fix(goal): reject ambiguous model checklist results

mateclaw-server/src/main/java/vip/mate/goal/model/GoalCriteriaCodec.java

@@ -60,6 +60,7 @@ public final class GoalCriteriaCodec {
      * Merge a per-round verdict delta into the full checklist by id. Criteria
      * absent from the delta retain their state unless their pass lacks evidence.
      * The criterion text is always kept from the existing item (the verdict never carries text).
+     * Duplicate verdict ids are ambiguous and rejected instead of taking the last value.
      */
     public static List<GoalCriterion> merge(List<GoalCriterion> existing,
                                             List<GoalChecklistVerdict.CriterionVerdict> verdicts) {
@@ -70,7 +71,9 @@ public final class GoalCriteriaCodec {
         if (verdicts != null) {
             for (GoalChecklistVerdict.CriterionVerdict v : verdicts) {
                 if (v != null && v.id() != null) {
-                    byId.put(v.id(), v);
+                    if (byId.putIfAbsent(v.id(), v) != null) {
+                        throw new IllegalArgumentException("Duplicate criterion verdict id");
+                    }
                 }
             }
         }

mateclaw-server/src/main/java/vip/mate/goal/service/GoalEvaluationService.java

@@ -81,10 +81,8 @@ public class GoalEvaluationService implements Evaluator {
     private final ProviderChatModelFactory chatModelFactory;
     private final ObjectMapper objectMapper;
 
-    private final BeanOutputConverter<GoalCriteriaDraft> draftConverter =
-            new BeanOutputConverter<>(GoalCriteriaDraft.class);
-    private final BeanOutputConverter<GoalChecklistVerdict> verdictConverter =
-            new BeanOutputConverter<>(GoalChecklistVerdict.class);
+    private final BeanOutputConverter<GoalCriteriaDraft> draftConverter;
+    private final BeanOutputConverter<GoalChecklistVerdict> verdictConverter;
 
     public GoalEvaluationService(GoalProperties properties,
                                  ModelConfigService modelConfigService,
@@ -94,6 +92,13 @@ public class GoalEvaluationService implements Evaluator {
         this.modelConfigService = modelConfigService;
         this.chatModelFactory = chatModelFactory;
         this.objectMapper = objectMapper;
+        // Preserve converter tolerance for extra fields, but never silently
+        // choose the last value of an ambiguous model-produced JSON key.
+        ObjectMapper evaluatorJson = objectMapper.copy()
+                .disable(com.fasterxml.jackson.databind.DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)
+                .enable(com.fasterxml.jackson.core.JsonParser.Feature.STRICT_DUPLICATE_DETECTION);
+        this.draftConverter = new BeanOutputConverter<>(GoalCriteriaDraft.class, evaluatorJson);
+        this.verdictConverter = new BeanOutputConverter<>(GoalChecklistVerdict.class, evaluatorJson);
     }
 
     /**
@@ -233,7 +238,8 @@ public class GoalEvaluationService implements Evaluator {
                     + "Revoke it when such contradictory evidence exists, citing that evidence. "
                     + "An attempted action, a goal description or a claim of completion is not proof. "
                     + "Newly passed criteria require concrete observable evidence. Return only changed "
-                    + "criterion verdicts; omitted criteria retain their previous state. Keep evidence concise. "
+                    + "criterion verdicts; omitted criteria retain their previous state. Return at most one "
+                    + "verdict per criterion id. Keep evidence concise. "
                     + "Output only the requested JSON.";
 
     private String buildUserPrompt(GoalEntity goal,

mateclaw-server/src/test/java/vip/mate/goal/model/GoalCriteriaCodecTest.java

@@ -12,6 +12,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * Pure unit tests for the checklist (de)serialization + merge helpers.
@@ -51,6 +52,17 @@ class GoalCriteriaCodecTest {
         assertNull(GoalCriteriaCodec.serialize(null, mapper));
     }
 
+    @Test
+    void duplicateVerdictIdsAreRejectedInsteadOfLastWriteWinning() {
+        var existing = List.of(new GoalCriterion("C1", "report", false, ""));
+        var failed = new GoalChecklistVerdict.CriterionVerdict("C1", false, "missing");
+        var passed = new GoalChecklistVerdict.CriterionVerdict("C1", true, "claimed written");
+        assertThrows(IllegalArgumentException.class, () -> GoalCriteriaCodec.merge(existing, List.of(failed, passed)));
+        assertThrows(IllegalArgumentException.class, () -> GoalCriteriaCodec.merge(existing, List.of(passed, failed)));
+        assertThrows(IllegalArgumentException.class, () -> GoalCriteriaCodec.merge(existing, List.of(passed, passed)));
+        assertFalse(existing.getFirst().passed());
+    }
+
     // ---------- merge ----------
 
     @Test

mateclaw-server/src/test/java/vip/mate/goal/service/GoalEvaluationServiceTest.java

@@ -29,6 +29,7 @@ import java.util.List;
 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.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
@@ -269,6 +270,35 @@ class GoalEvaluationServiceTest {
         assertEquals(1.0, r.score(), 1e-9);
     }
 
+    @Test
+    void contradictoryDuplicateVerdictsCannotProduceCompletion() {
+        stubChatResponse("{\"criterionVerdicts\":["
+                + "{\"id\":\"C1\",\"passed\":false,\"evidence\":\"DNS missing\"},"
+                + "{\"id\":\"C1\",\"passed\":true,\"evidence\":\"DNS claimed ready\"},"
+                + "{\"id\":\"C2\",\"passed\":true,\"evidence\":\"TLS ready\"}],\"summary\":\"done\"}");
+        GoalEvaluationResult result = svc.evaluate(goalWithCriteria(), List.of(), "finished");
+        assertFalse(result.completed());
+        assertEquals(GoalEvaluationResult.DECISION_FALLBACK, result.decision());
+        assertEquals(1, result.llmCallsConsumed());
+        assertTrue(result.criterionVerdicts().isEmpty());
+    }
+
+    @Test
+    void duplicateJsonFieldsAreRejectedInVerdictAndBootstrap() {
+        for (boolean bootstrap : List.of(false, true)) {
+            stubChatResponse(bootstrap
+                    ? "{\"criteria\":[{\"text\":\"original requirement\",\"text\":\"replacement\"}]}"
+                    : "{\"criterionVerdicts\":[{\"id\":\"C1\",\"passed\":false,\"passed\":true,\"evidence\":\"claim\"},"
+                            + "{\"id\":\"C2\",\"passed\":true,\"evidence\":\"claim\"}]}");
+            GoalEvaluationResult result = svc.evaluate(bootstrap ? goal() : goalWithCriteria(), List.of(), "finished");
+            assertEquals(GoalEvaluationResult.DECISION_FALLBACK, result.decision());
+            assertFalse(result.completed());
+            assertEquals(1, result.llmCallsConsumed());
+            assertTrue(result.criterionVerdicts().isEmpty());
+            assertNull(result.bootstrapCriteria());
+        }
+    }
+
     // ==================== Parser tolerance ====================
 
     @Test