CB-554: weight <= 0 excludes a profile from automatic placement, not 1.0

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

@@ -1221,6 +1221,42 @@ class BridgedConfigTest {
         assertNull(w.maxLoad(), "absent maxLoad defaults to unlimited (null)");
     }
 
+    @Test
+    void explicitWeightZeroStaysZeroInsteadOfCoercingToOne(@TempDir Path dir) throws Exception {
+        // CB-554: weight: 0 used to be normalised to 1.0 by this same compact constructor, which
+        // made it read as "never auto-select" while behaving as "select like anyone else."
+        Path f = dir.resolve("weight-zero.yaml");
+        Files.writeString(f, """
+                bind:
+                  port: 8080
+                profiles:
+                  opus:
+                    baseUrl: http://gx10.gw:8000
+                    weight: 0
+                """);
+
+        BridgedConfig cfg = BridgedConfig.load(f);
+        BridgedConfig.Profile w = cfg.profiles().get("opus");
+        assertEquals(0.0f, w.weight(), 0.0001f, "an explicit weight: 0 must stay 0, not coerce to 1.0");
+    }
+
+    @Test
+    void negativeWeightNormalisesToZeroNotOne(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("weight-negative.yaml");
+        Files.writeString(f, """
+                bind:
+                  port: 8080
+                profiles:
+                  gx10:
+                    baseUrl: http://gx10.gw:8000
+                    weight: -3.0
+                """);
+
+        BridgedConfig cfg = BridgedConfig.load(f);
+        BridgedConfig.Profile w = cfg.profiles().get("gx10");
+        assertEquals(0.0f, w.weight(), 0.0001f, "a negative weight behaves as excluded (0), not as an error and not as 1.0");
+    }
+
     @Test
     void subscriptionFlagBindsAndDefaultsFalse(@TempDir Path dir) throws Exception {
         Path f = dir.resolve("subscription.yaml");

bridged/src/test/java/dev/ltms/bridged/member/CompositePeerLauncherTest.java

@@ -336,6 +336,42 @@ class CompositePeerLauncherTest {
         assertEquals(10, b);
     }
 
+    @Test
+    void weightedPolicySkipsWeightZeroProfileOnUnqualifiedSpawn() {
+        // CB-554: weight: 0 must exclude a profile from automatic placement, not coerce to 1.0.
+        FakeHerdr herdr = new FakeHerdr();
+        Map<String, BridgedConfig.Profile> profiles = ordered(
+                "a", stubWorker("a", 0.0f, null),
+                "b", stubWorker("b", 1.0f, null));
+        StubLauncher adapter = new StubLauncher("claude", herdr, profiles, "a", Set.of());
+        CompositePeerLauncher composite = new CompositePeerLauncher(
+                List.of(adapter), "a", profiles, PlacementPolicies.weighted(), _ -> 0);
+
+        for (int i = 0; i < 5; i++) {
+            PeerHandle h = composite.spawn(new SpawnRequest(null, null, null));
+            assertEquals("b", h.profile(), "profile a has weight 0, so every unqualified spawn must land on b");
+        }
+        assertEquals(0, adapter.spawnCount("a"), "a is never chosen automatically");
+    }
+
+    @Test
+    void explicitSpawnStillSucceedsOnWeightZeroProfile() {
+        // CB-554: weight: 0 excludes a profile from AUTOMATIC selection only — an explicit
+        // bridge_spawn{profile:"a"} must still work exactly as today (e.g. `opus` on the
+        // operator's own subscription, kept weight-0 so it is never picked automatically).
+        FakeHerdr herdr = new FakeHerdr();
+        Map<String, BridgedConfig.Profile> profiles = ordered(
+                "a", stubWorker("a", 0.0f, null),
+                "b", stubWorker("b", 1.0f, null));
+        StubLauncher adapter = new StubLauncher("claude", herdr, profiles, "b", Set.of());
+        CompositePeerLauncher composite = new CompositePeerLauncher(
+                List.of(adapter), "b", profiles, PlacementPolicies.weighted(), _ -> 0);
+
+        PeerHandle h = composite.spawn(new SpawnRequest("a", null, null));
+        assertEquals("a", h.profile(), "naming a weight-0 profile explicitly bypasses placement and still spawns it");
+        assertEquals(1, adapter.spawnCount("a"));
+    }
+
     @Test
     void failoverRetriesNextCandidateWhenProfileIsUnreachable() {
         FakeHerdr herdr = new FakeHerdr();

bridged/src/test/java/dev/ltms/bridged/placement/PlacementPolicyTest.java

@@ -237,6 +237,105 @@ class PlacementPolicyTest {
         assertTrue(e.getMessage().contains("1 unreachable"), e.getMessage());
     }
 
+    // --- CB-554: weight <= 0 excludes a candidate from automatic selection ------------------
+
+    @Test
+    void weightedSkipsWeightZeroProfile() {
+        PlacementPolicy policy = PlacementPolicies.weighted();
+        List<PlacementCandidate> candidates = List.of(
+                PlacementCandidate.profile("a", 0.0f, null),
+                PlacementCandidate.profile("b", 1.0f, null));
+        for (int i = 0; i < 5; i++) {
+            assertEquals("b", policy.select(ctx(candidates, noSessions())).profile(),
+                    "a has weight 0, so every pick lands on b");
+        }
+    }
+
+    @Test
+    void weightedThrowsWhenAllWeightZero() {
+        PlacementPolicy policy = PlacementPolicies.weighted();
+        List<PlacementCandidate> candidates = List.of(
+                PlacementCandidate.profile("a", 0.0f, null),
+                PlacementCandidate.profile("b", 0.0f, null));
+        PlacementException e = assertThrows(PlacementException.class,
+                () -> policy.select(ctx(candidates, noSessions())));
+        assertTrue(e.getMessage().contains("weight 0"), e.getMessage());
+    }
+
+    @Test
+    void weightedTreatsNegativeWeightAsExcludedNotError() {
+        PlacementPolicy policy = PlacementPolicies.weighted();
+        List<PlacementCandidate> candidates = List.of(
+                PlacementCandidate.profile("a", -1.0f, null),
+                PlacementCandidate.profile("b", 1.0f, null));
+        for (int i = 0; i < 5; i++) {
+            assertEquals("b", policy.select(ctx(candidates, noSessions())).profile(),
+                    "a has a negative weight, so it is excluded like weight 0 — never picked, never an error");
+        }
+    }
+
+    @Test
+    void weightZeroAndQuarantinedIsNotDoubleCounted() {
+        PlacementPolicy policy = PlacementPolicies.weighted();
+        List<PlacementCandidate> candidates = List.of(
+                PlacementCandidate.profile("a", 0.0f, null),
+                PlacementCandidate.profile("b", 1.0f, null),
+                PlacementCandidate.profile("c", 1.0f, null));
+        // a is BOTH weight-0 and quarantined; b and c are quarantined only. If a were counted
+        // into both buckets, "quarantined" would read 3 (or the arithmetic would go negative)
+        // instead of the true count of 2 candidates actually quarantined.
+        PlacementContext mixedCtx = ctx(candidates, noSessions(), Set.of(), Set.of("a", "b", "c"));
+        PlacementException e = assertThrows(PlacementException.class, () -> policy.select(mixedCtx));
+        assertTrue(e.getMessage().contains("1 weight-0"), e.getMessage());
+        assertTrue(e.getMessage().contains("2 quarantined"), e.getMessage());
+        assertTrue(e.getMessage().contains("0 remaining"), e.getMessage());
+    }
+
+    @Test
+    void roundRobinSkipsWeightZeroProfiles() {
+        PlacementPolicy policy = PlacementPolicies.roundRobin();
+        List<PlacementCandidate> candidates = List.of(
+                PlacementCandidate.profile("a", 0.0f, null),
+                PlacementCandidate.profile("b", 1.0f, null));
+        for (int i = 0; i < 5; i++) {
+            assertEquals("b", policy.select(ctx(candidates, noSessions())).profile(),
+                    "a has weight 0, so every pick lands on b");
+        }
+    }
+
+    @Test
+    void roundRobinThrowsWhenAllWeightZero() {
+        PlacementPolicy policy = PlacementPolicies.roundRobin();
+        List<PlacementCandidate> candidates = List.of(
+                PlacementCandidate.profile("a", 0.0f, null),
+                PlacementCandidate.profile("b", 0.0f, null));
+        PlacementException e = assertThrows(PlacementException.class,
+                () -> policy.select(ctx(candidates, noSessions())));
+        assertTrue(e.getMessage().contains("weight 0"), e.getMessage());
+    }
+
+    @Test
+    void fixedSkipsWeightZeroDefault() {
+        PlacementPolicy policy = PlacementPolicies.fixed();
+        PlacementContext ctx = new PlacementContext("b",
+                List.of(PlacementCandidate.profile("a", 1.0f, null),
+                        PlacementCandidate.profile("b", 0.0f, null)),
+                noSessions(), Set.of(), Set.of());
+        assertEquals("a", policy.select(ctx).profile(),
+                "the default 'b' has weight 0, so fixed falls through to the first available candidate");
+    }
+
+    @Test
+    void fixedThrowsWhenDefaultAndEveryCandidateWeightZero() {
+        PlacementPolicy policy = PlacementPolicies.fixed();
+        PlacementContext ctx = new PlacementContext("b",
+                List.of(PlacementCandidate.profile("a", 0.0f, null),
+                        PlacementCandidate.profile("b", 0.0f, null)),
+                noSessions(), Set.of(), Set.of());
+        PlacementException e = assertThrows(PlacementException.class, () -> policy.select(ctx));
+        assertTrue(e.getMessage().contains("weight 0"), e.getMessage());
+    }
+
     @Test
     void unknownPolicyNameThrows() {
         assertThrows(IllegalArgumentException.class, () -> PlacementPolicies.fromName("random"));