fleetd #395: warn when exhaustedPattern detection is silently off

exhaustedPattern is opt-in per profile: unset means a usage-limit
refusal on that profile is never classified BACKEND_EXHAUSTED and
never quarantines its credential, with nothing telling the operator.
Add a startup WARN naming every unarmed profile (a louder, separate
WARN for a subscription: true profile, since that is the operator's
own metered plan). Surface the same fact per profile in fleet_profiles
as exhaustionDetectionArmed, so an operator can tell "healthy" from
"can never be caught" without reading fleetd.yaml.

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

@@ -134,6 +134,10 @@ public final class Fleetd {
         // secret is reported above, so upgrading past this commit never silently drops CB-592's
         // protection.
         reportMemberCredentialsGap(cfg);
+        // fleetd #395: an unset exhaustedPattern is a silent opt-out of usage-limit detection for
+        // that profile — say so loudly, the same way the two reports above do, rather than let an
+        // operator discover it only when a limit goes undetected.
+        reportExhaustedPatternGap(cfg);
         // CB-559: `cfg` stays the startup snapshot — every validation and every piece of one-time
         // wiring below reads it, and must, because those decisions cannot be unmade. `config` is the
         // live reference the hot paths read per use. Which keys can actually move is ConfigRef's
@@ -664,7 +668,13 @@ public final class Fleetd {
         FleetMcp.QuarantineSource quarantineSource = new FleetMcp.QuarantineSource(profile -> {
             var configured = config.get().profiles().get(profile);
             return configured == null ? null : configured.effectiveCredentialId();
-        }, quarantine);
+        }, quarantine, profile -> {
+            // fleetd #395: read live off the current config, like credentialIdFor above — an
+            // exhaustedPattern edit takes effect on the next fleet_profiles/fleet_list call, no
+            // restart needed, same as the credential-id lookup it sits beside.
+            var configured = config.get().profiles().get(profile);
+            return configured != null && configured.hasExhaustedPattern();
+        });
         FleetMcp.OutageSource outageSource = new FleetMcp.OutageSource(profile -> {
             var configured = config.get().profiles().get(profile);
             return configured == null ? null : configured.effectiveCredentialId();
@@ -1323,6 +1333,52 @@ public final class Fleetd {
                 + "fleetd.yaml — see fleetd.example.yaml — and restart.");
     }
 
+    /**
+     * fleetd #395: {@code exhaustedPattern} (see {@link FleetConfig.Profile#exhaustedPattern}) is
+     * deliberately opt-in — {@code null}/blank means a backend refusal on that profile is never
+     * classified as {@code BACKEND_EXHAUSTED}, so its credential is never quarantined. That is a
+     * legitimate choice (guessing the vendor's wording would be worse), but an operator who never
+     * opted a profile in should not discover the gap only when a usage limit silently goes
+     * undetected. Warn once at startup, naming every unarmed profile, exactly like {@link
+     * #reportMemberCredentialsGap} — never refuse to start over it.
+     *
+     * <p>A {@code subscription: true} profile that is unarmed gets a SECOND, louder WARN of its
+     * own: it bills the operator's metered Claude plan, the case where an undetected usage limit
+     * costs the most.
+     *
+     * <p>Package-private so a test can capture the real log via a {@link
+     * ch.qos.logback.core.read.ListAppender}, the same pattern {@link
+     * #reportMemberCredentialsGap}'s own test uses.
+     */
+    static void reportExhaustedPatternGap(FleetConfig cfg) {
+        List<String> unarmedSubscription = new ArrayList<>();
+        List<String> unarmedOther = new ArrayList<>();
+        cfg.profiles().forEach((name, profile) -> {
+            if (!profile.hasExhaustedPattern()) {
+                (profile.isSubscription() ? unarmedSubscription : unarmedOther).add(name);
+            }
+        });
+        if (unarmedSubscription.isEmpty() && unarmedOther.isEmpty()) {
+            log.info("exhaustedPattern: every configured profile has usage-limit detection armed");
+            return;
+        }
+        List<String> allUnarmed = new ArrayList<>(unarmedSubscription);
+        allUnarmed.addAll(unarmedOther);
+        allUnarmed = allUnarmed.stream().sorted().toList();
+        log.warn("exhaustedPattern: profile(s) {} have no exhaustedPattern configured — a "
+                        + "usage-limit refusal on any of them is never detected and never "
+                        + "quarantines its credential. Set exhaustedPattern (see "
+                        + "fleetd.example.yaml) to arm detection for a profile.",
+                allUnarmed);
+        if (!unarmedSubscription.isEmpty()) {
+            List<String> sortedSubscription = unarmedSubscription.stream().sorted().toList();
+            log.warn("exhaustedPattern: subscription profile(s) {} run on the operator's metered "
+                            + "Claude plan and have NO usage-limit detection armed — this is the "
+                            + "case where a missed usage limit costs the most.",
+                    sortedSubscription);
+        }
+    }
+
     /**
      * Poll herdr's {@code ping} until it answers or {@link #HERDR_WAIT_SECONDS} elapses (CB-504).
      *

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

@@ -119,9 +119,28 @@ 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
+     *                      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.
      */
-    public record QuarantineSource(Function<String, String> credentialIdFor, BackendQuarantine quarantine) {
-        /** Inert source — no profile is ever reported quarantined. Explicit stand-in, not a default. */
+    public record QuarantineSource(Function<String, String> credentialIdFor, BackendQuarantine quarantine,
+                                    Function<String, Boolean> exhaustedPatternArmed) {
+        /**
+         * Backward-compatible 2-arg form, before fleetd #395 added {@code exhaustedPatternArmed} —
+         * reports every profile unarmed. 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) {
+            this(credentialIdFor, quarantine, _ -> false);
+        }
+
+        /** Inert source — no profile is ever reported quarantined or armed. Explicit stand-in, not a default. */
         public static QuarantineSource none() { return new QuarantineSource(_ -> null, BackendQuarantine.none()); }
     }
 
@@ -1109,6 +1128,14 @@ public final class FleetMcp {
      * not the other, and the two then disagree about a live outage. That is exactly what fleetd
      * #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".
      */
     public static Map<String, Object> profilesView(PeerLauncher workers, QuarantineSource quarantine, OutageSource outage) {
         Map<String, Object> result = new LinkedHashMap<>();
@@ -1116,7 +1143,9 @@ public final class FleetMcp {
         result.put("default", workers.defaultProfile() == null ? "" : workers.defaultProfile());
         Map<String, Object> quarantined = new LinkedHashMap<>();
         Map<String, Object> coolingOff = new LinkedHashMap<>();
+        Map<String, Object> exhaustionDetectionArmed = new LinkedHashMap<>();
         for (String profile : workers.profiles()) {
+            exhaustionDetectionArmed.put(profile, quarantine.exhaustedPatternArmed().apply(profile));
             String credentialId = quarantine.credentialIdFor().apply(profile);
             if (credentialId != null) {
                 quarantine.quarantine().remainingSeconds(credentialId).ifPresent(remaining -> {
@@ -1136,6 +1165,7 @@ public final class FleetMcp {
                 });
             }
         }
+        result.put("exhaustionDetectionArmed", exhaustionDetectionArmed);
         if (!quarantined.isEmpty()) {
             result.put("quarantined", quarantined);
         }
@@ -1663,7 +1693,11 @@ 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. "
+                        + "'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.",
                 objectSchema(Map.of(), List.of()));
     }
 

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

@@ -0,0 +1,150 @@
+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.FleetConfig;
+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.List;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #395: {@code exhaustedPattern} (see {@link FleetConfig.Profile#exhaustedPattern}) is
+ * deliberately opt-in — an unset one leaves usage-limit detection silently OFF for that profile,
+ * and nothing quarantines its credential. {@link Fleetd#reportExhaustedPatternGap} must say so at
+ * startup, naming every unarmed profile, and must never fire when every profile is armed. Mirrors
+ * {@link MemberCredentialsGapReportTest}'s pattern, capturing the real log via a
+ * {@link ListAppender}.
+ *
+ * <p>The 8-profile shape in {@link #theLiveEightProfileShapeWarnsExactlyTheSixUnarmedProfiles} is
+ * the live {@code fleetd.yaml} shape measured 2026-09-10 (fleetd #395's own ticket): 6 of 8
+ * profiles unarmed, 2 of those 6 ({@code opus}, {@code sonnet}) running on the operator's Claude
+ * subscription. {@code fleetd.yaml} itself is gitignored and unavailable to this test, so the
+ * shape is reproduced as a throwaway config in a {@code @TempDir} rather than read off disk.
+ */
+class ExhaustedPatternGapReportTest {
+
+    private static FleetConfig load(Path dir, String yaml) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml);
+        return FleetConfig.load(f);
+    }
+
+    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);
+    }
+
+    /** Every profile name mentioned by a WARN-level log line, across every WARN this call produced. */
+    private static List<String> warnMessages(ListAppender<ILoggingEvent> appender) {
+        return appender.list.stream()
+                .filter(e -> e.getLevel() == Level.WARN)
+                .map(ILoggingEvent::getFormattedMessage)
+                .toList();
+    }
+
+    @Test
+    void theLiveEightProfileShapeWarnsExactlyTheSixUnarmedProfiles(@TempDir Path dir) throws Exception {
+        // Reproduces the live shape measured 2026-09-10: 8 profiles, 2 armed (sol, terra), 6
+        // unarmed (local, local-direct, gx, opus, sonnet, xf) — 2 of the unarmed 6 (opus, sonnet)
+        // are subscription: true.
+        FleetConfig cfg = load(dir, """
+                profiles:
+                  local:
+                    baseUrl: http://gx00.gw:8000
+                  local-direct:
+                    baseUrl: http://gx01.gw:8000
+                  gx:
+                    kind: opencode
+                    baseUrl: https://llm.ltms.dev/v1
+                  opus:
+                    subscription: true
+                    model: claude-opus-5
+                  sonnet:
+                    subscription: true
+                    model: claude-sonnet-5
+                  sol:
+                    baseUrl: https://llm.ltms.dev/v1
+                    exhaustedPattern: "The usage limit has been reached"
+                  terra:
+                    baseUrl: https://llm.ltms.dev/v1
+                    exhaustedPattern: "The usage limit has been reached"
+                  xf:
+                    baseUrl: https://llm.ltms.dev/v1
+                """);
+
+        ListAppender<ILoggingEvent> appender = attach();
+        try {
+            Fleetd.reportExhaustedPatternGap(cfg);
+        } finally {
+            detach(appender);
+        }
+
+        List<String> warns = warnMessages(appender);
+        assertFalse(warns.isEmpty(), "6 of 8 profiles are unarmed — at least one WARN must fire");
+
+        // Exactly one WARN aggregates every unarmed profile, naming all 6 and none of the 2 armed.
+        String aggregate = warns.stream()
+                .filter(m -> m.contains("no exhaustedPattern configured"))
+                .findFirst()
+                .orElseThrow(() -> new AssertionError("expected an aggregate unarmed-profiles WARN: " + warns));
+        for (String unarmed : List.of("local", "local-direct", "gx", "opus", "sonnet", "xf")) {
+            assertTrue(aggregate.contains(unarmed), "aggregate WARN must name '" + unarmed + "': " + aggregate);
+        }
+        for (String armed : List.of("sol", "terra")) {
+            assertFalse(aggregate.contains(armed), "aggregate WARN must NOT name armed profile '" + armed + "': " + aggregate);
+        }
+
+        // A second, louder WARN calls out the subscription profiles specifically.
+        String subscriptionWarn = warns.stream()
+                .filter(m -> m.contains("metered Claude plan"))
+                .findFirst()
+                .orElseThrow(() -> new AssertionError("expected a subscription-specific WARN: " + warns));
+        assertTrue(subscriptionWarn.contains("opus"), subscriptionWarn);
+        assertTrue(subscriptionWarn.contains("sonnet"), subscriptionWarn);
+        assertFalse(subscriptionWarn.contains("local-direct"),
+                "the subscription WARN must not name a non-subscription profile: " + subscriptionWarn);
+    }
+
+    @Test
+    void everyProfileArmedProducesNoWarningAtAll(@TempDir Path dir) throws Exception {
+        FleetConfig cfg = load(dir, """
+                profiles:
+                  sol:
+                    baseUrl: https://llm.ltms.dev/v1
+                    exhaustedPattern: "The usage limit has been reached"
+                  terra:
+                    baseUrl: https://llm.ltms.dev/v1
+                    exhaustedPattern: "The usage limit has been reached"
+                  opus:
+                    subscription: true
+                    model: claude-opus-5
+                    exhaustedPattern: "5-hour limit reached"
+                """);
+
+        ListAppender<ILoggingEvent> appender = attach();
+        try {
+            Fleetd.reportExhaustedPatternGap(cfg);
+        } finally {
+            detach(appender);
+        }
+
+        assertTrue(warnMessages(appender).isEmpty(),
+                "every profile is armed — a checker that warns anyway always fires: " + warnMessages(appender));
+    }
+}

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

@@ -0,0 +1,62 @@
+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 io.modelcontextprotocol.spec.McpSchema;
+import org.junit.jupiter.api.Test;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #395: {@code fleet_profiles} must let an operator tell "this profile's usage-limit
+ * detection is armed" from "nothing can ever quarantine this profile" — see {@link
+ * FleetMcp.QuarantineSource#exhaustedPatternArmed()} and {@link
+ * FleetMcp#profilesView(PeerLauncher, FleetMcp.QuarantineSource, FleetMcp.OutageSource)}.
+ */
+class FleetProfilesArmedFieldTest {
+
+    private static PeerLauncher twoProfileLauncher(FakeHerdr h) {
+        FleetConfig.Profile armed = new FleetConfig.Profile(
+                "armed-profile", "http://gx00.gw:8000", "coder", null, "FLEETD_WORKER_TOKEN", null,
+                "tab", "fleetd-workers", "worker: {profile} #{n}", null, null, null);
+        FleetConfig.Profile unarmed = new FleetConfig.Profile(
+                "unarmed-profile", "http://gx01.gw:8000", "coder", null, "FLEETD_WORKER_TOKEN", null,
+                "tab", "fleetd-workers", "worker: {profile} #{n}", null, null, null);
+        Map<String, FleetConfig.Profile> profiles = new LinkedHashMap<>();
+        profiles.put(armed.profile(), armed);
+        profiles.put(unarmed.profile(), unarmed);
+        return new ClaudeCodeLauncher(new AgentControl(h), new WorkspaceControl(h),
+                new SubscriptionGuard(Set.of("gx00.gw", "gx01.gw")), profiles, armed.profile(), _ -> "tok");
+    }
+
+    private static String textOf(McpSchema.CallToolResult r) {
+        return ((McpSchema.TextContent) r.content().getFirst()).text();
+    }
+
+    @Test
+    void armedProfileReportsArmedAndUnarmedReportsUnarmed() {
+        FakeHerdr h = new FakeHerdr();
+        PeerLauncher workers = twoProfileLauncher(h);
+        FleetMcp.QuarantineSource source = new FleetMcp.QuarantineSource(
+                _ -> null, dev.ltms.fleet.placement.BackendQuarantine.none(),
+                profile -> "armed-profile".equals(profile));
+
+        McpSchema.CallToolResult res = FleetMcp.profiles(workers, source);
+        assertNotEquals(Boolean.TRUE, res.isError());
+        String out = textOf(res);
+
+        assertTrue(out.contains("\"exhaustionDetectionArmed\""), out);
+        assertTrue(out.contains("\"armed-profile\":true"), out);
+        assertTrue(out.contains("\"unarmed-profile\":false"), out);
+    }
+}