fleetd #248: make Fleetd's CompletionResolver wiring provable

Before this, dropping either #241's worktree lookup or Unit 5's
backend-error pair at Fleetd.main's new CompletionResolver(...) call
left all 1216 tests green with 0 compile errors. Every existing test
built its own CompletionResolver, so they proved the class and never
the wiring. BackendOutageFlowTest was the sharpest case: it copies
main's sink lambda line-for-line, so it proves the copy and cannot
notice the original being deleted.

The three inline arguments are now package-private static factories on
Fleetd, following the deliverableTo pattern the file already had, each
with its own behaviour test. backendErrorSink is public so a
cross-package test can drive the real production object rather than a
hand-mirrored copy.

The test that was actually missing is a source-text assertion. That is
the honest fallback for a composition root with no seam, and it is
labelled [SOURCE TEXT] in every test name and message so it cannot be
misread as a behaviour check. It is not vacuous: two tests pin that the
variables are assigned from the factories, and two pin that those
variables reach the call site, so renaming a variable while assigning
an inert value does not slip through.

Known cost, accepted: the assertions match exact source substrings, so
reformatting that statement will break them. That is the price of
covering a main method, and a spurious failure here is loud and
obvious, which is the right direction to fail.

Verified by the lead, both mutations re-run against the merged code —
see the merge check.

PR #251

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

@@ -365,11 +365,11 @@ public final class Fleetd {
                 errorPatternsByProfile.put(name, Pattern.compile(profile.errorPattern()));
             }
         });
-        BackendErrorPatternLookup backendErrorPatterns = target -> sessions.roster().stream()
-                .filter(session -> target.equals(session.terminalId()))
-                .findFirst()
-                .map(session -> errorPatternsByProfile.get(session.profile()))
-                .orElse(null);
+        // fleetd #248: extracted to a static factory (see backendErrorPatternLookup below) so a
+        // test can prove main() actually PASSES this into CompletionResolver, not only that the
+        // lookup itself behaves correctly — the exact gap fleetd #248 exists to close.
+        BackendErrorPatternLookup backendErrorPatterns = backendErrorPatternLookup(sessions::roster,
+                errorPatternsByProfile);
         log.info("backend-error classification (fleetd #201 Unit 5): {}",
                 CompletionResolver.coverage(cfg.profiles().keySet(), errorPatternsByProfile.keySet()));
         // CB-578 stage B: on a classification that actually wins, quarantine the exhausted profile's
@@ -424,59 +424,25 @@ public final class Fleetd {
         // construction-order cycle `exhaustionSinkRef` breaks above, broken the same way: a mutable
         // holder set once `pushLoop` exists, read lazily from inside the lambda built here.
         AtomicReference<ReplyPushLoop> pushLoopRef = new AtomicReference<>();
-        // Order: (1) mark the member BACKEND_ERROR; (2) resolve profile/credential through the
-        // roster — fail loud (never Optional.ifPresent, the fleetd #234 lesson applied to this new
-        // sink) and notify the lead via onBackendTargetUnmapped when it cannot be resolved; (3)
-        // record the error in BackendOutagePolicy; (4) on a NEW incident (the record() call that
-        // actually crosses the threshold), tell the lead via onBackendIncident.
-        BackendErrorSink backendErrorSink = (target, matchedLine, reason) -> {
-            sessions.onBackendError(target, reason);
-
-            String profileName = sessions.roster().stream()
-                    .filter(session -> target.equals(session.terminalId()))
-                    .findFirst()
-                    .map(MemberSession::profile)
-                    .orElse(null);
-            FleetConfig.Profile profile = profileName == null ? null : config.get().profiles().get(profileName);
-            if (profile == null) {
-                log.error("backend error on target '{}' ({}) but no profile could be resolved — the "
-                                + "target is not (yet) in the roster — no cool-off applied (fleetd #201 Unit 5)",
-                        target, reason);
-                ReplyPushLoop loop = pushLoopRef.get();
-                if (loop != null) {
-                    loop.onBackendTargetUnmapped(target, reason);
-                }
-                return;
-            }
-            String credentialId = profile.effectiveCredentialId();
-            Optional<BackendOutagePolicy.Incident> incident = outagePolicy.record(credentialId, target, reason);
-            incident.ifPresent(inc -> {
-                List<String> affectedProfiles = config.get().profiles().values().stream()
-                        .filter(p -> credentialId.equals(p.effectiveCredentialId()))
-                        .map(FleetConfig.Profile::profile)
-                        .sorted()
-                        .toList();
-                log.warn("credential '{}' cooling off for {}s after backend errors on {} distinct "
-                                + "target(s) (profile '{}'): {}", credentialId,
-                        inc.remainingCoolOffSeconds(), inc.evidenceCount(), profile.profile(), reason);
-                ReplyPushLoop loop = pushLoopRef.get();
-                if (loop != null) {
-                    loop.onBackendIncident(inc.id(), inc.targets(), credentialId, affectedProfiles,
-                            (int) inc.remainingCoolOffSeconds());
-                }
-            });
-        };
+        // fleetd #248: extracted to a static factory (see backendErrorSink below), public rather
+        // than package-private like the other two factories here, so
+        // dev.ltms.fleet.inject.BackendOutageFlowTest can exercise the REAL production sink
+        // directly instead of a hand-mirrored copy of this lambda — that copy was precisely the
+        // gap fleetd #248 exists to close (see that test's class doc for the history).
+        BackendErrorSink backendErrorSink = backendErrorSink(sessions, () -> config.get().profiles(),
+                outagePolicy, pushLoopRef::get);
         AgentControl agents = router.memberAgents();
         // Both fleetd#201 Unit 5 (backend-error patterns + sink) and fleetd#241 (the worktree/branch
         // lookup the fallback report names) land on this one call. The full constructor takes both,
         // so neither feature is dropped; nowNanos must be passed explicitly to reach it.
+        //
+        // fleetd #248: every argument built specifically for this call (backendErrorPatterns and
+        // backendErrorSink above, and the worktree/branch lookup right here) now comes from a
+        // static factory tested on its own; FleetdCompletionResolverWiringTest source-asserts that
+        // THIS call actually passes them, which is the coverage that was missing before.
         CompletionResolver completion = new CompletionResolver(agents, rendezvous, exhaustedPatterns,
                 exhaustionSink, backendErrorPatterns, backendErrorSink, System::nanoTime,
-                target -> sessions.roster().stream()
-                        .filter(session -> target.equals(session.terminalId()))
-                        .findFirst()
-                        .map(session -> new CompletionResolver.WorktreeBranch(session.worktree(), session.branch()))
-                        .orElse(null));
+                worktreeBranchLookup(sessions::roster));
         // CB-113: deliver only to an available worker (its MCP is connected), never its boot window.
         // CB-301: the manager's presence bridge records availability and drives SPAWNING → READY.
         MemberPresence presence = sessions.asPresence();
@@ -770,6 +736,123 @@ public final class Fleetd {
         return target -> presence.isPresent(target) || leads.get().containsKey(target);
     }
 
+    /**
+     * 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).
+     *
+     * <p>Before this ticket the lookup was an anonymous lambda built inline inside {@code main}'s
+     * {@code CompletionResolver} constructor call — provably untested wiring, the whole reason
+     * fleetd #248 exists: dropping that one argument (passing {@code _ -> null} instead) compiled
+     * clean and left every test green. Extracted here, {@code main} now calls this factory instead
+     * of building the lambda inline, and a source assertion on that call site
+     * ({@code FleetdCompletionResolverWiringTest}) proves the argument is still actually passed.
+     *
+     * <p>Takes the roster as a plain {@link Supplier} — not a {@link SessionManager} — so this is
+     * directly testable with a hand-built session list; no real {@code SessionManager} (launcher,
+     * worktrees, …) needs constructing. Follows the same {@code static} factory pattern as
+     * {@link #deliverableTo} above.
+     *
+     * @param roster the live member roster, normally {@code sessions::roster}
+     */
+    static Function<String, CompletionResolver.WorktreeBranch> worktreeBranchLookup(
+            Supplier<List<MemberSession>> roster) {
+        return target -> roster.get().stream()
+                .filter(session -> target.equals(session.terminalId()))
+                .findFirst()
+                .map(session -> new CompletionResolver.WorktreeBranch(session.worktree(), session.branch()))
+                .orElse(null);
+    }
+
+    /**
+     * fleetd #248 / fleetd#201 Unit 5: package-private factory for the per-target backend-error
+     * pattern lookup {@link CompletionResolver} classifies a pane scrape against. Closes over the
+     * live roster (to resolve a target to a profile) and {@code errorPatternsByProfile} (each
+     * profile's configured {@code errorPattern}, already compiled by the caller — the same map also
+     * feeds the coverage log next to where this is called) — nothing else, so it is directly
+     * testable. See {@link #worktreeBranchLookup} above for why this ticket exists and why the
+     * factory takes a roster {@link Supplier} rather than a {@link SessionManager}.
+     *
+     * @param roster                 the live member roster, normally {@code sessions::roster}
+     * @param errorPatternsByProfile every profile that has an {@code errorPattern} configured,
+     *                               keyed by profile name
+     */
+    static BackendErrorPatternLookup backendErrorPatternLookup(Supplier<List<MemberSession>> roster,
+            Map<String, Pattern> errorPatternsByProfile) {
+        return target -> roster.get().stream()
+                .filter(session -> target.equals(session.terminalId()))
+                .findFirst()
+                .map(session -> errorPatternsByProfile.get(session.profile()))
+                .orElse(null);
+    }
+
+    /**
+     * fleetd #248 / fleetd#201 Unit 5: factory for the production {@link BackendErrorSink} — the
+     * collaborator {@link CompletionResolver} notifies when a pane-scrape classification actually
+     * resolves a waiter as a backend error. Order: (1) mark the member BACKEND_ERROR; (2) resolve
+     * profile/credential through the roster — fail loud (never {@code Optional.ifPresent}, the
+     * fleetd #234 lesson applied to this sink) and notify the lead via {@code
+     * onBackendTargetUnmapped} when it cannot be resolved; (3) record the error in {@code
+     * outagePolicy}; (4) on a NEW incident (the {@code record()} call that actually crosses the
+     * threshold), tell the lead via {@code onBackendIncident}.
+     *
+     * <p>{@code public}, unlike {@link #worktreeBranchLookup} and {@link #backendErrorPatternLookup}
+     * above: {@code dev.ltms.fleet.inject.BackendOutageFlowTest} exercises this exact object as the
+     * real, wired production path, replacing what its own class doc used to call out as a
+     * hand-mirrored copy of this lambda ("mirrors {@code Fleetd.main}'s {@code backendErrorSink}
+     * lambda line-for-line") — that copy proved only itself, never that {@code main} still wires the
+     * real thing. That was precisely the gap fleetd #248 exists to close.
+     *
+     * @param sessions the session registry; both read (roster) and written (onBackendError)
+     * @param profiles the live profile map, normally {@code () -> config.get().profiles()} in
+     *                 {@code main}, or a fixed test map via {@code () -> profiles}
+     * @param pushLoop the lead-nudge loop, read lazily: {@code main} builds this sink before the
+     *                 real {@link ReplyPushLoop} exists (a genuine construction-order cycle, broken
+     *                 the same way {@code exhaustionSinkRef} is a few lines above it), so a
+     *                 {@link Supplier} reads whatever {@code main} has filled in by the time a real
+     *                 backend error fires
+     */
+    public static BackendErrorSink backendErrorSink(SessionManager sessions,
+            Supplier<Map<String, FleetConfig.Profile>> profiles, BackendOutagePolicy outagePolicy,
+            Supplier<ReplyPushLoop> pushLoop) {
+        return (target, matchedLine, reason) -> {
+            sessions.onBackendError(target, reason);
+
+            String profileName = sessions.roster().stream()
+                    .filter(session -> target.equals(session.terminalId()))
+                    .findFirst()
+                    .map(MemberSession::profile)
+                    .orElse(null);
+            FleetConfig.Profile profile = profileName == null ? null : profiles.get().get(profileName);
+            if (profile == null) {
+                log.error("backend error on target '{}' ({}) but no profile could be resolved — the "
+                                + "target is not (yet) in the roster — no cool-off applied (fleetd #201 Unit 5)",
+                        target, reason);
+                ReplyPushLoop loop = pushLoop.get();
+                if (loop != null) {
+                    loop.onBackendTargetUnmapped(target, reason);
+                }
+                return;
+            }
+            String credentialId = profile.effectiveCredentialId();
+            Optional<BackendOutagePolicy.Incident> incident = outagePolicy.record(credentialId, target, reason);
+            incident.ifPresent(inc -> {
+                List<String> affectedProfiles = profiles.get().values().stream()
+                        .filter(p -> credentialId.equals(p.effectiveCredentialId()))
+                        .map(FleetConfig.Profile::profile)
+                        .sorted()
+                        .toList();
+                log.warn("credential '{}' cooling off for {}s after backend errors on {} distinct "
+                                + "target(s) (profile '{}'): {}", credentialId,
+                        inc.remainingCoolOffSeconds(), inc.evidenceCount(), profile.profile(), reason);
+                ReplyPushLoop loop = pushLoop.get();
+                if (loop != null) {
+                    loop.onBackendIncident(inc.id(), inc.targets(), credentialId, affectedProfiles,
+                            (int) inc.remainingCoolOffSeconds());
+                }
+            });
+        };
+    }
+
     /** Injection seam for {@link #selectReplyInbox}: production binds {@link AmqpReplyInbox#open}. */
     @FunctionalInterface
     interface AmqpOpener {

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

@@ -0,0 +1,59 @@
+package dev.ltms.fleet;
+
+import dev.ltms.fleet.inject.BackendErrorPatternLookup;
+import dev.ltms.fleet.peer.MemberRole;
+import dev.ltms.fleet.session.MemberSession;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Map;
+import java.util.regex.Pattern;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+/**
+ * fleetd #248 / fleetd#201 Unit 5: {@link Fleetd#backendErrorPatternLookup} is the factory that
+ * replaced the local lambda {@code Fleetd.main} used to build {@code backendErrorPatterns} — one
+ * of the two arguments {@code CompletionResolver} lost cleanly (0 compile errors, every test still
+ * green) when this ticket's measurement dropped it alongside {@code backendErrorSink}. This class
+ * proves the factory's own behaviour; {@code FleetdCompletionResolverWiringTest} proves {@code
+ * main} still passes its result into {@code CompletionResolver}.
+ */
+class FleetdBackendErrorPatternLookupTest {
+
+    private static MemberSession session(String terminal, String profile) {
+        return new MemberSession("pane-" + terminal, terminal, profile, MemberRole.DEV,
+                "/cwd", null, 0L, 0L, 0, MemberSession.State.READY, null, null);
+    }
+
+    @Test
+    @DisplayName("a target on a profile with a configured pattern resolves to that pattern")
+    void configuredProfileResolves() {
+        Map<String, Pattern> byProfile = Map.of("terra", Pattern.compile("(?i)503"));
+        BackendErrorPatternLookup lookup =
+                Fleetd.backendErrorPatternLookup(() -> List.of(session("term1", "terra")), byProfile);
+
+        assertEquals("(?i)503", lookup.patternFor("term1").pattern());
+    }
+
+    @Test
+    @DisplayName("a target on a profile with no configured pattern resolves to null")
+    void unconfiguredProfileResolvesToNull() {
+        Map<String, Pattern> byProfile = Map.of("terra", Pattern.compile("x"));
+        BackendErrorPatternLookup lookup =
+                Fleetd.backendErrorPatternLookup(() -> List.of(session("term1", "sol")), byProfile);
+
+        assertNull(lookup.patternFor("term1"));
+    }
+
+    @Test
+    @DisplayName("an unknown target resolves to null")
+    void unknownTargetResolvesToNull() {
+        BackendErrorPatternLookup lookup =
+                Fleetd.backendErrorPatternLookup(List::of, Map.of("terra", Pattern.compile("x")));
+
+        assertNull(lookup.patternFor("term_stranger"));
+    }
+}

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

@@ -0,0 +1,229 @@
+package dev.ltms.fleet;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+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.HerdrClient;
+import dev.ltms.fleet.herdr.WorkspaceControl;
+import dev.ltms.fleet.inject.BackendErrorSink;
+import dev.ltms.fleet.member.ClaudeCodeLauncher;
+import dev.ltms.fleet.member.CompositePeerLauncher;
+import dev.ltms.fleet.mcp.PrimaryRegistry;
+import dev.ltms.fleet.msg.InMemoryReplyInbox;
+import dev.ltms.fleet.msg.ReplyPushLoop;
+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.BackendOutagePolicy;
+import dev.ltms.fleet.placement.BackendQuarantine;
+import dev.ltms.fleet.placement.PlacementPolicies;
+import dev.ltms.fleet.session.MemberSession;
+import dev.ltms.fleet.session.SessionManager;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #248 / fleetd#201 Unit 5: {@link Fleetd#backendErrorSink} is the factory that replaced
+ * the local lambda {@code Fleetd.main} used to build {@code backendErrorSink} — the other half of
+ * the pair this ticket's measurement dropped cleanly (0 compile errors, every test still green).
+ *
+ * <p>Before this ticket, the closest thing to coverage was {@code
+ * dev.ltms.fleet.inject.BackendOutageFlowTest}, whose own class doc said it "mirrors {@code
+ * Fleetd.main}'s {@code backendErrorSink} lambda line-for-line" — a hand-copy that proves itself,
+ * never that {@code main} still wires the real thing. This class exercises the actual production
+ * factory instead. {@code FleetdCompletionResolverWiringTest} proves {@code main} still passes its
+ * result into {@code CompletionResolver}.
+ */
+class FleetdBackendErrorSinkTest {
+
+    private final List<ScheduledExecutorService> schedulers = new ArrayList<>();
+
+    @AfterEach
+    void tearDown() {
+        schedulers.forEach(ScheduledExecutorService::shutdownNow);
+    }
+
+    private static FleetConfig.Profile stubWorker(String profile, String credentialId) {
+        return new FleetConfig.Profile(profile, "http://gx00.gw:8000", "coder",
+                null, "FLEETD_WORKER_TOKEN", List.of("claude"), "tab", "fleetd-workers",
+                "w #{n}", null, null, null, null, null, null, null, null, null,
+                null, null, credentialId, null);
+    }
+
+    private static Map<String, FleetConfig.Profile> orderedProfiles() {
+        Map<String, FleetConfig.Profile> m = new LinkedHashMap<>();
+        m.put("terra", stubWorker("terra", "shared-openai"));
+        m.put("sol", stubWorker("sol", "shared-openai"));
+        return m;
+    }
+
+    /** Minimal recording {@code HerdrClient} for the LEAD pane — mirrors ReplyPushLoopTest's own. */
+    private static final class RecordingLeadClient implements HerdrClient {
+        private static final ObjectMapper MAPPER = new ObjectMapper();
+        private final List<Object> prompts = new CopyOnWriteArrayList<>();
+        volatile CountDownLatch sendLatch = new CountDownLatch(1);
+
+        @Override
+        public JsonNode call(String method, Object params) {
+            if ("agent.get".equals(method)) {
+                return MAPPER.createObjectNode().set("agent", MAPPER.createObjectNode()
+                        .put("terminal_id", "term_primary").put("agent_status", "idle"));
+            }
+            if ("agent.prompt".equals(method)) {
+                prompts.add(params);
+                sendLatch.countDown();
+            }
+            return MAPPER.createObjectNode();
+        }
+
+        @Override
+        public void close() {
+        }
+
+        int sendCount() {
+            return prompts.size();
+        }
+    }
+
+    /** A {@link PeerLauncher} that never actually spawns — enough to construct a bare {@link SessionManager}. */
+    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 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;
+        }
+    }
+
+    @Test
+    @DisplayName("a target with no resolvable profile logs and returns without recording an incident (never throws)")
+    void unresolvableProfileDoesNotRecordOrThrow() {
+        SessionManager sessions = new SessionManager(new NeverSpawnsLauncher());
+        BackendOutagePolicy outagePolicy = new BackendOutagePolicy(() -> 0L);
+        RecordingLeadClient leadClient = new RecordingLeadClient();
+        InMemoryReplyInbox inbox = new InMemoryReplyInbox();
+        PrimaryRegistry registry = new PrimaryRegistry(null);
+        ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
+        schedulers.add(scheduler);
+        ReplyPushLoop pushLoop = new ReplyPushLoop(registry, new AgentControl(leadClient), inbox, scheduler, 3, 50);
+
+        BackendErrorSink sink = Fleetd.backendErrorSink(sessions, Map::of, outagePolicy, () -> pushLoop);
+        sink.onBackendError("term_unmapped", "matched line", "503 Service Unavailable");
+
+        assertTrue(outagePolicy.remainingCoolOffSeconds("shared-openai").isEmpty(),
+                "no credential is ever resolvable here, so nothing must be recorded");
+    }
+
+    @Test
+    @DisplayName("two distinct targets classified through the real factory start an incident and cool the credential")
+    void twoDistinctTargetsStartAnIncident() throws Exception {
+        FakeHerdr herdr = new FakeHerdr()
+                .readText("⏺ 503 Service Unavailable: upstream credential rejected\n❯ ");
+        Map<String, FleetConfig.Profile> profiles = orderedProfiles();
+        AtomicLong clockNanos = new AtomicLong(0L);
+        BackendOutagePolicy outagePolicy = new BackendOutagePolicy(clockNanos::get);
+        ClaudeCodeLauncher adapter = new ClaudeCodeLauncher(new AgentControl(herdr),
+                new WorkspaceControl(herdr), new SubscriptionGuard(Set.of("gx00.gw")),
+                profiles, "terra", _ -> "tok");
+        CompositePeerLauncher workers = new CompositePeerLauncher(List.of(adapter), "terra", profiles,
+                PlacementPolicies.weighted(), _ -> 0, null, BackendQuarantine.none(), outagePolicy);
+        SessionManager sessions = new SessionManager(workers);
+        MemberSession s1 = sessions.acquire("terra", null, null, null);
+        MemberSession s2 = sessions.acquire("terra", null, null, null);
+
+        PrimaryRegistry registry = new PrimaryRegistry(null);
+        registry.recordDelegation(s1.terminalId(), "term_primary");
+        registry.recordDelegation(s2.terminalId(), "term_primary");
+        InMemoryReplyInbox inbox = new InMemoryReplyInbox();
+        inbox.own(s1.terminalId());
+        inbox.own(s2.terminalId());
+        RecordingLeadClient leadClient = new RecordingLeadClient();
+        ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
+        schedulers.add(scheduler);
+        ReplyPushLoop pushLoop = new ReplyPushLoop(registry, new AgentControl(leadClient), inbox, scheduler, 3, 50);
+        AtomicReference<ReplyPushLoop> pushLoopRef = new AtomicReference<>(pushLoop);
+
+        // The exact object under test: Fleetd's real production factory, not a hand copy.
+        BackendErrorSink sink = Fleetd.backendErrorSink(sessions, () -> profiles, outagePolicy, pushLoopRef::get);
+
+        sink.onBackendError(s1.terminalId(), "matched line", "503 Service Unavailable");
+        assertTrue(outagePolicy.remainingCoolOffSeconds("shared-openai").isEmpty(),
+                "one distinct target must not start a cool-off");
+
+        sink.onBackendError(s2.terminalId(), "matched line", "503 Service Unavailable");
+
+        assertTrue(leadClient.sendLatch.await(3, TimeUnit.SECONDS),
+                "the second distinct target must cross the threshold and nudge the lead");
+        var remaining = outagePolicy.remainingCoolOffSeconds("shared-openai");
+        assertTrue(remaining.isPresent(), "two distinct targets must start a cool-off");
+        assertEquals(1, leadClient.sendCount());
+    }
+}

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

@@ -0,0 +1,89 @@
+package dev.ltms.fleet;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #248: this is the test that was actually missing. {@code Fleetd.main} builds its {@code
+ * CompletionResolver} from an 8-argument constructor, and the ticket's own measurement proved two
+ * ways to silently unwire it — both compiled with 0 errors and left every existing test green:
+ *
+ * <ul>
+ *   <li>replacing the worktree/branch argument (the 8th) with {@code _ -> null} — drops
+ *       fleetd#241's fallback-report location entirely;</li>
+ *   <li>replacing {@code backendErrorPatterns, backendErrorSink} (5th/6th) with {@code
+ *       BackendErrorPatternLookup.legacy(), BackendErrorSink.none()} — drops fleetd#201 Unit 5's
+ *       backend-error classification and cool-off entirely.</li>
+ * </ul>
+ *
+ * <p>Neither mutation could be caught by any test that constructs its own {@code
+ * CompletionResolver} (every test before this one did exactly that) or by a test of {@link
+ * Fleetd#worktreeBranchLookup}, {@link Fleetd#backendErrorPatternLookup}, or {@link
+ * Fleetd#backendErrorSink} in isolation (see {@code FleetdWorktreeBranchLookupTest}, {@code
+ * FleetdBackendErrorPatternLookupTest}, {@code FleetdBackendErrorSinkTest}) — those prove the
+ * factories work, never that {@code main} still calls them. This class is a plain source-text
+ * assertion on {@code Fleetd.java} — crude, but honest about what it checks, and it turns red the
+ * instant the wiring is dropped, mirroring the same fallback shape {@link
+ * FleetdFleetAppConstructionTest} already uses for a different constructor argument.
+ *
+ * <p><b>This test checks source text, not runtime behaviour.</b> It never constructs a {@code
+ * CompletionResolver} and never runs {@code main}.
+ */
+class FleetdCompletionResolverWiringTest {
+
+    private static String fleetdSource() throws Exception {
+        return Files.readString(Path.of("src/main/java/dev/ltms/fleet/Fleetd.java"));
+    }
+
+    @Test
+    @DisplayName("[SOURCE TEXT] CompletionResolver's construction call still names backendErrorPatterns and backendErrorSink")
+    void backendErrorArgumentsAreStillNamedAtTheCallSite() throws Exception {
+        String source = fleetdSource();
+        assertTrue(source.contains(
+                        "exhaustionSink, backendErrorPatterns, backendErrorSink, System::nanoTime,"),
+                "CompletionResolver's construction call must still pass backendErrorPatterns and "
+                        + "backendErrorSink as its 5th/6th arguments. Replacing them with "
+                        + "BackendErrorPatternLookup.legacy()/BackendErrorSink.none() (fleetd #248's measured "
+                        + "mutation) compiles with 0 errors and leaves every behavioural test green — this "
+                        + "source check is what must go red instead.");
+    }
+
+    @Test
+    @DisplayName("[SOURCE TEXT] CompletionResolver's construction call still passes worktreeBranchLookup(sessions::roster)")
+    void worktreeBranchLookupIsStillPassedAtTheCallSite() throws Exception {
+        String source = fleetdSource();
+        assertTrue(source.contains("worktreeBranchLookup(sessions::roster)"),
+                "CompletionResolver's construction call must still pass worktreeBranchLookup(sessions::roster) "
+                        + "as its 8th (last) argument. Replacing it with the inert `_ -> null` (fleetd #248's "
+                        + "other measured mutation) compiles with 0 errors and leaves every behavioural test "
+                        + "green — this source check is what must go red instead.");
+        assertFalse(source.contains("System::nanoTime,\n                _ -> null"),
+                "the worktree/branch argument must never regress to the inert `_ -> null` literal");
+    }
+
+    @Test
+    @DisplayName("[SOURCE TEXT] backendErrorPatterns is assigned from the extracted backendErrorPatternLookup(...) factory")
+    void backendErrorPatternsComesFromTheFactory() throws Exception {
+        String source = fleetdSource();
+        assertTrue(source.contains(
+                        "BackendErrorPatternLookup backendErrorPatterns = backendErrorPatternLookup(sessions::roster,"),
+                "backendErrorPatterns must be assigned from Fleetd.backendErrorPatternLookup(...), not an "
+                        + "inline lambda that a source check on the CompletionResolver call alone cannot see "
+                        + "through");
+    }
+
+    @Test
+    @DisplayName("[SOURCE TEXT] backendErrorSink is assigned from the extracted backendErrorSink(...) factory")
+    void backendErrorSinkComesFromTheFactory() throws Exception {
+        String source = fleetdSource();
+        assertTrue(source.contains(
+                        "BackendErrorSink backendErrorSink = backendErrorSink(sessions, () -> config.get().profiles(),"),
+                "backendErrorSink must be assigned from Fleetd.backendErrorSink(...), not an inline lambda "
+                        + "that a source check on the CompletionResolver call alone cannot see through");
+    }
+}

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

@@ -0,0 +1,64 @@
+package dev.ltms.fleet;
+
+import dev.ltms.fleet.inject.CompletionResolver;
+import dev.ltms.fleet.peer.MemberRole;
+import dev.ltms.fleet.session.MemberSession;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Function;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+/**
+ * fleetd #248: {@link Fleetd#worktreeBranchLookup} is the factory that replaced the anonymous
+ * lambda {@code Fleetd.main} used to build inline, as the 8th (last) argument to {@code
+ * CompletionResolver}'s constructor. Before this ticket that argument was untestable wiring:
+ * replacing it with {@code _ -> null} compiled clean and every existing test stayed green, because
+ * every existing test builds its own {@code CompletionResolver} directly rather than going through
+ * {@code main}. This class proves the factory's own behaviour; {@code
+ * FleetdCompletionResolverWiringTest} proves {@code main} still passes it in.
+ */
+class FleetdWorktreeBranchLookupTest {
+
+    private static MemberSession session(String terminal, String worktree, String branch) {
+        return new MemberSession("pane-" + terminal, terminal, "terra", MemberRole.DEV,
+                "/cwd", null, 0L, 0L, 0, MemberSession.State.READY, worktree, branch);
+    }
+
+    @Test
+    @DisplayName("a known target resolves to its session's worktree and branch")
+    void knownTargetResolves() {
+        Function<String, CompletionResolver.WorktreeBranch> lookup =
+                Fleetd.worktreeBranchLookup(() -> List.of(session("term1", "/wt/worker_x", "worker/x")));
+
+        CompletionResolver.WorktreeBranch resolved = lookup.apply("term1");
+
+        assertEquals("/wt/worker_x", resolved.worktree());
+        assertEquals("worker/x", resolved.branch());
+    }
+
+    @Test
+    @DisplayName("an unknown target resolves to null, not a thrown exception")
+    void unknownTargetResolvesToNull() {
+        Function<String, CompletionResolver.WorktreeBranch> lookup =
+                Fleetd.worktreeBranchLookup(() -> List.of(session("term1", "/wt/worker_x", "worker/x")));
+
+        assertNull(lookup.apply("term_stranger"));
+    }
+
+    @Test
+    @DisplayName("the roster is read through the supplier on every call, not snapshotted")
+    void rosterIsReadThroughOnEveryCall() {
+        List<MemberSession> roster = new ArrayList<>();
+        Function<String, CompletionResolver.WorktreeBranch> lookup = Fleetd.worktreeBranchLookup(() -> roster);
+
+        assertNull(lookup.apply("term_late"));
+        roster.add(session("term_late", "/wt/late", "worker/late"));
+
+        assertEquals("/wt/late", lookup.apply("term_late").worktree());
+    }
+}