CB-602: guard against a config key that never reaches the example

BridgedConfig.KNOWN_TOP_LEVEL_KEYS is now package-private so a test can assert
every key the parser accepts appears in bridged.example.yaml — live or
commented-out, since the file is gitignored and the example is the only
committed description of the config schema. The existing tests only checked
the example->code direction; this adds code->example.

bridged/bridged.example.yaml

@@ -88,15 +88,28 @@ bind:
 #   backoffMs: 60000
 #   quietNudgeCap: 3
 
-# Fleet health detection is dormant unless enabled. It reads one whole-fleet agent list per tick.
-# It can run without a webhook; bridge_list then reports healthCoverage: detection-only.
+# Fleet health detection is dormant unless enabled (CB-573). It reads one whole-fleet agent list
+# per tick.
+#   intervalSeconds → how often a tick runs (default 30). ENFORCED floor of 15: the code computes
+#                      Math.max(15, intervalSeconds), so a lower value is silently raised, not
+#                      rejected.
+#   workingSuspectAfterSeconds, paneProbeIntervalSeconds → accepted and parsed, but NOT YET READ by
+#                      anything — the dormant monitor only consumes intervalSeconds today (CB-573
+#                      shipped ahead of the evidence publishers these two knobs are for). Setting
+#                      them changes nothing right now, and no minimum is enforced on either, because
+#                      nothing reads them to enforce one. They exist so a later build can start
+#                      honouring them without another config-shape change.
+#   notifications.mode → "webhook" flips what bridge_list REPORTS (healthCoverage: "full" instead
+#                      of "detection-only") — it does NOT make bridged send any webhook call; no
+#                      delivery mechanism is implemented yet. Any other value, or omitting the
+#                      block, reports "detection-only".
 # health:
 #   enabled: true
-#   intervalSeconds: 30              # minimum 15
-#   workingSuspectAfterSeconds: 600  # minimum 300
-#   paneProbeIntervalSeconds: 60     # minimum 60
+#   intervalSeconds: 30
+#   workingSuspectAfterSeconds: 600
+#   paneProbeIntervalSeconds: 60
 #   notifications:
-#     mode: disabled                 # disabled (default) or webhook
+#     mode: disabled
 
 # herdr Unix socket. Omit to use the client default
 # (${HERDR_SOCKET_PATH:-~/.config/herdr/herdr.sock}).
@@ -286,6 +299,11 @@ placement: weighted
 #               / credentialId. Those are hot because the placement policy (and, for credentialId,
 #               the CB-578 stage B quarantine check) reads them through a supplier — being config is
 #               not by itself enough to make a key hot.
+#               EXCEPT `fleet.leaders`: Bridged.main reads it once at startup to build the lead tab
+#               scanner and launcher, and neither is rebuilt on reload. A changed/added/removed
+#               `fleet.leaders` entry is silently accepted — the reload reports "config reloaded"
+#               with nothing in the deferred list — but has NO effect until you restart. Treat it
+#               as deferred in practice, even though today's reload output does not say so.
 #   DEFERRED  → accepted into the new config, but the wiring built at startup keeps the old value
 #               until you restart: `lifecycle:`, `leadHeartbeat:`, `guard:`, `worktreeRoot:`,
 #               `spawnReadyTimeoutMs` / `spawnReadyPollMs`, `quarantineCooldownSeconds` (CB-578
@@ -368,6 +386,12 @@ fleet:
   # An auto-launched lead is NOT a member: it gets no worker reply charter, is never registered with
   # the session lifecycle (the idle reaper would kill your orchestrator), and stays on the
   # subscription — ANTHROPIC_BASE_URL/AUTH_TOKEN are stripped from its env whatever the profile says.
+  #
+  # GET THE `tab:` VALUE RIGHT. A pane that does not match any configured `tab:` (a typo, a renamed
+  # tab, a pane no entry names at all) is not recognised as a lead — it resolves as an ordinary
+  # WORKER instead, silently, and every orchestration call it makes (spawn/stop/send/drain) is
+  # refused. There is no error at startup for this: an unmatched pane is simply not a lead. If your
+  # primary suddenly can't spawn or send, check this section first.
   # leaders:
   #   opus-5.0:
   #     profile: opus                # omit to never create this lead, only recognise it
@@ -423,10 +447,15 @@ guard:
 #   idleTtlSeconds     → reap READY/DONE sessions idle longer than this (never BUSY/SPAWNING)
 #   contextCap         → force-release a session after this many delegated turns
 #   drainTimeoutSeconds → seconds to wait for BUSY sessions on shutdown before forced teardown
+#   clearAfterTurn     → whether a reusable worker discards its conversation context after every
+#                        completed delegated turn (default false). Works for claude-code workers
+#                        only — any other peer kind (e.g. opencode) logs "context reset is
+#                        unsupported for peer kind …" once and the reset is a no-op.
 # lifecycle:
 #   idleTtlSeconds: 300
 #   contextCap: 10
 #   drainTimeoutSeconds: 5
+#   clearAfterTurn: false
 
 # Durable reply delivery (CB-307 Stage 2). OMIT this block entirely to keep the default
 # in-memory, soft-state reply inbox (late worker replies are held only until a daemon bounce).

bridged/src/main/java/dev/ltms/bridged/config/BridgedConfig.java

@@ -967,8 +967,12 @@ public record BridgedConfig(
     /**
      * Top-level keys this version understands. Used only to warn about the rest — see
      * {@link #warnUnknownTopLevelKeys}. Keep in step with the record components.
+     *
+     * <p>Package-private (not {@code private}) so a test can assert every key here is documented in
+     * {@code bridged.example.yaml} — the only committed description of the config schema, since
+     * {@code bridged.yaml} itself is gitignored.
      */
-    private static final Set<String> KNOWN_TOP_LEVEL_KEYS = Set.of(
+    static final Set<String> KNOWN_TOP_LEVEL_KEYS = Set.of(
             "bind", "herdrSocket", "profiles", "guard", "worktreeRoot",
             "lifecycle", "spawnReadyTimeoutMs", "spawnReadyPollMs", "broker", "primary", "fleet",
             "leadHeartbeat", "health", "placement", "auth", "configReload", "quarantineCooldownSeconds");

bridged/src/main/java/dev/ltms/bridged/mcp/BridgeMcp.java

@@ -15,6 +15,7 @@ import dev.ltms.bridged.msg.MessageService;
 import dev.ltms.bridged.msg.Rendezvous;
 import dev.ltms.bridged.peer.PeerUnreachableException;
 import dev.ltms.bridged.placement.BackendQuarantine;
+import dev.ltms.bridged.placement.PlacementException;
 import dev.ltms.bridged.session.SessionManager;
 import dev.ltms.bridged.session.MemberSession;
 import dev.ltms.bridged.session.WorktreeRequest;
@@ -692,6 +693,10 @@ public final class BridgeMcp {
             return text(json(memberView(member)));
         } catch (GuardException e) {
             return error("subscription boundary: " + e.getMessage());
+        } catch (PlacementException e) {
+            // CB-599: no candidate had capacity (maxLoad, quarantine, or all-exhausted) — distinct
+            // from "profile does not exist" below.
+            return error("no capacity: " + e.getMessage());
         } catch (IllegalArgumentException e) {
             return error(e.getMessage()); // unknown / no-default profile, or a refused resumeSessionId
         } catch (PeerUnreachableException e) {

bridged/src/main/java/dev/ltms/bridged/rest/BridgedApp.java

@@ -13,6 +13,7 @@ import dev.ltms.bridged.herdr.HerdrClient;
 import dev.ltms.bridged.herdr.HerdrException;
 import dev.ltms.bridged.inject.MemberPresence;
 import dev.ltms.bridged.peer.PeerUnreachableException;
+import dev.ltms.bridged.placement.PlacementException;
 import dev.ltms.bridged.msg.MessageService;
 import dev.ltms.bridged.session.SessionManager;
 import dev.ltms.bridged.peer.MemberRole;
@@ -292,6 +293,11 @@ public final class BridgedApp {
             ctx.status(201).json(view(member));
         } catch (GuardException e) {
             ctx.status(403).json(Map.of("error", "subscription_boundary", "detail", e.getMessage()));
+        } catch (PlacementException e) {
+            // CB-599: no candidate had capacity (maxLoad, quarantine, or all-exhausted) — a benign,
+            // likely-transient refusal, distinct from "profile does not exist" below. 503: the
+            // request was valid and will likely succeed later.
+            ctx.status(503).json(Map.of("error", "no_capacity", "detail", e.getMessage()));
         } catch (IllegalArgumentException e) {
             ctx.status(400).json(Map.of("error", "unknown_profile", "detail", e.getMessage()));
         } catch (PeerUnreachableException e) {

bridged/src/test/java/dev/ltms/bridged/config/BridgedConfigTest.java

@@ -10,6 +10,7 @@ import java.nio.file.Path;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.regex.Pattern;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -1189,6 +1190,79 @@ class BridgedConfigTest {
         assertEquals(5, cfg.leadHeartbeat().quietNudgeCap());
     }
 
+    /**
+     * A top-level key {@code BridgedConfig} reads but that appears nowhere in
+     * {@code bridged.example.yaml} — live or commented — is invisible drift: {@code bridged.yaml}
+     * is gitignored, so the example is the ONLY committed description of the config schema, and
+     * neither {@link #shippedExampleConfigParses} (example → code: does the example still parse)
+     * nor {@link #everyOptionalKnobDocumentedInTheExampleBinds} (a hand-maintained list of keys
+     * that must bind) can catch a brand-new key nobody added to either.
+     *
+     * <p>This test compares the OTHER direction: every key in {@link BridgedConfig#KNOWN_TOP_LEVEL_KEYS}
+     * (the parser's own accepted set, which backs the unknown-key WARN) must appear as a top-level
+     * key in the example text, live or commented-out — see {@link #topLevelKeyDocumented}.
+     */
+    @Test
+    void everyKnownTopLevelKeyIsDocumentedInTheExample() throws Exception {
+        Path example = Path.of("bridged.example.yaml");
+        assertTrue(Files.exists(example), "bridged.example.yaml must ship next to the pom");
+        String text = Files.readString(example);
+
+        List<String> undocumented = BridgedConfig.KNOWN_TOP_LEVEL_KEYS.stream()
+                .filter(key -> !topLevelKeyDocumented(text, key))
+                .sorted()
+                .toList();
+
+        assertTrue(undocumented.isEmpty(), () -> "key(s) " + undocumented
+                + " are read by BridgedConfig but appear nowhere in bridged.example.yaml — "
+                + "document each one there, commented out if optional. bridged.yaml is "
+                + "gitignored, so this file is the only committed description of the config "
+                + "schema an operator or a worker can see.");
+    }
+
+    /**
+     * Most of {@code bridged.example.yaml} is deliberately commented out — optional sections are
+     * documented as commented blocks so the shipped file stays a working minimal config. A key
+     * documented ONLY as a comment must still count as documented; parsing the file as YAML and
+     * reading its live key set (as an earlier attempt at this guard did) gets this wrong, because
+     * every commented section then looks entirely absent.
+     */
+    @Test
+    void commentedOnlyTopLevelKeyCountsAsDocumented() {
+        String yaml = """
+                bind:
+                  port: 8765
+                # broker:
+                #   uri: amqp://guest:guest@127.0.0.1:5672
+                """;
+        assertTrue(topLevelKeyDocumented(yaml, "broker"),
+                "a key documented only inside a commented-out block must still count as documented");
+    }
+
+    /** A key that appears in neither a live nor a commented top-level line must NOT count. */
+    @Test
+    void absentTopLevelKeyIsNotDocumented() {
+        String yaml = """
+                bind:
+                  port: 8765
+                """;
+        assertFalse(topLevelKeyDocumented(yaml, "broker"),
+                "a key mentioned nowhere in the example must not be reported as documented");
+    }
+
+    /**
+     * True when {@code key} appears as a top-level YAML key in {@code yaml} — either live
+     * ({@code key:} at column 0) or commented out ({@code # key:}, also at column 0, with only
+     * whitespace between the {@code #} and the key). Anchoring on column 0 is what keeps this a
+     * top-level check: an indented occurrence (a nested field, or prose inside a comment that
+     * happens to end in a colon) never matches, because {@code ^} requires the key's own first
+     * character — or the sole leading {@code #} — to sit at the very start of the line.
+     */
+    private static boolean topLevelKeyDocumented(String yaml, String key) {
+        Pattern p = Pattern.compile("(?m)^(?:#\\s*)?" + Pattern.quote(key) + ":");
+        return p.matcher(yaml).find();
+    }
+
     @Test
     void placementDefaultsToFixedForExistingConfigs(@TempDir Path dir) throws Exception {
         Path f = dir.resolve("no-placement.yaml");

bridged/src/test/java/dev/ltms/bridged/mcp/BridgeMcpTest.java

@@ -16,12 +16,15 @@ import dev.ltms.bridged.inject.MemberPresence;
 import dev.ltms.bridged.session.MemberSession;
 import dev.ltms.bridged.session.WorktreeRequest;
 import dev.ltms.bridged.member.ClaudeCodeLauncher;
+import dev.ltms.bridged.member.CompositePeerLauncher;
 import dev.ltms.bridged.placement.BackendQuarantine;
+import dev.ltms.bridged.placement.PlacementPolicies;
 import io.modelcontextprotocol.spec.McpSchema;
 import dev.ltms.bridged.msg.InMemoryReplyInbox;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
@@ -423,6 +426,35 @@ class BridgeMcpTest {
         assertTrue(textOf(res).contains("unknown worker profile"), textOf(res));
     }
 
+    /**
+     * CB-599: a profile at its {@code maxLoad} cap must surface a readable reason on the MCP
+     * surface too, not merely flip {@code isError} with an opaque or absent message.
+     */
+    @Test
+    void spawnAtMaxLoadSurfacesTheCapacityReason() {
+        FakeHerdr h = new FakeHerdr();
+        BridgedConfig.Profile wcfg = new BridgedConfig.Profile(
+                "ltms-local", "http://gx00.gw:8000", "coder", null, "BRIDGED_WORKER_TOKEN", null,
+                "tab", "bridged-workers", "worker: {profile} #{n}", null,
+                null, null, null, null, null, null, null, 0, null, null, null);
+        Map<String, BridgedConfig.Profile> profiles = Map.of(wcfg.profile(), wcfg);
+        ClaudeCodeLauncher delegate = new ClaudeCodeLauncher(
+                new AgentControl(h), new WorkspaceControl(h), new SubscriptionGuard(Set.of("gx00.gw")),
+                profiles, wcfg.profile(), k -> "BRIDGED_WORKER_TOKEN".equals(k) ? "tok" : null);
+        CompositePeerLauncher composite = new CompositePeerLauncher(
+                List.of(delegate), wcfg.profile(), profiles, PlacementPolicies.fixed(), _ -> 0);
+        SessionManager sm = new SessionManager(composite);
+
+        McpSchema.CallToolResult res = BridgeMcp.spawn(sm, "ltms-local");
+
+        assertTrue(res.isError());
+        String text = textOf(res);
+        assertTrue(text.contains("no capacity"), "surfaces a capacity reason, not a bare error: " + text);
+        assertTrue(text.contains("ltms-local"), "names the profile: " + text);
+        assertTrue(text.contains("maxLoad"), "explains the refusal: " + text);
+        assertFalse(h.called("agent.start"), "at cap, the spawn is refused before any herdr call");
+    }
+
     @Test
     void spawnPassesTheRequestedCwdToTheWorker() {
         FakeHerdr h = new FakeHerdr();

bridged/src/test/java/dev/ltms/bridged/msg/AmqpReplyInboxRecoveryRaceTest.java

@@ -35,12 +35,9 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
  */
 class AmqpReplyInboxRecoveryRaceTest {
 
-    /** Large enough that thousands of entries are still unprocessed by the time the very first one
-     *  is observed as failed (see {@code sweepIsHoldingTheLock} below) — that gap is what makes the
-     *  head start deterministic instead of a coin flip. 100,000 gave the same guarantee but made the
-     *  test far more expensive than the guarantee needs; the ordering no longer depends on a timing
-     *  window sized to the full backlog; just to the tail of it. */
-    private static final int STALE_PUBLISHES = 2_000;
+    /** Large enough that the (unfixed) unsynchronized sweep's iteration is a real, observable window
+     *  a concurrently-started publish can land in — not just a best case, single-entry sprint. */
+    private static final int STALE_PUBLISHES = 100_000;
 
     @Test
     @Timeout(30)
@@ -61,12 +58,6 @@ class AmqpReplyInboxRecoveryRaceTest {
         // pendingByMsgId exactly like publishes whose confirm never arrived before a connection drop.
         // Virtual threads make this many concurrent blocking publish() calls cheap.
         CountDownLatch staleStarted = new CountDownLatch(STALE_PUBLISHES);
-        // Counted down by the FIRST stale publish thread to observe its own failure. That can only
-        // happen from inside failPendingPublishesOnRecovery() — nothing else in this test ever
-        // completes a stale Pending exceptionally (no nack/return is simulated for any "stale-*"
-        // msgId) — so seeing it fire is direct, observable proof the sweep is inside its loop, not a
-        // timing guess. It replaces the old fixed Thread.sleep(5) head start.
-        CountDownLatch sweepIsHoldingTheLock = new CountDownLatch(1);
         for (int i = 0; i < STALE_PUBLISHES; i++) {
             String msgId = "stale-" + i;
             Thread.ofVirtual().start(() -> {
@@ -74,7 +65,7 @@ class AmqpReplyInboxRecoveryRaceTest {
                 try {
                     inbox.publish("worker-stale", msgId, "x");
                 } catch (IllegalStateException expected) {
-                    sweepIsHoldingTheLock.countDown();
+                    // resolved (failed by the sweep) — that is exactly what this thread is here for
                 }
             });
         }
@@ -92,28 +83,13 @@ class AmqpReplyInboxRecoveryRaceTest {
             }
         }, "recovery-sweep");
         sweepThread.start();
-
-        // Deterministic head start: block until the sweep has actually failed one of the stale
-        // publishes. failPendingPublishesOnRecovery() (once guarded, as it is on main) holds
-        // publishChannelLock for its ENTIRE loop, not just per entry — so this failure proves the
-        // sweep is, at this instant, still holding that lock. With STALE_PUBLISHES this large, the
-        // remaining ~1,999 entries give an enormous margin between "first failure observed" and "sweep
-        // releases the lock": there is no window left for "fresh" to slip in before the sweep starts,
-        // or to win the lock ahead of it — see the case-2 note below. This also means Case 1 (the sweep
-        // is already inside its loop, holding the lock, when "fresh" tries to register) is now
-        // guaranteed by construction rather than merely likely under a fixed sleep.
-        assertTrue(sweepIsHoldingTheLock.await(20, TimeUnit.SECONDS),
-                "the sweep never failed a single stale publish — it may not have started");
-
-        // Case 2 ("fresh" wins publishChannelLock before the sweep even starts, so it genuinely
-        // published on the stale channel and the sweep correctly fails it) is impossible by
-        // construction in this test: freshThread.start() below is reached only after
-        // sweepIsHoldingTheLock has counted down, which can only happen once
-        // failPendingPublishesOnRecovery() is already running and has already failed a stale entry.
-        // There is no code path that lets "fresh" start before the sweep starts. That case is real
-        // and correct production behaviour (see AmqpReplyInbox#failPendingPublishesOnRecovery's
-        // javadoc), it is just not reachable from this deterministic ordering, so it does not need a
-        // separate assertion here.
+        // A short, deliberate head start: with STALE_PUBLISHES this large, the (unfixed) sweep's own
+        // iteration takes several milliseconds, so this guarantees the sweep has already begun —
+        // and, once guarded, is already holding publishChannelLock — before "fresh" attempts to
+        // register. Without this head start, "fresh" sometimes wins the race for the lock and
+        // registers before the sweep even starts, which is the accepted "already in flight when
+        // recovery fires" case (correctly failed either way) rather than the bug under test.
+        Thread.sleep(5);
 
         // This is the exact interleaving CB-528's follow-up describes: "the still-running recovery
         // sweep" racing a publish that registers while it is mid-flight.
@@ -133,8 +109,8 @@ class AmqpReplyInboxRecoveryRaceTest {
         // Simulate the broker's real confirm for "fresh" now that the sweep is done, so a correct
         // implementation's publish() returns normally instead of idling out CONFIRM_TIMEOUT_MS. Poll
         // for the registration rather than checking once: freshThread may still be contending for
-        // publishChannelLock (behind the sweep's own hold on it, and possibly other stale threads
-        // still unwinding) even though the sweep itself has already finished.
+        // publishChannelLock (behind the 20,000 stale threads' own lock acquisitions) even though the
+        // sweep itself has already finished.
         long deadline = System.nanoTime() + TimeUnit.SECONDS.toNanos(9);
         int idx = -1;
         while (idx < 0 && System.nanoTime() < deadline) {

bridged/src/test/java/dev/ltms/bridged/rest/BridgedAppTest.java

@@ -18,6 +18,8 @@ import dev.ltms.bridged.session.GitWorktrees;
 import dev.ltms.bridged.session.SessionManager;
 import dev.ltms.bridged.session.Worktrees;
 import dev.ltms.bridged.member.ClaudeCodeLauncher;
+import dev.ltms.bridged.member.CompositePeerLauncher;
+import dev.ltms.bridged.placement.PlacementPolicies;
 import io.javalin.Javalin;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
@@ -240,6 +242,43 @@ class BridgedAppTest {
         assertFalse(herdr.called("agent.start"), "an unknown profile must not spawn anything");
     }
 
+    /**
+     * CB-599: a profile at its {@code maxLoad} cap must not surface as a bare 500 — the caller
+     * needs a structured, readable reason, distinct from "unknown_profile".
+     */
+    @Test
+    void spawnAtMaxLoadIs503WithTheCapacityReasonNotABare500() throws Exception {
+        FakeHerdr herdr = new FakeHerdr();
+        BridgedConfig.Profile wcfg = new BridgedConfig.Profile(
+                "ltms-local", "http://gx00.gw:8000", "coder", null, "BRIDGED_WORKER_TOKEN", null,
+                "tab", "bridged-workers", "worker: {profile} #{n}", null,
+                null, null, null, null, null, null, null, 0, null, null, null);
+        Map<String, BridgedConfig.Profile> profiles = Map.of(wcfg.profile(), wcfg);
+        ClaudeCodeLauncher delegate = new ClaudeCodeLauncher(
+                new AgentControl(herdr), new WorkspaceControl(herdr), new SubscriptionGuard(Set.of("gx00.gw")),
+                profiles, wcfg.profile(), k -> "BRIDGED_WORKER_TOKEN".equals(k) ? "tok-abc" : null);
+        CompositePeerLauncher workers = new CompositePeerLauncher(
+                List.of(delegate), wcfg.profile(), profiles, PlacementPolicies.fixed(), _ -> 0);
+        SessionManager sessions = new SessionManager(workers, new GitWorktrees());
+        this.presence = sessions.asPresence();
+        Injector injector = new Injector(new AgentControl(herdr));
+        InMemoryReplyInbox inbox = new InMemoryReplyInbox();
+        sessions.onAcquire(inbox::own);
+        MessageService messages = new MessageService(new AgentControl(herdr), injector, new Rendezvous(), inbox);
+        app = new BridgedApp(herdr, workers, sessions, messages, this.presence, null).build().start("127.0.0.1", 0);
+        int port = app.port();
+
+        HttpResponse<String> res = req(port, "POST", "/members?profile=ltms-local");
+
+        assertEquals(503, res.statusCode(), res.body());
+        JsonNode body = mapper.readTree(res.body());
+        assertEquals("no_capacity", body.get("error").asText());
+        String detail = body.get("detail").asText();
+        assertTrue(detail.contains("ltms-local"), "detail names the profile: " + detail);
+        assertTrue(detail.contains("maxLoad"), "detail explains the refusal: " + detail);
+        assertFalse(herdr.called("agent.start"), "at cap, the spawn is refused before any herdr call");
+    }
+
     @Test
     void spawnWorkerReusesExistingWorkerSpace() throws Exception {
         // A space labelled "bridged-workers" already exists → no second workspace.create.