fleetd #446 round 3: extract exhaustionSink and pin its caller (Cell A/B)

Round 2 pinned usageLimitFixWarning/usageLimitFixWarningNoModel's TEXT via
FleetdUsageLimitFixWarningTest, but a mutation battery against the merged PR
proved two gaps in the caller that builds main()'s real quarantine
ExhaustionSink: nothing proved the sink's log.warn actually invokes either
method (Cell A), and nothing proved it picks the right one for a profile
with vs without a configured model: (Cell B).

Extract the inline lambda into a new static Fleetd.exhaustionSink(...)
factory (same refactor-for-testability class the lead approved in round 2
for the two static warning methods), behaviourally unchanged from the
lambda it replaces. FleetdExhaustionSinkWarningTest drives this factory's
return value directly and asserts on the real text a ListAppender attached
to Fleetd's own logger captures, covering both cells from one mechanism:

- Cell A (ternary result replaced by a literal string): confirmed red,
  1594 run / 1 failure, restored, confirmed green (1594/0).
- Cell B (ternary's two branches swapped): confirmed red, 1594 run /
  2 failures (both test methods independently caught it), restored,
  confirmed green (1594/0).

fleetd/fleetd.example.yaml

@@ -207,8 +207,12 @@ herdrSocket: ~/.config/herdr/herdr.sock
 #                      omit and this profile's completion fallback behaves exactly as before.
 #                      Every backend words its refusal differently, so this is config, never a
 #                      vendor string baked into fleetd itself.
-#                      DEFERRED: compiled once into a startup pattern map — editing it needs a
-#                      daemon restart, same as this profile's model/baseUrl/argv.
+#                      HOT (fleetd #446): read live, cached by profile name, at every
+#                      completion-fallback check AND by fleet_profiles' exhaustionDetectionArmed —
+#                      editing it and reloading arms or disarms usage-limit detection for this
+#                      profile with no daemon restart. (Before fleetd #446 this was DEFERRED,
+#                      compiled once into a startup pattern map like model/baseUrl/argv still are —
+#                      see errorPattern below, which is still deferred that way on purpose.)
 #   credentialId     → CB-578 stage B: the credential this profile quarantines WITH when a
 #                      BACKEND_EXHAUSTED classification fires. Two profiles that set the SAME
 #                      credentialId share one quarantine — the case this exists for is two models
@@ -227,8 +231,9 @@ herdrSocket: ~/.config/herdr/herdr.sock
 #                      happens, just without a profile-specific match; every backend words its
 #                      failure differently, so a hardcoded sentence would only ever match one
 #                      of them.
-#                      DEFERRED: compiled once into a startup pattern map, same as exhaustedPattern
-#                      — editing it needs a daemon restart.
+#                      DEFERRED: compiled once into a startup pattern map — editing it needs a
+#                      daemon restart. Unlike exhaustedPattern above (made hot by fleetd #446),
+#                      errorPattern was scoped out of that ticket on purpose and stays deferred.
 #                      # errorPattern: "503 Service Unavailable"   # opt-in: classify a backend outage
 #
 #                      What happens once a match fires (BackendOutagePolicy, credentialId-keyed,
@@ -468,9 +473,10 @@ placement: weighted
 # when the reload happens — not about how important the key is:
 #   HOT       → takes effect on the next spawn: the whole `fleet:` block (every role pool,
 #               `charters`, and `tabLabel`), `placement:`, and an existing profile's weight / maxLoad
-#               / credentialId. Those are hot because the placement policy (and, for credentialId,
-#               the CB-578 stage B quarantine check) reads them through a supplier — being config is
-#               not by itself enough to make a key hot.
+#               / credentialId / exhaustedPattern. Those are hot because the placement policy (and,
+#               for credentialId, the CB-578 stage B quarantine check; for exhaustedPattern, fleetd
+#               #446's LiveExhaustedPatterns) reads them through a supplier — being config is not by
+#               itself enough to make a key hot.
 #               EXCEPT `fleet.leaders`: Fleetd.main reads it once at startup to build the lead tab
 #               scanner and launcher, and neither is rebuilt on reload. A changed/added/removed
 #               `fleet.leaders` entry is silently accepted — the reload reports "config reloaded"
@@ -482,10 +488,10 @@ placement: weighted
 #               stage B — baked once into the quarantine tracker built at startup), ADDING or
 #               REMOVING a profile (a new backend needs its own launcher, and launchers are built
 #               once), AND an existing profile's launch settings — model, baseUrl, argv, env,
-#               configDir, mcpUrl, tabLabel, exhaustedPattern, errorPattern (fleetd #201 / #227 —
-#               compiled once into a startup pattern map the same way exhaustedPattern is). The
-#               launcher takes a copy of `profiles:` at startup and resolves every spawn out of
-#               that copy, so those never
+#               configDir, mcpUrl, tabLabel, errorPattern (fleetd #201 / #227 — compiled once into
+#               a startup pattern map; exhaustedPattern used to be compiled the same way until
+#               fleetd #446 made it hot — see above). The launcher takes a copy of `profiles:` at
+#               startup and resolves every spawn out of that copy, so those never
 #               reach a launch until you restart. The reload logs them by name rather than
 #               pretending they applied.
 #   COLD      → cannot change at all: `bind:`, `herdrSocket:`, `broker:` and `auth:`. The socket is

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

@@ -18,6 +18,7 @@ import dev.ltms.fleet.inject.BackendErrorSink;
 import dev.ltms.fleet.inject.CompletionResolver;
 import dev.ltms.fleet.inject.ExhaustedPatternLookup;
 import dev.ltms.fleet.inject.ExhaustionSink;
+import dev.ltms.fleet.inject.LiveExhaustedPatterns;
 import dev.ltms.fleet.inject.Injector;
 import dev.ltms.fleet.inject.StatusPoller;
 import dev.ltms.fleet.inject.TurnListener;
@@ -65,11 +66,13 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.TreeSet;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
@@ -78,6 +81,7 @@ import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 /**
  * {@code fleetd} entry point. Wires the real herdr socket client to the REST app and
@@ -378,28 +382,34 @@ public final class Fleetd {
         Rendezvous rendezvous = new Rendezvous();
         // CB-578 stage A: classify a completion-fallback scrape that matches a profile's configured
         // usage-limit refusal as BACKEND_EXHAUSTED rather than handing it back as a real answer.
-        // Compiled once at startup, keyed by profile name; a profile with no exhaustedPattern is
-        // simply absent here, so its workers keep today's completion-fallback behaviour unchanged.
-        Map<String, Pattern> exhaustedPatternsByProfile = new LinkedHashMap<>();
-        cfg.profiles().forEach((name, profile) -> {
-            if (profile.hasExhaustedPattern()) {
-                exhaustedPatternsByProfile.put(name, Pattern.compile(profile.exhaustedPattern()));
-            }
-        });
+        // fleetd #446: read live off `config` per lookup, cached by profile name — see
+        // LiveExhaustedPatterns's class doc for why this replaces the old compiled-once-at-startup
+        // map. A profile with no exhaustedPattern simply returns null here, so its workers keep
+        // today's completion-fallback behaviour unchanged.
+        LiveExhaustedPatterns liveExhaustedPatterns = new LiveExhaustedPatterns(() -> config.get().profiles());
         ExhaustedPatternLookup exhaustedPatterns = target -> sessions.roster().stream()
                 .filter(session -> target.equals(session.terminalId()))
                 .findFirst()
-                .map(session -> exhaustedPatternsByProfile.get(session.profile()))
+                .map(session -> liveExhaustedPatterns.patternFor(session.profile()))
                 .orElse(null);
+        // The startup coverage line still reports the boot-time snapshot only — it is printed once,
+        // here, and a reload no longer needs to change what it said; exhaustionDetectionArmed (via
+        // liveExhaustedPatterns.armed, wired into quarantineSource below) is what stays live.
+        Set<String> exhaustedConfiguredAtStartup = cfg.profiles().entrySet().stream()
+                .filter(e -> e.getValue().hasExhaustedPattern())
+                .map(Map.Entry::getKey)
+                .collect(Collectors.toCollection(LinkedHashSet::new));
         log.info("backend-exhausted classification (CB-578 stage A): {}",
-                exhaustedPatternCoverageLine(cfg.profiles().keySet(), exhaustedPatternsByProfile.keySet()));
+                exhaustedPatternCoverageLine(cfg.profiles().keySet(), exhaustedConfiguredAtStartup));
         // 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
-        // name, mirroring exhaustedPatternsByProfile above — a profile with no configured
-        // errorPattern is simply absent here, so CompletionResolver falls back to its built-in
-        // narrow {@code (?i)\bAPI Error\s*:} compatibility pattern for that profile's targets
-        // (BackendErrorPatternLookup#legacy's contract — see backendErrorPatterns below).
+        // rather than handing it back as a real answer. Still compiled once at startup, keyed by
+        // profile name — unlike exhaustedPattern above (fleetd #446), errorPattern was left DEFERRED
+        // on purpose: the ticket that made exhaustedPattern hot scoped errorPattern/cooling-off out
+        // explicitly. A profile with no configured errorPattern is simply absent here, so
+        // CompletionResolver falls back to its built-in narrow {@code (?i)\bAPI Error\s*:}
+        // compatibility pattern for that profile's targets (BackendErrorPatternLookup#legacy's
+        // contract — see backendErrorPatterns below).
         Map<String, Pattern> errorPatternsByProfile = new LinkedHashMap<>();
         cfg.profiles().forEach((name, profile) -> {
             if (profile.hasErrorPattern()) {
@@ -417,46 +427,20 @@ public final class Fleetd {
         // 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
         // the profile config live off `config`, so a credentialId edit is hot: no restart needed.
-        //
-        // fleetd #175: this sink is now also the quarantine target for OpenCodeLauncher's
-        // model-mismatch check — it needs nothing profile-specific from the caller beyond `target`
-        // (a herdr terminal id) and `reason`, so reusing it here is exactly "the existing
-        // ExhaustionSink path", not a new mechanism.
-        //
-        // fleetd #234: that check fires from SessionAwareHandle.agentSessionId(), which runs during
-        // SessionManager.acquire() BEFORE this session is registered in sessions.roster() — so the
-        // roster-only lookup below used to find nothing, .ifPresent silently no-op'd, and the
-        // ERROR the check had just logged ("quarantining this profile's credential") was a lie:
-        // nothing was quarantined, and nothing said so. Two changes: (1) OpenCodeLauncher now
-        // passes its OWN profile name via ExhaustionSink's 3-arg overload — it already has the
-        // FleetConfig.Profile in hand and does not need the roster at all — used here as a
-        // fallback whenever the roster lookup misses; (2) if a profile still cannot be resolved
-        // (neither the roster nor the hint names a configured one), this logs loudly at ERROR
-        // instead of silently doing nothing — a control that cannot act must say so.
-        // fleetd #234, round 4: the 3-arg overload is now ExhaustionSink's single abstract method,
-        // so this is safely a lambda — there is no separate 2-arg overload left for it to bind to
-        // instead and silently drop profileHint (that was rounds 1-3's whole hazard).
-        ExhaustionSink exhaustionSink = (target, reason, profileHint) -> {
-            String profileName = sessions.roster().stream()
-                    .filter(session -> target.equals(session.terminalId()))
-                    .findFirst()
-                    .map(MemberSession::profile)
-                    .orElse(profileHint);
-            FleetConfig.Profile profile = profileName == null ? null : config.get().profiles().get(profileName);
-            if (profile == null) {
-                log.error("quarantine requested for target '{}' ({}) but no profile could be "
-                                + "resolved — the target is not (yet) in the roster, and {} — "
-                                + "credential NOT quarantined (fleetd #234)",
-                        target, reason,
-                        profileHint == null ? "no profile hint was given"
-                                : "the hinted profile '" + profileHint + "' is not configured");
-                return;
-            }
-            String credentialId = profile.effectiveCredentialId();
-            quarantine.quarantine(credentialId);
-            log.warn("credential '{}' quarantined for {}s (profile '{}'): {}", credentialId,
-                    cfg.quarantineCooldownSeconds(), profile.profile(), reason);
-        };
+        // fleetd #446 criterion 3: the backend text that triggered the most recent quarantine of
+        // each credential, so fleet_profiles can report WHY a limit was hit, not only that it was.
+        // Keyed by credential id — the same key BackendQuarantine's own remainingSeconds uses —
+        // and written at the one call site that actually quarantines (inside exhaustionSink below),
+        // so a reason can never be reported for a quarantine that never happened. Bounded the same
+        // way BackendQuarantine's own internal map is documented to be: by the number of distinct
+        // credentials ever exhausted, not by how often the config is edited.
+        Map<String, String> quarantineReasonByCredential = new ConcurrentHashMap<>();
+        // fleetd #446 follow-up (round 3): extracted into exhaustionSink(...) below — see that
+        // method's javadoc for the full fleetd #175/#234/#446 history this used to carry inline —
+        // so a dedicated test can drive the exact ExhaustionSink main() builds, not a hand-rebuilt
+        // copy of its shape.
+        ExhaustionSink exhaustionSink = exhaustionSink(sessions, config, quarantine,
+                quarantineReasonByCredential, cfg);
         // fleetd #175: point the forwarding sink handed to OpenCodeLauncher above at the real one,
         // now that `sessions` exists to resolve target -> session -> profile.
         exhaustionSinkRef.set(exhaustionSink);
@@ -673,7 +657,7 @@ public final class Fleetd {
         // / BackendOutagePolicy would still be able to drift (e.g. a future edit to the credentialIdFor
         // closure in only one of the two places), exactly the shape #284 was.
         FleetMcp.QuarantineSource quarantineSource = quarantineSource(config, quarantine,
-                exhaustedPatternsByProfile);
+                liveExhaustedPatterns, quarantineReasonByCredential);
         FleetMcp.OutageSource outageSource = new FleetMcp.OutageSource(profile -> {
             var configured = config.get().profiles().get(profile);
             return configured == null ? null : configured.effectiveCredentialId();
@@ -805,16 +789,99 @@ public final class Fleetd {
     }
 
     /**
-     * fleetd #404: production source for quarantine reporting. Credential IDs are hot, but
-     * exhausted patterns are compiled once at startup for {@link CompletionResolver}, so the armed
-     * field must use that same compiled map until restart.
+     * fleetd #446 follow-up (round 3): the quarantine {@link ExhaustionSink} main() actually wires
+     * — extracted out of {@code main} for the same reason {@link #quarantineSource} below and
+     * {@link #usageLimitFixWarning}/{@link #usageLimitFixWarningNoModel} were. Round 2 pinned the
+     * WARNING text by having {@code FleetdUsageLimitFixWarningTest} call those two methods
+     * directly, but a mutation battery proved that left two gaps: nothing proved this sink's
+     * {@code log.warn} call actually uses either method (replacing the whole ternary with a
+     * literal string), and nothing proved it picks the right one for a profile WITH a configured
+     * {@code model:} versus one WITHOUT (swapping the ternary's two branches) — both mutations
+     * left round 2's full 1592-test suite green. {@code FleetdExhaustionSinkWarningTest} drives
+     * THIS factory's return value directly and asserts on the real text a {@code ListAppender}
+     * attached to this class's own logger captures — the only way to prove the caller, not just
+     * the two callees in isolation.
+     *
+     * <p>Behaviourally unchanged from the inline lambda this replaces:
+     * <ul>
+     *   <li>fleetd #175: also the quarantine target for {@code OpenCodeLauncher}'s model-mismatch
+     *       check — it needs nothing profile-specific beyond {@code target}/{@code reason}, so
+     *       reusing this sink is the existing {@code ExhaustionSink} path, not a new mechanism;</li>
+     *   <li>fleetd #234 (round 4): resolves {@code target} to a profile via the live session
+     *       roster first, falling back to {@code profileHint} — {@code
+     *       SessionAwareHandle.agentSessionId()} fires this sink during {@code
+     *       SessionManager.acquire()}, <em>before</em> that session is registered, so the
+     *       roster-only lookup alone used to silently miss it. A profile resolved neither way
+     *       logs loudly at ERROR instead of doing nothing;</li>
+     *   <li>fleetd #446 criterion 3: writes {@code quarantineReasonByCredential} at the one call
+     *       site that actually quarantines, keyed by credential id — see the field's declaration
+     *       in {@code main} for the bound on its size.</li>
+     * </ul>
+     *
+     * <p>{@code cfg} is the startup {@link FleetConfig} snapshot, read only for {@code
+     * quarantineCooldownSeconds()} in the log text — a Cold key (see {@code ConfigRef}'s class
+     * doc), so reading it off the snapshot rather than {@code config.get()} makes no observable
+     * difference and matches what the inline version already did.
+     */
+    static ExhaustionSink exhaustionSink(SessionManager sessions, ConfigRef config, BackendQuarantine quarantine,
+            Map<String, String> quarantineReasonByCredential, FleetConfig cfg) {
+        return (target, reason, profileHint) -> {
+            String profileName = sessions.roster().stream()
+                    .filter(session -> target.equals(session.terminalId()))
+                    .findFirst()
+                    .map(MemberSession::profile)
+                    .orElse(profileHint);
+            FleetConfig.Profile profile = profileName == null ? null : config.get().profiles().get(profileName);
+            if (profile == null) {
+                log.error("quarantine requested for target '{}' ({}) but no profile could be "
+                                + "resolved — the target is not (yet) in the roster, and {} — "
+                                + "credential NOT quarantined (fleetd #234)",
+                        target, reason,
+                        profileHint == null ? "no profile hint was given"
+                                : "the hinted profile '" + profileHint + "' is not configured");
+                return;
+            }
+            String credentialId = profile.effectiveCredentialId();
+            quarantine.quarantine(credentialId);
+            quarantineReasonByCredential.put(credentialId, reason);
+            log.warn("credential '{}' quarantined for {}s (profile '{}'): {}", credentialId,
+                    cfg.quarantineCooldownSeconds(), profile.profile(), reason);
+            // fleetd #446 criterion 2: name the fix, not just the fact — an operator reading this
+            // should not have to work out which of several configured models to touch.
+            String model = profile.model();
+            log.warn(model != null && !model.isBlank()
+                    ? usageLimitFixWarning(profile.profile(), model)
+                    : usageLimitFixWarningNoModel(profile.profile(), cfg.quarantineCooldownSeconds()));
+        };
+    }
+
+    /**
+     * fleetd #404, superseded by fleetd #446: production source for quarantine reporting.
+     * Credential IDs were already hot; {@code exhaustedPattern} used to be compiled once at
+     * startup for {@link CompletionResolver}, so the armed field had to read that same frozen map
+     * until restart — the exact asymmetry #446 exists to close. Both {@code exhaustedPatternArmed}
+     * here and {@link CompletionResolver}'s own classification now read the ONE live {@link
+     * LiveExhaustedPatterns} instance ({@code exhaustedPatterns.armed}/{@code .patternFor}), so a
+     * reload that arms or disarms a profile's detection is visible to both at once — never two
+     * independently-updated copies that could disagree, the fleetd #404 rule this method used to
+     * violate on purpose and now upholds.
+     *
+     * <p>{@code modelFor} and {@code reasonFor} back fleetd #446 criterion 3 — {@code
+     * fleet_profiles}'s quarantined row naming which model a quarantined profile runs
+     * ({@code modelFor}, read live off {@code config} the same way {@code credentialIdFor} already
+     * is) and the backend text that triggered the most recent quarantine of that credential
+     * ({@code reasonFor}, backed by {@code reasonByCredential} — see its call site in {@code main}
+     * for where that map is written, at the one place a credential is actually quarantined).
      */
     static FleetMcp.QuarantineSource quarantineSource(ConfigRef config, BackendQuarantine quarantine,
-            Map<String, Pattern> startupExhaustedPatterns) {
+            LiveExhaustedPatterns exhaustedPatterns, Map<String, String> reasonByCredential) {
         return new FleetMcp.QuarantineSource(profile -> {
             var configured = config.get().profiles().get(profile);
             return configured == null ? null : configured.effectiveCredentialId();
-        }, quarantine, profile -> startupExhaustedPatterns.containsKey(profile));
+        }, quarantine, exhaustedPatterns::armed, profile -> {
+            var configured = config.get().profiles().get(profile);
+            return configured == null ? null : configured.model();
+        }, reasonByCredential::get);
     }
 
     /**
@@ -833,6 +900,40 @@ public final class Fleetd {
      * with 0 errors and left all 1506 existing tests green before {@code
      * FleetdPatternCoverageLineTest} was added to catch exactly that swap.
      */
+    /**
+     * fleetd #446 follow-up: the criterion-2 WARNING text — "name the fix, not just the fact" —
+     * for a profile whose {@code model:} is configured. Extracted out of the {@code
+     * exhaustionSink} lambda the same way {@link #exhaustedPatternCoverageLine} was extracted out
+     * of {@code main}: the inline version compiled, ran, and read correctly, but nothing pinned
+     * its text, so a later edit could silently stop naming the fix and every test would stay
+     * green (measured: renaming the leading {@code "usage-limit fix:"} tag left all 1586
+     * pre-follow-up tests passing). {@link FleetdUsageLimitFixWarningTest} asserts on the return
+     * value of this method directly, which is exactly what the caller logs — {@code log.warn} is
+     * called with this method's result as a single, already-formatted argument, so the string a
+     * test sees here is byte-identical to what {@code fleetd.out} receives.
+     *
+     * <p>Deliberately asserts on three substrings, not the whole sentence (the profile name, the
+     * model name, and the literal {@code enabled: false} / {@code models.allow} action) — see that
+     * test's class doc for why a whole-sentence pin is the wrong granularity here.
+     */
+    static String usageLimitFixWarning(String profile, String model) {
+        return "usage-limit fix: profile '" + profile + "' runs model '" + model + "' — set "
+                + "`enabled: false` on that model's entry under models.allow in fleetd.yaml to "
+                + "stop new spawns landing on it (models: is hot, no restart needed); remove the "
+                + "line again once the subscription window resets";
+    }
+
+    /**
+     * fleetd #446 follow-up: the {@link #usageLimitFixWarning} counterpart for a profile with no
+     * {@code model:} configured — {@code models.allow} gates by model name, so there is nothing
+     * for an operator to flip, and this says so instead of naming a fix that does not exist.
+     */
+    static String usageLimitFixWarningNoModel(String profile, Integer quarantineCooldownSeconds) {
+        return "usage-limit fix: profile '" + profile + "' has no model: configured, so "
+                + "models.allow cannot gate it by name — the " + quarantineCooldownSeconds
+                + "s quarantine above is the only thing keeping new spawns off it for now";
+    }
+
     static String exhaustedPatternCoverageLine(Set<String> allProfiles, Set<String> configuredProfiles) {
         return CompletionResolver.coverage("exhaustedPattern", CompletionResolver.UnsetMeaning.OFF,
                 allProfiles, configuredProfiles);

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

@@ -51,7 +51,17 @@ import java.util.function.Supplier;
  *       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>
+ *       to report; it moved here from deferred rather than joining split. An existing profile's
+ *       {@code exhaustedPattern} (fleetd #446) joined this class the same way: it used to be
+ *       compiled once into {@code Fleetd.main}'s startup pattern map (see the Deferred bullet's old
+ *       wording, and {@code LiveExhaustedPatterns}'s class doc for the history), and is now read
+ *       live, cached by profile name, by both {@code CompletionResolver}'s classification (via
+ *       {@code LiveExhaustedPatterns.patternFor}) and {@code fleet_profiles}'s {@code
+ *       exhaustionDetectionArmed} (via {@code LiveExhaustedPatterns.armed}) — the one live object
+ *       both read, so a reload that arms or disarms a profile's usage-limit detection takes effect
+ *       on the next check with no restart. {@code errorPattern}, {@code exhaustedPattern}'s sibling
+ *       key for backend-error (not usage-limit) classification, was deliberately left OUT of this
+ *       fleetd #446 change and stays deferred below — the ticket scoped it out explicitly.</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
@@ -81,15 +91,17 @@ import java.util.function.Supplier;
  *       (if any) simply keeps its old settings), adding or removing a profile (a new backend needs its own launcher,
  *       which is constructed once), <em>and an existing profile's launch settings</em> —
  *       {@code model}, {@code baseUrl}, {@code argv}, {@code env}, {@code mcpUrl},
- *       {@code exhaustedPattern} (CB-578 stage A — compiled once into {@code Fleetd.main}'s
- *       pattern map at startup), {@code errorPattern} (fleetd #201 Unit 5 — compiled once into
- *       {@code Fleetd.main}'s backend-error pattern map at startup, the same way),
+ *       {@code errorPattern} (fleetd #201 Unit 5 — compiled once into
+ *       {@code Fleetd.main}'s backend-error pattern map at startup; deliberately NOT made hot
+ *       alongside {@code exhaustedPattern} by fleetd #446 — that ticket scoped {@code errorPattern}
+ *       and cooling-off out explicitly),
  *       {@code ideProjectDir} / {@code ideOpenCommand} / {@code autoCompactWindow} (fleetd #323
  *       instance 1 — all three are read at spawn off the same frozen profile map and were missing
  *       from {@link #sameLaunchSettings}), and the rest of {@link #sameLaunchSettings}.
- *       {@code credentialId} (CB-578 stage B) is NOT on
- *       this list — it is read live off the config supplier at every quarantine check and
- *       exhaustion event, exactly like {@code weight} / {@code maxLoad}, so it is hot instead.
+ *       {@code credentialId} (CB-578 stage B) and {@code exhaustedPattern} (fleetd #446) are NOT on
+ *       this list — both are read live off the config supplier at every quarantine check and
+ *       exhaustion event, exactly like {@code weight} / {@code maxLoad}, so both are hot instead
+ *       (see the Hot bullet above for {@code exhaustedPattern}'s history).
  *       {@code HerdrPeerLauncher} takes {@code Map.copyOf(profiles)} at construction and resolves
  *       each spawn out of that copy, so those never reach a launch until the daemon restarts. A
  *       reload logs these rather than pretending they applied.</li>
@@ -583,12 +595,16 @@ public final class ConfigRef implements Supplier<FleetConfig> {
      * {@link #sameLaunchSettings} because they are read <em>live</em>, not baked in at spawn — see
      * the class doc's <em>Hot</em> bullet. {@code weight} and {@code maxLoad} are read live by the
      * placement policy on every spawn; {@code credentialId} is read live by
-     * {@code CompositePeerLauncher} and the CB-578 stage B exhaustion sink. Nothing else is
+     * {@code CompositePeerLauncher} and the CB-578 stage B exhaustion sink; {@code exhaustedPattern}
+     * (fleetd #446) is read live, cached by profile name, by {@code LiveExhaustedPatterns} — see
+     * that class's doc and the class doc's <em>Hot</em> bullet for the history (it used to be
+     * compared here, deferred, like its sibling {@code errorPattern} still is). Nothing else is
      * excluded — see {@code sameLaunchSettingsComparesEveryProfileComponentOrExcludesIt} in
      * {@code ConfigRefProfileCoverageTest}, which enumerates every {@code Profile} record component
      * by reflection and fails the build if one is neither compared below nor named here.
      */
-    static final Set<String> LAUNCH_SETTINGS_EXCLUDED = Set.of("weight", "maxLoad", "credentialId");
+    static final Set<String> LAUNCH_SETTINGS_EXCLUDED =
+            Set.of("weight", "maxLoad", "credentialId", "exhaustedPattern");
 
     /**
      * Whether two versions of a profile would launch a peer identically.
@@ -625,13 +641,15 @@ public final class ConfigRef implements Supplier<FleetConfig> {
                 && Objects.equals(a.kind(), b.kind())
                 && Objects.equals(a.env(), b.env())
                 && Objects.equals(a.subscription(), b.subscription())
-                // CB-578 stage B: exhaustedPattern is compiled once into Fleetd.main's pattern map
-                // at startup (see ExhaustedPatternLookup wiring) — a reload never re-reads it, so a
-                // changed pattern must be reported as deferred, exactly like model/baseUrl/argv.
-                && Objects.equals(a.exhaustedPattern(), b.exhaustedPattern())
+                // fleetd #446: exhaustedPattern moved to LAUNCH_SETTINGS_EXCLUDED — it is now read
+                // live, cached by profile name, through LiveExhaustedPatterns (see that class's doc
+                // and ConfigRef's class doc Hot bullet), so it must NOT be compared here any more: a
+                // reload that changes only exhaustedPattern must report "config reloaded", not
+                // "these changes need a restart".
                 // fleetd #201 Unit 5: errorPattern is compiled once into Fleetd.main's backend-error
-                // pattern map at startup (see BackendErrorPatternLookup wiring), the same way
-                // exhaustedPattern is — a reload never re-reads it either.
+                // pattern map at startup (see BackendErrorPatternLookup wiring) — unlike its sibling
+                // exhaustedPattern above (fleetd #446), a reload still never re-reads it; fleetd #446
+                // scoped errorPattern out on purpose (see the class doc's Hot bullet).
                 && Objects.equals(a.errorPattern(), b.errorPattern())
                 // fleetd #323 instance 1: ideProjectDir and ideOpenCommand are read at spawn off the
                 // same frozen profile map as ideMcpUrl above (ClaudeCodeLauncher.java:267/269,

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

@@ -424,6 +424,12 @@ public record FleetConfig(
      *                       {@code null}/blank ⇒ the classification never fires for this profile and
      *                       today's completion-fallback behaviour is unchanged. Every backend words
      *                       its refusal differently, so this is config, never a vendor string in code.
+     *                       Read live off the current config through {@code LiveExhaustedPatterns},
+     *                       cached by profile name (fleetd #446), so it is HOT: an operator can arm
+     *                       or disarm this profile's usage-limit detection by editing this key and
+     *                       reloading, with no restart. Before fleetd #446 this was compiled once at
+     *                       daemon startup, the same deferred shape its sibling {@code errorPattern}
+     *                       (below) still has.
      * @param credentialId   the shared account this profile authenticates as (CB-578 stage B). Two
      *                       or more profiles setting the <em>same</em> non-blank value are quarantined
      *                       together by one {@code exhaustedPattern} classification on any one of

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

@@ -0,0 +1,91 @@
+package dev.ltms.fleet.inject;
+
+import dev.ltms.fleet.config.FleetConfig;
+
+import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Supplier;
+import java.util.regex.Pattern;
+
+/**
+ * fleetd #446: the single live source for "is {@code exhaustedPattern} configured for this
+ * profile, and what does it compile to". Read fresh off the config supplier on every call — the
+ * same reason {@code CompositePeerLauncher#models0} is a live supplier read rather than a value
+ * captured at construction (see that class's doc) — so an operator can arm or disarm usage-limit
+ * detection for a profile by editing {@code exhaustedPattern} and reloading, with no restart.
+ *
+ * <p>Before this class, {@code exhaustedPattern} was compiled once into a {@code Map<String,
+ * Pattern>} built inside {@code Fleetd.main} at startup ({@code ConfigRef}'s class doc used to
+ * list it under <em>Deferred</em>, CB-578 stage A) — the asymmetry fleetd #446 exists to close:
+ * an operator could turn a model off at runtime ({@code models.allow}'s {@code enabled: false},
+ * hot since fleetd #422) but could not arm the detector that would tell them to, without a
+ * restart. That was backwards for a feature whose whole point is to react while the fleet runs.
+ *
+ * <p>{@link #patternFor} is what {@link CompletionResolver} enforces on (via the {@link
+ * ExhaustedPatternLookup} production wiring in {@code Fleetd.main}); {@link #armed} is what
+ * {@code fleet_profiles}/{@code GET /profiles} report as {@code exhaustionDetectionArmed}. Both
+ * read this ONE object, so the report can never disagree with the behaviour — the same rule
+ * {@code CompositePeerLauncher#modelGateState()}'s javadoc states for the model gate's own
+ * armed/off pair (fleetd #404): "armed" and "which models are off" must come from one read of the
+ * same accessor the gate enforces on.
+ *
+ * <h2>Cache eviction</h2>
+ * Cached by profile NAME, not by pattern text. A {@code Map<String, Pattern>} keyed by the
+ * pattern STRING would grow by one entry per distinct regex ever typed for any profile across the
+ * daemon's uptime — unbounded in practice, because tuning a regex to match a backend's exact
+ * wording is exactly the kind of edit an operator makes several times while getting it right, and
+ * every edit-and-reload cycle would leave the previous attempt's compiled {@link Pattern} behind
+ * forever. Keyed by profile name instead, this cache holds at most one entry per profile name that
+ * has ever been looked up — and that key space is bounded by the (small, human-authored) set of
+ * configured profiles, which changes only on a restart: adding or removing a profile is itself a
+ * deferred key (a new backend needs its own launcher, built once — see {@code ConfigRef}'s class
+ * doc), so profile names do not churn the way pattern text does. Re-editing an EXISTING profile's
+ * {@code exhaustedPattern} — the case this class exists to make hot — simply overwrites that
+ * profile's one cache entry; it never adds a new one.
+ */
+public final class LiveExhaustedPatterns {
+
+    /** A compiled pattern paired with the source string it was compiled from, for change detection. */
+    private record Cached(String source, Pattern compiled) {
+    }
+
+    private final Supplier<Map<String, FleetConfig.Profile>> profiles;
+    private final ConcurrentHashMap<String, Cached> cache = new ConcurrentHashMap<>();
+
+    public LiveExhaustedPatterns(Supplier<Map<String, FleetConfig.Profile>> profiles) {
+        this.profiles = Objects.requireNonNull(profiles, "profiles");
+    }
+
+    /**
+     * The compiled {@code exhaustedPattern} currently configured for {@code profileName}, or
+     * {@code null} when that profile is unknown or has none configured. Recompiles only when the
+     * live pattern text differs from what is cached for this profile name; {@code
+     * FleetConfig#rejectMalformedProfilePatterns} already refuses a config (at load and at reload)
+     * whose {@code exhaustedPattern} does not compile, so this is not expected to throw in
+     * production — it is not defended against here for that reason, the same trust
+     * {@code CompositePeerLauncher#models0} places in config validation having already run.
+     */
+    public Pattern patternFor(String profileName) {
+        if (profileName == null) {
+            return null;
+        }
+        FleetConfig.Profile profile = profiles.get().get(profileName);
+        if (profile == null || !profile.hasExhaustedPattern()) {
+            return null;
+        }
+        String source = profile.exhaustedPattern();
+        Cached cached = cache.get(profileName);
+        if (cached != null && cached.source().equals(source)) {
+            return cached.compiled();
+        }
+        Cached fresh = new Cached(source, Pattern.compile(source));
+        cache.put(profileName, fresh);
+        return fresh.compiled();
+    }
+
+    /** Whether {@code profileName} currently has a usage-limit pattern configured (live). */
+    public boolean armed(String profileName) {
+        return patternFor(profileName) != null;
+    }
+}

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

@@ -121,17 +121,46 @@ public final class FleetMcp {
      * CB-578 stage B quarantine facts used by {@code fleet_profiles}: a profile → credential id
      * lookup, plus the shared {@link BackendQuarantine} to read remaining cooldowns off.
      *
-     * @param exhaustedPatternArmed fleetd #395: profile → whether that profile's {@code
-     *                      exhaustedPattern} is configured (see {@code
+     * @param exhaustedPatternArmed fleetd #395, made live by fleetd #446: profile → whether that
+     *                      profile's {@code exhaustedPattern} is configured right now (see {@code
      *                      FleetConfig.Profile#hasExhaustedPattern}), i.e. whether a backend refusal
      *                      on it can EVER be classified {@code BACKEND_EXHAUSTED} and quarantine its
      *                      credential. Bundled here, not a separate Source, because it answers the
      *                      exact question {@code fleet_profiles}'s quarantine facts already answer
      *                      for a QUARANTINED profile — "can this profile's usage limit ever be
-     *                      caught?" — just for every profile, not only one currently caught.
+     *                      caught?" — just for every profile, not only one currently caught. In
+     *                      production this reads {@link dev.ltms.fleet.inject.LiveExhaustedPatterns#armed} —
+     *                      the SAME live accessor {@link dev.ltms.fleet.inject.CompletionResolver}
+     *                      enforces on — so a reload that arms or disarms detection is reported
+     *                      correctly on the very next call, no restart (see that class's doc).
+     * @param modelFor      fleetd #446 criterion 3: profile → the {@code model:} it runs, or
+     *                      {@code null} when the profile names none. Read live off the current
+     *                      config, the same way {@code credentialIdFor} already is. Used to name,
+     *                      in a QUARANTINED profile's row, which of the operator's configured models
+     *                      the fix (\"set {@code enabled: false} on it under {@code models.allow}\")
+     *                      actually applies to.
+     * @param reasonFor     fleetd #446 criterion 3: credential id → the backend text that triggered
+     *                      its most recent quarantine, or {@code null} when none is known (e.g. an
+     *                      inert source, or a quarantine recorded before this field existed). Never
+     *                      consulted on its own to decide whether a credential is quarantined —
+     *                      callers gate on {@link BackendQuarantine#remainingSeconds} first, exactly
+     *                      like {@code credentialId} itself, so a stale reason left behind after a
+     *                      quarantine expires is never surfaced.
      */
     public record QuarantineSource(Function<String, String> credentialIdFor, BackendQuarantine quarantine,
-                                    Function<String, Boolean> exhaustedPatternArmed) {
+                                    Function<String, Boolean> exhaustedPatternArmed,
+                                    Function<String, String> modelFor,
+                                    Function<String, String> reasonFor) {
+        /**
+         * Backward-compatible 3-arg form, before fleetd #446 added {@code modelFor}/{@code
+         * reasonFor} — neither is ever reported. Keeps every pre-existing call site (production and
+         * test) compiling and behaving identically for the quarantine facts they actually asked for.
+         */
+        public QuarantineSource(Function<String, String> credentialIdFor, BackendQuarantine quarantine,
+                                 Function<String, Boolean> exhaustedPatternArmed) {
+            this(credentialIdFor, quarantine, exhaustedPatternArmed, _ -> null, _ -> null);
+        }
+
         /**
          * Backward-compatible 2-arg form, before fleetd #395 added {@code exhaustedPatternArmed} —
          * reports every profile unarmed. Keeps every pre-existing call site (production and test)
@@ -1210,13 +1239,21 @@ public final class FleetMcp {
      * #284 was, where one rule computed in two places was widened in only one and a single response
      * contradicted itself. Shared inputs do not make duplicated computation safe.
      *
-     * <p>fleetd #395: also reports {@code exhaustionDetectionArmed}, one boolean per configured
-     * profile — {@code true} when that profile's {@code exhaustedPattern} is set, {@code false}
-     * when it is not, so an operator can tell "this profile is healthy" from "nothing can ever
-     * quarantine this profile" without reading {@code fleetd.yaml}. Unlike {@code quarantined}/
-     * {@code coolingOff}, this map always names every profile: an unarmed profile never enters a
-     * transient state to be absent from, so silence here would read as "healthy" rather than "not
-     * being watched at all".
+     * <p>fleetd #395, made live by fleetd #446: also reports {@code exhaustionDetectionArmed}, one
+     * boolean per configured profile — {@code true} when that profile's {@code exhaustedPattern} is
+     * set RIGHT NOW, {@code false} when it is not, so an operator can tell "this profile is
+     * healthy" from "nothing can ever quarantine this profile" without reading {@code fleetd.yaml}.
+     * Unlike {@code quarantined}/{@code coolingOff}, this map always names every profile: an
+     * unarmed profile never enters a transient state to be absent from, so silence here would read
+     * as "healthy" rather than "not being watched at all". Hot since fleetd #446: a reload that
+     * arms or disarms a profile's {@code exhaustedPattern} changes this map's answer on the very
+     * next call, no restart — see {@link dev.ltms.fleet.inject.LiveExhaustedPatterns}'s class doc.
+     *
+     * <p>fleetd #446 criterion 3: each {@code quarantined} row also names {@code model} (the
+     * profile's configured {@code model:}, omitted when the profile names none) and {@code reason}
+     * (the backend text that triggered the most recent quarantine of that credential, omitted when
+     * none is known) — so a lead can see WHICH model to turn off and WHY, without reading the
+     * daemon log.
      */
     public static Map<String, Object> profilesView(PeerLauncher workers, QuarantineSource quarantine, OutageSource outage) {
         Map<String, Object> result = new LinkedHashMap<>();
@@ -1233,6 +1270,14 @@ public final class FleetMcp {
                     Map<String, Object> row = new LinkedHashMap<>();
                     row.put("credentialId", credentialId);
                     row.put("quarantinedForSeconds", remaining);
+                    String model = quarantine.modelFor().apply(profile);
+                    if (model != null && !model.isBlank()) {
+                        row.put("model", model);
+                    }
+                    String reason = quarantine.reasonFor().apply(credentialId);
+                    if (reason != null && !reason.isBlank()) {
+                        row.put("reason", reason);
+                    }
                     quarantined.put(profile, row);
                 });
             }
@@ -1815,11 +1860,16 @@ public final class FleetMcp {
                 "List the configured worker profiles (backends) and which one fleet_spawn uses by "
                         + "default. A 'quarantined' map is present when a backend-exhausted refusal put "
                         + "a profile's credential on cooldown — fleet_spawn onto it is refused until "
-                        + "quarantinedForSeconds elapses; a profile sharing that credential is listed too. "
+                        + "quarantinedForSeconds elapses; a profile sharing that credential is listed too, "
+                        + "each row naming 'model' (the model that profile runs, when configured) and "
+                        + "'reason' (the backend text that triggered the quarantine, when known) — the fix "
+                        + "is usually `enabled: false` on that model under models.allow. "
                         + "'exhaustionDetectionArmed' reports, per profile, whether a usage-limit refusal "
                         + "on it can EVER be classified and quarantined (its exhaustedPattern is "
                         + "configured) — false means that profile's credential can never be quarantined "
-                        + "by this mechanism, however many usage-limit refusals it sees.",
+                        + "by this mechanism, however many usage-limit refusals it sees. Both "
+                        + "exhaustedPattern and models.allow's on/off state are hot: editing fleetd.yaml "
+                        + "and reloading arms/disarms detection or flips a model off with no restart.",
                 objectSchema(Map.of(), List.of()));
     }
 

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

@@ -2,6 +2,7 @@ package dev.ltms.fleet;
 
 import dev.ltms.fleet.config.ConfigRef;
 import dev.ltms.fleet.config.FleetConfig;
+import dev.ltms.fleet.inject.LiveExhaustedPatterns;
 import dev.ltms.fleet.mcp.FleetMcp;
 import dev.ltms.fleet.placement.BackendQuarantine;
 import org.junit.jupiter.api.DisplayName;
@@ -11,16 +12,31 @@ import org.junit.jupiter.api.io.TempDir;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Map;
-import java.util.regex.Pattern;
+
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
- * fleetd #404: {@code exhaustionDetectionArmed} must describe the startup pattern map, not the
- * reloaded config snapshot.
+ * fleetd #446: {@code exhaustionDetectionArmed} must describe the LIVE config, not a startup
+ * snapshot — the opposite of what fleetd #404 asked for. #404 pinned {@code exhaustedPattern} as
+ * compiled once at startup (matching {@code CompletionResolver}'s then-frozen behaviour); #446's
+ * whole point is that both sides — the classification {@code CompletionResolver} enforces and the
+ * {@code exhaustionDetectionArmed} field this reports — now read the SAME live {@link
+ * LiveExhaustedPatterns} instance, so a reload arms or disarms detection with no restart, and the
+ * report can never disagree with the behaviour (the fleetd #404 rule, now upheld for real instead
+ * of by freezing both sides).
  *
  * <p>This test needs a reload. At startup the two snapshots agree, so a test of only a newly
  * started daemon would not detect a live {@code config.get()} lookup in the report field.
+ *
+ * <p><b>The hotness proof criterion 1 demands:</b> run this against the fixed code (green) and
+ * against the pre-#446 compile site — {@code Fleetd.main}'s {@code exhaustedPatternsByProfile}
+ * compiled once into a {@code Map<String, Pattern>} at startup, handed to {@code quarantineSource}
+ * — and show it fails there. See the class doc history above: that shape is exactly what
+ * {@code reloadedPatternArmsDetectionWithNoRestart} below is written to catch, and it is the test
+ * that used to assert the opposite (see git history for this file's pre-#446 version, which
+ * asserted {@code assertFalse(...)} on the identical scenario this now asserts {@code assertTrue}
+ * on).
  */
 class FleetdExhaustionDetectionArmedWiringTest {
 
@@ -54,41 +70,68 @@ class FleetdExhaustionDetectionArmedWiringTest {
             """;
 
     @Test
-    @DisplayName("reloading an exhaustedPattern does not arm the startup detection source")
-    void reloadedPatternDoesNotChangeTheArmedFieldUntilRestart(@TempDir Path dir) throws Exception {
+    @DisplayName("reloading a profile's exhaustedPattern IN arms exhaustionDetectionArmed, no restart")
+    void reloadedPatternArmsDetectionWithNoRestart(@TempDir Path dir) throws Exception {
         Path file = dir.resolve("fleetd.yaml");
         Files.writeString(file, NO_PATTERN);
         ConfigRef config = new ConfigRef(file, FleetConfig.load(file));
 
+        FleetMcp.QuarantineSource before = Fleetd.quarantineSource(config, BackendQuarantine.none(),
+                new LiveExhaustedPatterns(() -> config.get().profiles()), Map.of());
+        assertFalse(before.exhaustedPatternArmed().apply("terra"),
+                "no exhaustedPattern configured yet — must report unarmed");
+
         Files.writeString(file, WITH_PATTERN);
         assertTrue(config.reload().applied());
         assertTrue(config.get().profiles().get("terra").hasExhaustedPattern());
 
-        FleetMcp.QuarantineSource source = Fleetd.quarantineSource(config, BackendQuarantine.none(),
-                Map.of());
-        assertFalse(source.exhaustedPatternArmed().apply("terra"),
-                "exhaustionDetectionArmed must use the startup pattern map, not config.get()");
+        // Re-read exhaustedPatternArmed off the SAME QuarantineSource built BEFORE the reload — no
+        // new object, no new wiring — to prove the field itself is live, not merely that a freshly
+        // built source would be. This is the exact axis the pre-#446 code fails on: the same
+        // Function<String,Boolean> lambda, called again after a reload, sees the new answer only if
+        // it re-reads config.get() on every call rather than a value captured earlier.
+        assertTrue(before.exhaustedPatternArmed().apply("terra"),
+                "exhaustionDetectionArmed must read the LIVE config on every call — fleetd #446 made "
+                        + "this hot; it must reflect a reload with no restart and no new QuarantineSource");
     }
 
     @Test
-    @DisplayName("a profile in the startup pattern map is reported as armed")
-    void aProfileInTheStartupMapIsArmed(@TempDir Path dir) throws Exception {
-        // fleetd #404, second direction. The test above only ever passes an EMPTY startup map, so
-        // it cannot tell a correct lookup from one that is permanently off. Measured: replacing the
-        // armed lambda with `profile -> false` left the whole suite green at 1475 tests. That
-        // mutation would make #395's visibility feature dead — an operator fixing a detection gap
-        // would be told the gap is still open after fixing it, forever. Both directions are needed:
-        // this test is the only thing that fails when the field stops reporting armed at all.
+    @DisplayName("reloading exhaustedPattern OUT disarms exhaustionDetectionArmed, no restart")
+    void reloadedPatternRemovalDisarmsDetectionWithNoRestart(@TempDir Path dir) throws Exception {
         Path file = dir.resolve("fleetd.yaml");
         Files.writeString(file, WITH_PATTERN);
         ConfigRef config = new ConfigRef(file, FleetConfig.load(file));
 
         FleetMcp.QuarantineSource source = Fleetd.quarantineSource(config, BackendQuarantine.none(),
-                Map.of("terra", Pattern.compile("usage limit")));
+                new LiveExhaustedPatterns(() -> config.get().profiles()), Map.of());
+        assertTrue(source.exhaustedPatternArmed().apply("terra"),
+                "exhaustedPattern is configured from the start — must report armed");
+
+        Files.writeString(file, NO_PATTERN);
+        assertTrue(config.reload().applied());
+
+        assertFalse(source.exhaustedPatternArmed().apply("terra"),
+                "removing exhaustedPattern and reloading must disarm detection with no restart — an "
+                        + "operator turning detection off (e.g. while debugging a false positive) "
+                        + "must see that reflected immediately, exactly like arming it is");
+    }
+
+    @Test
+    @DisplayName("a profile with no exhaustedPattern configured is reported unarmed")
+    void aProfileWithNoPatternIsUnarmed(@TempDir Path dir) throws Exception {
+        // fleetd #404's second direction, carried forward: this test alone fails if
+        // exhaustedPatternArmed degenerates to a constant `profile -> true` — it needs at least one
+        // profile that is genuinely unarmed to catch that.
+        Path file = dir.resolve("fleetd.yaml");
+        Files.writeString(file, WITH_PATTERN);
+        ConfigRef config = new ConfigRef(file, FleetConfig.load(file));
+
+        FleetMcp.QuarantineSource source = Fleetd.quarantineSource(config, BackendQuarantine.none(),
+                new LiveExhaustedPatterns(() -> config.get().profiles()), Map.of());
 
         assertTrue(source.exhaustedPatternArmed().apply("terra"),
-                "a profile whose pattern was compiled at startup must report armed");
+                "a profile whose exhaustedPattern is configured must report armed");
         assertFalse(source.exhaustedPatternArmed().apply("sonnet"),
-                "a profile absent from the startup map must not report armed");
+                "a profile absent from config entirely must not report armed");
     }
 }

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

@@ -0,0 +1,175 @@
+package dev.ltms.fleet;
+
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
+import dev.ltms.fleet.config.ConfigRef;
+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.inject.ExhaustionSink;
+import dev.ltms.fleet.member.ClaudeCodeLauncher;
+import dev.ltms.fleet.placement.BackendQuarantine;
+import dev.ltms.fleet.session.SessionManager;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+import org.slf4j.LoggerFactory;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #446 follow-up (round 3): round 2's {@link FleetdUsageLimitFixWarningTest} calls {@link
+ * Fleetd#usageLimitFixWarning}/{@link Fleetd#usageLimitFixWarningNoModel} directly, which pins
+ * the two methods' TEXT but cannot see whether {@link Fleetd#exhaustionSink}'s {@code log.warn}
+ * call actually invokes either one, or invokes the right one. A mutation battery run against
+ * round 2's merge (1592 green tests) proved both gaps real:
+ *
+ * <ul>
+ *   <li><b>Cell A</b> — replacing the whole ternary result with a literal string
+ *       ({@code "usage-limit fix: MUTANT"}) left every test green;</li>
+ *   <li><b>Cell B</b> — swapping the ternary's two branches, so a profile WITH a {@code model:}
+ *       gets the no-model fallback message and vice versa, was measured unmeasured by the lead
+ *       but the existing test file shows no call that would notice it either.</li>
+ * </ul>
+ *
+ * <p>This class drives {@link Fleetd#exhaustionSink} — the actual factory {@code main} wires,
+ * since round 3's extraction pulled it out of the inline lambda for exactly this reason — and
+ * asserts on the REAL text a {@link ListAppender} attached to {@code Fleetd}'s own logger
+ * captures, mirroring {@code ExhaustedPatternGapReportTest}'s idiom. Chosen over a source-text
+ * assertion (the {@code FleetMcpAuthzTest} {@code everyRegisteredToolHasItsHandlerActionPinned}
+ * idiom) because that route can prove Cell A (the ternary is still there, still built from the
+ * two named methods) but not Cell B (which branch a given profile actually reaches) — this route
+ * answers both from one mechanism, since it reads what the sink actually logged for each shape of
+ * profile.
+ *
+ * <p>Each test filters for the WARN line starting {@code "usage-limit fix:"} specifically — {@link
+ * Fleetd#exhaustionSink} also logs a separate {@code "credential '...' quarantined for..."} WARN
+ * on every call, and asserting against the wrong one would pass or fail for the wrong reason. That
+ * prefix survives even under the M5 mutation above (the mutant keeps the tag, only the body
+ * becomes {@code "MUTANT"}), so the filter itself is not what either mutation defeats.
+ */
+class FleetdExhaustionSinkWarningTest {
+
+    private static final String YAML = """
+            bind:
+              host: 127.0.0.1
+              port: 8765
+            herdrSocket: ~/.config/herdr/herdr.sock
+            profiles:
+              terra:
+                baseUrl: http://gx00.gw:8000
+                model: claude-opus-5
+              gx:
+                baseUrl: http://gx00.gw:8000
+            guard:
+              offSubscriptionHosts:
+                - gx00.gw
+            """;
+
+    private static SessionManager emptyRosterSessions() {
+        FakeHerdr h = new FakeHerdr();
+        FleetConfig.Profile dummy = new FleetConfig.Profile(
+                "dummy", "http://gx00.gw:8000", "coder", null, "FLEETD_WORKER_TOKEN", null,
+                "tab", "fleetd-workers", "worker: {profile} #{n}", null, null, null);
+        ClaudeCodeLauncher launcher = new ClaudeCodeLauncher(new AgentControl(h), new WorkspaceControl(h),
+                new SubscriptionGuard(Set.of("gx00.gw")), Map.of(dummy.profile(), dummy), dummy.profile(), _ -> "tok");
+        // Never acquires a session — exhaustionSink's roster lookup is expected to miss and fall
+        // back to the profileHint argument, exactly like OpenCodeLauncher's real call site does
+        // (fleetd #234) — so the sink under test never needs a populated roster.
+        return new SessionManager(launcher);
+    }
+
+    private static ListAppender<ILoggingEvent> attach() {
+        Logger logger = (Logger) LoggerFactory.getLogger(Fleetd.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        logger.addAppender(appender);
+        return appender;
+    }
+
+    private static void detach(ListAppender<ILoggingEvent> appender) {
+        ((Logger) LoggerFactory.getLogger(Fleetd.class)).detachAppender(appender);
+    }
+
+    /** The one WARN line {@code exhaustionSink} builds from the ternary under test, or {@code null}. */
+    private static String fixWarning(ListAppender<ILoggingEvent> appender) {
+        List<String> warns = appender.list.stream()
+                .filter(e -> e.getLevel() == Level.WARN)
+                .map(ILoggingEvent::getFormattedMessage)
+                .filter(m -> m.startsWith("usage-limit fix:"))
+                .toList();
+        assertTrue(warns.size() == 1,
+                "expected exactly one 'usage-limit fix:' WARN per onExhausted call, got " + warns.size()
+                        + ": " + warns);
+        return warns.getFirst();
+    }
+
+    @Test
+    @DisplayName("a profile WITH a configured model gets the actionable models.allow fix, not the fallback")
+    void profileWithModelGetsTheActionableFix(@TempDir Path dir) throws Exception {
+        Path file = dir.resolve("fleetd.yaml");
+        Files.writeString(file, YAML);
+        FleetConfig cfg = FleetConfig.load(file);
+        ConfigRef config = ConfigRef.fixed(cfg);
+        BackendQuarantine quarantine = new BackendQuarantine(() -> 0L, TimeUnit.MINUTES.toNanos(30));
+        Map<String, String> reasonByCredential = new HashMap<>();
+        ExhaustionSink sink = Fleetd.exhaustionSink(emptyRosterSessions(), config, quarantine,
+                reasonByCredential, cfg);
+
+        ListAppender<ILoggingEvent> appender = attach();
+        try {
+            sink.onExhausted("term_x", "The usage limit has been reached", "terra");
+        } finally {
+            detach(appender);
+        }
+
+        String warning = fixWarning(appender);
+        assertTrue(warning.contains("terra"), "must name the profile: " + warning);
+        assertTrue(warning.contains("claude-opus-5"), "must name the model: " + warning);
+        assertTrue(warning.contains("enabled: false"), "must name the action: " + warning);
+        assertTrue(warning.contains("models.allow"), "must name where the action goes: " + warning);
+        assertFalse(warning.contains("has no model: configured"),
+                "a profile WITH a model must not get the no-model fallback text: " + warning);
+    }
+
+    @Test
+    @DisplayName("a profile with NO configured model gets the fallback, never a fix that does not exist")
+    void profileWithNoModelGetsTheFallbackNotAFix(@TempDir Path dir) throws Exception {
+        Path file = dir.resolve("fleetd.yaml");
+        Files.writeString(file, YAML);
+        FleetConfig cfg = FleetConfig.load(file);
+        ConfigRef config = ConfigRef.fixed(cfg);
+        BackendQuarantine quarantine = new BackendQuarantine(() -> 0L, TimeUnit.MINUTES.toNanos(30));
+        Map<String, String> reasonByCredential = new HashMap<>();
+        ExhaustionSink sink = Fleetd.exhaustionSink(emptyRosterSessions(), config, quarantine,
+                reasonByCredential, cfg);
+
+        ListAppender<ILoggingEvent> appender = attach();
+        try {
+            sink.onExhausted("term_y", "The usage limit has been reached", "gx");
+        } finally {
+            detach(appender);
+        }
+
+        String warning = fixWarning(appender);
+        assertTrue(warning.contains("gx"), "must name the profile: " + warning);
+        assertTrue(warning.contains("has no model: configured"),
+                "must say there is no model to gate by name: " + warning);
+        assertFalse(warning.contains("enabled: false"),
+                "a profile with no model: configured has no models.allow entry to flip — must "
+                        + "not claim one exists: " + warning);
+    }
+}

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

@@ -0,0 +1,75 @@
+package dev.ltms.fleet;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #446 follow-up (criterion 2): {@code exhaustionSink} used to build the "name the fix"
+ * WARNING inline with two SLF4J {@code {}}-placeholder {@code log.warn} calls. Nothing pinned
+ * that text — a mutation battery run against the merged PR #457 proved it: renaming the leading
+ * {@code "usage-limit fix:"} tag to {@code "MUTANT no fix named:"} at both call sites left all
+ * 1586 existing tests green. This class is what makes that mutation red.
+ *
+ * <p>{@link Fleetd#usageLimitFixWarning} and {@link Fleetd#usageLimitFixWarningNoModel} are the
+ * extracted call sites {@code exhaustionSink} actually invokes — {@code log.warn} is called with
+ * each method's return value as a single, already-formatted argument, so the string these tests
+ * assert on is byte-identical to what {@code fleetd.out} receives. Same extracted-static-method +
+ * dedicated-test idiom as {@link Fleetd#exhaustedPatternCoverageLine} /
+ * {@link FleetdPatternCoverageLineTest}, chosen over the {@link ch.qos.logback.core.read.ListAppender}
+ * idiom {@code ExhaustedPatternGapReportTest} uses — this warning is built once, at one call site,
+ * from a single method with no branching inside the message itself, so there is no real log
+ * plumbing left to prove; capturing an appender would only add setup/teardown around the same
+ * assertion.
+ *
+ * <p>Each assertion below checks for a specific substring — the leading {@code "usage-limit fix:"}
+ * tag an operator would grep the log for, the profile name, the model name, and the literal
+ * action ({@code enabled: false} under {@code models.allow}) — rather than the whole sentence.
+ * Criterion 2 promised those facts, not a particular wording of the prose that carries them; a
+ * whole-sentence {@code assertEquals} breaks on every copy-edit of that surrounding prose and
+ * teaches the next person to delete the test rather than read why it failed. The leading tag is
+ * pinned on purpose, unlike the rest of the sentence: it is the identifying label the fleetd #446
+ * follow-up's own mutation battery renamed ({@code "usage-limit fix:"} → {@code "MUTANT no fix
+ * named:"}) to prove this class did not yet catch a tag rename — only the three-fact substrings
+ * above would have missed it, since none of them mention the tag itself.
+ */
+class FleetdUsageLimitFixWarningTest {
+
+    @Test
+    @DisplayName("usageLimitFixWarning names the profile, the model, and the models.allow fix")
+    void usageLimitFixWarningNamesProfileModelAndFix() {
+        String warning = Fleetd.usageLimitFixWarning("terra", "claude-opus-5");
+
+        assertTrue(warning.startsWith("usage-limit fix:"),
+                "must carry the grep-able identifying tag: " + warning);
+        assertTrue(warning.contains("terra"), "must name the profile: " + warning);
+        assertTrue(warning.contains("claude-opus-5"), "must name the model: " + warning);
+        assertTrue(warning.contains("enabled: false"), "must name the action: " + warning);
+        assertTrue(warning.contains("models.allow"), "must name where the action goes: " + warning);
+    }
+
+    @Test
+    @DisplayName("usageLimitFixWarning does not cross-name a different profile or model")
+    void usageLimitFixWarningDoesNotCrossName() {
+        String warning = Fleetd.usageLimitFixWarning("terra", "claude-opus-5");
+
+        // Guards against the mutation of swapping the two profile/model arguments at the call
+        // site — a test that only checks "some name appears" cannot catch that.
+        assertTrue(!warning.contains("sonnet"), "must not name an unrelated model: " + warning);
+    }
+
+    @Test
+    @DisplayName("usageLimitFixWarningNoModel names the profile but no fix, since none exists")
+    void usageLimitFixWarningNoModelNamesProfileNotAFix() {
+        String warning = Fleetd.usageLimitFixWarningNoModel("gx", 1800);
+
+        assertTrue(warning.startsWith("usage-limit fix:"),
+                "must carry the grep-able identifying tag: " + warning);
+        assertTrue(warning.contains("gx"), "must name the profile: " + warning);
+        assertTrue(warning.contains("1800"), "must name the quarantine duration it falls back to: " + warning);
+        assertTrue(!warning.contains("enabled: false"),
+                "a profile with no model: configured has no models.allow entry to flip — the "
+                        + "fallback message must not claim one exists: " + warning);
+    }
+}

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

@@ -161,7 +161,15 @@ class ConfigRefProfileCoverageTest {
         // the #323 bug. Only ideProjectDir and worktreeGroup were saved by a behavioural test in
         // ConfigRefTest; the other two had none. So: growing this set now requires editing this
         // line as well, which is a visible, deliberate diff rather than a quiet one.
-        assertEquals(Set.of("weight", "maxLoad", "credentialId"), excluded,
+        //
+        // fleetd #446: "exhaustedPattern" joined the set legitimately — it moved from compiled
+        // once at Fleetd.main startup to read live, cached by profile name, through
+        // LiveExhaustedPatterns (see that class's doc and ConfigRef's class doc). Unlike the #323
+        // hazard this comment warns about, it is pinned by its OWN behavioural tests:
+        // FleetdExhaustionDetectionArmedWiringTest proves the reload takes effect with no restart,
+        // and the same test rerun against the pre-#446 compile site (see that ticket's report) is
+        // what proves the assertion would have failed before the fix.
+        assertEquals(Set.of("weight", "maxLoad", "credentialId", "exhaustedPattern"), excluded,
                 "ConfigRef.LAUNCH_SETTINGS_EXCLUDED changed. A component belongs in it ONLY if it "
                         + "is read live off the config supplier, not baked into a launcher at "
                         + "startup. If you are adding one to silence this test, that is fleetd #323 "

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

@@ -339,12 +339,18 @@ class ConfigRefTest {
     }
 
     /**
-     * CB-578 stage B: exhaustedPattern is compiled once into Fleetd.main's pattern map at startup
-     * (see ExhaustedPatternLookup), so a reload never re-reads it — a changed pattern must be
-     * reported deferred exactly like model/baseUrl, not silently claimed as applied.
+     * fleetd #446: exhaustedPattern moved from deferred to hot — {@code LiveExhaustedPatterns}
+     * reads {@code config.get()} fresh on every lookup, cached by profile name (not baked into a
+     * frozen map inside {@code Fleetd.main} any more, the way it was before this ticket, and the
+     * way its sibling {@code errorPattern} still is — see
+     * {@code changingAProfilesErrorPatternIsReportedAsDeferred} right below for the contrast).
+     * So a reload that changes ONLY exhaustedPattern must report a plain "config reloaded", with
+     * nothing deferred — the opposite of what this test asserted before fleetd #446, when
+     * ConfigRef.sameLaunchSettings still compared exhaustedPattern and this reload reported it as
+     * one of the changes needing a restart.
      */
     @Test
-    void changingAProfilesExhaustedPatternIsReportedAsDeferred(@TempDir Path dir) throws Exception {
+    void changingAProfilesExhaustedPatternTakesEffectWithNoRestart(@TempDir Path dir) throws Exception {
         Path f = dir.resolve("fleetd.yaml");
         Files.writeString(f, """
                 bind:
@@ -379,17 +385,21 @@ class ConfigRefTest {
         ConfigRef.Outcome out = ref.reload();
 
         assertTrue(out.applied());
-        assertEquals(1, out.deferred().size(), out.deferred().toString());
-        assertTrue(out.deferred().getFirst().contains("sonnet"), out.deferred().toString());
-        assertTrue(out.deferred().getFirst().contains("launch settings"), out.deferred().toString());
-        // The snapshot still carries the new value — a restart is what makes it take effect.
+        assertEquals(0, out.deferred().size(),
+                "exhaustedPattern is hot since fleetd #446 — changing only this key must not be "
+                        + "reported as needing a restart: " + out.deferred());
+        assertEquals(0, out.split().size(), out.split().toString());
+        assertEquals("config reloaded", out.summary());
+        // The snapshot carries the new value immediately — this IS the live value now, not
+        // merely what a restart would eventually pick up.
         assertEquals("rate limit exceeded", ref.get().profiles().get("sonnet").exhaustedPattern());
     }
 
     /**
      * fleetd #201 Unit 5: errorPattern is compiled once into Fleetd.main's backend-error pattern
-     * map at startup (see BackendErrorPatternLookup), the same way exhaustedPattern is above — a
-     * reload never re-reads it either, so a changed value must be reported deferred.
+     * map at startup (see BackendErrorPatternLookup) — unlike its sibling exhaustedPattern above,
+     * which fleetd #446 made hot, errorPattern was scoped OUT of that ticket on purpose and stays
+     * deferred: a reload still never re-reads it, so a changed value must be reported deferred.
      */
     @Test
     void changingAProfilesErrorPatternIsReportedAsDeferred(@TempDir Path dir) throws Exception {

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

@@ -0,0 +1,138 @@
+package dev.ltms.fleet.inject;
+
+import dev.ltms.fleet.config.FleetConfig;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.Map;
+import java.util.regex.Pattern;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #446: {@code LiveExhaustedPatterns} is the mechanism that makes {@code exhaustedPattern}
+ * hot — read fresh off a config supplier per lookup, cached by profile name. This is the direct,
+ * minimal unit test of that mechanism: read the pattern once, mutate the backing "config", read
+ * again, and assert the second read saw the new value — the exact hotness proof shape.
+ *
+ * <p>This class alone does not prove {@code Fleetd.main} actually wires the live source into
+ * production — {@link dev.ltms.fleet.FleetdExhaustionDetectionArmedWiringTest} and {@code
+ * CompletionResolverTest}'s {@code ExhaustedPatternLookup} tests do that at the wiring level. What
+ * this class proves is that the mechanism itself is genuinely live and genuinely cached, not that
+ * it is used.
+ */
+class LiveExhaustedPatternsTest {
+
+    private static FleetConfig.Profile profileWithPattern(String pattern) {
+        return new FleetConfig.Profile("terra", "http://gx00.gw:8000", "terra",
+                null, null, null, "tab", "fleetd-workers", "w #{n}", null, null, null,
+                null, null, null, null, null, null, null, pattern);
+    }
+
+    /** Simple mutable holder standing in for {@code ConfigRef} — swapped, never mutated in place. */
+    private static final class MutableProfiles {
+        private volatile Map<String, FleetConfig.Profile> profiles;
+
+        MutableProfiles(Map<String, FleetConfig.Profile> initial) {
+            this.profiles = initial;
+        }
+
+        Map<String, FleetConfig.Profile> get() {
+            return profiles;
+        }
+
+        void set(Map<String, FleetConfig.Profile> fresh) {
+            this.profiles = fresh;
+        }
+    }
+
+    @Test
+    @DisplayName("patternFor reads the live config: read, change, read again, see the change — no restart")
+    void patternForIsHotAcrossAConfigChange() {
+        MutableProfiles live = new MutableProfiles(Map.of("terra", profileWithPattern("usage limit")));
+        LiveExhaustedPatterns patterns = new LiveExhaustedPatterns(live::get);
+
+        Pattern before = patterns.patternFor("terra");
+        assertTrue(before.matcher("your usage limit has been reached").find());
+
+        // Change the "config" — the exact thing a reload does to ConfigRef in production.
+        live.set(Map.of("terra", profileWithPattern("rate limit exceeded")));
+
+        Pattern after = patterns.patternFor("terra");
+        assertTrue(after.matcher("429: rate limit exceeded, try later").find(),
+                "the second read must see the NEW pattern text with no restart");
+        assertFalse(after.matcher("your usage limit has been reached").find(),
+                "the second read must have actually recompiled — not just reused a stale match");
+    }
+
+    @Test
+    @DisplayName("armed follows the same live read: on, then off, after a config change — no restart")
+    void armedIsHotAcrossAConfigChange() {
+        MutableProfiles live = new MutableProfiles(Map.of("terra", profileWithPattern("usage limit")));
+        LiveExhaustedPatterns patterns = new LiveExhaustedPatterns(live::get);
+
+        assertTrue(patterns.armed("terra"));
+
+        live.set(Map.of("terra", profileWithPattern(null)));
+
+        assertFalse(patterns.armed("terra"),
+                "removing exhaustedPattern and 'reloading' must disarm detection with no restart");
+    }
+
+    @Test
+    @DisplayName("an unchanged pattern string is not recompiled — the cache is reused")
+    void unchangedPatternTextReusesTheCompiledInstance() {
+        MutableProfiles live = new MutableProfiles(Map.of("terra", profileWithPattern("usage limit")));
+        LiveExhaustedPatterns patterns = new LiveExhaustedPatterns(live::get);
+
+        Pattern first = patterns.patternFor("terra");
+        // A NEW Profile object, same pattern text — a reload of an unrelated key produces a fresh
+        // FleetConfig even though this profile's own text did not change.
+        live.set(Map.of("terra", profileWithPattern("usage limit")));
+        Pattern second = patterns.patternFor("terra");
+
+        assertSame(first, second,
+                "identical pattern text must reuse the cached compiled Pattern, not recompile it — "
+                        + "recompiling a regex on every check is exactly the cost the cache exists to avoid");
+    }
+
+    @Test
+    @DisplayName("a changed pattern string is recompiled, not silently reused from the cache")
+    void changedPatternTextIsRecompiled() {
+        MutableProfiles live = new MutableProfiles(Map.of("terra", profileWithPattern("usage limit")));
+        LiveExhaustedPatterns patterns = new LiveExhaustedPatterns(live::get);
+
+        Pattern first = patterns.patternFor("terra");
+        live.set(Map.of("terra", profileWithPattern("rate limit")));
+        Pattern second = patterns.patternFor("terra");
+
+        assertNotSame(first, second, "changed pattern text must produce a freshly compiled Pattern");
+    }
+
+    @Test
+    void unknownProfileReturnsNullAndUnarmed() {
+        LiveExhaustedPatterns patterns = new LiveExhaustedPatterns(Map::of);
+        assertNull(patterns.patternFor("nope"));
+        assertFalse(patterns.armed("nope"));
+    }
+
+    @Test
+    void nullProfileNameReturnsNullAndUnarmed() {
+        LiveExhaustedPatterns patterns = new LiveExhaustedPatterns(
+                () -> Map.of("terra", profileWithPattern("usage limit")));
+        assertNull(patterns.patternFor(null));
+        assertFalse(patterns.armed(null));
+    }
+
+    @Test
+    void profileWithNoPatternConfiguredReturnsNull() {
+        LiveExhaustedPatterns patterns = new LiveExhaustedPatterns(
+                () -> Map.of("terra", profileWithPattern(null)));
+        assertNull(patterns.patternFor("terra"));
+        assertFalse(patterns.armed("terra"));
+    }
+}

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

@@ -0,0 +1,111 @@
+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.peer.PeerLauncher;
+import dev.ltms.fleet.placement.BackendQuarantine;
+import io.modelcontextprotocol.spec.McpSchema;
+import org.junit.jupiter.api.Test;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #446 follow-up (criterion 3): a mutation battery run against the merged PR #457 proved
+ * that deleting either {@code row.put("model", model);} or {@code row.put("reason", reason);}
+ * from {@link FleetMcp#profilesView} left all 1586 existing tests green — nothing exercised a
+ * {@link FleetMcp.QuarantineSource} whose {@code modelFor}/{@code reasonFor} actually return a
+ * value. This class is what makes both deletions red, and also pins the two "must be omitted, not
+ * emitted as null/blank" branches those two {@code if} guards exist for — {@link
+ * FleetMcpTest#profilesReportsAQuarantinedCredential} covers the credential/quarantine-duration
+ * shape but supplies neither function, so it cannot distinguish "the field is missing" from "the
+ * field was never asked for".
+ */
+class FleetProfilesQuarantineModelReasonFieldsTest {
+
+    private static final String PROFILE = "terra";
+    private static final String CREDENTIAL = "cred-terra";
+
+    private static PeerLauncher launcher(FakeHerdr h) {
+        FleetConfig.Profile profile = new FleetConfig.Profile(
+                PROFILE, "http://gx00.gw:8000", "claude-opus-5", null, "FLEETD_WORKER_TOKEN", null,
+                "tab", "fleetd-workers", "worker: {profile} #{n}", null, null, null);
+        return new ClaudeCodeLauncher(new AgentControl(h), new WorkspaceControl(h),
+                new SubscriptionGuard(Set.of("gx00.gw")), Map.of(PROFILE, profile), PROFILE, _ -> "tok");
+    }
+
+    private static BackendQuarantine quarantined(String credentialId) {
+        BackendQuarantine quarantine = new BackendQuarantine(() -> 0L, TimeUnit.MINUTES.toNanos(30));
+        quarantine.quarantine(credentialId);
+        return quarantine;
+    }
+
+    private static String textOf(McpSchema.CallToolResult r) {
+        return ((McpSchema.TextContent) r.content().getFirst()).text();
+    }
+
+    @Test
+    void quarantinedRowNamesTheModelAndTheReason() {
+        FakeHerdr h = new FakeHerdr();
+        FleetMcp.QuarantineSource source = new FleetMcp.QuarantineSource(
+                _ -> CREDENTIAL, quarantined(CREDENTIAL), _ -> true,
+                _ -> "claude-opus-5", _ -> "The usage limit has been reached");
+
+        McpSchema.CallToolResult res = FleetMcp.profiles(launcher(h), source);
+        assertNotEquals(Boolean.TRUE, res.isError());
+        String out = textOf(res);
+
+        assertTrue(out.contains("\"quarantined\""), out);
+        assertTrue(out.contains("\"model\":\"claude-opus-5\""),
+                "the quarantined row must name the model the fix applies to: " + out);
+        assertTrue(out.contains("\"reason\":\"The usage limit has been reached\""),
+                "the quarantined row must name why it was quarantined: " + out);
+    }
+
+    @Test
+    void quarantinedRowOmitsModelWhenNoneIsConfigured() {
+        FakeHerdr h = new FakeHerdr();
+        // null and "" (blank) both exercise the same production guard (`!model.isBlank()`) —
+        // covered together since both must produce the identical outcome: the key absent.
+        for (String noModel : new String[] {null, "", "   "}) {
+            FleetMcp.QuarantineSource source = new FleetMcp.QuarantineSource(
+                    _ -> CREDENTIAL, quarantined(CREDENTIAL), _ -> true,
+                    _ -> noModel, _ -> "some reason");
+
+            McpSchema.CallToolResult res = FleetMcp.profiles(launcher(h), source);
+            String out = textOf(res);
+
+            assertTrue(out.contains("\"quarantined\""), out);
+            assertFalse(out.contains("\"model\""),
+                    "modelFor returned " + (noModel == null ? "null" : "'" + noModel + "'")
+                            + " — the key must be ABSENT, not emitted as null or an empty string: " + out);
+        }
+    }
+
+    @Test
+    void quarantinedRowOmitsReasonWhenNoneIsKnown() {
+        FakeHerdr h = new FakeHerdr();
+        for (String noReason : new String[] {null, "", "  "}) {
+            FleetMcp.QuarantineSource source = new FleetMcp.QuarantineSource(
+                    _ -> CREDENTIAL, quarantined(CREDENTIAL), _ -> true,
+                    _ -> "claude-opus-5", _ -> noReason);
+
+            McpSchema.CallToolResult res = FleetMcp.profiles(launcher(h), source);
+            String out = textOf(res);
+
+            assertTrue(out.contains("\"quarantined\""), out);
+            assertFalse(out.contains("\"reason\""),
+                    "reasonFor returned " + (noReason == null ? "null" : "'" + noReason + "'")
+                            + " — the key must be ABSENT, not emitted as null or an empty string: " + out);
+        }
+    }
+}