fleetd #474: ConfigRef.reload() runs the charter tool-surface gate too

A charter naming an MCP tool the server does not register refused Fleetd.main
at startup but slipped through ConfigRef.reload(), because reload() only ran
FleetConfig.validateAll(), which never looks at what a charter's text names.

CharterToolSurface stays in the mcp package (config must not depend on it), so
ConfigRef now accepts the check as a Consumer<FleetConfig> extraValidation,
run inside reload()'s same try/catch as validateAll(). Fleetd.main wires a new
package-private adapter, Fleetd.assertChartersNameOnlyRegisteredTools, into
both the startup call site and ConfigRef's constructor, so the two call sites
can never check different things.

Tests: ConfigRefTest (reload refuses/accepts, via a locally-built equivalent
consumer since Fleetd's method is package-private to dev.ltms.fleet) and the
new FleetdConfigRefCharterToolSurfaceWiringTest (same proof through the exact
Fleetd::assertChartersNameOnlyRegisteredTools reference production uses).
Verified deleting the new extraValidation.accept(fresh) call site fails both
new "refuses" tests by name.

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

@@ -148,7 +148,10 @@ public final class Fleetd {
         // wiring below reads it, and must, because those decisions cannot be unmade. `config` is the
         // live reference the hot paths read per use. Which keys can actually move is ConfigRef's
         // contract; adding a reader here does not make a key reloadable by itself.
-        ConfigRef config = new ConfigRef(configPath, cfg);
+        // fleetd #474: pass the charter/tool-surface check in as ConfigRef's extraValidation, so
+        // ConfigRef#reload() runs the same gate main() runs below, without dev.ltms.fleet.config
+        // gaining a dependency on dev.ltms.fleet.mcp — Fleetd is the seam that already holds both.
+        ConfigRef config = new ConfigRef(configPath, cfg, Fleetd::assertChartersNameOnlyRegisteredTools);
 
         // The primary/host env that launched fleetd must not be tainted.
         SubscriptionGuard guard = new SubscriptionGuard(cfg.guard().hostSet());
@@ -172,9 +175,9 @@ public final class Fleetd {
         // inside FleetConfig#validateCharters() — config loads before the MCP server exists, and
         // must not gain a dependency on the mcp package — so it runs here instead, at the one seam
         // that already holds both a loaded FleetConfig and the mcp package, before anything below
-        // opens a socket or spawns a member.
-        CharterToolSurface.assertChartersNameOnlyRegisteredTools(
-                cfg.fleet() == null ? Map.of() : cfg.fleet().charters());
+        // opens a socket or spawns a member. fleetd #474: the same check is also wired into `config`
+        // above as ConfigRef's extraValidation, so a reload refuses what this line refuses at startup.
+        assertChartersNameOnlyRegisteredTools(cfg);
 
         Path socket = cfg.herdrSocket() != null && !cfg.herdrSocket().isBlank()
                 ? Path.of(cfg.herdrSocket())
@@ -1594,6 +1597,28 @@ public final class Fleetd {
         }
     }
 
+    /**
+     * fleetd #474: the one place both the startup call (right after {@code cfg.validateAll()} in
+     * {@link #main}) and the reload call (wired into {@code config}'s {@code extraValidation} above,
+     * via a method reference to this method) go through, so the two can never drift into checking
+     * different things. Extracted only to give {@link ConfigRef}'s {@code Consumer<FleetConfig>}
+     * hook a {@code FleetConfig -> void} shape to bind to — {@link CharterToolSurface} itself still
+     * takes the raw charter map and knows nothing about {@code ConfigRef} or {@code Fleetd}.
+     *
+     * <p>Package-private so a test can call it directly the same way the other startup-report
+     * helpers above are tested, without needing to drive {@link #main} for a unit-level check;
+     * {@code FleetdStartupValidationTest} proves the startup call site, and {@code
+     * FleetdConfigRefCharterToolSurfaceWiringTest} — by constructing {@code ConfigRef} with this
+     * exact method reference, the same way {@code main} does above — proves the reload call site.
+     * {@code dev.ltms.fleet.config.ConfigRefTest} pins the same reload behaviour too, through an
+     * equivalent {@code Consumer<FleetConfig>} it builds locally (it cannot see this package-private
+     * method from {@code dev.ltms.fleet.config}).
+     */
+    static void assertChartersNameOnlyRegisteredTools(FleetConfig cfg) {
+        CharterToolSurface.assertChartersNameOnlyRegisteredTools(
+                cfg.fleet() == null ? Map.of() : cfg.fleet().charters());
+    }
+
     /**
      * Poll herdr's {@code ping} until it answers or {@link #HERDR_WAIT_SECONDS} elapses (CB-504).
      *

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

@@ -11,6 +11,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 /**
@@ -211,6 +212,24 @@ import java.util.function.Supplier;
  * <p>A reload that fails to parse or fails validation is also refused, and the previous config keeps
  * running. A config file being edited is normally read once mid-save; degrading a working daemon
  * because it caught a half-written file would be a bad trade.
+ *
+ * <p><strong>fleetd #474</strong> — {@link FleetConfig#validateAll()} is not the only gate startup
+ * runs before a config takes effect: {@code Fleetd.main} also calls {@code
+ * dev.ltms.fleet.mcp.CharterToolSurface#assertChartersNameOnlyRegisteredTools}, right after {@code
+ * cfg.validateAll()}, to refuse a charter that names an MCP tool the server does not register. That
+ * check cannot live inside {@link FleetConfig} — {@code CharterToolSurface} lives in the {@code mcp}
+ * package because the canonical tool set ({@code FleetTool}) does, and config is loaded before the
+ * MCP server exists, so {@code FleetConfig} must not gain a dependency on {@code mcp}. {@link
+ * #reload} cannot import {@code mcp} either, for the same reason applied one layer up: {@code
+ * dev.ltms.fleet.config} is loaded before {@code dev.ltms.fleet.mcp} exists, same as {@code
+ * FleetConfig}. So this class accepts the check as a {@code Consumer<FleetConfig>} —
+ * {@link #extraValidation} — supplied by whichever caller already sits at the seam that holds both
+ * a loaded {@code FleetConfig} and the {@code mcp} package: {@code Fleetd.main}. It is invoked
+ * inside the same try/catch as {@code fresh.validateAll()}, so a charter that would have refused to
+ * boot refuses a reload too, and keeps the running config exactly like any other {@code
+ * validateAll()} failure. A ref built through the two-argument constructor (every test fixture that
+ * does not care about this check, and {@link #fixed}) gets a no-op consumer, so nothing outside
+ * {@code Fleetd.main} needs to know this hook exists.
  */
 public final class ConfigRef implements Supplier<FleetConfig> {
 
@@ -255,10 +274,27 @@ public final class ConfigRef implements Supplier<FleetConfig> {
 
     private final Path path;
     private final AtomicReference<FleetConfig> current;
+    private final Consumer<FleetConfig> extraValidation;
 
+    /** Equivalent to the three-argument constructor with a no-op {@code extraValidation}. */
     public ConfigRef(Path path, FleetConfig initial) {
+        this(path, initial, cfg -> { });
+    }
+
+    /**
+     * @param extraValidation run on every {@link #reload} candidate, inside the same try/catch as
+     *                        {@code fresh.validateAll()} — see the class doc's fleetd #474 note.
+     *                        {@code Fleetd.main} passes {@code
+     *                        Fleetd::assertChartersNameOnlyRegisteredTools} (a package-private
+     *                        {@code FleetConfig -> void} adapter over {@code
+     *                        CharterToolSurface#assertChartersNameOnlyRegisteredTools}), so a reload
+     *                        runs the same gate startup does without this class depending on the
+     *                        {@code mcp} package.
+     */
+    public ConfigRef(Path path, FleetConfig initial, Consumer<FleetConfig> extraValidation) {
         this.path = path;
         this.current = new AtomicReference<>(Objects.requireNonNull(initial, "initial config"));
+        this.extraValidation = Objects.requireNonNull(extraValidation, "extraValidation");
     }
 
     /** A fixed reference that never reloads — for tests and for wiring built from a config in code. */
@@ -360,6 +396,12 @@ public final class ConfigRef implements Supplier<FleetConfig> {
             // at all — see FleetConfig#validateAll's javadoc for why the fix is one reflective call,
             // not a longer hand-maintained list.
             fresh.validateAll();
+            // fleetd #474: validateAll() does not cover everything startup refuses on — the charter
+            // tool-surface check (Fleetd.main, right after cfg.validateAll()) lives outside
+            // FleetConfig on purpose (see this class's doc) and is supplied here as extraValidation.
+            // Same try/catch as validateAll() above, on purpose: either failure must refuse the whole
+            // reload and keep the running config the same way.
+            extraValidation.accept(fresh);
         } catch (RuntimeException e) {
             String msg = e.getMessage() == null ? e.toString() : e.getMessage();
             log.warn("config reload from {} refused, keeping the running config: {}", path, msg);

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

@@ -25,6 +25,20 @@ import java.util.regex.Pattern;
  * {@code fleetd.yaml} could ever fail it. This class is what a real charter is actually checked
  * against at boot; {@code FleetdStartupValidationTest} exercises it through {@code Fleetd.main}
  * itself, the same way it proves every other {@code validateXxx()} still runs there.
+ *
+ * <p><strong>fleetd #474</strong> — startup was not the only door: {@code
+ * dev.ltms.fleet.config.ConfigRef#reload()} used to run {@code FleetConfig#validateAll()} alone,
+ * which does not look at what a charter's text names, so a charter naming an unregistered tool
+ * that could not have booted the daemon could still be installed into a running one through a
+ * reload. This class still knows nothing about {@code ConfigRef} — {@code Fleetd.main} wires a
+ * small {@code FleetConfig -> void} adapter over {@link #assertChartersNameOnlyRegisteredTools}
+ * ({@code Fleetd::assertChartersNameOnlyRegisteredTools}) into {@code ConfigRef}'s constructor as
+ * its {@code Consumer<FleetConfig>} {@code extraValidation}, run inside {@code reload()}'s same
+ * try/catch as {@code validateAll()}, so both call sites — {@code Fleetd.main} at startup and
+ * {@code ConfigRef#reload()} afterwards — go through this one method and can never check different
+ * things. {@code dev.ltms.fleet.config.ConfigRefTest} and {@code
+ * FleetdConfigRefCharterToolSurfaceWiringTest} are what prove the reload call site, the same way
+ * {@code FleetdStartupValidationTest} proves the startup one.
  */
 public final class CharterToolSurface {
 

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

@@ -0,0 +1,106 @@
+package dev.ltms.fleet;
+
+import dev.ltms.fleet.config.ConfigRef;
+import dev.ltms.fleet.config.FleetConfig;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * fleetd #474: proves the exact wiring {@code Fleetd.main} uses to construct its live {@code
+ * ConfigRef} — {@code new ConfigRef(configPath, cfg, Fleetd::assertChartersNameOnlyRegisteredTools)}
+ * — actually makes {@link ConfigRef#reload()} refuse a charter that names an MCP tool the server
+ * does not register, the same way {@code Fleetd.main} itself refuses one at startup (see {@code
+ * FleetdStartupValidationTest#mainRefusesACharterNamingAnUnregisteredTool}).
+ *
+ * <p>{@code dev.ltms.fleet.config.ConfigRefTest} pins the same behaviour through a locally-built
+ * {@code Consumer<FleetConfig>} adapter that calls the same production {@code CharterToolSurface}
+ * method, because that test lives in {@code dev.ltms.fleet.config} and cannot see {@code
+ * Fleetd#assertChartersNameOnlyRegisteredTools} (package-private to {@code dev.ltms.fleet}). This
+ * class is the companion proof that lives where the real method reference is visible, so the literal
+ * expression {@code Fleetd::assertChartersNameOnlyRegisteredTools} — not just an equivalent — is
+ * what gets exercised. {@code Fleetd.main} itself cannot be driven this far in a unit test: every
+ * fixture in {@code FleetdStartupValidationTest} is deliberately invalid so {@code main} throws
+ * before opening a socket, binding Javalin, or doing anything else with a real side effect, so a
+ * test cannot get {@code main} far enough to hold a running daemon it could then reload — this test
+ * builds the {@code ConfigRef} the same way {@code main} does and drives {@link ConfigRef#reload()}
+ * directly instead, the same shape {@code FleetdExhaustionDetectionArmedWiringTest} and its
+ * siblings already use for the rest of {@code Fleetd.main}'s wiring.
+ */
+class FleetdConfigRefCharterToolSurfaceWiringTest {
+
+    private static final String BASE = """
+            bind:
+              host: 127.0.0.1
+              port: 8765
+            herdrSocket: ~/.config/herdr/herdr.sock
+            profiles:
+              sonnet:
+                baseUrl: http://gx00.gw:8000
+                model: sonnet
+            guard:
+              offSubscriptionHosts:
+                - gx00.gw
+            """;
+
+    @Test
+    void reloadRefusesACharterNamingAnUnregisteredToolThroughFleetdsOwnWiring(@TempDir Path dir)
+            throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, BASE + """
+                fleet:
+                  charters:
+                    dev: |
+                      Send the final handoff through fleet_reply.
+                """);
+        ConfigRef config = new ConfigRef(f, FleetConfig.load(f),
+                Fleetd::assertChartersNameOnlyRegisteredTools);
+        FleetConfig before = config.get();
+
+        Files.writeString(f, BASE + """
+                fleet:
+                  charters:
+                    dev: |
+                      Send the final handoff through bridge_send.
+                """);
+        ConfigRef.Outcome out = config.reload();
+
+        assertFalse(out.applied());
+        assertNotNull(out.error());
+        assertTrue(out.error().contains("dev"), out.error());
+        assertTrue(out.error().contains("bridge_send"), out.error());
+        assertSame(before, config.get());
+    }
+
+    @Test
+    void reloadAcceptsACharterNamingOnlyRegisteredToolsThroughFleetdsOwnWiring(@TempDir Path dir)
+            throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, BASE + """
+                fleet:
+                  charters:
+                    dev: old charter
+                """);
+        ConfigRef config = new ConfigRef(f, FleetConfig.load(f),
+                Fleetd::assertChartersNameOnlyRegisteredTools);
+
+        Files.writeString(f, BASE + """
+                fleet:
+                  charters:
+                    dev: |
+                      Send the final handoff through fleet_reply.
+                """);
+        ConfigRef.Outcome out = config.reload();
+
+        assertTrue(out.applied());
+        assertEquals("config reloaded", out.summary());
+    }
+}

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

@@ -1,10 +1,13 @@
 package dev.ltms.fleet.config;
 
+import dev.ltms.fleet.mcp.CharterToolSurface;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.Map;
+import java.util.function.Consumer;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -38,6 +41,23 @@ class ConfigRefTest {
         return new ConfigRef(f, FleetConfig.load(f));
     }
 
+    /**
+     * The exact {@code Consumer<FleetConfig>} {@code Fleetd.main} wires into {@code ConfigRef}'s
+     * constructor as {@code extraValidation} (fleetd #474) — an adapter from {@code FleetConfig} to
+     * the raw charter map {@link CharterToolSurface#assertChartersNameOnlyRegisteredTools} takes.
+     * Built here rather than referencing {@code dev.ltms.fleet.Fleetd} directly, because that method
+     * is package-private to {@code dev.ltms.fleet} and this test lives in {@code
+     * dev.ltms.fleet.config} — but it calls the SAME production {@link CharterToolSurface} method
+     * {@code Fleetd} calls, so this proves the real check runs on reload, not a stand-in for it.
+     */
+    private static final Consumer<FleetConfig> CHARTER_TOOL_SURFACE = cfg ->
+            CharterToolSurface.assertChartersNameOnlyRegisteredTools(
+                    cfg.fleet() == null ? Map.of() : cfg.fleet().charters());
+
+    private static ConfigRef refForWithCharterToolSurface(Path f) {
+        return new ConfigRef(f, FleetConfig.load(f), CHARTER_TOOL_SURFACE);
+    }
+
     @Test
     void aHotChangeIsAppliedAndReadThroughGet(@TempDir Path dir) throws Exception {
         Path f = dir.resolve("fleetd.yaml");
@@ -124,6 +144,87 @@ class ConfigRefTest {
         assertSame(before, ref.get());
     }
 
+    /**
+     * fleetd #474: {@code validateAll()} (via {@code validateCharters()}) only checks that a
+     * charter's KEY is a role wire name and its text is non-blank — it never looks at what the text
+     * names, so a charter naming {@code bridge_send} (the pre-CB-634 name, removed from the tool
+     * surface — #469's own motivating example) passes {@code validateAll()} and used to be applied
+     * on reload with nothing refusing it, even though the identical charter refuses {@code
+     * Fleetd.main} at startup ({@code FleetdStartupValidationTest
+     * #mainRefusesACharterNamingAnUnregisteredTool}). This is the reload-path proof: it drives
+     * {@link ConfigRef#reload()} itself (not a direct call to {@link
+     * CharterToolSurface#assertChartersNameOnlyRegisteredTools}), through the exact {@code
+     * extraValidation} wiring {@code Fleetd.main} uses, and the failure message must name both the
+     * charter key and the unknown tool — the same information the startup failure gives (ticket
+     * acceptance criterion 1).
+     */
+    @Test
+    void aReloadRefusesACharterNamingAnUnregisteredTool(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml("""
+                fleet:
+                  charters:
+                    dev: |
+                      Send the final handoff through fleet_reply.
+                """));
+        ConfigRef ref = refForWithCharterToolSurface(f);
+        FleetConfig before = ref.get();
+
+        Files.writeString(f, yaml("""
+                fleet:
+                  charters:
+                    dev: |
+                      Send the final handoff through bridge_send.
+                """));
+        ConfigRef.Outcome out = ref.reload();
+
+        assertFalse(out.applied());
+        assertNotNull(out.error());
+        assertTrue(out.error().contains("dev"),
+                "expected the charter key 'dev' in the refusal, got: " + out.error());
+        assertTrue(out.error().contains("bridge_send"),
+                "expected the unknown tool 'bridge_send' in the refusal, got: " + out.error());
+        assertTrue(out.summary().startsWith("config reload refused"), out.summary());
+        // The running config must not move at all — half-applying this would leave the daemon in a
+        // state that could never have booted, exactly the outcome ConfigRef.java's class doc warns
+        // a cold-key refusal must avoid, and this check must avoid the same way.
+        assertSame(before, ref.get());
+        assertEquals("Send the final handoff through fleet_reply.\n",
+                ref.get().fleet().charterFor(dev.ltms.fleet.peer.MemberRole.DEV));
+    }
+
+    /**
+     * fleetd #474 acceptance criterion 3, the positive case: a reload whose charter names only
+     * registered tools must still be ACCEPTED. An inverted filter (one that refuses every charter,
+     * or refuses on any {@code fleet_*}/{@code bridge_*} token regardless of registration) would pass
+     * the refusal test above alone — #469's own M5 mutation cell showed exactly that shape surviving
+     * a negative-only suite. This is the test that catches it.
+     */
+    @Test
+    void aReloadAcceptsACharterNamingOnlyRegisteredTools(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml("""
+                fleet:
+                  charters:
+                    dev: old charter, no tool names
+                """));
+        ConfigRef ref = refForWithCharterToolSurface(f);
+
+        Files.writeString(f, yaml("""
+                fleet:
+                  charters:
+                    dev: |
+                      Send the final handoff through fleet_reply, using fleet_send to delegate.
+                """));
+        ConfigRef.Outcome out = ref.reload();
+
+        assertTrue(out.applied());
+        assertTrue(out.deferred().isEmpty(), out.deferred().toString());
+        assertEquals("config reloaded", out.summary());
+        assertEquals("Send the final handoff through fleet_reply, using fleet_send to delegate.\n",
+                ref.get().fleet().charterFor(dev.ltms.fleet.peer.MemberRole.DEV));
+    }
+
     /**
      * The point of the whole class: a consumer holding the ref sees the new value without being
      * rebuilt. A component that captured {@code get()} into a field would still show the old one.