Merge worker/562-loop-health-wiring-test-99611c-5

CLAUDE.md

@@ -144,7 +144,7 @@ the merge — and merging on a reviewer's word is delegating it by proxy.
 | Confirm your own role | `fleet_whoami` |
 | See backends available | `fleet_profiles` |
 | Start a member | `fleet_spawn{role?, profile?, cwd?, worktree?, ticket?, sessionName?, resumeSessionId?}` → `sessionId` + `paneId` |
-| See the fleet | `fleet_list` → `leads` (your peers) + `members` (each carries `agentSessionId` when its backend knows one) · one peer's state: `fleet_status{sessionId}` |
+| See the fleet | `fleet_list` → `leads` (your peers) + `members` (each carries `agentSessionId` when its backend knows one) + `loopHealth` (`RUNNING`, `STALLED`, or `STOPPED` for `statusPoller` and `sessionReaper`) · one peer's state: `fleet_status{sessionId}` |
 | Delegate (blocking) | `fleet_send{sessionId, content}` |
 | Delegate (long task) | `fleet_send{sessionId, content, wait:false}` → ticket → `fleet_poll{ticket}` |
 | Answer a member's `fleet_ask` | `fleet_send{turnId, content}` — **not** `sessionId` |

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

@@ -21,6 +21,7 @@ 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.LoopWatchdog;
 import dev.ltms.fleet.inject.StatusPoller;
 import dev.ltms.fleet.inject.TurnListener;
 import dev.ltms.fleet.inject.MemberPresence;
@@ -665,10 +666,12 @@ public final class Fleetd {
             return configured == null ? null : configured.effectiveCredentialId();
         }, outagePolicy);
 
+        FleetMcp.LoopHealthSource loopHealth = loopHealthSource(poller, reaper);
         FleetMcp mcp = new FleetMcp(messages, workers, sessions, identity, presence,
                 primaryRegistry, callers, FleetMcp.AuthorizationMode.ENFORCED, metrics,
                 capacitySource(config, cfg, profile -> liveCountRef.get().apply(profile)),
                 healthCoverageSource(config),
+                loopHealth,
                 quarantineSource,
                 leadMailbox,
                 outageSource,
@@ -760,7 +763,7 @@ public final class Fleetd {
         Javalin app = new FleetApp(herdr, memberHerdr, workers, sessions, messages, presence, mcp.servlet(),
                 callers, metrics, deliverable,
                 () -> MemberCredentialPolicyView.of(config.get().memberCredentials()),
-                quarantineSource, outageSource).build();
+                quarantineSource, outageSource, loopHealth).build();
         app.start(cfg.bind().host(), cfg.bind().port());
         log.info("fleetd listening on {}:{}, herdr socket {}",
                 cfg.bind().host(), cfg.bind().port(), socket);
@@ -1038,6 +1041,31 @@ public final class Fleetd {
         });
     }
 
+    /**
+     * fleetd #562 follow-up: package-private factory for {@code fleet_list}'s and {@code
+     * /healthz}'s {@code loopHealth} source, extracted out of {@code main} for the same reason
+     * {@link #capacitySource} and {@link #healthCoverageSource} were. Before this ticket the
+     * {@link FleetMcp.LoopHealthSource} was built inline with a bare {@code new}, so there was
+     * nothing a test could call directly — measured: replacing {@code poller::health} with a
+     * constant {@code () -> LoopWatchdog.State.RUNNING} at the call site compiled clean and left
+     * the full suite green, meaning the daemon could report the {@link StatusPoller} as always
+     * {@code RUNNING} even while it was actually stalled. That is a false negative on the exact
+     * signal this ticket exists to surface, and is the mirror of a false positive muting a real
+     * monitoring component — worse, because there is no noise for anyone to notice and then
+     * silence. {@link FleetdLoopHealthSourceWiringTest} calls this factory directly and pins both
+     * halves separately, plus the {@code reaper == null} branch below.
+     *
+     * <p>{@code reaper} may be {@code null} — a {@link SessionReaper} is only constructed when
+     * {@code lifecycle.idleTtlSeconds} is configured (see the {@code reaper} local above) — and
+     * this factory preserves the existing behaviour of reporting {@link LoopWatchdog.State#STOPPED}
+     * in that case, rather than a {@code NullPointerException} on the first {@code fleet_list} or
+     * {@code /healthz} call.
+     */
+    static FleetMcp.LoopHealthSource loopHealthSource(StatusPoller poller, SessionReaper reaper) {
+        return new FleetMcp.LoopHealthSource(poller::health,
+                () -> reaper == null ? LoopWatchdog.State.STOPPED : reaper.health());
+    }
+
     /**
      * fleetd #248: package-private factory for the member worktree/branch lookup {@link
      * CompletionResolver} uses to name a fallback report's worktree and branch (fleetd#241).

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

@@ -20,6 +20,7 @@ import dev.ltms.fleet.msg.Rendezvous;
 import dev.ltms.fleet.peer.PeerUnreachableException;
 import dev.ltms.fleet.placement.BackendOutagePolicy;
 import dev.ltms.fleet.placement.BackendQuarantine;
+import dev.ltms.fleet.inject.LoopWatchdog;
 import dev.ltms.fleet.placement.PlacementException;
 import dev.ltms.fleet.session.SessionManager;
 import dev.ltms.fleet.session.MemberSession;
@@ -108,6 +109,7 @@ public final class FleetMcp {
     private final Metrics metrics;      // CB-502: null → auth failures not counted
     private final CapacitySource capacity;
     private final HealthCoverageSource healthCoverage;
+    private final LoopHealthSource loopHealth;
     private final QuarantineSource quarantine;
     /** fleetd #201 Unit 5: SEPARATE from {@link #quarantine} — see {@link OutageSource}'s doc. */
     private final OutageSource outage;
@@ -136,6 +138,15 @@ public final class FleetMcp {
     /** Coverage is supplied by the health wiring, not inferred from a missing dependency. */
     public record HealthCoverageSource(Supplier<String> value) { }
 
+    /** Progress states for fleetd's singleton background loops, read by {@code fleet_list} and {@code /healthz}. */
+    public record LoopHealthSource(Supplier<LoopWatchdog.State> statusPoller,
+                                   Supplier<LoopWatchdog.State> sessionReaper) {
+        /** Inert source for callers that do not wire the background loops. */
+        public static LoopHealthSource none() {
+            return new LoopHealthSource(() -> LoopWatchdog.State.STOPPED, () -> LoopWatchdog.State.STOPPED);
+        }
+    }
+
     /**
      * 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.
@@ -328,11 +339,22 @@ public final class FleetMcp {
      *                     instead of throwing. See {@link #handover}.
      */
     public FleetMcp(MessageService messages, PeerLauncher workers, SessionManager sessions,
-                     ConnectionIdentity identity, MemberPresence presence, PrimaryRegistry primaryRegistry,
-                      CallerResolver callers, AuthorizationMode authorizationMode, Metrics metrics,
-                      CapacitySource capacity, HealthCoverageSource healthCoverage,
-                      QuarantineSource quarantine, LeadChannel leadChannel, OutageSource outage,
-                      LeadSeatSource leadSeats, List<String> peers, LeadRollover leadRollover) {
+                      ConnectionIdentity identity, MemberPresence presence, PrimaryRegistry primaryRegistry,
+                       CallerResolver callers, AuthorizationMode authorizationMode, Metrics metrics,
+                       CapacitySource capacity, HealthCoverageSource healthCoverage,
+                       QuarantineSource quarantine, LeadChannel leadChannel, OutageSource outage,
+                       LeadSeatSource leadSeats, List<String> peers, LeadRollover leadRollover) {
+        this(messages, workers, sessions, identity, presence, primaryRegistry, callers, authorizationMode, metrics,
+                capacity, healthCoverage, LoopHealthSource.none(), quarantine, leadChannel, outage, leadSeats,
+                peers, leadRollover);
+    }
+
+    public FleetMcp(MessageService messages, PeerLauncher workers, SessionManager sessions,
+                    ConnectionIdentity identity, MemberPresence presence, PrimaryRegistry primaryRegistry,
+                    CallerResolver callers, AuthorizationMode authorizationMode, Metrics metrics,
+                    CapacitySource capacity, HealthCoverageSource healthCoverage, LoopHealthSource loopHealth,
+                    QuarantineSource quarantine, LeadChannel leadChannel, OutageSource outage,
+                    LeadSeatSource leadSeats, List<String> peers, LeadRollover leadRollover) {
         Objects.requireNonNull(callers, "callers");
         this.authorizationEnforced = Objects.requireNonNull(authorizationMode, "authorizationMode")
                 == AuthorizationMode.ENFORCED;
@@ -343,6 +365,7 @@ public final class FleetMcp {
         this.outage = Objects.requireNonNull(outage, "outage");
         this.leadSeats = Objects.requireNonNull(leadSeats, "leadSeats");
         this.healthCoverage = healthCoverage;
+        this.loopHealth = Objects.requireNonNull(loopHealth, "loopHealth");
         this.leadRollover = leadRollover;
         McpJsonMapper json = new JacksonMcpJsonMapperSupplier().get();
         this.transport = HttpServletStreamableServerTransportProvider.builder()
@@ -474,7 +497,7 @@ public final class FleetMcp {
                 (exchange, _) -> {
                     McpSchema.CallToolResult denied = deny(exchange, toolAction("fleet_list", Map.of()), null);
                     if (denied != null) return denied;
-                    return listFleet(workers, sessions, messages, capacity, healthCoverage, quarantine, outage,
+                    return listFleet(workers, sessions, messages, capacity, healthCoverage, loopHealth, quarantine, outage,
                             leadSeats, callers.leads(),
                             callerTerminal(exchange),
                             new CoordinationSource(leadChannel, peers),
@@ -1552,25 +1575,42 @@ public final class FleetMcp {
      * @param selfTerm the calling pane's terminal id, or blank for a caller with no pane
      */
     static McpSchema.CallToolResult listFleet(PeerLauncher workers, SessionManager sessions,
-                                              Map<String, String> leads, String selfTerm) {
+                                               Map<String, String> leads, String selfTerm) {
         return listFleet(workers, sessions, null, CapacitySource.none(), new HealthCoverageSource(() -> "off"),
-                QuarantineSource.none(), leads, selfTerm);
+                LoopHealthSource.none(), QuarantineSource.none(), leads, selfTerm);
+    }
+
+    static McpSchema.CallToolResult listFleet(PeerLauncher workers, SessionManager sessions, MessageService messages,
+                                                CapacitySource capacity, HealthCoverageSource healthCoverage,
+                                                QuarantineSource quarantine, Map<String, String> leads, String selfTerm) {
+        return listFleet(workers, sessions, messages, capacity, healthCoverage, LoopHealthSource.none(), quarantine, leads, selfTerm,
+                CoordinationSource.none());
     }
 
     static McpSchema.CallToolResult listFleet(PeerLauncher workers, SessionManager sessions, MessageService messages,
                                                CapacitySource capacity, HealthCoverageSource healthCoverage,
-                                               QuarantineSource quarantine, Map<String, String> leads, String selfTerm) {
-        return listFleet(workers, sessions, messages, capacity, healthCoverage, quarantine, leads, selfTerm,
+                                               LoopHealthSource loopHealth, QuarantineSource quarantine,
+                                               Map<String, String> leads, String selfTerm) {
+        return listFleet(workers, sessions, messages, capacity, healthCoverage, loopHealth, quarantine, leads, selfTerm,
                 CoordinationSource.none());
     }
 
+    static McpSchema.CallToolResult listFleet(PeerLauncher workers, SessionManager sessions, MessageService messages,
+                                               CapacitySource capacity, HealthCoverageSource healthCoverage,
+                                               LoopHealthSource loopHealth, QuarantineSource quarantine,
+                                               Map<String, String> leads, String selfTerm,
+                                               CoordinationSource coordination) {
+        return listFleet(workers, sessions, messages, capacity, healthCoverage, loopHealth, quarantine,
+                OutageSource.none(), LeadSeatSource.none(), leads, selfTerm, coordination, false);
+    }
+
     /** As above, plus fleetd #201 Unit 5 cool-off facts (see {@link OutageSource}). */
     static McpSchema.CallToolResult listFleet(PeerLauncher workers, SessionManager sessions, MessageService messages,
                                                CapacitySource capacity, HealthCoverageSource healthCoverage,
                                                QuarantineSource quarantine, OutageSource outage,
                                                Map<String, String> leads, String selfTerm) {
-        return listFleet(workers, sessions, messages, capacity, healthCoverage, quarantine, outage,
-                LeadSeatSource.none(), leads, selfTerm, CoordinationSource.none());
+        return listFleet(workers, sessions, messages, capacity, healthCoverage, LoopHealthSource.none(), quarantine, outage,
+                LeadSeatSource.none(), leads, selfTerm, CoordinationSource.none(), false);
     }
 
     /**
@@ -1586,8 +1626,8 @@ public final class FleetMcp {
                                                CapacitySource capacity, HealthCoverageSource healthCoverage,
                                                QuarantineSource quarantine, Map<String, String> leads, String selfTerm,
                                                CoordinationSource coordination) {
-        return listFleet(workers, sessions, messages, capacity, healthCoverage, quarantine, OutageSource.none(),
-                LeadSeatSource.none(), leads, selfTerm, coordination);
+        return listFleet(workers, sessions, messages, capacity, healthCoverage, LoopHealthSource.none(), quarantine, OutageSource.none(),
+                LeadSeatSource.none(), leads, selfTerm, coordination, false);
     }
 
     /** As above, plus fleetd #201 Unit 5 cool-off facts (see {@link OutageSource}). */
@@ -1595,8 +1635,8 @@ public final class FleetMcp {
                                                CapacitySource capacity, HealthCoverageSource healthCoverage,
                                                QuarantineSource quarantine, OutageSource outage,
                                                Map<String, String> leads, String selfTerm, CoordinationSource coordination) {
-        return listFleet(workers, sessions, messages, capacity, healthCoverage, quarantine, outage,
-                LeadSeatSource.none(), leads, selfTerm, coordination);
+        return listFleet(workers, sessions, messages, capacity, healthCoverage, LoopHealthSource.none(), quarantine, outage,
+                LeadSeatSource.none(), leads, selfTerm, coordination, false);
     }
 
     /**
@@ -1617,7 +1657,7 @@ public final class FleetMcp {
                                                QuarantineSource quarantine, OutageSource outage,
                                                LeadSeatSource leadSeats, Map<String, String> leads, String selfTerm,
                                                CoordinationSource coordination) {
-        return listFleet(workers, sessions, messages, capacity, healthCoverage, quarantine, outage,
+        return listFleet(workers, sessions, messages, capacity, healthCoverage, LoopHealthSource.none(), quarantine, outage,
                 leadSeats, leads, selfTerm, coordination, false);
     }
 
@@ -1637,8 +1677,18 @@ public final class FleetMcp {
      *                        an explicit {@code true}
      */
     static McpSchema.CallToolResult listFleet(PeerLauncher workers, SessionManager sessions, MessageService messages,
-                                               CapacitySource capacity, HealthCoverageSource healthCoverage,
-                                               QuarantineSource quarantine, OutageSource outage,
+                                                CapacitySource capacity, HealthCoverageSource healthCoverage,
+                                                QuarantineSource quarantine, OutageSource outage,
+                                                LeadSeatSource leadSeats, Map<String, String> leads, String selfTerm,
+                                                CoordinationSource coordination, boolean callerIsPrimary) {
+        return listFleet(workers, sessions, messages, capacity, healthCoverage, LoopHealthSource.none(), quarantine,
+                outage, leadSeats, leads, selfTerm, coordination, callerIsPrimary);
+    }
+
+    static McpSchema.CallToolResult listFleet(PeerLauncher workers, SessionManager sessions, MessageService messages,
+                                                 CapacitySource capacity, HealthCoverageSource healthCoverage,
+                                                 LoopHealthSource loopHealth,
+                                                QuarantineSource quarantine, OutageSource outage,
                                                LeadSeatSource leadSeats, Map<String, String> leads, String selfTerm,
                                                CoordinationSource coordination, boolean callerIsPrimary) {
         try {
@@ -1662,6 +1712,9 @@ public final class FleetMcp {
             Map<String, Object> result = new LinkedHashMap<>();
             result.put("leads", leadRows); result.put("members", out);
             result.put("healthCoverage", healthCoverage.value().get());
+            result.put("loopHealth", Map.of(
+                    "statusPoller", loopHealth.statusPoller().get().name(),
+                    "sessionReaper", loopHealth.sessionReaper().get().name()));
             // fleetd #439: coordinator/coordinatorView is lead-to-lead coordination state and must
             // never reach a worker or an architect -- gate BEFORE assembling it, not after, so the
             // key is absent rather than present-and-empty.
@@ -2141,9 +2194,10 @@ public final class FleetMcp {
                         + "cannot reliably re-identify: some backends (e.g. opencode) resolve it from the "
                         + "member's working directory, which only uniquely identifies a member when it "
                         + "was spawned into its own fleetd-provisioned worktree (worktree:true/<slug>); a "
-                        + "member spawned without one shares its directory with others and never reports "
-                        + "an id, however long it runs (fleetd #249). An empty 'members' "
-                        + "means no members are spawned; it says nothing about peers. When capacity "
+                         + "member spawned without one shares its directory with others and never reports "
+                         + "an id, however long it runs (fleetd #249). An empty 'members' "
+                        + "means no members are spawned; it says nothing about peers. 'loopHealth' reports "
+                        + "the RUNNING, STALLED, or STOPPED state of statusPoller and sessionReaper. When capacity "
                         + "facts are configured, a 'capacity' row per profile reports 'free' — the "
                         + "slots a fresh fleet_spawn on that profile will actually be granted right "
                         + "now (max(0, maxLoad - live)), the same check the spawn gate itself runs. A "

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

@@ -94,6 +94,7 @@ public final class FleetApp {
     // .none() (the honest "feature not wired" view) for every constructor that does not pass one.
     private final FleetMcp.QuarantineSource quarantine;
     private final FleetMcp.OutageSource outage;
+    private final FleetMcp.LoopHealthSource loopHealth;
     private final ObjectMapper mapper = new ObjectMapper();
 
     /**
@@ -155,7 +156,8 @@ public final class FleetApp {
                        HttpServlet mcpServlet, CallerResolver auth, Metrics metrics,
                        Predicate<String> deliverable, Supplier<MemberCredentialPolicyView> memberCredentials) {
         this(herdr, memberHerdr, workers, sessions, messages, presence, mcpServlet, auth, metrics,
-                deliverable, memberCredentials, FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none());
+                deliverable, memberCredentials, FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(),
+                FleetMcp.LoopHealthSource.none());
     }
 
     /**
@@ -169,8 +171,18 @@ public final class FleetApp {
     public FleetApp(HerdrClient herdr, HerdrClient memberHerdr, PeerLauncher workers, SessionManager sessions,
                        MessageService messages, MemberPresence presence,
                        HttpServlet mcpServlet, CallerResolver auth, Metrics metrics,
-                       Predicate<String> deliverable, Supplier<MemberCredentialPolicyView> memberCredentials,
-                       FleetMcp.QuarantineSource quarantine, FleetMcp.OutageSource outage) {
+                        Predicate<String> deliverable, Supplier<MemberCredentialPolicyView> memberCredentials,
+                        FleetMcp.QuarantineSource quarantine, FleetMcp.OutageSource outage) {
+        this(herdr, memberHerdr, workers, sessions, messages, presence, mcpServlet, auth, metrics, deliverable,
+                memberCredentials, quarantine, outage, FleetMcp.LoopHealthSource.none());
+    }
+
+    public FleetApp(HerdrClient herdr, HerdrClient memberHerdr, PeerLauncher workers, SessionManager sessions,
+                    MessageService messages, MemberPresence presence,
+                    HttpServlet mcpServlet, CallerResolver auth, Metrics metrics,
+                    Predicate<String> deliverable, Supplier<MemberCredentialPolicyView> memberCredentials,
+                    FleetMcp.QuarantineSource quarantine, FleetMcp.OutageSource outage,
+                    FleetMcp.LoopHealthSource loopHealth) {
         this.herdr = herdr;
         this.memberHerdr = memberHerdr != null ? memberHerdr : herdr;
         this.workers = workers;
@@ -183,6 +195,7 @@ public final class FleetApp {
         this.memberCredentials = memberCredentials != null ? memberCredentials : MemberCredentialPolicyView::absent;
         this.quarantine = quarantine != null ? quarantine : FleetMcp.QuarantineSource.none();
         this.outage = outage != null ? outage : FleetMcp.OutageSource.none();
+        this.loopHealth = loopHealth != null ? loopHealth : FleetMcp.LoopHealthSource.none();
     }
 
     /** Wire routes onto a fresh, unstarted Javalin instance. Caller starts it. */
@@ -291,15 +304,19 @@ public final class FleetApp {
      * spotted by comparing two numbers by eye.
      */
     private void healthz(Context ctx) {
+        HealthzResponse response = healthzResponse(herdr, memberHerdr, loopHealth);
+        ctx.status(response.status()).json(response.body());
+    }
+
+    record HealthzResponse(int status, Map<String, Object> body) { }
+
+    static HealthzResponse healthzResponse(HerdrClient herdr, HerdrClient memberHerdr,
+                                            FleetMcp.LoopHealthSource loopHealth) {
         JsonNode pong;
         try {
             pong = herdr.call("ping");
         } catch (HerdrException e) {
-            ctx.status(503).json(Map.of(
-                    "status", "degraded",
-                    "herdr", "unreachable",
-                    "detail", e.getMessage()));
-            return;
+            return degradedResponse("unreachable", e.getMessage(), loopHealth);
         }
         Map<String, Object> body = new LinkedHashMap<>();
         body.put("status", "ok");
@@ -311,11 +328,11 @@ public final class FleetApp {
             try {
                 memberPong = memberHerdr.call("ping");
             } catch (HerdrException e) {
-                ctx.status(503).json(Map.of(
+                return new HealthzResponse(503, Map.of(
                         "status", "degraded",
                         "herdr", "member unreachable",
-                        "detail", e.getMessage()));
-                return;
+                        "detail", e.getMessage(),
+                        "loopHealth", loopHealthView(loopHealth)));
             }
             int leadProtocol = pong.path("protocol").asInt();
             int memberProtocol = memberPong.path("protocol").asInt();
@@ -326,7 +343,20 @@ public final class FleetApp {
                 body.put("protocolMismatch", true);
             }
         }
-        ctx.status(200).json(body);
+        body.put("loopHealth", loopHealthView(loopHealth));
+        return new HealthzResponse(200, body);
+    }
+
+    private static Map<String, String> loopHealthView(FleetMcp.LoopHealthSource loopHealth) {
+        return Map.of("statusPoller", loopHealth.statusPoller().get().name(),
+                "sessionReaper", loopHealth.sessionReaper().get().name());
+    }
+
+    private static HealthzResponse degradedResponse(String herdr, String detail,
+                                                    FleetMcp.LoopHealthSource loopHealth) {
+        return new HealthzResponse(503, Map.of(
+                "status", "degraded", "herdr", herdr, "detail", detail,
+                "loopHealth", loopHealthView(loopHealth)));
     }
 
     /**

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

@@ -0,0 +1,174 @@
+package dev.ltms.fleet;
+
+import dev.ltms.fleet.herdr.AgentControl;
+import dev.ltms.fleet.herdr.FakeHerdr;
+import dev.ltms.fleet.inject.Injector;
+import dev.ltms.fleet.inject.LoopWatchdog;
+import dev.ltms.fleet.inject.StatusPoller;
+import dev.ltms.fleet.mcp.FleetMcp;
+import dev.ltms.fleet.peer.Capability;
+import dev.ltms.fleet.peer.PeerHandle;
+import dev.ltms.fleet.peer.PeerLauncher;
+import dev.ltms.fleet.peer.SpawnRequest;
+import dev.ltms.fleet.placement.PlacementDecision;
+import dev.ltms.fleet.session.SessionManager;
+import dev.ltms.fleet.session.SessionReaper;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * fleetd #562 follow-up (issue comment "HOLD on PR #579"): {@code Fleetd.main}'s {@code loopHealth}
+ * local used to be a bare {@code new FleetMcp.LoopHealthSource(poller::health, ...)} built inline,
+ * with nothing a test could call directly. Measured on that shape: replacing {@code
+ * poller::health} with a constant {@code () -> LoopWatchdog.State.RUNNING} at the call site
+ * compiled with 0 errors and left all 1771 existing tests green — the daemon could be changed to
+ * always report the {@link StatusPoller} as {@code RUNNING}, so the watchdog could never fire and
+ * a stalled poller would be invisible, while every test stayed green. That is exactly the false
+ * negative this ticket exists to prevent.
+ *
+ * <p>The five tests PR #579 added ({@code FleetMcpTest}, {@code FleetAppTest}) all build their own
+ * {@link FleetMcp.LoopHealthSource} directly with fixed lambdas — they prove the seam ({@code
+ * LoopHealthSource} reports what it is given) and nothing about what {@code Fleetd.main} actually
+ * gives it. This is the same hand-built-vs-config-wired shape as fleetd #561/#248/#426.
+ *
+ * <p>The fix extracts the inline {@code new} into {@link Fleetd#loopHealthSource}, a package-private
+ * factory in the same style as {@link Fleetd#capacitySource} and {@link Fleetd#healthCoverageSource}
+ * — which is exactly what makes it directly callable here. This test calls that factory with real
+ * {@link StatusPoller}/{@link SessionReaper} instances (never started, so no herdr or git I/O
+ * happens) and pins each half separately, plus the {@code reaper == null} branch: one invariant
+ * wired at three places needs three assertions, not one combined check whose non-zero total could
+ * hide a gap at any single place.
+ */
+class FleetdLoopHealthSourceWiringTest {
+
+    @Test
+    @DisplayName("the statusPoller half reports the real poller's health, not a hardcoded state")
+    void statusPollerHalfReflectsThePollersRealHealth() {
+        // Stopped without ever being started — stop() still marks the watchdog STOPPED. A poller
+        // that has never reported RUNNING is the discriminating case: if Fleetd.loopHealthSource
+        // ever hardcoded RUNNING (the exact mutation this test exists to catch), this would fail.
+        StatusPoller stoppedPoller = freshPoller();
+        stoppedPoller.stop();
+        SessionReaper unusedReaper = freshReaper(); // present only to satisfy the signature
+
+        FleetMcp.LoopHealthSource source = Fleetd.loopHealthSource(stoppedPoller, unusedReaper);
+
+        assertEquals(LoopWatchdog.State.STOPPED, source.statusPoller().get(),
+                "the statusPoller supplier must delegate to the real poller's health() — "
+                        + "replacing poller::health with a constant () -> RUNNING at the "
+                        + "Fleetd.loopHealthSource call site must fail this assertion");
+    }
+
+    @Test
+    @DisplayName("the sessionReaper half reports the real reaper's health, not a hardcoded state")
+    void sessionReaperHalfReflectsTheReapersRealHealth() {
+        StatusPoller unusedPoller = freshPoller(); // present only to satisfy the signature
+        SessionReaper stoppedReaper = freshReaper();
+        stoppedReaper.stop();
+
+        FleetMcp.LoopHealthSource source = Fleetd.loopHealthSource(unusedPoller, stoppedReaper);
+
+        assertEquals(LoopWatchdog.State.STOPPED, source.sessionReaper().get(),
+                "the sessionReaper supplier must delegate to the real reaper's health() — "
+                        + "replacing reaper.health() with a constant at the "
+                        + "Fleetd.loopHealthSource call site must fail this assertion");
+    }
+
+    @Test
+    @DisplayName("a null reaper (idle ttl not configured) still reports STOPPED, not a crash")
+    void nullReaperStillReportsStopped() {
+        // SessionReaper is only constructed when lifecycle.idleTtlSeconds is configured (see the
+        // `reaper` local in Fleetd.main) — a real deployment routinely passes null here. That null
+        // check is real behaviour, not a simplification to delete: it must keep reporting STOPPED
+        // rather than throwing a NullPointerException on the first fleet_list/healthz call.
+        StatusPoller runningPoller = freshPoller();
+
+        FleetMcp.LoopHealthSource source = Fleetd.loopHealthSource(runningPoller, null);
+
+        assertEquals(LoopWatchdog.State.STOPPED, source.sessionReaper().get(),
+                "reaper == null must still report STOPPED, exactly like an intentionally-stopped "
+                        + "reaper would — do not delete this null check to simplify the wiring");
+    }
+
+    /** Never started, so no herdr call is ever made; freshly constructed reports RUNNING. */
+    private static StatusPoller freshPoller() {
+        AgentControl agents = new AgentControl(new FakeHerdr());
+        return new StatusPoller(agents, new Injector(agents), 1000);
+    }
+
+    /** Never started, so no git/session I/O is ever made; freshly constructed reports RUNNING. */
+    private static SessionReaper freshReaper() {
+        return new SessionReaper(new SessionManager(new NeverSpawnsLauncher()), 60, 1000);
+    }
+
+    /**
+     * Same minimal shape as {@code FleetdBackendErrorSinkTest.NeverSpawnsLauncher} — every method
+     * throws or returns an empty/no-op value, since a {@link SessionReaper} that is only ever
+     * constructed and then stopped (never started) never calls any of them.
+     */
+    private static final class NeverSpawnsLauncher implements PeerLauncher {
+        @Override
+        public Set<Capability> capabilities() {
+            return Set.of();
+        }
+
+        @Override
+        public Set<Capability> capabilitiesFor(String profileName) {
+            return Set.of();
+        }
+
+        @Override
+        public PeerHandle spawn(SpawnRequest req) {
+            throw new UnsupportedOperationException("not reachable — this test never acquires a session");
+        }
+
+        @Override
+        public PeerHandle spawn(SpawnRequest req, PlacementDecision decision) {
+            throw new UnsupportedOperationException("not reachable — this test never acquires a session");
+        }
+
+        @Override
+        public Set<String> profiles() {
+            return Set.of();
+        }
+
+        @Override
+        public String defaultProfile() {
+            return null;
+        }
+
+        @Override
+        public String effectiveCwd(SpawnRequest req) {
+            throw new UnsupportedOperationException("not reachable — this test never acquires a session");
+        }
+
+        @Override
+        public List<String> parityOverlay(String profileName) {
+            return List.of();
+        }
+
+        @Override
+        public List<?> list() {
+            return List.of();
+        }
+
+        @Override
+        public int reapOrphanWorkers() {
+            return 0;
+        }
+
+        @Override
+        public void stop(String id) {
+        }
+
+        @Override
+        public boolean clearContext(String id) {
+            return false;
+        }
+    }
+}

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

@@ -9,6 +9,7 @@ import dev.ltms.fleet.guard.SubscriptionGuard;
 import dev.ltms.fleet.herdr.AgentControl;
 import dev.ltms.fleet.herdr.AgentStatus;
 import dev.ltms.fleet.herdr.FakeHerdr;
+import dev.ltms.fleet.inject.LoopWatchdog;
 import dev.ltms.fleet.herdr.PaneLocator;
 import dev.ltms.fleet.herdr.WorkspaceControl;
 import dev.ltms.fleet.inject.Injector;
@@ -1084,6 +1085,36 @@ class FleetMcpTest {
         assertFalse(out.contains("quarantinedForSeconds"), out);
     }
 
+    @Test
+    void loopHealthReportsStalledStatusPoller() {
+        String out = loopHealth(LoopWatchdog.State.STALLED, LoopWatchdog.State.RUNNING);
+        assertTrue(out.contains("\"statusPoller\":\"STALLED\""),
+                "fleet_list must report a stalled StatusPoller: " + out);
+    }
+
+    @Test
+    void loopHealthReportsStoppedSessionReaperAsStopped() {
+        String out = loopHealth(LoopWatchdog.State.RUNNING, LoopWatchdog.State.STOPPED);
+        assertTrue(out.contains("\"sessionReaper\":\"STOPPED\""),
+                "fleet_list must report a deliberately stopped SessionReaper as STOPPED, not an alarm: " + out);
+    }
+
+    @Test
+    void loopHealthReportsRunningStatusPoller() {
+        String out = loopHealth(LoopWatchdog.State.RUNNING, LoopWatchdog.State.STOPPED);
+        assertTrue(out.contains("\"statusPoller\":\"RUNNING\""),
+                "fleet_list must report a running StatusPoller: " + out);
+    }
+
+    private static String loopHealth(LoopWatchdog.State statusPoller, LoopWatchdog.State sessionReaper) {
+        FakeHerdr herdr = new FakeHerdr();
+        return textOf(FleetMcp.listFleet(workerService(herdr, "http://gx00.gw:8000", Set.of("gx00.gw")),
+                new SessionManager(workerService(herdr, "http://gx00.gw:8000", Set.of("gx00.gw"))), null,
+                FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
+                new FleetMcp.LoopHealthSource(() -> statusPoller, () -> sessionReaper),
+                FleetMcp.QuarantineSource.none(), Map.of(), ""));
+    }
+
     @Test
     void capacityIncludesConfiguredProfileWithoutMembers() {
         FakeHerdr h = new FakeHerdr();

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

@@ -8,6 +8,7 @@ import dev.ltms.fleet.herdr.AgentControl;
 import dev.ltms.fleet.herdr.FakeHerdr;
 import dev.ltms.fleet.herdr.WorkspaceControl;
 import dev.ltms.fleet.inject.Injector;
+import dev.ltms.fleet.inject.LoopWatchdog;
 import dev.ltms.fleet.inject.StatusPoller;
 import dev.ltms.fleet.inject.MemberPresence;
 import dev.ltms.fleet.msg.InMemoryReplyInbox;
@@ -165,6 +166,29 @@ class FleetAppTest {
         assertEquals("degraded", mapper.readTree(res.body()).get("status").asText());
     }
 
+    @Test
+    void healthzKeepsOkStatusAndReportsLoopHealthInItsBody() {
+        FleetMcp.LoopHealthSource loops = new FleetMcp.LoopHealthSource(
+                () -> LoopWatchdog.State.RUNNING, () -> LoopWatchdog.State.STOPPED);
+
+        FleetApp.HealthzResponse ok = FleetApp.healthzResponse(new FakeHerdr(), new FakeHerdr(), loops);
+        assertEquals(200, ok.status(), "a healthy herdr must keep /healthz at 200 regardless of loop states");
+        assertEquals(Map.of("statusPoller", "RUNNING", "sessionReaper", "STOPPED"), ok.body().get("loopHealth"),
+                "the /healthz body must report each loop state without making STOPPED an alarm");
+    }
+
+    @Test
+    void healthzKeepsDegradedStatusAndReportsLoopHealthInItsBody() {
+        FleetMcp.LoopHealthSource loops = new FleetMcp.LoopHealthSource(
+                () -> LoopWatchdog.State.RUNNING, () -> LoopWatchdog.State.STOPPED);
+        FleetApp.HealthzResponse degraded = FleetApp.healthzResponse(new FakeHerdr().healthy(false),
+                new FakeHerdr(), loops);
+        assertEquals(503, degraded.status(),
+                "an unreachable herdr must keep /healthz at 503 regardless of loop states");
+        assertEquals(Map.of("statusPoller", "RUNNING", "sessionReaper", "STOPPED"),
+                degraded.body().get("loopHealth"), "the degraded /healthz body must retain loop states");
+    }
+
     @Test
     void sessionsMapsWorkspaceList() throws Exception {
         int port = startHealthy();