminal_id → qualified slot key}; guarded by {@code terminalToSlot}. */
     private final Map<String, String> terminalToSlot = new HashMap<>();
     /** Slot keys held between reservation and the terminal binding. Guarded by terminalToSlot. */
     private final java.util.Set<String> reservedSlots = new java.util.HashSet<>();
 
-    /** Flatten every role pool in {@code fleet} into one registry. Leaders are not members. */
+    /**
+     * Freeze the pool at construction — for tests, and for the rare case of wiring a fixed,
+     * code-built config. Production wiring should prefer {@link #live}, which re-reads
+     * {@code fleet:} on every call.
+     */
     public MemberRegistry(FleetConfig.Fleet fleet) {
+        this(() -> fleet);
+    }
+
+    private MemberRegistry(Supplier<FleetConfig.Fleet> fleet) {
+        this.fleet = fleet;
+    }
+
+    /**
+     * Live variant (fleetd #424): {@code fleet} is read fresh on every {@link #slots()} call — pass
+     * {@code () -> config.get().fleet()}, the same supplier shape {@code CompositePeerLauncher}
+     * already uses for placement — so a reload that adds or removes an architect slot governs the
+     * next spawn's {@link #reserve}/{@link #requireSlotFor} check with no restart. A separate,
+     * private constructor rather than a same-arity public overload of
+     * {@link #MemberRegistry(FleetConfig.Fleet)}: a {@code FleetConfig.Fleet} and a
+     * {@code Supplier<FleetConfig.Fleet>} overload are ambiguous for a literal {@code null} — the
+     * same reason {@code CallerResolver.withLeads} is a static factory rather than a fourth
+     * constructor overload.
+     */
+    public static MemberRegistry live(Supplier<FleetConfig.Fleet> fleet) {
+        return new MemberRegistry(Objects.requireNonNull(fleet, "fleet"));
+    }
+
+    /** Flatten every role pool in {@code fleet} into one map. Leaders are not members. */
+    private static Map<String, Entry> flatten(FleetConfig.Fleet fleet) {
         Map<String, Entry> flat = new LinkedHashMap<>();
         if (fleet != null) {
             for (MemberRole role : MemberRole.values()) {
@@ -74,18 +130,22 @@ public final class MemberRegistry implements MemberLifecycle {
                 });
             }
         }
-        this.slots = Collections.unmodifiableMap(flat);
+        return Collections.unmodifiableMap(flat);
     }
 
-    /** The configured slots, keyed by qualified {@link Entry#key()}. Unmodifiable snapshot. */
+    /**
+     * The configured slots, keyed by qualified {@link Entry#key()}. Unmodifiable snapshot of
+     * {@code fleet:} <em>as of this call</em> — see the class doc for which constructor makes that
+     * live versus frozen.
+     */
     public Map<String, Entry> slots() {
-        return slots;
+        return flatten(fleet.get());
     }
 
-    /** The slots belonging to {@code role}, in definition order. */
+    /** The slots belonging to {@code role}, in definition order, as of this call. */
     public Map<String, Entry> slotsFor(MemberRole role) {
         Map<String, Entry> out = new LinkedHashMap<>();
-        slots.forEach((key, e) -> {
+        slots().forEach((key, e) -> {
             if (e.role() == role) {
                 out.put(key, e);
             }
@@ -123,25 +183,35 @@ public final class MemberRegistry implements MemberLifecycle {
      *         declares none
      */
     public String profileForSlot(String slotName) {
-        Entry e = slots.get(slotName);
+        Entry e = slots().get(slotName);
         return (e == null || e.profile() == null) ? null : e.profile();
     }
 
-    /** The role a qualified slot key belongs to, or {@code null} when the key is unknown. */
+    /**
+     * The role a qualified slot key belongs to, or {@code null} when the key is not currently
+     * configured. Deliberately live, with no cache (fleetd #424, see the class doc's binding rule):
+     * removing a slot from config must make {@link CallerResolver#resolve} stop granting the
+     * ARCHITECT role for it on the very next request from a terminal that was bound to it, which is
+     * the ticket's whole point — revoking a slot must actually revoke it, not just refuse the next
+     * spawn.
+     */
     public MemberRole roleForSlot(String slotName) {
-        Entry e = slots.get(slotName);
+        Entry e = slots().get(slotName);
         return e == null ? null : e.role();
     }
 
-    /** The unqualified configured name for a slot, or {@code null} if it is unknown. */
+    /**
+     * The unqualified configured name for a slot, or {@code null} if it is not currently configured.
+     * Live for the same reason as {@link #roleForSlot} — see the class doc's binding rule.
+     */
     public String nameForSlot(String slotName) {
-        Entry e = slots.get(slotName);
+        Entry e = slots().get(slotName);
         return e == null ? null : e.name();
     }
 
     /** True when {@code slotName} is a configured architect slot. */
     public boolean isSlot(String slotName) {
-        return slots.containsKey(slotName);
+        return slots().containsKey(slotName);
     }
 
     /**

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

@@ -32,18 +32,26 @@ import java.util.function.Supplier;
  *       not the fact that they are config. Most of {@code fleet:} — every role pool
  *       ({@code architects}/{@code developers}/{@code reviewers}), {@code charters}, and
  *       {@code tabLabel} — is read the same live way, through the same supplier
- *       ({@code () -> config.get().fleet()}). <strong>But {@code fleet:} as a whole is NOT in this
- *       class</strong>: {@code fleet.leaders} inside the same key is frozen, which is exactly what
- *       makes {@code fleet:} split rather than hot — see below. {@code models:} (fleetd #422) joined
- *       this class whole: {@link FleetConfig#validateModels()} re-runs fully against the fresh
- *       config on every {@link #reload()} (via {@link FleetConfig#validateAll()}), refusing a bad
- *       edit outright rather than caching a stale copy anywhere, and the on/off half added by
- *       fleetd #422 is read live both by {@code CompositePeerLauncher}'s spawn gate
- *       ({@code enforceModelEnabled} and its candidate filter) and by {@code fleet_profiles}/
- *       {@code GET /profiles} (via {@code PeerLauncher.disabledModels()}). Nothing about
- *       {@code models:} is baked into an object built at startup, so — unlike the deferred keys
- *       below — there is no frozen half left to report; it moved here from deferred rather than
- *       joining split.</li>
+ *       ({@code () -> config.get().fleet()}). {@code architects} in particular is hot for
+ *       <strong>two independent consumers</strong> (fleetd #424): {@code CompositePeerLauncher}
+ *       reads it live for placement (which profile an unqualified architect spawn may land on), and
+ *       {@code MemberRegistry} separately reads it live, through its own instance of the same
+ *       supplier shape, for identity — both which slot a spawn may bind to <em>and</em> what a slot
+ *       already bound still grants. Removing an architect slot from config therefore revokes the
+ *       {@link dev.ltms.fleet.auth.Role#ARCHITECT} role on the bound pane's very next request; only
+ *       the slot <em>occupancy</em> survives, so the demoted session still holds its slot key until
+ *       it unbinds. See {@code MemberRegistry}'s class doc for that binding rule.
+ *       <strong>But {@code fleet:} as a whole is NOT in this class</strong>: {@code fleet.leaders}
+ *       inside the same key is frozen, which is exactly what makes {@code fleet:} split rather than
+ *       hot — see below. {@code models:} (fleetd #422) joined this class whole: {@link
+ *       FleetConfig#validateModels()} re-runs fully against the fresh config on every {@link
+ *       #reload()} (via {@link FleetConfig#validateAll()}), refusing a bad edit outright rather than
+ *       caching a stale copy anywhere, and the on/off half added by fleetd #422 is read live both by
+ *       {@code CompositePeerLauncher}'s spawn gate ({@code enforceModelEnabled} and its candidate
+ *       filter) and by {@code fleet_profiles}/{@code GET /profiles} (via
+ *       {@code PeerLauncher.disabledModels()}). Nothing about {@code models:} is baked into an
+ *       object built at startup, so — unlike the deferred keys below — there is no frozen half left
+ *       to report; it moved here from deferred rather than joining split.</li>
  *   <li><strong>Deferred</strong> — accepted into the new snapshot, but the wiring built at startup
  *       keeps the old value until a restart: {@code lifecycle:}, {@code leadHeartbeat:},
  *       {@code idleSleepGuard:} ({@code Fleetd.java} reads it once, at startup, to decide whether
@@ -525,26 +533,35 @@ public final class ConfigRef implements Supplier<FleetConfig> {
                     + "opened once and needs a restart; the broker URI env-var name kept out of a "
                     + "member's environment is read live on every spawn and already applied");
         }
-        // fleetd #333: unlike health/coordinator above, most of `fleet:` (architects, developers,
-        // reviewers, charters, tabLabel) is genuinely hot — ConfigRefTest.aHotChangeIsAppliedAndRead-
+        // fleetd #333: unlike health/coordinator above, most of `fleet:` (developers, reviewers,
+        // charters, tabLabel) is genuinely hot — ConfigRefTest.aHotChangeIsAppliedAndRead-
         // ThroughGet and aCharterChangeIsHotAndReachesTheLiveConfig prove it reaches the live config
-        // with no restart note. Only fleet.leaders is frozen (Fleetd.java:281 reads
-        // cfg.fleet().leaders() off the startup snapshot to build both the LeadTabScanner's
-        // tab-label-to-name map, wired into CallerResolver.withLeadsAndMembers at Fleetd.java:620/624,
-        // and — when herdr answered — LeadLauncher(...).ensureLeads() at Fleetd.java:315, which
-        // auto-launches each lead up to its `instances` count; neither is rebuilt on reload). So this
-        // compares fleet.leaders alone, not the whole Fleet record: comparing the whole record would
-        // report "split" for a tabLabel-only or charters-only change that is actually fully hot,
-        // which is the over-claim mirror of the under-claim bug this class exists to prevent.
+        // with no restart note. `architects` is hot too, and — since fleetd #424 — hot for BOTH of
+        // its consumers, not just the one this comment used to name: CompositePeerLauncher reads it
+        // live for PLACEMENT through the () -> config.get().fleet() supplier named in the class doc's
+        // Hot bullet, and MemberRegistry separately reads it live for IDENTITY (which slot a spawn
+        // may bind to, AND what a slot already bound still grants) through its own instance of that
+        // same supplier shape — see MemberRegistry.live and its class doc for the binding rule:
+        // removing a slot revokes ARCHITECT on the bound pane's very next request, and only the slot
+        // OCCUPANCY survives, so the demoted session keeps its slot key until it unbinds. Only
+        // fleet.leaders is frozen (Fleetd.java:281 reads cfg.fleet().leaders() off the startup
+        // snapshot to build both the LeadTabScanner's tab-label-to-name map, wired into
+        // CallerResolver.withLeadsAndMembers at Fleetd.java:620/624, and — when herdr answered —
+        // LeadLauncher(...).ensureLeads() at Fleetd.java:315, which auto-launches each lead up to its
+        // `instances` count; neither is rebuilt on reload). So this compares fleet.leaders alone, not
+        // the whole Fleet record: comparing the whole record would report "split" for a tabLabel-only
+        // or architects-only change that is actually fully hot, which is the over-claim mirror of the
+        // under-claim bug this class exists to prevent.
         if (!Objects.equals(leadersOf(old), leadersOf(fresh))) {
             changed.add("fleet: fleet.leaders (each lead's tab, workspace, cwd, profile and "
                     + "instances count) is read once at startup to build the LeadTabScanner's "
                     + "identity map and to auto-launch leads, and neither is rebuilt on reload, so a "
                     + "lead added, removed, or given a new tab: label needs a restart — until then it "
                     + "stays unrecognised, and a caller from its new tab resolves as a worker, not a "
-                    + "lead; the rest of fleet: (architects, developers, reviewers, charters, "
-                    + "tabLabel) is read live through the supplier on CompositePeerLauncher and "
-                    + "already applied");
+                    + "lead; the rest of fleet: (developers, reviewers, charters, tabLabel) is read "
+                    + "live through the supplier on CompositePeerLauncher, and architects is read "
+                    + "live through that same supplier for placement AND through a separate supplier "
+                    + "on MemberRegistry for spawn-time identity — both already applied");
         }
         // Kept in step with SPLIT_KEYS the same way changedColdKeys is kept in step with COLD_KEYS —
         // every message here must be traceable to one of the split keys the class doc documents.

fleetd/src/main/java/dev/ltms/fleet/inject/CompletionResolver.java

@@ -698,17 +698,57 @@ public final class CompletionResolver implements TurnListener {
     }
 
     /**
-     * Coverage summary for the CB-578 stage A exhausted-pattern classification, logged at startup
+     * What an unset pattern key means for the classification it configures (fleetd#415).
+     * {@code coverage()} cannot infer this from the key's name — the two keys it currently
+     * describes disagree on it, and a string comparison on the name would just move the same bug
+     * to a new spot — so every caller must state it explicitly.
+     *
+     * <p><strong>This alone does not prove a caller passes the right one for its key.</strong> A
+     * test that calls {@code coverage()} directly and supplies the meaning itself only proves this
+     * enum is worded correctly, never that {@code Fleetd}'s two call sites pair each key with its
+     * true meaning — that pairing is #415's actual defect. Measured on review: swapping the two
+     * {@code UnsetMeaning} arguments at those call sites (giving {@code exhaustedPattern} the
+     * built-in-default wording and {@code errorPattern} the off wording — #415's exact defect with
+     * the keys exchanged) compiled with 0 errors and left all 1506 existing tests green. See
+     * {@code dev.ltms.fleet.Fleetd#exhaustedPatternCoverageLine}/{@code #errorPatternCoverageLine}
+     * and {@code FleetdPatternCoverageLineTest}, which exists specifically to catch that swap.
+     */
+    public enum UnsetMeaning {
+        /** No fallback exists: a profile with no configured pattern truly has this classification off. */
+        OFF,
+        /** A built-in pattern applies when unset: the classification still runs for that profile. */
+        BUILT_IN_DEFAULT
+    }
+
+    /**
+     * Coverage summary for a fleetd#201/CB-578-style pattern-key classification, logged at startup
      * the way {@link dev.ltms.fleet.health.FleetHealthMonitor#coverage} is — so an operator can
      * see whether the classification is on, and for which profiles, without reading every
      * profile's config by hand.
      *
+     * <p>fleetd#415: this method measures <em>pattern coverage</em> — how many profiles set the
+     * key — which is not the same thing as <em>feature state</em> for a key with a fallback. For
+     * {@code errorPattern}, an empty {@code configuredProfiles} still runs the classification
+     * against {@code CompletionResolver}'s built-in compatibility pattern ({@link #BACKEND_ERROR}
+     * at line ~84); for {@code exhaustedPattern} there is no fallback, so empty really does mean
+     * off. {@code unsetMeaning} is the single, required source of that fact — see
+     * {@link dev.ltms.fleet.config.FleetConfig#rejectMalformedProfilePatterns} lines ~2029-2032 for
+     * where it is documented for config authors. It is a required parameter, not a defaulted
+     * overload: a third pattern key added later must supply one to compile at all, rather than
+     * silently inheriting whichever wording this method happened to default to.
+     *
      * @param allProfiles        every configured profile name
-     * @param configuredProfiles the subset of {@code allProfiles} that carry an exhausted pattern
+     * @param configuredProfiles the subset of {@code allProfiles} that carry the pattern
      */
-    public static String coverage(String patternKey, Set<String> allProfiles, Set<String> configuredProfiles) {
+    public static String coverage(String patternKey, UnsetMeaning unsetMeaning, Set<String> allProfiles,
+                                   Set<String> configuredProfiles) {
         if (configuredProfiles.isEmpty()) {
-            return "off (no profile has an " + patternKey + " configured; profiles: " + sorted(allProfiles) + ")";
+            return switch (unsetMeaning) {
+                case OFF -> "off (no profile has an " + patternKey + " configured; profiles: "
+                        + sorted(allProfiles) + ")";
+                case BUILT_IN_DEFAULT -> "built-in default for all profiles (no profile customises "
+                        + patternKey + "; profiles: " + sorted(allProfiles) + ")";
+            };
         }
         Set<String> unconfigured = new TreeSet<>(allProfiles);
         unconfigured.removeAll(configuredProfiles);

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

@@ -1181,12 +1181,21 @@ public final class FleetMcp {
             result.put("coolingOff", coolingOff);
         }
         // fleetd #422: read the exact same accessor CompositePeerLauncher's spawn gate reads
-        // (PeerLauncher.disabledModels(), which for the composite is models0().offIds()) — never a
+        // (PeerLauncher.modelGateState(), which for the composite is models0() read live) — never a
         // separately-derived answer, so this status can never overstate or understate what the gate
         // actually enforces (the fleetd #404 lesson).
-        Set<String> modelsOff = workers.disabledModels();
-        if (!modelsOff.isEmpty()) {
-            result.put("modelsOff", new ArrayList<>(modelsOff));
+        //
+        // fleetd #422 follow-up: "armed" and "off" come from the ONE modelGateState() call below,
+        // never two independent reads of the gate — a reload landing between two separate reads
+        // could otherwise make them disagree. modelGateArmed is reported unconditionally (never
+        // omitted like quarantined/coolingOff above) precisely so a lead can tell "no models: block
+        // at all" (false) apart from "a models: block with nothing currently off" (true, with
+        // modelsOff simply absent below) — the two states PeerLauncher.disabledModels() alone
+        // cannot distinguish, both reporting an empty set.
+        PeerLauncher.ModelGateState modelGate = workers.modelGateState();
+        result.put("modelGateArmed", modelGate.configured());
+        if (!modelGate.off().isEmpty()) {
+            result.put("modelsOff", new ArrayList<>(modelGate.off()));
         }
         return result;
     }

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

@@ -644,14 +644,29 @@ public final class CompositePeerLauncher implements PeerLauncher {
     }
 
     /**
-     * fleetd #422: read live off {@link #models0()} — the exact same accessor {@link
+     * fleetd #422 follow-up: the single live read that answers both "is the models.allow: gate
+     * armed" and "which models are off", off the exact same accessor ({@link #models0()}) {@link
      * #enforceModelEnabled} and {@link #modelOffProfiles} read — so {@code fleet_profiles}/{@code
-     * GET /profiles} can never report a different answer than the gate enforces (the fleetd #404
-     * lesson).
+     * GET /profiles} (via {@link PeerLauncher#disabledModels()}, which now delegates here) can
+     * never report a different answer than the gate enforces (the fleetd #404 lesson), and the
+     * startup log line built from this can never disagree with either.
+     *
+     * <p>{@link #models0()} itself normalizes a {@code null} {@link #models} read to the shared
+     * {@link #NO_MODELS_CONFIGURED} sentinel — deliberately the one object no config-supplied
+     * {@code Models} instance can ever be identical to, since it is private to this class — so
+     * comparing by reference here recovers exactly the fact {@code models0()}'s normalization
+     * would otherwise erase: whether the live source was {@code null} (no {@code models:} block,
+     * armed = false) or a real, config-supplied block (armed = true, even one whose {@code allow:}
+     * is itself empty or absent — {@link FleetConfig.Models}'s "absent or empty allow: is off"
+     * wording governs config-load validation, a distinct question from whether this gate is armed
+     * for reporting).
      */
     @Override
-    public Set<String> disabledModels() {
-        return models0().offIds();
+    public PeerLauncher.ModelGateState modelGateState() {
+        FleetConfig.Models m = models0();
+        return m == NO_MODELS_CONFIGURED
+                ? PeerLauncher.ModelGateState.notConfigured()
+                : PeerLauncher.ModelGateState.armed(m.offIds());
     }
 
     @Override

fleetd/src/main/java/dev/ltms/fleet/peer/PeerLauncher.java

@@ -202,8 +202,56 @@ public interface PeerLauncher {
      * can drift from what the gate ({@code CompositePeerLauncher.enforceModelEnabled} and its
      * candidate filter) actually enforces. A default of {@code Set.of()} keeps every other {@link
      * PeerLauncher} implementer (the herdr adapters, and the two test-fake implementers) unchanged.
+     *
+     * <p>fleetd #422 follow-up: this alone cannot tell "no {@code models:} block at all" from "a
+     * {@code models:} block where nothing is currently off" — both report an empty set here. Delegates
+     * to {@link #modelGateState()} so the two facts always come from the one read {@link
+     * #modelGateState()}'s implementer makes; do not override this method separately from that one.
      */
     default Set<String> disabledModels() {
-        return Set.of();
+        return modelGateState().off();
+    }
+
+    /**
+     * Whether the central {@code models.allow:} gate (fleetd #422) is armed at all, together with
+     * which model ids are currently off — fleetd #422 follow-up. {@link #disabledModels()} alone
+     * cannot distinguish two states that both report an empty set: a host with no {@code models:}
+     * block (nothing is gated, and nothing can be) and a host WITH a {@code models:} block where
+     * nothing is currently turned off (the gate is armed and reporting zero). This method exists so
+     * a caller — the startup log, {@code fleet_profiles}/{@code GET /profiles} — can tell the two
+     * apart, the same reason {@code CompletionResolver.UnsetMeaning} exists: an accessor that can
+     * legitimately report "empty" must never let a caller guess why.
+     *
+     * <p>Default {@link ModelGateState#notConfigured()} — every launcher without a {@code models:}
+     * block to read from (the herdr adapters, and the two test-fake implementers), matching {@link
+     * #disabledModels()}'s own default of an empty set.
+     */
+    default ModelGateState modelGateState() {
+        return ModelGateState.notConfigured();
+    }
+
+    /**
+     * fleetd #422 follow-up: the result of {@link #modelGateState()} — see that method's javadoc
+     * for why "armed" and "off" must be reported together from one read rather than as two
+     * separately-derived facts that a reload landing between them could make disagree.
+     *
+     * @param configured {@code true} when a {@code models:} block exists at all (armed), regardless
+     *                   of whether anything in it is currently turned off; {@code false} when there
+     *                   is no block to gate against
+     * @param off        the model ids currently turned off; always empty when {@code configured} is
+     *                   {@code false}
+     */
+    record ModelGateState(boolean configured, Set<String> off) {
+        public ModelGateState {
+            off = Set.copyOf(off);
+        }
+
+        public static ModelGateState notConfigured() {
+            return new ModelGateState(false, Set.of());
+        }
+
+        public static ModelGateState armed(Set<String> off) {
+            return new ModelGateState(true, off);
+        }
     }
 }

fleetd/src/test/java/dev/ltms/fleet/FleetdModelGateCoverageLineTest.java

@@ -0,0 +1,62 @@
+package dev.ltms.fleet;
+
+import dev.ltms.fleet.peer.PeerLauncher;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+/**
+ * fleetd #422 follow-up: {@code Fleetd.modelGateCoverageLine} is the startup-log counterpart of
+ * {@code exhaustedPatternCoverageLine}/{@code errorPatternCoverageLine} — see {@code
+ * FleetdPatternCoverageLineTest} for the identical shape this follows — except here there is no
+ * {@code UnsetMeaning} choice for a caller to get backwards: {@link
+ * PeerLauncher.ModelGateState#configured()} already states, unambiguously, whether an empty
+ * {@link PeerLauncher.ModelGateState#off()} means "no {@code models:} block to gate with at all"
+ * or "a block armed and currently reporting zero off". This class proves {@code
+ * modelGateCoverageLine} words those two states — plus the third, N off — distinctly, so a
+ * mutation that made it ignore {@code configured()} either way is caught here.
+ */
+class FleetdModelGateCoverageLineTest {
+
+    @Test
+    @DisplayName("no models: block reports not configured, distinct from armed-with-zero")
+    void noModelsBlockReportsNotConfigured() {
+        String line = Fleetd.modelGateCoverageLine(PeerLauncher.ModelGateState.notConfigured());
+        assertEquals("not configured (no models: block — nothing is gated, and nothing can be)", line);
+    }
+
+    @Test
+    @DisplayName("a models: block armed with nothing off reports armed, distinct from not configured")
+    void armedWithNothingOffReportsArmed() {
+        String line = Fleetd.modelGateCoverageLine(PeerLauncher.ModelGateState.armed(Set.of()));
+        assertEquals("armed (models: block present; 0 models currently turned off)", line);
+    }
+
+    @Test
+    @DisplayName("a models: block with N off names the off models")
+    void armedWithModelsOffNamesThem() {
+        String line = Fleetd.modelGateCoverageLine(
+                PeerLauncher.ModelGateState.armed(Set.of("deepseek-v4-flash", "claude-opus-9000")));
+        assertEquals("armed (2 model(s) turned off: [claude-opus-9000, deepseek-v4-flash])", line);
+    }
+
+    @Test
+    @DisplayName("the three states produce pairwise-distinct wording for the same empty-looking input")
+    void theThreeStatesProduceDistinctWording() {
+        String notConfigured = Fleetd.modelGateCoverageLine(PeerLauncher.ModelGateState.notConfigured());
+        String armedZero = Fleetd.modelGateCoverageLine(PeerLauncher.ModelGateState.armed(Set.of()));
+        String armedOne = Fleetd.modelGateCoverageLine(PeerLauncher.ModelGateState.armed(Set.of("x")));
+
+        // Pinned individually above; restated here so this test alone still catches a regression
+        // even if one of the three tests above were ever deleted — the exact FleetdPatternCoverageLineTest
+        // pattern, adapted from "two keys" to "three states of one gate".
+        assertNotEquals(notConfigured, armedZero,
+                "collapsing 'no models: block' into 'armed, zero off' is fleetd #422 follow-up's exact defect");
+        assertNotEquals(armedZero, armedOne);
+        assertNotEquals(notConfigured, armedOne);
+    }
+}

fleetd/src/test/java/dev/ltms/fleet/FleetdPatternCoverageLineTest.java

@@ -0,0 +1,67 @@
+package dev.ltms.fleet;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+/**
+ * fleetd #415 (review follow-up): {@code CompletionResolverTest} proves {@code coverage()} words
+ * {@code UnsetMeaning.OFF} and {@code UnsetMeaning.BUILT_IN_DEFAULT} correctly — but every one of
+ * those tests supplies the meaning itself. That proves the enum's wording, never that {@code
+ * Fleetd} pairs the right meaning with the right pattern key. That pairing is #415's actual
+ * defect: {@code coverage()} had no way to know what unset meant for its key, so the fix moved
+ * the fact to the caller — and nothing yet proved the caller states it correctly.
+ *
+ * <p><b>Measured or it didn't happen:</b> swapping the two {@code UnsetMeaning} arguments at
+ * {@code Fleetd}'s two coverage call sites — giving {@code exhaustedPattern} the built-in-default
+ * wording and {@code errorPattern} the off wording, #415's exact defect with the keys exchanged —
+ * compiled with 0 errors and left all 1506 existing tests green. This class exists to turn that
+ * swap red.
+ *
+ * <p>It calls {@link Fleetd#exhaustedPatternCoverageLine} and {@link Fleetd#errorPatternCoverageLine}
+ * directly rather than reading {@code Fleetd.java} as source text (the shape {@code
+ * FleetdCompletionResolverWiringTest} uses for a different wiring gap): those two methods are the
+ * extracted call sites {@code main} actually invokes, following the same {@code static} factory +
+ * dedicated-test pattern as {@link Fleetd#capacitySource} and {@link Fleetd#worktreeBranchLookup}.
+ */
+class FleetdPatternCoverageLineTest {
+
+    private static final Set<String> PROFILES = Set.of("terra", "gx10");
+
+    @Test
+    @DisplayName("exhaustedPatternCoverageLine says off when no profile configures exhaustedPattern")
+    void exhaustedPatternCoverageLineSaysOffWhenNoProfileConfiguresIt() {
+        assertEquals("off (no profile has an exhaustedPattern configured; profiles: [gx10, terra])",
+                Fleetd.exhaustedPatternCoverageLine(PROFILES, Set.of()));
+    }
+
+    @Test
+    @DisplayName("errorPatternCoverageLine says built-in default when no profile configures errorPattern")
+    void errorPatternCoverageLineSaysBuiltInDefaultWhenNoProfileConfiguresIt() {
+        assertEquals("built-in default for all profiles (no profile customises errorPattern; "
+                        + "profiles: [gx10, terra])",
+                Fleetd.errorPatternCoverageLine(PROFILES, Set.of()));
+    }
+
+    @Test
+    @DisplayName("the two keys produce different wording for the identical empty-coverage input")
+    void theTwoKeysProduceDifferentWordingForTheSameEmptyInput() {
+        String exhaustedLine = Fleetd.exhaustedPatternCoverageLine(PROFILES, Set.of());
+        String errorLine = Fleetd.errorPatternCoverageLine(PROFILES, Set.of());
+
+        // Pinned individually above; restated here so this test alone still catches a swap even
+        // if one of the two tests above were ever deleted.
+        assertEquals("off (no profile has an exhaustedPattern configured; profiles: [gx10, terra])",
+                exhaustedLine);
+        assertEquals("built-in default for all profiles (no profile customises errorPattern; "
+                        + "profiles: [gx10, terra])", errorLine);
+        assertNotEquals(exhaustedLine, errorLine,
+                "swapping which UnsetMeaning pairs with which pattern key at Fleetd's call sites "
+                        + "must be caught here — that pairing, not coverage()'s own wording in isolation, "
+                        + "is fleetd #415's actual defect");
+    }
+}

fleetd/src/test/java/dev/ltms/fleet/auth/MemberRegistryLiveTest.java

@@ -0,0 +1,257 @@
+package dev.ltms.fleet.auth;
+
+import dev.ltms.fleet.config.ConfigRef;
+import dev.ltms.fleet.config.FleetConfig;
+import dev.ltms.fleet.herdr.FakeHerdr;
+import dev.ltms.fleet.herdr.PaneLocator;
+import dev.ltms.fleet.mcp.ConnectionIdentity;
+import dev.ltms.fleet.peer.MemberRole;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * fleetd #424 — revoking (or granting) an architect slot must take effect on the next spawn with
+ * no restart. A session already bound to a slot keeps its <em>binding</em> (the {@code
+ * terminalToSlot} occupancy) even after that slot drops out of config, but NOT the ARCHITECT
+ * <em>privilege</em> the slot used to grant — that is revoked on the bound session's very next
+ * request. See {@link MemberRegistry}'s class doc for the exact rule: "config governs what a
+ * bound slot still grants, as well as what may be bound next."
+ *
+ * <p>Every test here drives a REAL {@link ConfigRef#reload()} against a {@code @TempDir} file and
+ * asserts {@link ConfigRef.Outcome#applied()}, rather than comparing two frozen
+ * {@code MemberRegistry} instances in memory — the defect this ticket fixes is specifically that
+ * {@link MemberRegistry} used to ignore a live reload, so a test that never reloads cannot tell the
+ * fixed registry from the broken one. {@code requireSlotFor} and {@code reserve} are pinned in
+ * separate tests, in both directions (removed and added), so a registry that simply refuses (or
+ * simply allows) everything cannot pass by accident — see {@link MemberRegistryTest} for the
+ * registry's other invariants (bind/unbind cardinality, thread-safety), which are unaffected by
+ * this ticket and still exercised against the frozen constructor.
+ */
+class MemberRegistryLiveTest {
+
+    private static String yaml(String fleetBlock) {
+        return """
+                bind:
+                  host: 127.0.0.1
+                  port: 8765
+                herdrSocket: ~/.config/herdr/herdr.sock
+                profiles:
+                  sonnet:
+                    baseUrl: http://gx00.gw:8000
+                    model: sonnet
+                  opus:
+                    baseUrl: http://gx00.gw:8001
+                    model: opus
+                guard:
+                  offSubscriptionHosts:
+                    - gx00.gw
+                """ + fleetBlock;
+    }
+
+    private static final String WITH_SONNET_SLOT = """
+            fleet:
+              architects:
+                designer:
+                  profile: sonnet
+            """;
+
+    /** No architect pool at all — developers is unrelated dead data for this registry (#424 out of scope). */
+    private static final String WITHOUT_ARCHITECT_SLOTS = """
+            fleet:
+              developers:
+                dev1:
+                  profile: sonnet
+            """;
+
+    private static ConfigRef refFor(Path f) {
+        return new ConfigRef(f, FleetConfig.load(f));
+    }
+
+    // ── requireSlotFor is live (criteria 1, 2, 4) ──────────────────────────────────────────────
+
+    @Test
+    void requireSlotForRefusesAProfileWhoseSlotWasRemovedByReload(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml(WITH_SONNET_SLOT));
+        ConfigRef ref = refFor(f);
+        MemberRegistry registry = MemberRegistry.live(() -> ref.get().fleet());
+
+        assertDoesNotThrow(() -> registry.requireSlotFor(MemberRole.ARCHITECT, "sonnet"),
+                "the slot is configured before the reload");
+
+        Files.writeString(f, yaml(WITHOUT_ARCHITECT_SLOTS));
+        ConfigRef.Outcome out = ref.reload();
+        assertTrue(out.applied(), "the reload must actually take effect: " + out.summary());
+
+        assertThrows(IllegalArgumentException.class,
+                () -> registry.requireSlotFor(MemberRole.ARCHITECT, "sonnet"),
+                "revoking the slot must refuse the NEXT spawn that names it");
+    }
+
+    @Test
+    void requireSlotForAllowsAProfileWhoseSlotWasAddedByReload(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml(WITHOUT_ARCHITECT_SLOTS));
+        ConfigRef ref = refFor(f);
+        MemberRegistry registry = MemberRegistry.live(() -> ref.get().fleet());
+
+        assertThrows(IllegalArgumentException.class,
+                () -> registry.requireSlotFor(MemberRole.ARCHITECT, "sonnet"),
+                "no architect slot is configured yet");
+
+        Files.writeString(f, yaml(WITH_SONNET_SLOT));
+        ConfigRef.Outcome out = ref.reload();
+        assertTrue(out.applied(), "the reload must actually take effect: " + out.summary());
+
+        assertDoesNotThrow(() -> registry.requireSlotFor(MemberRole.ARCHITECT, "sonnet"),
+                "a slot added by reload must be usable with no restart");
+    }
+
+    // ── reserve is live too — tested separately from requireSlotFor (criteria 1, 2, 4) ────────
+
+    @Test
+    void reserveRefusesAProfileWhoseSlotWasRemovedByReload(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml(WITH_SONNET_SLOT));
+        ConfigRef ref = refFor(f);
+        MemberRegistry registry = MemberRegistry.live(() -> ref.get().fleet());
+
+        MemberLifecycle.SlotReservation before = registry.reserve(MemberRole.ARCHITECT, "sonnet");
+        assertEquals("architect:designer", before.slot());
+        registry.release(before); // free it back up so the reload-side reserve below starts clean
+
+        Files.writeString(f, yaml(WITHOUT_ARCHITECT_SLOTS));
+        ConfigRef.Outcome out = ref.reload();
+        assertTrue(out.applied(), "the reload must actually take effect: " + out.summary());
+
+        assertThrows(IllegalArgumentException.class,
+                () -> registry.reserve(MemberRole.ARCHITECT, "sonnet"),
+                "revoking the slot must refuse the NEXT reservation for it");
+    }
+
+    @Test
+    void reserveAllowsAProfileWhoseSlotWasAddedByReload(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml(WITHOUT_ARCHITECT_SLOTS));
+        ConfigRef ref = refFor(f);
+        MemberRegistry registry = MemberRegistry.live(() -> ref.get().fleet());
+
+        assertThrows(IllegalArgumentException.class,
+                () -> registry.reserve(MemberRole.ARCHITECT, "sonnet"),
+                "no architect slot is configured yet");
+
+        Files.writeString(f, yaml(WITH_SONNET_SLOT));
+        ConfigRef.Outcome out = ref.reload();
+        assertTrue(out.applied(), "the reload must actually take effect: " + out.summary());
+
+        MemberLifecycle.SlotReservation after = registry.reserve(MemberRole.ARCHITECT, "sonnet");
+        assertEquals("architect:designer", after.slot(),
+                "a slot added by reload must be reservable with no restart");
+    }
+
+    // ── a bound architect is demoted, but the binding itself is not touched (fleetd #424) ───────
+    // The lead's corrected ruling: the PRIVILEGE a slot grants is revoked on the bound session's
+    // very next request, but the terminalToSlot BINDING itself is untouched by a reload — dropping
+    // it would double-book the slot key and break unbind's compare-safe contract. See the class
+    // doc's binding rule.
+
+    /** A caller identity resolving the one canned pane (terminal {@code term_a}) in {@link FakeHerdr}. */
+    private static ConnectionIdentity boundPaneIdentity() {
+        return new ConnectionIdentity(new PaneLocator(new FakeHerdr()), _ -> FakeHerdr.WORKER_PID);
+    }
+
+    @Test
+    void anArchitectAlreadyBoundToASlotIsDemotedByReload(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml(WITH_SONNET_SLOT));
+        ConfigRef ref = refFor(f);
+        MemberRegistry registry = MemberRegistry.live(() -> ref.get().fleet());
+
+        MemberLifecycle.SlotReservation reservation = registry.reserve(MemberRole.ARCHITECT, "sonnet");
+        assertTrue(registry.bind(reservation, "term_a"));
+        assertEquals("architect:designer", registry.slotForTerminal("term_a"));
+
+        // Drive the real caller path, not the roleForSlot seam directly: CallerResolver.resolve is
+        // what a live request actually goes through (CallerResolver.java:220), and a resolver that
+        // ignored roleForSlot entirely would still pass a test that only checked the seam.
+        CallerResolver resolver = CallerResolver.withLeadsAndMembers(
+                boundPaneIdentity(), false, null, Map::of, registry);
+
+        Principal before = resolver.resolve("127.0.0.1", 42, null);
+        assertEquals(Role.ARCHITECT, before.role(), "sanity check: the harness binds term_a as an architect");
+        assertEquals("designer", before.name());
+
+        Files.writeString(f, yaml(WITHOUT_ARCHITECT_SLOTS));
+        ConfigRef.Outcome out = ref.reload();
+        assertTrue(out.applied(), "the reload must actually take effect: " + out.summary());
+
+        Principal after = resolver.resolve("127.0.0.1", 42, null);
+        assertEquals(Role.WORKER, after.role(),
+                "removing the slot from config must demote the bound session to worker on its "
+                        + "NEXT request — this is the ticket's whole point");
+        assertEquals("term_a", after.terminal(), "same pane, same terminal — only the role changed");
+    }
+
+    @Test
+    void theOriginalBindingStillOccupiesTheRemovedSlotSoASecondTerminalCannotClaimIt(@TempDir Path dir)
+            throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml(WITH_SONNET_SLOT));
+        ConfigRef ref = refFor(f);
+        MemberRegistry registry = MemberRegistry.live(() -> ref.get().fleet());
+
+        MemberLifecycle.SlotReservation reservation = registry.reserve(MemberRole.ARCHITECT, "sonnet");
+        assertTrue(registry.bind(reservation, "term_a"));
+
+        Files.writeString(f, yaml(WITHOUT_ARCHITECT_SLOTS));
+        ConfigRef.Outcome removed = ref.reload();
+        assertTrue(removed.applied(), "the reload must actually take effect: " + removed.summary());
+
+        // The binding survives the removal untouched.
+        assertEquals("architect:designer", registry.slotForTerminal("term_a"),
+                "a live binding must never be retroactively unbound by a config edit");
+        assertEquals(Map.of("term_a", "architect:designer"), registry.snapshot());
+
+        // Bring the slot back into config. If the binding had been silently dropped by the removal
+        // (rather than merely losing the privilege it grants), a second terminal could now claim
+        // the "freed" key — the exact double-booking the class doc's binding rule rules out.
+        Files.writeString(f, yaml(WITH_SONNET_SLOT));
+        ConfigRef.Outcome restored = ref.reload();
+        assertTrue(restored.applied(), "the reload must actually take effect: " + restored.summary());
+
+        assertFalse(registry.bind("architect:designer", "term_b"),
+                "the slot is still occupied by term_a — a second terminal must not bind to it");
+        assertThrows(IllegalArgumentException.class,
+                () -> registry.reserve(MemberRole.ARCHITECT, "sonnet"),
+                "the slot is still occupied by term_a — a fresh reservation must not find it free");
+        assertEquals("architect:designer", registry.slotForTerminal("term_a"),
+                "the original binding is unchanged throughout");
+    }
+
+    @Test
+    void unbindStillSucceedsForTheOriginalTerminalAfterItsSlotIsRemoved(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml(WITH_SONNET_SLOT));
+        ConfigRef ref = refFor(f);
+        MemberRegistry registry = MemberRegistry.live(() -> ref.get().fleet());
+
+        MemberLifecycle.SlotReservation reservation = registry.reserve(MemberRole.ARCHITECT, "sonnet");
+        assertTrue(registry.bind(reservation, "term_a"));
+
+        Files.writeString(f, yaml(WITHOUT_ARCHITECT_SLOTS));
+        ConfigRef.Outcome out = ref.reload();
+        assertTrue(out.applied(), "the reload must actually take effect: " + out.summary());
+
+        assertTrue(registry.unbind("architect:designer", "term_a"),
+                "unbind must still work for a slot that config has since removed, or a session "
+                        + "that outlives its slot's removal could never release it");
+        assertNull(registry.slotForTerminal("term_a"));
+        assertEquals(Map.of(), registry.snapshot());
+    }
+}

fleetd/src/test/java/dev/ltms/fleet/inject/CompletionResolverTest.java

@@ -20,6 +20,7 @@ import java.util.regex.Pattern;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /** Unit behaviour of the CB-106 completion resolver in isolation from the injector. */
@@ -884,19 +885,22 @@ class CompletionResolverTest {
     @Test
     void coverageIsOffWhenNoProfileHasAPatternConfigured() {
         assertEquals("off (no profile has an exhaustedPattern configured; profiles: [terra])",
-                CompletionResolver.coverage("exhaustedPattern", Set.of("terra"), Set.of()));
+                CompletionResolver.coverage("exhaustedPattern", CompletionResolver.UnsetMeaning.OFF,
+                        Set.of("terra"), Set.of()));
     }
 
     @Test
     void coverageIsFullWhenEveryProfileHasAPatternConfigured() {
         assertEquals("full (all profiles configured: [gx10, terra])",
-                CompletionResolver.coverage("exhaustedPattern", Set.of("terra", "gx10"), Set.of("terra", "gx10")));
+                CompletionResolver.coverage("exhaustedPattern", CompletionResolver.UnsetMeaning.OFF,
+                        Set.of("terra", "gx10"), Set.of("terra", "gx10")));
     }
 
     @Test
     void coverageIsPartialAndNamesWhichProfilesAreConfigured() {
         assertEquals("partial (configured: [terra]; not configured: [gx10])",
-                CompletionResolver.coverage("exhaustedPattern", Set.of("terra", "gx10"), Set.of("terra")));
+                CompletionResolver.coverage("exhaustedPattern", CompletionResolver.UnsetMeaning.OFF,
+                        Set.of("terra", "gx10"), Set.of("terra")));
     }
 
     /**
@@ -910,11 +914,42 @@ class CompletionResolverTest {
      *
      * <p>Every earlier test here passed the exhaustion case only, so none of them could see it. This
      * one pins that the message names the key the caller actually meant.
+     *
+     * <p>fleetd#415: the expected wording changed here too. {@code errorPattern} has a built-in
+     * fallback ({@link CompletionResolver#BACKEND_ERROR}), so an empty {@code configuredProfiles}
+     * for it is not "off" — see {@link #coverageDistinguishesOffFromBuiltInDefaultForTheSameEmptyInput}
+     * for the test built specifically to pin that distinction.
      */
     @Test
     void coverageNamesTheConfigKeyItsCallerMeansRatherThanAlwaysSayingExhaustedPattern() {
-        assertEquals("off (no profile has an errorPattern configured; profiles: [gx10, terra])",
-                CompletionResolver.coverage("errorPattern", Set.of("terra", "gx10"), Set.of()));
+        assertEquals("built-in default for all profiles (no profile customises errorPattern; "
+                        + "profiles: [gx10, terra])",
+                CompletionResolver.coverage("errorPattern", CompletionResolver.UnsetMeaning.BUILT_IN_DEFAULT,
+                        Set.of("terra", "gx10"), Set.of()));
+    }
+
+    /**
+     * fleetd#415: {@code coverage()} measures pattern coverage (how many profiles set the key), but
+     * for {@code errorPattern} the empty case is not the feature-off state — a profile with no
+     * configured {@code errorPattern} still runs the classification against
+     * {@link CompletionResolver#BACKEND_ERROR}. For {@code exhaustedPattern} there is no fallback,
+     * so empty really is off. Same shape of input (empty {@code configuredProfiles}, one profile),
+     * different {@link CompletionResolver.UnsetMeaning} — the wording must differ, or this method is
+     * back to conflating pattern coverage with feature state for the one key where they disagree.
+     */
+    @Test
+    void coverageDistinguishesOffFromBuiltInDefaultForTheSameEmptyInput() {
+        String exhaustedLine = CompletionResolver.coverage("exhaustedPattern",
+                CompletionResolver.UnsetMeaning.OFF, Set.of("gx10", "terra"), Set.of());
+        String errorLine = CompletionResolver.coverage("errorPattern",
+                CompletionResolver.UnsetMeaning.BUILT_IN_DEFAULT, Set.of("gx10", "terra"), Set.of());
+
+        assertEquals("off (no profile has an exhaustedPattern configured; profiles: [gx10, terra])",
+                exhaustedLine);
+        assertEquals("built-in default for all profiles (no profile customises errorPattern; "
+                        + "profiles: [gx10, terra])", errorLine);
+        assertNotEquals(exhaustedLine, errorLine,
+                "the same empty-coverage input must not read as the same feature state for both keys");
     }
 
     // --- fleetd#201 Unit 1: target-keyed backend-error pattern + typed sink ----------------------

fleetd/src/test/java/dev/ltms/fleet/mcp/FleetProfilesModelGateStateTest.java

@@ -0,0 +1,109 @@
+package dev.ltms.fleet.mcp;
+
+import dev.ltms.fleet.config.FleetConfig;
+import dev.ltms.fleet.guard.SubscriptionGuard;
+import dev.ltms.fleet.herdr.AgentControl;
+import dev.ltms.fleet.herdr.FakeHerdr;
+import dev.ltms.fleet.herdr.WorkspaceControl;
+import dev.ltms.fleet.member.ClaudeCodeLauncher;
+import dev.ltms.fleet.member.CompositePeerLauncher;
+import dev.ltms.fleet.member.HerdrPeerLauncher;
+import dev.ltms.fleet.peer.PeerLauncher;
+import dev.ltms.fleet.placement.BackendOutagePolicy;
+import dev.ltms.fleet.placement.BackendQuarantine;
+import dev.ltms.fleet.placement.PlacementPolicies;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+/**
+ * fleetd #422 follow-up: {@code fleet_profiles}/{@code GET /profiles} — the reporting surface a
+ * lead actually reads — must let it tell apart the three states {@link
+ * dev.ltms.fleet.peer.PeerLauncher#disabledModels()} alone collapses into one empty set: no
+ * {@code models:} block at all, a block armed with nothing currently off, and a block with N
+ * models off. See {@link dev.ltms.fleet.peer.PeerLauncher.ModelGateState}'s javadoc for why a
+ * bare {@code disabledModels()} read cannot make this distinction, and {@link
+ * FleetMcp#profilesView} for where {@code modelGateArmed} is added alongside the existing {@code
+ * modelsOff} key.
+ *
+ * <p>Every assertion here goes through {@link FleetMcp#profilesView}, never {@code
+ * PeerLauncher.modelGateState()} directly — {@code CompositePeerLauncherTest} already proves the
+ * accessor itself; this class proves the surface a lead reads (fleet_profiles / GET /profiles)
+ * renders what that accessor reports.
+ */
+class FleetProfilesModelGateStateTest {
+
+    private static FleetConfig.Profile profile(String name, String model) {
+        return new FleetConfig.Profile(name, "http://gx00.gw:8000", model, null, "FLEETD_WORKER_TOKEN",
+                null, "tab", "fleetd-workers", "worker: {profile} #{n}", null, null, null);
+    }
+
+    private static FleetMcp.QuarantineSource noQuarantine() {
+        return new FleetMcp.QuarantineSource(_ -> null, BackendQuarantine.none(), _ -> false);
+    }
+
+    private static HerdrPeerLauncher claudeAdapter(FakeHerdr h, Map<String, FleetConfig.Profile> profiles) {
+        return new ClaudeCodeLauncher(new AgentControl(h), new WorkspaceControl(h),
+                new SubscriptionGuard(Set.of("gx00.gw")), profiles, "local", _ -> "tok");
+    }
+
+    /**
+     * State 1: no {@code models:} block at all — a plain {@code ClaudeCodeLauncher} (no {@code
+     * models:} supplier exists for it to read) has nothing to gate against, matching the fleet01
+     * host measured for this ticket: {@code grep -c '^models:' fleetd.yaml} returns 0 there.
+     */
+    @Test
+    void noModelsBlockReportsGateNotArmed() {
+        FakeHerdr h = new FakeHerdr();
+        Map<String, FleetConfig.Profile> profiles = Map.of("local", profile("local", "deepseek-v4-flash"));
+        PeerLauncher workers = claudeAdapter(h, profiles);
+
+        Map<String, Object> view = FleetMcp.profilesView(workers, noQuarantine(), FleetMcp.OutageSource.none());
+
+        assertEquals(Boolean.FALSE, view.get("modelGateArmed"),
+                "no models: block to read from — nothing is gated, and nothing can be");
+        assertFalse(view.containsKey("modelsOff"), "nothing configured, so no off set to report either");
+    }
+
+    /** State 2: a {@code models:} block is present, but nothing in it is currently turned off. */
+    @Test
+    void modelsBlockWithNothingOffReportsGateArmedAndZeroOff() {
+        FakeHerdr h = new FakeHerdr();
+        Map<String, FleetConfig.Profile> profiles = Map.of("local", profile("local", "deepseek-v4-flash"));
+        FleetConfig.Models models = new FleetConfig.Models(
+                List.of(new FleetConfig.Models.ModelEntry("deepseek-v4-flash", true)));
+        PeerLauncher workers = new CompositePeerLauncher(List.of(claudeAdapter(h, profiles)), "local", profiles,
+                PlacementPolicies.fixed(), _ -> 0, null, BackendQuarantine.none(),
+                new BackendOutagePolicy(System::nanoTime), () -> models);
+
+        Map<String, Object> view = FleetMcp.profilesView(workers, noQuarantine(), FleetMcp.OutageSource.none());
+
+        assertEquals(Boolean.TRUE, view.get("modelGateArmed"),
+                "a models: block is present, so the gate is armed even though nothing is off yet");
+        assertFalse(view.containsKey("modelsOff"),
+                "nothing is off, so the key stays absent — an empty list here would be indistinguishable "
+                        + "from today's modelsOff omission, exactly the ambiguity modelGateArmed exists to remove");
+    }
+
+    /** State 3: a {@code models:} block is present with one model currently turned off. */
+    @Test
+    void modelsBlockWithModelsOffReportsGateArmedAndTheOffSet() {
+        FakeHerdr h = new FakeHerdr();
+        Map<String, FleetConfig.Profile> profiles = Map.of("local", profile("local", "deepseek-v4-flash"));
+        FleetConfig.Models models = new FleetConfig.Models(
+                List.of(new FleetConfig.Models.ModelEntry("deepseek-v4-flash", false)));
+        PeerLauncher workers = new CompositePeerLauncher(List.of(claudeAdapter(h, profiles)), "local", profiles,
+                PlacementPolicies.fixed(), _ -> 0, null, BackendQuarantine.none(),
+                new BackendOutagePolicy(System::nanoTime), () -> models);
+
+        Map<String, Object> view = FleetMcp.profilesView(workers, noQuarantine(), FleetMcp.OutageSource.none());
+
+        assertEquals(Boolean.TRUE, view.get("modelGateArmed"));
+        assertEquals(List.of("deepseek-v4-flash"), view.get("modelsOff"));
+    }
+}

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

@@ -1453,6 +1453,108 @@ class CompositePeerLauncherTest {
         assertEquals(2, adapter.spawnCount("local"));
     }
 
+    /**
+     * fleetd #422 follow-up, acceptance criterion 2: {@link CompositePeerLauncher#modelGateState()}
+     * is LIVE — no restart — proven through a REAL {@link ConfigRef#reload()}, exactly like {@link
+     * #modelOnOffIsHotReloadedThroughARealConfigRef} above proves for the on/off gate itself. This
+     * single reload sequence walks through all three states the ticket asks for: no {@code models:}
+     * block, a block armed with nothing off, and a block with one model off — so a reload that flips
+     * between any of the three is proven live, not just the on/off edit within an already-armed block.
+     */
+    @Test
+    void modelGateStateIsHotReloadedThroughARealConfigRef(@TempDir Path dir) throws Exception {
+        Path yaml = dir.resolve("fleetd.yaml");
+        Files.writeString(yaml, """
+                bind:
+                  port: 8080
+                profiles:
+                  local:
+                    baseUrl: http://local.gw:8000
+                    model: deepseek-v4-flash
+                """);
+        FleetConfig initial = FleetConfig.load(yaml);
+        ConfigRef configRef = new ConfigRef(yaml, initial);
+
+        FakeHerdr herdr = new FakeHerdr();
+        StubLauncher adapter = new StubLauncher("claude", herdr,
+                Map.of("local", stubWorker("local")), "local", Set.of());
+        CompositePeerLauncher composite = new CompositePeerLauncher(
+                List.of(adapter), "local", configRef, _ -> 0, BackendQuarantine.none(), NO_OUTAGE);
+
+        PeerLauncher.ModelGateState notConfigured = composite.modelGateState();
+        assertFalse(notConfigured.configured(), "no models: block in the config at all");
+        assertEquals(Set.of(), notConfigured.off());
+
+        Files.writeString(yaml, """
+                bind:
+                  port: 8080
+                profiles:
+                  local:
+                    baseUrl: http://local.gw:8000
+                    model: deepseek-v4-flash
+                models:
+                  allow:
+                    - model: deepseek-v4-flash
+                      enabled: false
+                """);
+        assertTrue(configRef.reload().applied(), "adding a models: block must apply live, no restart");
+        PeerLauncher.ModelGateState armedWithOneOff = composite.modelGateState();
+        assertTrue(armedWithOneOff.configured(), "a models: block now exists — the gate is armed");
+        assertEquals(Set.of("deepseek-v4-flash"), armedWithOneOff.off());
+
+        Files.writeString(yaml, """
+                bind:
+                  port: 8080
+                profiles:
+                  local:
+                    baseUrl: http://local.gw:8000
+                    model: deepseek-v4-flash
+                models:
+                  allow:
+                    - model: deepseek-v4-flash
+                      enabled: true
+                """);
+        assertTrue(configRef.reload().applied(), "flipping the entry back on must apply live too");
+        PeerLauncher.ModelGateState armedWithZeroOff = composite.modelGateState();
+        assertTrue(armedWithZeroOff.configured(),
+                "the block is still present — armed and reporting zero, not the same as no block at all");
+        assertEquals(Set.of(), armedWithZeroOff.off());
+    }
+
+    /**
+     * fleetd #422 follow-up, acceptance criterion 3: the invariant is that an absent {@code
+     * models:} block stays permitted and must never be fatal. Proved, not assumed — a config
+     * without one loads, validates, reports the gate as not configured, AND still spawns normally
+     * (no {@link PlacementException} from a gate that has nothing to check against), using the same
+     * production-shaped {@code Supplier<FleetConfig>} wiring {@code Fleetd.main} actually uses.
+     */
+    @Test
+    void noModelsBlockConfigStillLoadsAndSpawnsNormally(@TempDir Path dir) throws Exception {
+        Path yaml = dir.resolve("fleetd.yaml");
+        Files.writeString(yaml, """
+                bind:
+                  port: 8080
+                profiles:
+                  local:
+                    baseUrl: http://local.gw:8000
+                    model: deepseek-v4-flash
+                """);
+        FleetConfig cfg = FleetConfig.load(yaml);
+        assertDoesNotThrow(cfg::validateAll, "a config with no models: block must load and validate cleanly");
+        ConfigRef configRef = new ConfigRef(yaml, cfg);
+
+        FakeHerdr herdr = new FakeHerdr();
+        StubLauncher adapter = new StubLauncher("claude", herdr,
+                Map.of("local", stubWorker("local")), "local", Set.of());
+        CompositePeerLauncher composite = new CompositePeerLauncher(
+                List.of(adapter), "local", configRef, _ -> 0, BackendQuarantine.none(), NO_OUTAGE);
+
+        assertFalse(composite.modelGateState().configured());
+        assertDoesNotThrow(() -> composite.spawn(new SpawnRequest("local", null, null)),
+                "no models: block means nothing to gate against — the spawn must go through");
+        assertEquals(1, adapter.spawnCount("local"));
+    }
+
     /** {@code fleet_profiles}/{@code GET /profiles} must read the exact same live source the gate reads. */
     @Test
     void disabledModelsReportsWhatTheGateActuallyEnforces() {