fleetd #463: default listFleet's callerIsPrimary to false, fail closed

The compat overload at FleetMcp.java:1373 defaulted callerIsPrimary to a
literal true, so a caller that forgot the argument silently got the
coordinator row (this daemon's coord-id, mailbox state, held-mail previews,
peer reachability) -- lead-to-lead state fleetd #439 just gated. Flip the
default to false: a forgotten argument now yields a missing row instead of
a leaked one.

Six FleetMcpTest methods relied on the implicit true to see the coordinator
row at all; they now pass true explicitly through the canonical overload.
listIsByteForByteUnchangedForThePrimaryCaller's own premise (comparing the
implicit-default path against an explicit-true path) was the shape of the
bug, so it now only exercises the explicit-true path.

Added listCompatOverloadWithNoCallerIsPrimaryArgumentOmitsTheCoordinatorKey
to pin the new default: a compat overload called with no callerIsPrimary
argument, against a fully-configured lead channel, must produce a result
with the coordinator key absent -- not empty, not redacted, absent.

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

@@ -1362,10 +1362,12 @@ public final class FleetMcp {
     /**
      * As above, plus fleetd #176 lead-seat facts (see {@link LeadSeatSource}).
      *
-     * <p>Assumes the caller is the primary — every wrapper overload above delegates here without
-     * carrying a caller identity, which is exactly right for them: they exist for call sites (and
-     * unit tests) that have no {@link Principal} to hand over, and this preserves their pre-#439
-     * behavior unchanged. The one call site that has a real caller ({@code fleet_list}'s MCP
+     * <p>Assumes the caller is <strong>not</strong> the primary (fleetd #463) — every wrapper
+     * overload above delegates here without carrying a caller identity, which is exactly right for
+     * them: they exist for call sites (and unit tests) that have no {@link Principal} to hand over,
+     * and a missing identity should fail closed rather than fail open onto lead-to-lead state. A
+     * test that wants the {@code coordinator} row must call the canonical overload below with an
+     * explicit {@code true}. The one call site that has a real caller ({@code fleet_list}'s MCP
      * handler) uses {@link #listFleet(PeerLauncher, SessionManager, MessageService, CapacitySource,
      * HealthCoverageSource, QuarantineSource, OutageSource, LeadSeatSource, Map, String,
      * CoordinationSource, boolean)} instead, so it can pass the true answer.
@@ -1376,7 +1378,7 @@ public final class FleetMcp {
                                                LeadSeatSource leadSeats, Map<String, String> leads, String selfTerm,
                                                CoordinationSource coordination) {
         return listFleet(workers, sessions, messages, capacity, healthCoverage, quarantine, outage,
-                leadSeats, leads, selfTerm, coordination, true);
+                leadSeats, leads, selfTerm, coordination, false);
     }
 
     /**
@@ -1390,7 +1392,9 @@ public final class FleetMcp {
      * @param callerIsPrimary whether the {@code fleet_list} caller is the primary; only the MCP
      *                        handler computes this from the real connection (see
      *                        {@code Principal#isPrimary()}) — every other overload passes
-     *                        {@code true}
+     *                        {@code false} (fleetd #463: a forgotten argument fails closed, not
+     *                        open), so a test that wants the {@code coordinator} row must pass
+     *                        an explicit {@code true}
      */
     static McpSchema.CallToolResult listFleet(PeerLauncher workers, SessionManager sessions, MessageService messages,
                                                CapacitySource capacity, HealthCoverageSource healthCoverage,

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

@@ -626,8 +626,8 @@ class FleetMcpTest {
         McpSchema.CallToolResult res = FleetMcp.listFleet(
                 workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
                 FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
-                FleetMcp.QuarantineSource.none(), Map.of(), "",
-                new FleetMcp.CoordinationSource(channel, List.of()));
+                FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(), FleetMcp.LeadSeatSource.none(),
+                Map.of(), "", new FleetMcp.CoordinationSource(channel, List.of()), true);
 
         String out = textOf(res);
         // fleetd #361: reports both which coord-id a peer must use to reach ME, and this daemon's
@@ -655,8 +655,8 @@ class FleetMcpTest {
         McpSchema.CallToolResult res = FleetMcp.listFleet(
                 workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
                 FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
-                FleetMcp.QuarantineSource.none(), Map.of(), "",
-                new FleetMcp.CoordinationSource(channel, List.of()));
+                FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(), FleetMcp.LeadSeatSource.none(),
+                Map.of(), "", new FleetMcp.CoordinationSource(channel, List.of()), true);
 
         String out = textOf(res);
         assertTrue(out.contains("\"mailbox\":{\"status\":\"unknown\"}"), out);
@@ -676,6 +676,32 @@ class FleetMcpTest {
                 "an ordinary fleet's output must be unchanged by this feature");
     }
 
+    /**
+     * fleetd #463: a compat overload called with no {@code callerIsPrimary} argument at all must
+     * fail closed, not open. Before this fix the hidden default was {@code true}, so a caller that
+     * forgot the argument silently got lead-to-lead coordination state. Lead coordination is fully
+     * configured here (a real channel, a real mailbox) specifically so this is not conflated with
+     * {@link #listOmitsTheCoordinatorRowWhenLeadCoordinationIsOff} -- the row is capable of being
+     * assembled, and the missing argument is the only reason it is not.
+     */
+    @Test
+    void listCompatOverloadWithNoCallerIsPrimaryArgumentOmitsTheCoordinatorKey() {
+        FakeHerdr h = new FakeHerdr();
+        SessionManager sessions = new SessionManager(workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")));
+        FakeLeadChannel channel = new FakeLeadChannel("mac-opus")
+                .withMailbox("mac-opus", LeadChannel.MailboxState.exists("mac-opus", 0, 1));
+
+        McpSchema.CallToolResult res = FleetMcp.listFleet(
+                workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
+                FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
+                FleetMcp.QuarantineSource.none(), Map.of(), "",
+                new FleetMcp.CoordinationSource(channel, List.of()));
+
+        String out = textOf(res);
+        assertFalse(out.contains("\"coordinator\""),
+                "no callerIsPrimary argument must fail closed (absent), not open (present): " + out);
+    }
+
     /**
      * fleetd #439: a worker calling {@code fleet_list} must get a result with the {@code
      * coordinator} key <strong>absent</strong> -- not an empty object, not a redacted one -- even
@@ -730,11 +756,15 @@ class FleetMcpTest {
     }
 
     /**
-     * fleetd #439 acceptance criterion 3: the primary's {@code fleet_list} is byte-for-byte
-     * unchanged by this fix. Proven by comparing the new gated overload (with {@code
-     * callerIsPrimary=true}, exactly what the MCP handler passes for the primary) against the
-     * pre-#439 overload that always assembled the row -- if the gate changed anything for a
-     * primary caller, these two strings would differ.
+     * fleetd #439 acceptance criterion 3: an explicitly-primary caller sees the coordinator row
+     * fully assembled, with the same content #439 always produced for a primary.
+     *
+     * <p>fleetd #463 flipped the compat overloads' hidden default from {@code true} to
+     * {@code false} (fail closed), so the old "pre-#439 overload" this test used to compare
+     * against no longer stands in for a primary caller -- it is now exactly the implicit-default
+     * path #463 closes. Verifying the primary path means calling the canonical overload with an
+     * explicit {@code callerIsPrimary=true} directly, as the production {@code fleet_list} handler
+     * does.
      */
     @Test
     void listIsByteForByteUnchangedForThePrimaryCaller() {
@@ -743,19 +773,12 @@ class FleetMcpTest {
         FakeLeadChannel channel = new FakeLeadChannel("mac-opus")
                 .withMailbox("mac-opus", LeadChannel.MailboxState.exists("mac-opus", 0, 1));
 
-        String preExisting = textOf(FleetMcp.listFleet(
-                workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
-                FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
-                FleetMcp.QuarantineSource.none(), Map.of(), "",
-                new FleetMcp.CoordinationSource(channel, List.of())));
         String gatedAsPrimary = textOf(FleetMcp.listFleet(
                 workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
                 FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
                 FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(), FleetMcp.LeadSeatSource.none(),
                 Map.of(), "", new FleetMcp.CoordinationSource(channel, List.of()), true));
 
-        assertEquals(preExisting, gatedAsPrimary,
-                "a primary caller must see byte-for-byte the same result as before this fix");
         assertTrue(gatedAsPrimary.contains("\"coordinator\""), gatedAsPrimary);
         assertTrue(gatedAsPrimary.contains("\"selfId\":\"mac-opus\""), gatedAsPrimary);
         assertTrue(gatedAsPrimary.contains("\"mailbox\""), gatedAsPrimary);
@@ -780,8 +803,8 @@ class FleetMcpTest {
         McpSchema.CallToolResult res = FleetMcp.listFleet(
                 workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
                 FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
-                FleetMcp.QuarantineSource.none(), Map.of(), "",
-                new FleetMcp.CoordinationSource(channel, List.of()));
+                FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(), FleetMcp.LeadSeatSource.none(),
+                Map.of(), "", new FleetMcp.CoordinationSource(channel, List.of()), true);
 
         String out = textOf(res);
         assertTrue(out.contains("\"msgId\":\"m1\""), out);
@@ -812,8 +835,8 @@ class FleetMcpTest {
         McpSchema.CallToolResult res = FleetMcp.listFleet(
                 workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
                 FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
-                FleetMcp.QuarantineSource.none(), Map.of(), "",
-                new FleetMcp.CoordinationSource(channel, List.of()));
+                FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(), FleetMcp.LeadSeatSource.none(),
+                Map.of(), "", new FleetMcp.CoordinationSource(channel, List.of()), true);
 
         String out = textOf(res);
         assertTrue(out.contains("\"pending\":0"), out);
@@ -841,8 +864,8 @@ class FleetMcpTest {
         McpSchema.CallToolResult res = FleetMcp.listFleet(
                 workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
                 FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
-                FleetMcp.QuarantineSource.none(), Map.of(), "",
-                new FleetMcp.CoordinationSource(channel, List.of()));
+                FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(), FleetMcp.LeadSeatSource.none(),
+                Map.of(), "", new FleetMcp.CoordinationSource(channel, List.of()), true);
 
         String out = textOf(res);
         assertTrue(out.contains("\"heldDurable\":false"),
@@ -909,8 +932,9 @@ class FleetMcpTest {
         McpSchema.CallToolResult res = FleetMcp.listFleet(
                 workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")), sessions, null,
                 FleetMcp.CapacitySource.none(), new FleetMcp.HealthCoverageSource(() -> "off"),
-                FleetMcp.QuarantineSource.none(), Map.of(), "",
-                new FleetMcp.CoordinationSource(channel, List.of("fleet01-lead", "fleet02-lead", "fleet03-lead")));
+                FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(), FleetMcp.LeadSeatSource.none(),
+                Map.of(), "",
+                new FleetMcp.CoordinationSource(channel, List.of("fleet01-lead", "fleet02-lead", "fleet03-lead")), true);
 
         String out = textOf(res);
         assertTrue(out.contains("\"coordId\":\"fleet01-lead\",\"status\":\"exists\",\"pending\":2,\"consumers\":1"), out);