feat(harness): improve trace fallback and reasoning audit

src/main/java/com/superbiz/agent/config/HarnessChatConfiguration.java

@@ -50,8 +50,10 @@ import com.superbiz.agent.harness.application.KnowledgeQueryOperation;
 import com.superbiz.agent.harness.application.SystemChatOperation;
 import com.superbiz.agent.harness.application.IntentRouting;
 import com.superbiz.agent.harness.audit.HarnessAgentAuditHook;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
 import com.superbiz.agent.harness.audit.ToolInvocationAuditSink;
 import com.superbiz.agent.repository.AgentStepRepository;
+import com.superbiz.agent.repository.AgentReasoningAuditRepository;
 import com.superbiz.agent.tool.LookupKnowledgeTool;
 import com.superbiz.agent.agent.tool.QueryLogsTools;
 import org.springframework.ai.chat.model.ChatModel;
@@ -232,11 +234,13 @@ public class HarnessChatConfiguration {
 
     @Bean
     public DiagnosisAgentFactory diagnosisAgentFactory(ChatModel chatModel, DiagnosisHarnessCore core,
-                                                        HarnessEvidenceTools tools, ObjectMapper mapper,
-                                                        AgentStepRepository steps) {
+                                                         HarnessEvidenceTools tools, ObjectMapper mapper,
+                                                         AgentStepRepository steps,
+                                                         AgentReasoningAuditRepository reasoningAudits,
+                                                         DiagnosisTraceRecorder traceRecorder) {
         return new DiagnosisAgentFactory(chatModel, core, tools, mapper,
                 List.of(new HarnessAgentAuditHook(
-                        steps, mapper, DiagnosisAgentFactory.AGENT_NAME)));
+                        steps, mapper, DiagnosisAgentFactory.AGENT_NAME, traceRecorder, reasoningAudits)));
     }
 
     @Bean
@@ -258,28 +262,32 @@ public class HarnessChatConfiguration {
     @Bean
     public EvidenceRepair evidenceRepair(DiagnosisHarnessCore core, HarnessRetryExecutor retries,
                                          GuardModelCall modelCall, ObjectMapper mapper,
-                                         ChatHarnessProperties properties) {
+                                         ChatHarnessProperties properties,
+                                         DiagnosisTraceRecorder traceRecorder) {
         return new EvidenceRepair(core, retries, modelCall, mapper,
                 new EvidenceRepairLimits(properties.getRepairMaxInputBytes(), properties.getRepairMaxOutputBytes(),
                         properties.getRepairTimeout()),
-                attempt -> { });
+                attempt -> { }, traceRecorder);
     }
 
     @Bean
     public SemanticGuard semanticGuard(DiagnosisHarnessCore core, HarnessRetryExecutor retries,
                                        GuardModelCall modelCall, ObjectMapper mapper,
-                                       ChatHarnessProperties properties) {
+                                       ChatHarnessProperties properties,
+                                       DiagnosisTraceRecorder traceRecorder) {
         return new SemanticGuard(core, retries, modelCall, mapper,
                 new SemanticGuardLimits(properties.getSemanticMaxInputBytes(), properties.getSemanticMaxOutputBytes(),
                         properties.getSemanticAttemptTimeout(), properties.getSemanticTotalTimeout()),
-                attempt -> { });
+                attempt -> { }, traceRecorder);
     }
 
     @Bean
     public DiagnosisReleaseUseCase diagnosisReleaseUseCase(EvidenceGuard evidenceGuard,
                                                            EvidenceRepair repair,
-                                                           SemanticGuard semanticGuard) {
-        return new DiagnosisReleaseUseCase(evidenceGuard, repair, semanticGuard, new SafeFallbackFactory());
+                                                           SemanticGuard semanticGuard,
+                                                           DiagnosisTraceRecorder traceRecorder) {
+        return new DiagnosisReleaseUseCase(
+                evidenceGuard, repair, semanticGuard, new SafeFallbackFactory(), traceRecorder);
     }
 
     @Bean
@@ -290,11 +298,12 @@ public class HarnessChatConfiguration {
     @Bean
     public IntentRouting intentRouter(DiagnosisHarnessCore core, HarnessRetryExecutor retries,
                                       GuardModelCall modelCall, ObjectMapper mapper,
-                                      ChatHarnessProperties properties) {
+                                      ChatHarnessProperties properties,
+                                      DiagnosisTraceRecorder traceRecorder) {
         return new IntentRouter(core, retries, modelCall, mapper,
                 new IntentRouterLimits(properties.getRouterMaxInputBytes(), properties.getRouterMaxOutputBytes(),
                         properties.getRouterAttemptTimeout(), properties.getRouterTotalTimeout()),
-                attempt -> { });
+                attempt -> { }, traceRecorder);
     }
 
     @Bean
@@ -330,9 +339,10 @@ public class HarnessChatConfiguration {
                                                          SystemChatOperation system,
                                                          KnowledgeQueryOperation knowledge,
                                                          DiagnosisOperation diagnosis,
-                                                         ObjectMapper mapper) {
+                                                         ObjectMapper mapper,
+                                                         DiagnosisTraceRecorder traceRecorder) {
         return new ChatApplicationUseCase(core, () -> UUID.randomUUID().toString(), runStore,
-                router, system, knowledge, diagnosis, mapper);
+                router, system, knowledge, diagnosis, mapper, traceRecorder);
     }
 
     private static ThreadPoolExecutor boundedExecutor(int core, int max, int queue, String prefix) {

src/main/java/com/superbiz/agent/controller/DiagnosisTraceController.java

@@ -11,6 +11,8 @@ import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import java.util.List;
+
 @RestController
 @RequestMapping("/api/diagnosis")
 @RequiredArgsConstructor
@@ -25,4 +27,13 @@ public class DiagnosisTraceController {
     ) {
         return ResponseEntity.ok(Result.success(diagnosisTraceService.getTrace(sessionId, runId)));
     }
+
+    @GetMapping("/{sessionId}/trace/reasoning")
+    public ResponseEntity<Result<List<DiagnosisTraceResponse.AgentReasoningTrace>>> getReasoning(
+            @PathVariable String sessionId,
+            @RequestParam String runId
+    ) {
+        return ResponseEntity.ok(Result.success(
+                diagnosisTraceService.getReasoning(sessionId, runId)));
+    }
 }

src/main/java/com/superbiz/agent/domain/entity/AgentReasoningAudit.java

@@ -0,0 +1,61 @@
+package com.superbiz.agent.domain.entity;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Index;
+import jakarta.persistence.PrePersist;
+import jakarta.persistence.Table;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Table(name = "agent_reasoning_audit", indexes = {
+        @Index(name = "idx_reasoning_run_step", columnList = "run_id, step_index"),
+        @Index(name = "idx_reasoning_session_created", columnList = "session_id, created_at")
+})
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class AgentReasoningAudit {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(name = "session_id", nullable = false, length = 64)
+    private String sessionId;
+
+    @Column(name = "run_id", nullable = false, length = 64)
+    private String runId;
+
+    @Column(name = "step_index", nullable = false)
+    private Integer stepIndex;
+
+    @Column(name = "agent_name", nullable = false, length = 64)
+    private String agentName;
+
+    @Column(name = "reasoning_available", nullable = false)
+    private Boolean reasoningAvailable;
+
+    @Column(name = "reasoning_content", columnDefinition = "LONGTEXT")
+    private String reasoningContent;
+
+    @Column(name = "content_bytes", nullable = false)
+    private Integer contentBytes;
+
+    @Column(name = "created_at", nullable = false, updatable = false)
+    private LocalDateTime createdAt;
+
+    @PrePersist
+    protected void onCreate() {
+        createdAt = LocalDateTime.now();
+    }
+}

src/main/java/com/superbiz/agent/domain/entity/DiagnosisTraceEvent.java

@@ -0,0 +1,73 @@
+package com.superbiz.agent.domain.entity;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Index;
+import jakarta.persistence.PrePersist;
+import jakarta.persistence.Table;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import org.hibernate.annotations.JdbcTypeCode;
+import org.hibernate.type.SqlTypes;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Table(name = "diagnosis_trace_event", indexes = {
+    @Index(name = "idx_trace_event_run_sequence", columnList = "run_id, sequence_no, id"),
+    @Index(name = "idx_trace_event_session_created", columnList = "session_id, created_at, id"),
+    @Index(name = "idx_trace_event_phase", columnList = "phase, event_type")
+})
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class DiagnosisTraceEvent {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(name = "session_id", nullable = false, length = 64)
+    private String sessionId;
+
+    @Column(name = "run_id", nullable = false, length = 64)
+    private String runId;
+
+    @Column(name = "sequence_no", nullable = false)
+    private Integer sequenceNo;
+
+    @Column(name = "phase", nullable = false, length = 32)
+    private String phase;
+
+    @Column(name = "event_type", nullable = false, length = 48)
+    private String eventType;
+
+    @Column(name = "status", nullable = false, length = 32)
+    private String status;
+
+    @Column(name = "attempt_no")
+    private Integer attemptNo;
+
+    @Column(name = "duration_ms")
+    private Integer durationMs;
+
+    @JdbcTypeCode(SqlTypes.JSON)
+    @Column(name = "details", nullable = false, columnDefinition = "JSON")
+    private String details;
+
+    @Column(name = "created_at", nullable = false, updatable = false)
+    private LocalDateTime createdAt;
+
+    @PrePersist
+    protected void onCreate() {
+        if (createdAt == null) {
+            createdAt = LocalDateTime.now();
+        }
+    }
+}

src/main/java/com/superbiz/agent/dto/DiagnosisTraceResponse.java

@@ -21,6 +21,7 @@ public class DiagnosisTraceResponse {
     private RunTrace run;
     private List<AgentStepTrace> steps;
     private List<ToolInvocationTrace> toolInvocations;
+    private List<TraceEventTrace> timeline;
     private TraceSummary summary;
 
     @Data
@@ -47,6 +48,8 @@ public class DiagnosisTraceResponse {
         private String query;
         private String status;
         private String agentFlow;
+        private String intent;
+        private String releaseOutcome;
         private Integer totalDurationMs;
         private Integer totalTokenCount;
         private Integer stepCount;
@@ -70,6 +73,8 @@ public class DiagnosisTraceResponse {
         private String query;
         private String status;
         private String agentFlow;
+        private String intent;
+        private String releaseOutcome;
         private Integer totalDurationMs;
         private Integer totalTokenCount;
         private Integer stepCount;
@@ -129,6 +134,41 @@ public class DiagnosisTraceResponse {
         private LocalDateTime createdAt;
     }
 
+    @Data
+    @Builder
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class TraceEventTrace {
+        private Long id;
+        private String sessionId;
+        private String runId;
+        private Integer sequenceNo;
+        private String phase;
+        private String eventType;
+        private String status;
+        private Integer attemptNo;
+        private Integer durationMs;
+        private String detailsRaw;
+        private Map<String, Object> details;
+        private LocalDateTime createdAt;
+    }
+
+    @Data
+    @Builder
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class AgentReasoningTrace {
+        private Long id;
+        private String sessionId;
+        private String runId;
+        private Integer stepIndex;
+        private String agentName;
+        private Boolean reasoningAvailable;
+        private String reasoningContent;
+        private Integer contentBytes;
+        private LocalDateTime createdAt;
+    }
+
     @Data
     @Builder
     @NoArgsConstructor
@@ -139,6 +179,8 @@ public class DiagnosisTraceResponse {
         private int returnedStepCount;
         private int persistedToolCallCount;
         private int returnedToolCallCount;
+        private int persistedTraceEventCount;
+        private int returnedTraceEventCount;
         private boolean hasVerifierEvaluation;
         private boolean hasFeedback;
     }
@@ -153,6 +195,8 @@ public class DiagnosisTraceResponse {
         private String query;
         private String status;
         private String agentFlow;
+        private String intent;
+        private String releaseOutcome;
         private String answerPreview;
         private Integer stepCount;
         private Integer toolCallCount;

src/main/java/com/superbiz/agent/harness/agent/DiagnosisAgentFactory.java

@@ -47,6 +47,7 @@ public final class DiagnosisAgentFactory {
                         new HarnessToolInterceptor(context, evidenceTools, objectMapper))
                 .hooks(auditHooks)
                 .outputSchema(new DiagnosisDraftOutputSchema(objectMapper).getFormat())
+                .returnReasoningContents(true)
                 .parallelToolExecution(false)
                 .releaseThread(true)
                 .build();

src/main/java/com/superbiz/agent/harness/application/ChatApplicationUseCase.java

@@ -3,6 +3,8 @@ package com.superbiz.agent.harness.application;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.harness.application.persistence.ChatRunStore;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceAuditEvents;
 import com.superbiz.agent.harness.application.persistence.RoutingHistory;
 import com.superbiz.agent.harness.application.routing.IntentRouterInput;
 import com.superbiz.agent.harness.application.routing.IntentRoutingException;
@@ -33,6 +35,7 @@ public final class ChatApplicationUseCase {
     private final KnowledgeQueryOperation knowledgeQuery;
     private final DiagnosisOperation diagnosis;
     private final ObjectMapper objectMapper;
+    private final DiagnosisTraceRecorder traceRecorder;
 
     public ChatApplicationUseCase(DiagnosisHarnessCore core,
                                   Supplier<String> sessionIdSupplier,
@@ -42,6 +45,19 @@ public final class ChatApplicationUseCase {
                                   KnowledgeQueryOperation knowledgeQuery,
                                   DiagnosisOperation diagnosis,
                                   ObjectMapper objectMapper) {
+        this(core, sessionIdSupplier, runStore, router, systemChat, knowledgeQuery,
+                diagnosis, objectMapper, DiagnosisTraceRecorder.noop());
+    }
+
+    public ChatApplicationUseCase(DiagnosisHarnessCore core,
+                                  Supplier<String> sessionIdSupplier,
+                                  ChatRunStore runStore,
+                                  IntentRouting router,
+                                  SystemChatOperation systemChat,
+                                  KnowledgeQueryOperation knowledgeQuery,
+                                  DiagnosisOperation diagnosis,
+                                  ObjectMapper objectMapper,
+                                  DiagnosisTraceRecorder traceRecorder) {
         this.core = Objects.requireNonNull(core, "core must not be null");
         this.sessionIdSupplier = Objects.requireNonNull(
                 sessionIdSupplier, "sessionIdSupplier must not be null");
@@ -51,6 +67,7 @@ public final class ChatApplicationUseCase {
         this.knowledgeQuery = Objects.requireNonNull(knowledgeQuery, "knowledgeQuery must not be null");
         this.diagnosis = Objects.requireNonNull(diagnosis, "diagnosis must not be null");
         this.objectMapper = Objects.requireNonNull(objectMapper, "objectMapper must not be null");
+        this.traceRecorder = Objects.requireNonNull(traceRecorder, "traceRecorder must not be null");
     }
 
     public ChatApplicationResult execute(ChatApplicationRequest request) {
@@ -78,12 +95,14 @@ public final class ChatApplicationUseCase {
         IntentType intent = null;
         try {
             persistStart(context, request.query());
+            traceRecorder.record(TraceAuditEvents.runStarted(context));
             observer.onStarted(new CoreRunControl(core, context));
             observer.onStatus(ChatApplicationStatus.ROUTING);
             intent = router.route(context, new IntentRouterInput(
                     request.query(),
                     history.map(RoutingHistory::intent).orElse(null),
                     history.map(RoutingHistory::userQuery).orElse(null)));
+            traceRecorder.record(TraceAuditEvents.routingDecision(context, intent));
             persistIntent(context.runId(), intent);
 
             PathResult path = executePath(
@@ -93,6 +112,8 @@ public final class ChatApplicationUseCase {
             String safeJson = write(path.content());
             persistFinish(context, intent, path.outcome(), safeJson,
                     path.publishedResult(), durationMillis(startedNanos));
+            traceRecorder.record(TraceAuditEvents.runFinished(
+                    context, intent, path.outcome(), durationMillis(startedNanos)));
             return new ChatApplicationResult(
                     context.sessionId(), context.runId(), intent, path.outcome(),
                     path.content().contentType(), path.content());
@@ -104,6 +125,8 @@ public final class ChatApplicationUseCase {
             } catch (RuntimeException persistenceFailure) {
                 exception.addSuppressed(persistenceFailure);
             }
+            traceRecorder.record(TraceAuditEvents.runFinished(
+                    context, intent, terminal, durationMillis(startedNanos)));
             throw safeFailure(exception, terminal);
         }
     }

src/main/java/com/superbiz/agent/harness/application/executor/KnowledgeQueryExecutor.java

@@ -24,6 +24,7 @@ import com.superbiz.agent.harness.tool.contract.RagToolResult;
 import org.springframework.ai.chat.messages.SystemMessage;
 import org.springframework.ai.chat.messages.UserMessage;
 import org.springframework.ai.chat.prompt.Prompt;
+import org.springframework.ai.converter.BeanOutputConverter;
 
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -39,7 +40,8 @@ public final class KnowledgeQueryExecutor implements KnowledgeQueryOperation {
 
     private static final String SYSTEM_PROMPT = """
             你只根据提供的有界知识库证据回答原始问题。每个 answer item 必须引用 exact tool_call_id 和实际 document_ids。
-            不要使用外部知识，不要改写问题，不要输出 markdown fence。返回严格 KnowledgeAnswerDraft JSON。
+            不要使用外部知识，不要改写问题。answer_items 必须是非空数组；每个 item 必须包含非空 text、
+            exact tool_call_id 和至少一个 actual document_id。limitations 必须是字符串数组。
             """;
 
     private final DiagnosisHarnessCore core;
@@ -48,6 +50,7 @@ public final class KnowledgeQueryExecutor implements KnowledgeQueryOperation {
     private final ObjectMapper objectMapper;
     private final ObjectReader ragReader;
     private final ObjectReader answerReader;
+    private final String prompt;
     private final Supplier<String> callIdSupplier;
     private final KnowledgeQueryLimits limits;
 
@@ -67,6 +70,8 @@ public final class KnowledgeQueryExecutor implements KnowledgeQueryOperation {
         this.answerReader = objectMapper.readerFor(KnowledgeAnswerDraft.class)
                 .with(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)
                 .with(DeserializationFeature.FAIL_ON_TRAILING_TOKENS);
+        this.prompt = SYSTEM_PROMPT + System.lineSeparator()
+                + new BeanOutputConverter<>(KnowledgeAnswerDraft.class, objectMapper).getFormat();
         this.callIdSupplier = Objects.requireNonNull(callIdSupplier, "callIdSupplier must not be null");
         this.limits = Objects.requireNonNull(limits, "limits must not be null");
     }
@@ -102,7 +107,7 @@ public final class KnowledgeQueryExecutor implements KnowledgeQueryOperation {
         core.reserveRunBytes(context, bytes);
         String output = modelCall.call(
                 context,
-                new Prompt(List.of(new SystemMessage(SYSTEM_PROMPT), new UserMessage(modelInput))),
+                new Prompt(List.of(new SystemMessage(prompt), new UserMessage(modelInput))),
                 limits.modelTimeout(),
                 limits.maxModelOutputBytes());
         KnowledgeAnswerDraft draft = readAnswer(output);

src/main/java/com/superbiz/agent/harness/application/routing/IntentRouter.java

@@ -4,6 +4,8 @@ import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.harness.contract.IntentType;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceAuditEvents;
 import com.superbiz.agent.harness.application.IntentRouting;
 import com.superbiz.agent.harness.core.DiagnosisHarnessCore;
 import com.superbiz.agent.harness.core.RunContext;
@@ -36,6 +38,7 @@ public final class IntentRouter implements IntentRouting {
     private final ObjectMapper objectMapper;
     private final IntentRouterLimits limits;
     private final Consumer<RetryAttempt> attemptRecorder;
+    private final DiagnosisTraceRecorder traceRecorder;
     private final String systemPrompt;
 
     public IntentRouter(DiagnosisHarnessCore core,
@@ -44,12 +47,24 @@ public final class IntentRouter implements IntentRouting {
                         ObjectMapper objectMapper,
                         IntentRouterLimits limits,
                         Consumer<RetryAttempt> attemptRecorder) {
+        this(core, retryExecutor, modelCall, objectMapper, limits,
+                attemptRecorder, DiagnosisTraceRecorder.noop());
+    }
+
+    public IntentRouter(DiagnosisHarnessCore core,
+                        HarnessRetryExecutor retryExecutor,
+                        GuardModelCall modelCall,
+                        ObjectMapper objectMapper,
+                        IntentRouterLimits limits,
+                        Consumer<RetryAttempt> attemptRecorder,
+                        DiagnosisTraceRecorder traceRecorder) {
         this.core = Objects.requireNonNull(core, "core must not be null");
         this.retryExecutor = Objects.requireNonNull(retryExecutor, "retryExecutor must not be null");
         this.modelCall = Objects.requireNonNull(modelCall, "modelCall must not be null");
         this.objectMapper = Objects.requireNonNull(objectMapper, "objectMapper must not be null");
         this.limits = Objects.requireNonNull(limits, "limits must not be null");
         this.attemptRecorder = Objects.requireNonNull(attemptRecorder, "attemptRecorder must not be null");
+        this.traceRecorder = Objects.requireNonNull(traceRecorder, "traceRecorder must not be null");
         this.systemPrompt = IntentRouterPrompt.load();
     }
 
@@ -73,7 +88,10 @@ public final class IntentRouter implements IntentRouting {
                     () -> parse(modelCall.call(
                             context, prompt, remaining(started), limits.maxOutputBytes())),
                     this::classify,
-                    attemptRecorder);
+                    attempt -> {
+                        attemptRecorder.accept(attempt);
+                        traceRecorder.record(TraceAuditEvents.routingAttempt(context, attempt));
+                    });
         } catch (RetryExecutionException exception) {
             if (exception.failure() == RetryFailure.CANCELLED
                     || exception.failure() == RetryFailure.BUDGET_EXHAUSTED) {

src/main/java/com/superbiz/agent/harness/audit/DiagnosisTraceAuditEvent.java

@@ -0,0 +1,37 @@
+package com.superbiz.agent.harness.audit;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Objects;
+
+public record DiagnosisTraceAuditEvent(
+        String sessionId,
+        String runId,
+        TracePhase phase,
+        TraceEventType eventType,
+        TraceEventStatus status,
+        Integer attemptNo,
+        Integer durationMs,
+        Map<String, Object> details) {
+
+    public DiagnosisTraceAuditEvent {
+        requireText(sessionId, "sessionId");
+        requireText(runId, "runId");
+        Objects.requireNonNull(phase, "phase must not be null");
+        Objects.requireNonNull(eventType, "eventType must not be null");
+        Objects.requireNonNull(status, "status must not be null");
+        if (attemptNo != null && attemptNo < 1) {
+            throw new IllegalArgumentException("attemptNo must be positive");
+        }
+        if (durationMs != null && durationMs < 0) {
+            throw new IllegalArgumentException("durationMs must not be negative");
+        }
+        details = details == null ? Map.of() : Map.copyOf(new LinkedHashMap<>(details));
+    }
+
+    private static void requireText(String value, String name) {
+        if (value == null || value.isBlank()) {
+            throw new IllegalArgumentException(name + " must not be blank");
+        }
+    }
+}

src/main/java/com/superbiz/agent/harness/audit/DiagnosisTraceRecorder.java

@@ -0,0 +1,12 @@
+package com.superbiz.agent.harness.audit;
+
+@FunctionalInterface
+public interface DiagnosisTraceRecorder {
+
+    void record(DiagnosisTraceAuditEvent event);
+
+    static DiagnosisTraceRecorder noop() {
+        return ignored -> {
+        };
+    }
+}

src/main/java/com/superbiz/agent/harness/audit/HarnessAgentAuditHook.java

@@ -8,6 +8,8 @@ import com.alibaba.cloud.ai.graph.agent.hook.messages.MessagesModelHook;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.domain.entity.AgentStep;
+import com.superbiz.agent.domain.entity.AgentReasoningAudit;
+import com.superbiz.agent.repository.AgentReasoningAuditRepository;
 import com.superbiz.agent.repository.AgentStepRepository;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -17,6 +19,7 @@ import org.springframework.ai.chat.messages.Message;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.nio.charset.StandardCharsets;
 import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -28,16 +31,31 @@ public final class HarnessAgentAuditHook extends MessagesModelHook {
     private final AgentStepRepository repository;
     private final ObjectMapper objectMapper;
     private final String agentName;
+    private final DiagnosisTraceRecorder traceRecorder;
+    private final AgentReasoningAuditRepository reasoningRepository;
     private final ConcurrentHashMap<String, Integer> stepCounters = new ConcurrentHashMap<>();
     private final ConcurrentHashMap<String, PendingStep> pendingSteps = new ConcurrentHashMap<>();
 
     public HarnessAgentAuditHook(AgentStepRepository repository, ObjectMapper objectMapper, String agentName) {
+        this(repository, objectMapper, agentName, DiagnosisTraceRecorder.noop());
+    }
+
+    public HarnessAgentAuditHook(AgentStepRepository repository, ObjectMapper objectMapper,
+                                 String agentName, DiagnosisTraceRecorder traceRecorder) {
+        this(repository, objectMapper, agentName, traceRecorder, null);
+    }
+
+    public HarnessAgentAuditHook(AgentStepRepository repository, ObjectMapper objectMapper,
+                                 String agentName, DiagnosisTraceRecorder traceRecorder,
+                                 AgentReasoningAuditRepository reasoningRepository) {
         this.repository = Objects.requireNonNull(repository, "repository must not be null");
         this.objectMapper = Objects.requireNonNull(objectMapper, "objectMapper must not be null");
         if (agentName == null || agentName.isBlank()) {
             throw new IllegalArgumentException("agentName must not be blank");
         }
         this.agentName = agentName;
+        this.traceRecorder = Objects.requireNonNull(traceRecorder, "traceRecorder must not be null");
+        this.reasoningRepository = reasoningRepository;
     }
 
     @Override
@@ -53,6 +71,7 @@ public final class HarnessAgentAuditHook extends MessagesModelHook {
             return new AgentCommand(messages);
         }
         int stepIndex = stepCounters.merge(identity.runId(), 0, (current, ignored) -> current + 1);
+        PendingStep pending = new PendingStep(null, System.nanoTime(), inputMetadata(messages));
         try {
             AgentStep saved = repository.save(AgentStep.builder()
                     .sessionId(identity.sessionId())
@@ -62,11 +81,11 @@ public final class HarnessAgentAuditHook extends MessagesModelHook {
                     .modelInput(write(inputMetadata(messages)))
                     .hasToolCall(false)
                     .build());
-            pendingSteps.put(stepKey(identity.runId(), stepIndex),
-                    new PendingStep(saved.getId(), System.nanoTime()));
+            pending = new PendingStep(saved.getId(), pending.startedNanos(), pending.input());
         } catch (RuntimeException exception) {
             log.warn("Failed to persist AgentStep audit before model: agent={}", agentName);
         }
+        pendingSteps.put(stepKey(identity.runId(), stepIndex), pending);
         return new AgentCommand(messages);
     }
 
@@ -79,26 +98,33 @@ public final class HarnessAgentAuditHook extends MessagesModelHook {
         }
         int stepIndex = stepCounters.getOrDefault(identity.runId(), 0);
         PendingStep pending = pendingSteps.remove(stepKey(identity.runId(), stepIndex));
-        if (pending == null || pending.id() == null) {
+        if (pending == null) {
             return new AgentCommand(messages);
         }
+        AssistantMessage assistant = lastAssistant(messages);
+        List<String> toolNames = assistant == null || assistant.getToolCalls() == null
+                ? List.of()
+                : assistant.getToolCalls().stream().map(AssistantMessage.ToolCall::name)
+                        .distinct().sorted().toList();
+        ReasoningContent reasoning = reasoningContent(assistant);
+        Map<String, Object> output = outputMetadata(assistant, toolNames, reasoning);
+        int durationMs = durationMillis(pending.startedNanos());
         try {
-            AgentStep step = repository.findById(pending.id()).orElse(null);
+            AgentStep step = pending.id() == null ? null : repository.findById(pending.id()).orElse(null);
             if (step != null) {
-                AssistantMessage assistant = lastAssistant(messages);
-                List<String> toolNames = assistant == null || assistant.getToolCalls() == null
-                        ? List.of()
-                        : assistant.getToolCalls().stream().map(AssistantMessage.ToolCall::name)
-                                .distinct().sorted().toList();
-                step.setModelOutput(write(outputMetadata(assistant, toolNames)));
+                step.setModelOutput(write(output));
                 step.setThought(null);
                 step.setHasToolCall(!toolNames.isEmpty());
-                step.setDurationMs(durationMillis(pending.startedNanos()));
+                step.setDurationMs(durationMs);
                 repository.save(step);
             }
         } catch (RuntimeException exception) {
             log.warn("Failed to complete AgentStep audit: agent={}", agentName);
         }
+        persistReasoning(identity, stepIndex, reasoning);
+        traceRecorder.record(TraceAuditEvents.agentModelStep(
+                identity.sessionId(), identity.runId(), agentName, stepIndex,
+                durationMs, pending.input(), output));
         return new AgentCommand(messages);
     }
 
@@ -112,14 +138,56 @@ public final class HarnessAgentAuditHook extends MessagesModelHook {
         return metadata;
     }
 
-    private Map<String, Object> outputMetadata(AssistantMessage assistant, List<String> toolNames) {
+    private Map<String, Object> outputMetadata(AssistantMessage assistant, List<String> toolNames,
+                                               ReasoningContent reasoning) {
         Map<String, Object> metadata = new LinkedHashMap<>();
         metadata.put("has_text", assistant != null
                 && assistant.getText() != null && !assistant.getText().isBlank());
         metadata.put("tool_names", toolNames);
+        metadata.put("reasoning_available", reasoning.available());
+        metadata.put("reasoning_bytes", reasoning.bytes());
         return metadata;
     }
 
+    private ReasoningContent reasoningContent(AssistantMessage assistant) {
+        if (assistant == null || assistant.getMetadata() == null) {
+            return ReasoningContent.empty();
+        }
+        for (String key : List.of("reasoning_content", "reasoningContent", "reasoning", "thinking")) {
+            Object value = assistant.getMetadata().get(key);
+            if (value instanceof CharSequence text && !text.toString().isBlank()) {
+                String content = bounded(text.toString());
+                return new ReasoningContent(content, true,
+                        content.getBytes(StandardCharsets.UTF_8).length);
+            }
+        }
+        return ReasoningContent.empty();
+    }
+
+    private void persistReasoning(AuditIdentity identity, int stepIndex, ReasoningContent reasoning) {
+        if (reasoningRepository == null) {
+            return;
+        }
+        try {
+            reasoningRepository.save(AgentReasoningAudit.builder()
+                    .sessionId(identity.sessionId())
+                    .runId(identity.runId())
+                    .stepIndex(stepIndex)
+                    .agentName(agentName)
+                    .reasoningAvailable(reasoning.available())
+                    .reasoningContent(reasoning.content())
+                    .contentBytes(reasoning.bytes())
+                    .build());
+        } catch (RuntimeException exception) {
+            log.warn("Failed to persist reasoning audit: agent={}, step={}", agentName, stepIndex);
+        }
+    }
+
+    private static String bounded(String value) {
+        int maxChars = 32_000;
+        return value.length() <= maxChars ? value : value.substring(0, maxChars);
+    }
+
     private AuditIdentity identity(RunnableConfig config) {
         if (config == null) {
             return null;
@@ -165,6 +233,12 @@ public final class HarnessAgentAuditHook extends MessagesModelHook {
     private record AuditIdentity(String sessionId, String runId) {
     }
 
-    private record PendingStep(Long id, long startedNanos) {
+    private record ReasoningContent(String content, boolean available, int bytes) {
+        private static ReasoningContent empty() {
+            return new ReasoningContent(null, false, 0);
+        }
+    }
+
+    private record PendingStep(Long id, long startedNanos, Map<String, Object> input) {
     }
 }

src/main/java/com/superbiz/agent/harness/audit/JpaDiagnosisTraceRecorder.java

@@ -0,0 +1,67 @@
+package com.superbiz.agent.harness.audit;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.superbiz.agent.domain.entity.DiagnosisTraceEvent;
+import com.superbiz.agent.repository.DiagnosisTraceEventRepository;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
+
+@Component
+public final class JpaDiagnosisTraceRecorder implements DiagnosisTraceRecorder {
+
+    private static final Logger log = LoggerFactory.getLogger(JpaDiagnosisTraceRecorder.class);
+
+    private final DiagnosisTraceEventRepository repository;
+    private final ObjectMapper objectMapper;
+    private final ConcurrentHashMap<String, AtomicInteger> sequences = new ConcurrentHashMap<>();
+
+    public JpaDiagnosisTraceRecorder(DiagnosisTraceEventRepository repository, ObjectMapper objectMapper) {
+        this.repository = Objects.requireNonNull(repository, "repository must not be null");
+        this.objectMapper = Objects.requireNonNull(objectMapper, "objectMapper must not be null");
+    }
+
+    @Override
+    public void record(DiagnosisTraceAuditEvent event) {
+        Objects.requireNonNull(event, "event must not be null");
+        try {
+            int sequence = sequences.computeIfAbsent(event.runId(), this::loadSequence)
+                    .incrementAndGet();
+            repository.save(DiagnosisTraceEvent.builder()
+                    .sessionId(event.sessionId())
+                    .runId(event.runId())
+                    .sequenceNo(sequence)
+                    .phase(event.phase().name())
+                    .eventType(event.eventType().name())
+                    .status(event.status().name())
+                    .attemptNo(event.attemptNo())
+                    .durationMs(event.durationMs())
+                    .details(writeDetails(event))
+                    .build());
+        } catch (RuntimeException exception) {
+            log.warn("Failed to persist diagnosis trace event: phase={}, type={}",
+                    event.phase(), event.eventType());
+        } finally {
+            if (event.eventType() == TraceEventType.RUN_FINISHED) {
+                sequences.remove(event.runId());
+            }
+        }
+    }
+
+    private AtomicInteger loadSequence(String runId) {
+        return new AtomicInteger(repository.findMaxSequenceNoByRunId(runId));
+    }
+
+    private String writeDetails(DiagnosisTraceAuditEvent event) {
+        try {
+            return objectMapper.writeValueAsString(event.details());
+        } catch (JsonProcessingException exception) {
+            throw new IllegalStateException("Trace event details are not serializable", exception);
+        }
+    }
+}

src/main/java/com/superbiz/agent/harness/audit/JpaToolInvocationAuditSink.java

@@ -5,6 +5,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.domain.entity.ToolInvocation;
 import com.superbiz.agent.harness.contract.InvocationStatus;
 import com.superbiz.agent.repository.ToolInvocationRepository;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
 import java.util.LinkedHashMap;
@@ -16,15 +17,24 @@ public final class JpaToolInvocationAuditSink implements ToolInvocationAuditSink
 
     private final ToolInvocationRepository repository;
     private final ObjectMapper objectMapper;
+    private final DiagnosisTraceRecorder traceRecorder;
 
     public JpaToolInvocationAuditSink(ToolInvocationRepository repository, ObjectMapper objectMapper) {
+        this(repository, objectMapper, DiagnosisTraceRecorder.noop());
+    }
+
+    @Autowired
+    public JpaToolInvocationAuditSink(ToolInvocationRepository repository, ObjectMapper objectMapper,
+                                      DiagnosisTraceRecorder traceRecorder) {
         this.repository = Objects.requireNonNull(repository, "repository must not be null");
         this.objectMapper = Objects.requireNonNull(objectMapper, "objectMapper must not be null");
+        this.traceRecorder = Objects.requireNonNull(traceRecorder, "traceRecorder must not be null");
     }
 
     @Override
     public void record(ToolInvocationAuditEvent event) {
         Objects.requireNonNull(event, "event must not be null");
+        traceRecorder.record(TraceAuditEvents.toolInvocation(event));
         repository.save(ToolInvocation.builder()
                 .sessionId(event.sessionId())
                 .runId(event.runId())

src/main/java/com/superbiz/agent/harness/audit/TraceAuditEvents.java

@@ -0,0 +1,203 @@
+package com.superbiz.agent.harness.audit;
+
+import com.superbiz.agent.harness.contract.DiagnosisDraft;
+import com.superbiz.agent.harness.contract.FallbackType;
+import com.superbiz.agent.harness.contract.IntentType;
+import com.superbiz.agent.harness.contract.ReleaseOutcome;
+import com.superbiz.agent.harness.contract.SemanticVerdict;
+import com.superbiz.agent.harness.core.RunContext;
+import com.superbiz.agent.harness.guard.evidence.EvidenceGuardResult;
+import com.superbiz.agent.harness.guard.evidence.EvidenceViolation;
+import com.superbiz.agent.harness.retry.RetryAttempt;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.regex.Pattern;
+
+public final class TraceAuditEvents {
+
+    private static final Pattern SAFE_TOOL_CALL_ID =
+            Pattern.compile("[A-Za-z0-9][A-Za-z0-9._-]{0,127}");
+
+    private TraceAuditEvents() {
+    }
+
+    public static DiagnosisTraceAuditEvent runStarted(RunContext context) {
+        return event(context, TracePhase.RUN, TraceEventType.RUN_STARTED,
+                TraceEventStatus.STARTED, null, null, Map.of());
+    }
+
+    public static DiagnosisTraceAuditEvent runFinished(
+            RunContext context, IntentType intent, ReleaseOutcome outcome, int durationMs) {
+        Map<String, Object> details = new LinkedHashMap<>();
+        if (intent != null) {
+            details.put("intent", intent.name());
+        }
+        details.put("release_outcome", outcome.name());
+        return event(context, TracePhase.RUN, TraceEventType.RUN_FINISHED,
+                terminalStatus(outcome), null, durationMs, details);
+    }
+
+    public static DiagnosisTraceAuditEvent routingAttempt(
+            RunContext context, RetryAttempt attempt) {
+        return retry(context, TracePhase.ROUTING, TraceEventType.ROUTING_ATTEMPT, attempt);
+    }
+
+    public static DiagnosisTraceAuditEvent routingDecision(
+            RunContext context, IntentType intent) {
+        return event(context, TracePhase.ROUTING, TraceEventType.ROUTING_DECISION,
+                TraceEventStatus.SUCCEEDED, null, null, Map.of("intent", intent.name()));
+    }
+
+    public static DiagnosisTraceAuditEvent agentModelStep(
+            String sessionId, String runId, String agentName, int stepIndex,
+            int durationMs, Map<String, Object> input, Map<String, Object> output) {
+        Map<String, Object> details = new LinkedHashMap<>();
+        details.put("agent_name", agentName);
+        details.put("step_index", stepIndex);
+        details.put("input", input);
+        details.put("output", output);
+        return new DiagnosisTraceAuditEvent(
+                sessionId, runId, TracePhase.AGENT, TraceEventType.AGENT_MODEL_STEP,
+                TraceEventStatus.SUCCEEDED, stepIndex + 1, durationMs, details);
+    }
+
+    public static DiagnosisTraceAuditEvent toolInvocation(ToolInvocationAuditEvent tool) {
+        Map<String, Object> details = new LinkedHashMap<>();
+        details.put("tool_call_id", tool.toolCallId());
+        details.put("tool_name", tool.toolName());
+        details.put("invocation_status", tool.status().name());
+        details.put("evidence_status", tool.evidenceStatus().name());
+        details.put("request_bytes", tool.requestBytes());
+        details.put("agent_result_bytes", tool.agentResultBytes());
+        if (tool.errorCode() != null) {
+            details.put("error_code", tool.errorCode());
+        }
+        return new DiagnosisTraceAuditEvent(
+                tool.sessionId(), tool.runId(), TracePhase.TOOL, TraceEventType.TOOL_INVOCATION,
+                tool.status() == com.superbiz.agent.harness.contract.InvocationStatus.READY
+                        ? TraceEventStatus.READY : TraceEventStatus.ERROR,
+                null, tool.durationMs(), details);
+    }
+
+    public static DiagnosisTraceAuditEvent evidenceValidation(
+            RunContext context, TraceEventType type,
+            EvidenceGuardResult result, DiagnosisDraft draft) {
+        Map<String, Object> details = new LinkedHashMap<>();
+        details.put("violation_count", result.violations().size());
+        details.put("violations", violations(result.violations()));
+        ToolReferences references = toolReferences(draft);
+        details.put("referenced_tool_call_ids", references.safeIds());
+        details.put("invalid_tool_reference_count", references.invalidCount());
+        result.verifiedSnapshot().ifPresent(snapshot -> {
+            details.put("verified_analysis_count", snapshot.analyses().size());
+            details.put("verified_source_count", snapshot.verifiedSources().size());
+        });
+        return event(context, TracePhase.EVIDENCE, type,
+                result.valid() ? TraceEventStatus.PASSED : TraceEventStatus.REJECTED,
+                null, null, details);
+    }
+
+    public static DiagnosisTraceAuditEvent evidenceRepairAttempt(
+            RunContext context, RetryAttempt attempt) {
+        return retry(context, TracePhase.EVIDENCE,
+                TraceEventType.EVIDENCE_REPAIR_ATTEMPT, attempt);
+    }
+
+    public static DiagnosisTraceAuditEvent semanticAttempt(
+            RunContext context, RetryAttempt attempt) {
+        return retry(context, TracePhase.SEMANTIC,
+                TraceEventType.SEMANTIC_GUARD_ATTEMPT, attempt);
+    }
+
+    public static DiagnosisTraceAuditEvent semanticDecision(
+            RunContext context, SemanticVerdict verdict) {
+        TraceEventStatus status = verdict == SemanticVerdict.SUPPORTED
+                ? TraceEventStatus.SUPPORTED : TraceEventStatus.UNSUPPORTED;
+        return event(context, TracePhase.SEMANTIC, TraceEventType.SEMANTIC_GUARD_DECISION,
+                status, null, null, Map.of("verdict", verdict.name()));
+    }
+
+    public static DiagnosisTraceAuditEvent semanticUnavailable(RunContext context) {
+        return event(context, TracePhase.SEMANTIC, TraceEventType.SEMANTIC_GUARD_DECISION,
+                TraceEventStatus.UNAVAILABLE, null, null, Map.of());
+    }
+
+    public static DiagnosisTraceAuditEvent releaseDecision(
+            RunContext context, ReleaseOutcome outcome, FallbackType fallbackType) {
+        Map<String, Object> details = new LinkedHashMap<>();
+        details.put("release_outcome", outcome.name());
+        if (fallbackType != null) {
+            details.put("fallback_type", fallbackType.name());
+        }
+        return event(context, TracePhase.RELEASE, TraceEventType.RELEASE_DECISION,
+                terminalStatus(outcome), null, null, details);
+    }
+
+    private static DiagnosisTraceAuditEvent retry(
+            RunContext context, TracePhase phase, TraceEventType type, RetryAttempt attempt) {
+        Map<String, Object> details = new LinkedHashMap<>();
+        if (attempt.failure() != null) {
+            details.put("failure", attempt.failure().name());
+        }
+        return event(context, phase, type,
+                attempt.success() ? TraceEventStatus.SUCCEEDED : TraceEventStatus.FAILED,
+                attempt.attemptNumber(), null, details);
+    }
+
+    private static DiagnosisTraceAuditEvent event(
+            RunContext context, TracePhase phase, TraceEventType type, TraceEventStatus status,
+            Integer attemptNo, Integer durationMs, Map<String, Object> details) {
+        return new DiagnosisTraceAuditEvent(
+                context.sessionId(), context.runId(), phase, type, status,
+                attemptNo, durationMs, details);
+    }
+
+    private static TraceEventStatus terminalStatus(ReleaseOutcome outcome) {
+        return switch (outcome) {
+            case SUCCESS -> TraceEventStatus.SUCCEEDED;
+            case FALLBACK -> TraceEventStatus.FALLBACK;
+            case FAILED -> TraceEventStatus.FAILED;
+            case CANCELLED -> TraceEventStatus.CANCELLED;
+        };
+    }
+
+    private static List<Map<String, String>> violations(List<EvidenceViolation> violations) {
+        List<Map<String, String>> result = new ArrayList<>();
+        for (EvidenceViolation violation : violations) {
+            Map<String, String> item = new LinkedHashMap<>();
+            item.put("code", violation.code().name());
+            item.put("target", violation.target());
+            result.add(Map.copyOf(item));
+        }
+        return List.copyOf(result);
+    }
+
+    private static ToolReferences toolReferences(DiagnosisDraft draft) {
+        if (draft == null) {
+            return new ToolReferences(List.of(), 0);
+        }
+        Set<String> safeIds = new LinkedHashSet<>();
+        int invalid = 0;
+        for (DiagnosisDraft.AnalysisItem item : draft.analysis()) {
+            if (item == null) {
+                continue;
+            }
+            for (String id : item.toolCallIds()) {
+                if (id != null && SAFE_TOOL_CALL_ID.matcher(id).matches()) {
+                    safeIds.add(id);
+                } else {
+                    invalid++;
+                }
+            }
+        }
+        return new ToolReferences(List.copyOf(safeIds), invalid);
+    }
+
+    private record ToolReferences(List<String> safeIds, int invalidCount) {
+    }
+}

src/main/java/com/superbiz/agent/harness/audit/TraceEventStatus.java

@@ -0,0 +1,16 @@
+package com.superbiz.agent.harness.audit;
+
+public enum TraceEventStatus {
+    STARTED,
+    SUCCEEDED,
+    FAILED,
+    READY,
+    ERROR,
+    PASSED,
+    REJECTED,
+    SUPPORTED,
+    UNSUPPORTED,
+    UNAVAILABLE,
+    FALLBACK,
+    CANCELLED
+}

src/main/java/com/superbiz/agent/harness/audit/TraceEventType.java

@@ -0,0 +1,16 @@
+package com.superbiz.agent.harness.audit;
+
+public enum TraceEventType {
+    RUN_STARTED,
+    ROUTING_ATTEMPT,
+    ROUTING_DECISION,
+    AGENT_MODEL_STEP,
+    TOOL_INVOCATION,
+    EVIDENCE_GUARD_INITIAL,
+    EVIDENCE_REPAIR_ATTEMPT,
+    EVIDENCE_GUARD_RECHECK,
+    SEMANTIC_GUARD_ATTEMPT,
+    SEMANTIC_GUARD_DECISION,
+    RELEASE_DECISION,
+    RUN_FINISHED
+}

src/main/java/com/superbiz/agent/harness/audit/TracePhase.java

@@ -0,0 +1,11 @@
+package com.superbiz.agent.harness.audit;
+
+public enum TracePhase {
+    RUN,
+    ROUTING,
+    AGENT,
+    TOOL,
+    EVIDENCE,
+    SEMANTIC,
+    RELEASE
+}

src/main/java/com/superbiz/agent/harness/contract/SafeFallback.java

@@ -10,12 +10,27 @@ public record SafeFallback(
         @JsonProperty("message") String message,
         @JsonProperty("verified_sources") List<VerifiedSource> verifiedSources,
         @JsonProperty("limitations") List<String> limitations,
-        @JsonProperty("next_steps") List<String> nextSteps) {
+        @JsonProperty("next_steps") List<String> nextSteps,
+        @JsonProperty("failure_stage") String failureStage,
+        @JsonProperty("observed_facts") List<ObservedFact> observedFacts,
+        @JsonProperty("validation_issues") List<ValidationIssue> validationIssues) {
 
     public SafeFallback {
         verifiedSources = ContractCollections.immutable(verifiedSources);
         limitations = ContractCollections.immutable(limitations);
         nextSteps = ContractCollections.immutable(nextSteps);
+        observedFacts = ContractCollections.immutable(observedFacts);
+        validationIssues = ContractCollections.immutable(validationIssues);
+    }
+
+    public SafeFallback(FallbackType type,
+                        String conclusion,
+                        String message,
+                        List<VerifiedSource> verifiedSources,
+                        List<String> limitations,
+                        List<String> nextSteps) {
+        this(type, conclusion, message, verifiedSources, limitations, nextSteps,
+                null, List.of(), List.of());
     }
 
     public record VerifiedSource(
@@ -23,4 +38,16 @@ public record SafeFallback(
             @JsonProperty("source") String source,
             @JsonProperty("scope") String scope) {
     }
+
+    public record ObservedFact(
+            @JsonProperty("source_type") String sourceType,
+            @JsonProperty("source") String source,
+            @JsonProperty("scope") String scope,
+            @JsonProperty("summary") String summary) {
+    }
+
+    public record ValidationIssue(
+            @JsonProperty("code") String code,
+            @JsonProperty("target") String target) {
+    }
 }

src/main/java/com/superbiz/agent/harness/guard/semantic/SemanticGuard.java

@@ -4,6 +4,8 @@ import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.harness.contract.SemanticVerdict;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceAuditEvents;
 import com.superbiz.agent.harness.core.DiagnosisHarnessCore;
 import com.superbiz.agent.harness.core.RunContext;
 import com.superbiz.agent.harness.retry.HarnessRetryExecutor;
@@ -31,6 +33,7 @@ public final class SemanticGuard {
     private final ObjectMapper objectMapper;
     private final SemanticGuardLimits limits;
     private final Consumer<RetryAttempt> attemptRecorder;
+    private final DiagnosisTraceRecorder traceRecorder;
     private final String prompt;
 
     public SemanticGuard(DiagnosisHarnessCore core,
@@ -39,6 +42,17 @@ public final class SemanticGuard {
                          ObjectMapper objectMapper,
                          SemanticGuardLimits limits,
                          Consumer<RetryAttempt> attemptRecorder) {
+        this(core, retryExecutor, modelCall, objectMapper, limits,
+                attemptRecorder, DiagnosisTraceRecorder.noop());
+    }
+
+    public SemanticGuard(DiagnosisHarnessCore core,
+                         HarnessRetryExecutor retryExecutor,
+                         GuardModelCall modelCall,
+                         ObjectMapper objectMapper,
+                         SemanticGuardLimits limits,
+                         Consumer<RetryAttempt> attemptRecorder,
+                         DiagnosisTraceRecorder traceRecorder) {
         this.core = Objects.requireNonNull(core, "core must not be null");
         this.retryExecutor = Objects.requireNonNull(retryExecutor, "retryExecutor must not be null");
         this.modelCall = Objects.requireNonNull(modelCall, "modelCall must not be null");
@@ -46,6 +60,7 @@ public final class SemanticGuard {
         this.limits = Objects.requireNonNull(limits, "limits must not be null");
         this.attemptRecorder = Objects.requireNonNull(
                 attemptRecorder, "attemptRecorder must not be null");
+        this.traceRecorder = Objects.requireNonNull(traceRecorder, "traceRecorder must not be null");
         this.prompt = SemanticGuardPrompt.load();
     }
 
@@ -68,7 +83,10 @@ public final class SemanticGuard {
                 () -> parse(modelCall.call(
                         context, modelPrompt, remainingTimeout(startedNanos), limits.maxOutputBytes())),
                 this::classify,
-                attemptRecorder);
+                attempt -> {
+                    attemptRecorder.accept(attempt);
+                    traceRecorder.record(TraceAuditEvents.semanticAttempt(context, attempt));
+                });
     }
 
     private SemanticGuardDecision parse(String output) {

src/main/java/com/superbiz/agent/harness/release/DiagnosisReleaseUseCase.java

@@ -1,6 +1,10 @@
 package com.superbiz.agent.harness.release;
 
 import com.superbiz.agent.harness.contract.DiagnosisDraft;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceAuditEvents;
+import com.superbiz.agent.harness.audit.TraceEventType;
+import com.superbiz.agent.harness.contract.FallbackType;
 import com.superbiz.agent.harness.contract.SemanticVerdict;
 import com.superbiz.agent.harness.core.BudgetExceededException;
 import com.superbiz.agent.harness.core.RunAbortedException;
@@ -22,16 +26,27 @@ public final class DiagnosisReleaseUseCase {
     private final EvidenceRepair evidenceRepair;
     private final SemanticGuard semanticGuard;
     private final SafeFallbackFactory fallbackFactory;
+    private final DiagnosisTraceRecorder traceRecorder;
 
     public DiagnosisReleaseUseCase(EvidenceGuard evidenceGuard,
                                    EvidenceRepair evidenceRepair,
                                    SemanticGuard semanticGuard,
                                    SafeFallbackFactory fallbackFactory) {
+        this(evidenceGuard, evidenceRepair, semanticGuard, fallbackFactory,
+                DiagnosisTraceRecorder.noop());
+    }
+
+    public DiagnosisReleaseUseCase(EvidenceGuard evidenceGuard,
+                                   EvidenceRepair evidenceRepair,
+                                   SemanticGuard semanticGuard,
+                                   SafeFallbackFactory fallbackFactory,
+                                   DiagnosisTraceRecorder traceRecorder) {
         this.evidenceGuard = Objects.requireNonNull(evidenceGuard, "evidenceGuard must not be null");
         this.evidenceRepair = Objects.requireNonNull(evidenceRepair, "evidenceRepair must not be null");
         this.semanticGuard = Objects.requireNonNull(semanticGuard, "semanticGuard must not be null");
         this.fallbackFactory = Objects.requireNonNull(
                 fallbackFactory, "fallbackFactory must not be null");
+        this.traceRecorder = Objects.requireNonNull(traceRecorder, "traceRecorder must not be null");
     }
 
     public DiagnosisReleaseResult execute(RunContext context, String query, DiagnosisDraft draft) {
@@ -43,16 +58,20 @@ public final class DiagnosisReleaseUseCase {
 
         DiagnosisDraft candidate = draft;
         EvidenceGuardResult evidence = evidenceGuard.validate(context, candidate);
+        traceRecorder.record(TraceAuditEvents.evidenceValidation(
+                context, TraceEventType.EVIDENCE_GUARD_INITIAL, evidence, candidate));
         if (!evidence.valid()) {
             try {
                 candidate = evidenceRepair.repair(context, query, draft, evidence.violations());
                 evidence = evidenceGuard.validate(context, candidate);
+                traceRecorder.record(TraceAuditEvents.evidenceValidation(
+                        context, TraceEventType.EVIDENCE_GUARD_RECHECK, evidence, candidate));
             } catch (RuntimeException exception) {
                 propagateTerminal(exception);
-                return evidenceFailure();
+                return evidenceFailure(context, evidence);
             }
             if (!evidence.valid()) {
-                return evidenceFailure();
+                return evidenceFailure(context, evidence);
             }
         }
 
@@ -63,18 +82,32 @@ public final class DiagnosisReleaseUseCase {
                     context, SemanticGuardInput.from(query, candidate, snapshot));
         } catch (RuntimeException exception) {
             propagateTerminal(exception);
+            traceRecorder.record(TraceAuditEvents.semanticUnavailable(context));
+            traceRecorder.record(TraceAuditEvents.releaseDecision(
+                    context, com.superbiz.agent.harness.contract.ReleaseOutcome.FALLBACK,
+                    FallbackType.SEMANTIC_UNAVAILABLE));
             return DiagnosisReleaseResult.fallback(
                     fallbackFactory.semanticUnavailable(snapshot));
         }
-        return decision.verdict() == SemanticVerdict.SUPPORTED
-                ? DiagnosisReleaseResult.success(candidate, snapshot)
-                : DiagnosisReleaseResult.fallback(
-                        fallbackFactory.semanticUnsupported(snapshot));
+        traceRecorder.record(TraceAuditEvents.semanticDecision(context, decision.verdict()));
+        if (decision.verdict() == SemanticVerdict.SUPPORTED) {
+            traceRecorder.record(TraceAuditEvents.releaseDecision(
+                    context, com.superbiz.agent.harness.contract.ReleaseOutcome.SUCCESS, null));
+            return DiagnosisReleaseResult.success(candidate, snapshot);
+        }
+        traceRecorder.record(TraceAuditEvents.releaseDecision(
+                context, com.superbiz.agent.harness.contract.ReleaseOutcome.FALLBACK,
+                FallbackType.SEMANTIC_UNSUPPORTED));
+        return DiagnosisReleaseResult.fallback(fallbackFactory.semanticUnsupported(snapshot));
     }
 
-    private DiagnosisReleaseResult evidenceFailure() {
+    private DiagnosisReleaseResult evidenceFailure(
+            RunContext context, EvidenceGuardResult evidence) {
+        traceRecorder.record(TraceAuditEvents.releaseDecision(
+                context, com.superbiz.agent.harness.contract.ReleaseOutcome.FALLBACK,
+                FallbackType.EVIDENCE_VALIDATION_FAILED));
         return DiagnosisReleaseResult.fallback(
-                fallbackFactory.evidenceValidationFailed());
+                fallbackFactory.evidenceValidationFailed(evidence.violations()));
     }
 
     private void propagateTerminal(RuntimeException exception) {

src/main/java/com/superbiz/agent/harness/release/EvidenceRepair.java

@@ -5,6 +5,8 @@ import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectReader;
 import com.superbiz.agent.harness.contract.DiagnosisDraft;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceAuditEvents;
 import com.superbiz.agent.harness.core.DiagnosisHarnessCore;
 import com.superbiz.agent.harness.core.RunContext;
 import com.superbiz.agent.harness.guard.evidence.EvidenceViolation;
@@ -32,6 +34,7 @@ public final class EvidenceRepair {
     private final ObjectReader draftReader;
     private final EvidenceRepairLimits limits;
     private final Consumer<RetryAttempt> attemptRecorder;
+    private final DiagnosisTraceRecorder traceRecorder;
     private final String prompt;
 
     public EvidenceRepair(DiagnosisHarnessCore core,
@@ -40,6 +43,17 @@ public final class EvidenceRepair {
                           ObjectMapper objectMapper,
                           EvidenceRepairLimits limits,
                           Consumer<RetryAttempt> attemptRecorder) {
+        this(core, retryExecutor, modelCall, objectMapper, limits,
+                attemptRecorder, DiagnosisTraceRecorder.noop());
+    }
+
+    public EvidenceRepair(DiagnosisHarnessCore core,
+                          HarnessRetryExecutor retryExecutor,
+                          GuardModelCall modelCall,
+                          ObjectMapper objectMapper,
+                          EvidenceRepairLimits limits,
+                          Consumer<RetryAttempt> attemptRecorder,
+                          DiagnosisTraceRecorder traceRecorder) {
         this.core = Objects.requireNonNull(core, "core must not be null");
         this.retryExecutor = Objects.requireNonNull(retryExecutor, "retryExecutor must not be null");
         this.modelCall = Objects.requireNonNull(modelCall, "modelCall must not be null");
@@ -50,6 +64,7 @@ public final class EvidenceRepair {
         this.limits = Objects.requireNonNull(limits, "limits must not be null");
         this.attemptRecorder = Objects.requireNonNull(
                 attemptRecorder, "attemptRecorder must not be null");
+        this.traceRecorder = Objects.requireNonNull(traceRecorder, "traceRecorder must not be null");
         this.prompt = EvidenceRepairPrompt.load();
     }
 
@@ -87,7 +102,10 @@ public final class EvidenceRepair {
                     return repaired;
                 },
                 this::classify,
-                attemptRecorder);
+                attempt -> {
+                    attemptRecorder.accept(attempt);
+                    traceRecorder.record(TraceAuditEvents.evidenceRepairAttempt(context, attempt));
+                });
     }
 
     private DiagnosisDraft parse(String output) {

src/main/java/com/superbiz/agent/harness/release/SafeFallbackFactory.java

@@ -2,50 +2,109 @@ package com.superbiz.agent.harness.release;
 
 import com.superbiz.agent.harness.contract.FallbackType;
 import com.superbiz.agent.harness.contract.SafeFallback;
+import com.superbiz.agent.harness.guard.evidence.EvidenceViolation;
+import com.superbiz.agent.harness.guard.evidence.VerifiedEvidence;
 import com.superbiz.agent.harness.guard.evidence.VerifiedEvidenceSnapshot;
 
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 
 public final class SafeFallbackFactory {
 
-    public SafeFallback evidenceValidationFailed() {
+    private static final int MAX_OBSERVED_FACTS = 12;
+    private static final int MAX_SUMMARY_CHARS = 320;
+
+    public SafeFallback evidenceValidationFailed(List<EvidenceViolation> violations) {
         return fallback(
                 FallbackType.EVIDENCE_VALIDATION_FAILED,
                 List.of(),
-                "当前证据无法完成真实性校验，无法确认根因",
-                "证据引用校验未通过",
-                "重新收集当前诊断范围内的证据后再发起诊断");
+                "已完成证据引用检查，但当前报告无法通过真实性校验，因此不能确认根因",
+                List.of("证据引用或报告结构校验未通过"),
+                List.of("根据 validation_issues 修正报告结构，或补充对应范围的证据后重试"),
+                "EVIDENCE_VALIDATION",
+                List.of(),
+                issues(violations));
     }
 
     public SafeFallback semanticUnsupported(VerifiedEvidenceSnapshot snapshot) {
         return fallback(
                 FallbackType.SEMANTIC_UNSUPPORTED,
                 sources(snapshot),
-                "当前证据不足，无法确认根因",
-                "语义校验未通过",
-                "补充当前缺失的数据后重新发起诊断");
+                "已收集到可验证事实，但这些事实不足以支持当前根因结论",
+                List.of("语义校验未通过，已确认事实仍可用于后续排查"),
+                List.of("围绕 observed_facts 补充缺失的实时日志、指标或数据库证据后重试"),
+                "SEMANTIC_VALIDATION",
+                facts(snapshot),
+                List.of());
     }
 
     public SafeFallback semanticUnavailable(VerifiedEvidenceSnapshot snapshot) {
         return fallback(
                 FallbackType.SEMANTIC_UNAVAILABLE,
                 sources(snapshot),
-                "当前证据暂时无法完成语义校验，无法确认根因",
-                "语义校验暂不可用",
-                "稍后重试或补充当前缺失的数据");
+                "已收集到可验证事实，但当前无法完成语义校验，因此暂不发布根因结论",
+                List.of("语义校验暂不可用"),
+                List.of("稍后重试；已确认事实可继续用于人工排查"),
+                "SEMANTIC_VALIDATION",
+                facts(snapshot),
+                List.of());
     }
 
     private SafeFallback fallback(FallbackType type,
                                   List<SafeFallback.VerifiedSource> sources,
                                   String message,
-                                  String limitation,
-                                  String nextStep) {
+                                  List<String> limitations,
+                                  List<String> nextSteps,
+                                  String failureStage,
+                                  List<SafeFallback.ObservedFact> observedFacts,
+                                  List<SafeFallback.ValidationIssue> validationIssues) {
         return new SafeFallback(
-                type, null, message, sources, List.of(limitation), List.of(nextStep));
+                type, null, message, sources, limitations, nextSteps,
+                failureStage, observedFacts, validationIssues);
     }
 
     private List<SafeFallback.VerifiedSource> sources(VerifiedEvidenceSnapshot snapshot) {
         return Objects.requireNonNull(snapshot, "snapshot must not be null").verifiedSources();
     }
+
+    private List<SafeFallback.ObservedFact> facts(VerifiedEvidenceSnapshot snapshot) {
+        Objects.requireNonNull(snapshot, "snapshot must not be null");
+        Map<String, SafeFallback.ObservedFact> unique = new LinkedHashMap<>();
+        for (var analysis : snapshot.analyses()) {
+            for (VerifiedEvidence evidence : analysis.evidence()) {
+                if (unique.size() >= MAX_OBSERVED_FACTS) {
+                    return List.copyOf(unique.values());
+                }
+                String summary = bounded(evidence.excerpt());
+                if (summary == null) {
+                    summary = "已验证结构化证据，具体值保留在受限审计记录中";
+                }
+                String key = evidence.sourceType() + '\u0000' + evidence.source()
+                        + '\u0000' + evidence.scope() + '\u0000' + summary;
+                unique.putIfAbsent(key, new SafeFallback.ObservedFact(
+                        evidence.sourceType(), evidence.source(), evidence.scope(), summary));
+            }
+        }
+        return List.copyOf(unique.values());
+    }
+
+    private List<SafeFallback.ValidationIssue> issues(List<EvidenceViolation> violations) {
+        List<SafeFallback.ValidationIssue> result = new ArrayList<>();
+        for (EvidenceViolation violation : violations == null ? List.<EvidenceViolation>of() : violations) {
+            result.add(new SafeFallback.ValidationIssue(
+                    violation.code().name(), violation.target()));
+        }
+        return List.copyOf(result);
+    }
+
+    private String bounded(String value) {
+        if (value == null || value.isBlank()) {
+            return null;
+        }
+        return value.length() <= MAX_SUMMARY_CHARS
+                ? value : value.substring(0, MAX_SUMMARY_CHARS);
+    }
 }

src/main/java/com/superbiz/agent/repository/AgentReasoningAuditRepository.java

@@ -0,0 +1,13 @@
+package com.superbiz.agent.repository;
+
+import com.superbiz.agent.domain.entity.AgentReasoningAudit;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public interface AgentReasoningAuditRepository extends JpaRepository<AgentReasoningAudit, Long> {
+
+    List<AgentReasoningAudit> findByRunIdOrderByStepIndex(String runId);
+}

src/main/java/com/superbiz/agent/repository/DiagnosisTraceEventRepository.java

@@ -0,0 +1,18 @@
+package com.superbiz.agent.repository;
+
+import com.superbiz.agent.domain.entity.DiagnosisTraceEvent;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public interface DiagnosisTraceEventRepository extends JpaRepository<DiagnosisTraceEvent, Long> {
+
+    List<DiagnosisTraceEvent> findByRunIdOrderBySequenceNoAscIdAsc(String runId);
+
+    @Query("select coalesce(max(event.sequenceNo), 0) from DiagnosisTraceEvent event where event.runId = :runId")
+    int findMaxSequenceNoByRunId(@Param("runId") String runId);
+}

src/main/java/com/superbiz/agent/service/DiagnosisTraceService.java

@@ -3,16 +3,20 @@ package com.superbiz.agent.service;
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.domain.entity.AgentStep;
+import com.superbiz.agent.domain.entity.AgentReasoningAudit;
 import com.superbiz.agent.domain.entity.ChatSession;
 import com.superbiz.agent.domain.entity.DiagnosisRun;
 import com.superbiz.agent.domain.entity.DiagnosisSession;
+import com.superbiz.agent.domain.entity.DiagnosisTraceEvent;
 import com.superbiz.agent.domain.entity.ToolInvocation;
 import com.superbiz.agent.dto.DiagnosisTraceResponse;
 import com.superbiz.agent.exception.SessionNotFoundException;
 import com.superbiz.agent.repository.AgentStepRepository;
+import com.superbiz.agent.repository.AgentReasoningAuditRepository;
 import com.superbiz.agent.repository.ChatSessionRepository;
 import com.superbiz.agent.repository.DiagnosisRunRepository;
 import com.superbiz.agent.repository.DiagnosisSessionRepository;
+import com.superbiz.agent.repository.DiagnosisTraceEventRepository;
 import com.superbiz.agent.repository.ToolInvocationRepository;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
@@ -32,7 +36,9 @@ public class DiagnosisTraceService {
     private final ChatSessionRepository chatSessionRepository;
     private final DiagnosisRunRepository diagnosisRunRepository;
     private final AgentStepRepository agentStepRepository;
+    private final AgentReasoningAuditRepository agentReasoningAuditRepository;
     private final ToolInvocationRepository toolInvocationRepository;
+    private final DiagnosisTraceEventRepository diagnosisTraceEventRepository;
     private final ObjectMapper objectMapper;
 
     public DiagnosisTraceResponse getTrace(String sessionId) {
@@ -71,6 +77,8 @@ public class DiagnosisTraceService {
     private DiagnosisTraceResponse buildRunTraceResponse(String sessionId, DiagnosisRun run) {
         List<AgentStep> steps = orderStepsForTrace(agentStepRepository.findByRunIdOrderByStepIndex(run.getRunId()));
         List<ToolInvocation> toolInvocations = toolInvocationRepository.findByRunIdOrderByIdAsc(run.getRunId());
+        List<DiagnosisTraceEvent> timeline =
+                diagnosisTraceEventRepository.findByRunIdOrderBySequenceNoAscIdAsc(run.getRunId());
         DiagnosisTraceResponse.RunTrace runTrace = toRunTrace(run);
 
         return DiagnosisTraceResponse.builder()
@@ -82,7 +90,8 @@ public class DiagnosisTraceService {
                 .run(runTrace)
                 .steps(steps.stream().map(this::toAgentStepTrace).toList())
                 .toolInvocations(toolInvocations.stream().map(this::toToolInvocationTrace).toList())
-                .summary(toSummary(runTrace, steps, toolInvocations))
+                .timeline(timeline.stream().map(this::toTraceEventTrace).toList())
+                .summary(toSummary(runTrace, steps, toolInvocations, timeline))
                 .build();
     }
 
@@ -101,6 +110,7 @@ public class DiagnosisTraceService {
                 .run(null)
                 .steps(steps.stream().map(this::toAgentStepTrace).toList())
                 .toolInvocations(toolInvocations.stream().map(this::toToolInvocationTrace).toList())
+                .timeline(List.of())
                 .summary(toSummary(session, steps, toolInvocations))
                 .build();
     }
@@ -153,6 +163,8 @@ public class DiagnosisTraceService {
                 .query(run.getQuery())
                 .status(run.getStatus())
                 .agentFlow(run.getAgentFlow())
+                .intent(run.getIntent())
+                .releaseOutcome(run.getReleaseOutcome())
                 .totalDurationMs(run.getTotalDurationMs())
                 .totalTokenCount(run.getTotalTokenCount())
                 .stepCount(run.getStepCount())
@@ -174,6 +186,8 @@ public class DiagnosisTraceService {
                 .query(run.getQuery())
                 .status(run.getStatus())
                 .agentFlow(run.getAgentFlow())
+                .intent(run.getIntent() == null ? null : run.getIntent().name())
+                .releaseOutcome(run.getReleaseOutcome() == null ? null : run.getReleaseOutcome().name())
                 .totalDurationMs(run.getTotalDurationMs())
                 .totalTokenCount(run.getTotalTokenCount())
                 .stepCount(run.getStepCount())
@@ -187,6 +201,49 @@ public class DiagnosisTraceService {
                 .build();
     }
 
+    public List<DiagnosisTraceResponse.AgentReasoningTrace> getReasoning(
+            String sessionId, String runId) {
+        if (runId == null || runId.isBlank()) {
+            throw new IllegalArgumentException("runId is required for reasoning audit");
+        }
+        diagnosisRunRepository.findBySessionIdAndRunId(sessionId, runId)
+                .orElseThrow(() -> buildRunLookupException(sessionId, runId));
+        return agentReasoningAuditRepository.findByRunIdOrderByStepIndex(runId).stream()
+                .map(this::toReasoningTrace)
+                .toList();
+    }
+
+    private DiagnosisTraceResponse.TraceEventTrace toTraceEventTrace(DiagnosisTraceEvent event) {
+        return DiagnosisTraceResponse.TraceEventTrace.builder()
+                .id(event.getId())
+                .sessionId(event.getSessionId())
+                .runId(event.getRunId())
+                .sequenceNo(event.getSequenceNo())
+                .phase(event.getPhase())
+                .eventType(event.getEventType())
+                .status(event.getStatus())
+                .attemptNo(event.getAttemptNo())
+                .durationMs(event.getDurationMs())
+                .detailsRaw(event.getDetails())
+                .details(parseJsonObject(event.getDetails()))
+                .createdAt(event.getCreatedAt())
+                .build();
+    }
+
+    private DiagnosisTraceResponse.AgentReasoningTrace toReasoningTrace(AgentReasoningAudit audit) {
+        return DiagnosisTraceResponse.AgentReasoningTrace.builder()
+                .id(audit.getId())
+                .sessionId(audit.getSessionId())
+                .runId(audit.getRunId())
+                .stepIndex(audit.getStepIndex())
+                .agentName(audit.getAgentName())
+                .reasoningAvailable(audit.getReasoningAvailable())
+                .reasoningContent(audit.getReasoningContent())
+                .contentBytes(audit.getContentBytes())
+                .createdAt(audit.getCreatedAt())
+                .build();
+    }
+
     private DiagnosisTraceResponse.AgentStepTrace toAgentStepTrace(AgentStep step) {
         return DiagnosisTraceResponse.AgentStepTrace.builder()
                 .id(step.getId())
@@ -237,6 +294,8 @@ public class DiagnosisTraceService {
                 .query(run.getQuery())
                 .status(run.getStatus())
                 .agentFlow(run.getAgentFlow())
+                .intent(run.getIntent() == null ? null : run.getIntent().name())
+                .releaseOutcome(run.getReleaseOutcome() == null ? null : run.getReleaseOutcome().name())
                 .answerPreview(preview(run.getAnswer(), 160))
                 .stepCount(run.getStepCount())
                 .toolCallCount(run.getToolCallCount())
@@ -257,6 +316,8 @@ public class DiagnosisTraceService {
                 .returnedStepCount(steps.size())
                 .persistedToolCallCount(defaultInt(session.getToolCallCount()))
                 .returnedToolCallCount(toolInvocations.size())
+                .persistedTraceEventCount(0)
+                .returnedTraceEventCount(0)
                 .hasVerifierEvaluation(selfEvaluation != null && selfEvaluation.containsKey("verifier_evaluation"))
                 .hasFeedback(session.getFeedback() != null && !session.getFeedback().isBlank())
                 .build();
@@ -265,7 +326,8 @@ public class DiagnosisTraceService {
     private DiagnosisTraceResponse.TraceSummary toSummary(
             DiagnosisTraceResponse.RunTrace run,
             List<AgentStep> steps,
-            List<ToolInvocation> toolInvocations
+            List<ToolInvocation> toolInvocations,
+            List<DiagnosisTraceEvent> timeline
     ) {
         Map<String, Object> selfEvaluation = run.getSelfEvaluation();
         return DiagnosisTraceResponse.TraceSummary.builder()
@@ -274,6 +336,8 @@ public class DiagnosisTraceService {
                 .returnedStepCount(steps.size())
                 .persistedToolCallCount(defaultInt(run.getToolCallCount()))
                 .returnedToolCallCount(toolInvocations.size())
+                .persistedTraceEventCount(timeline.size())
+                .returnedTraceEventCount(timeline.size())
                 .hasVerifierEvaluation(selfEvaluation != null && selfEvaluation.containsKey("verifier_evaluation"))
                 .hasFeedback(run.getFeedback() != null && !run.getFeedback().isBlank())
                 .build();

src/main/resources/db/migration/V014__create_diagnosis_trace_event.sql

@@ -0,0 +1,17 @@
+CREATE TABLE diagnosis_trace_event (
+    id BIGINT PRIMARY KEY AUTO_INCREMENT,
+    session_id VARCHAR(64) NOT NULL COMMENT 'Owning Chat Session identity',
+    run_id VARCHAR(64) NOT NULL COMMENT 'Owning Diagnosis Run identity',
+    sequence_no INT NOT NULL COMMENT 'Monotonic event order within one run',
+    phase VARCHAR(32) NOT NULL COMMENT 'RUN/ROUTING/AGENT/TOOL/EVIDENCE/SEMANTIC/RELEASE',
+    event_type VARCHAR(48) NOT NULL COMMENT 'Stable trace event type',
+    status VARCHAR(32) NOT NULL COMMENT 'Stable event outcome',
+    attempt_no INT NULL COMMENT 'Retry or model attempt number when applicable',
+    duration_ms INT NULL COMMENT 'Event duration in milliseconds when available',
+    details JSON NOT NULL COMMENT 'Bounded safe metadata; no prompt, thought, draft text, or raw tool payload',
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+
+    INDEX idx_trace_event_run_sequence (run_id, sequence_no, id),
+    INDEX idx_trace_event_session_created (session_id, created_at, id),
+    INDEX idx_trace_event_phase (phase, event_type)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='Append-only unified diagnosis trace timeline';

src/main/resources/db/migration/V015__create_agent_reasoning_audit.sql

@@ -0,0 +1,14 @@
+CREATE TABLE agent_reasoning_audit (
+    id BIGINT PRIMARY KEY AUTO_INCREMENT,
+    session_id VARCHAR(64) NOT NULL COMMENT 'Chat session identity',
+    run_id VARCHAR(64) NOT NULL COMMENT 'Diagnosis run identity',
+    step_index INT NOT NULL COMMENT 'Agent model step index',
+    agent_name VARCHAR(64) NOT NULL COMMENT 'Agent identity',
+    reasoning_available BOOLEAN NOT NULL COMMENT 'Whether the provider returned reasoning content',
+    reasoning_content LONGTEXT NULL COMMENT 'Provider reasoning content, bounded by the audit hook',
+    content_bytes INT NOT NULL COMMENT 'UTF-8 byte length of reasoning content',
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+
+    INDEX idx_reasoning_run_step (run_id, step_index),
+    INDEX idx_reasoning_session_created (session_id, created_at)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='Restricted agent reasoning audit records';

src/test/java/com/superbiz/agent/config/HarnessChatConfigurationTest.java

@@ -2,6 +2,7 @@ package com.superbiz.agent.config;
 
 import com.superbiz.agent.harness.core.DiagnosisHarnessCore;
 import com.superbiz.agent.harness.audit.ToolInvocationAuditSink;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
 import com.superbiz.agent.harness.application.persistence.ChatRunStore;
 import com.superbiz.agent.harness.tool.contract.MysqlToolRequest;
 import com.superbiz.agent.harness.tool.mysql.MysqlSqlValidator;
@@ -13,6 +14,7 @@ import com.superbiz.agent.service.KnowledgeEvidencePostProcessor;
 import com.superbiz.agent.service.KnowledgeQueryTransformer;
 import com.superbiz.agent.service.LookupResultAssembler;
 import com.superbiz.agent.repository.AgentStepRepository;
+import com.superbiz.agent.repository.AgentReasoningAuditRepository;
 import org.springframework.ai.chat.model.ChatModel;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.data.redis.core.RedisTemplate;
@@ -75,7 +77,10 @@ class HarnessChatConfigurationTest {
                 .withBean(KnowledgeContextPacker.class, () -> mock(KnowledgeContextPacker.class))
                 .withBean(LookupResultAssembler.class, () -> mock(LookupResultAssembler.class))
                 .withBean(ToolInvocationAuditSink.class, ToolInvocationAuditSink::noop)
+                .withBean(DiagnosisTraceRecorder.class, DiagnosisTraceRecorder::noop)
                 .withBean(AgentStepRepository.class, () -> mock(AgentStepRepository.class))
+                .withBean(AgentReasoningAuditRepository.class,
+                        () -> mock(AgentReasoningAuditRepository.class))
                 .withBean(ChatRunStore.class, () -> mock(ChatRunStore.class))
                 .withBean(MysqlToolProperties.class, MysqlToolProperties::new)
                 .run(context -> {

src/test/java/com/superbiz/agent/harness/application/ApplicationExecutorsTest.java

@@ -7,6 +7,9 @@ import com.superbiz.agent.harness.application.executor.KnowledgeQueryLimits;
 import com.superbiz.agent.harness.application.executor.SingleTurnExecutorLimits;
 import com.superbiz.agent.harness.application.executor.SystemChatExecutor;
 import com.superbiz.agent.harness.application.routing.IntentRouter;
+import com.superbiz.agent.harness.audit.DiagnosisTraceAuditEvent;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceEventType;
 import com.superbiz.agent.harness.application.routing.IntentRouterInput;
 import com.superbiz.agent.harness.application.routing.IntentRouterLimits;
 import com.superbiz.agent.harness.application.routing.IntentRoutingException;
@@ -61,7 +64,8 @@ class ApplicationExecutorsTest {
         ScriptedModel model = new ScriptedModel(
                 "{\"intent\":\"OTHER\"}", "{\"intent\":\"DIAGNOSIS\"}");
         List<RetryAttempt> attempts = new ArrayList<>();
-        IntentRouter router = router(core, model, attempts::add);
+        List<DiagnosisTraceAuditEvent> trace = new ArrayList<>();
+        IntentRouter router = router(core, model, attempts::add, trace::add);
 
         IntentType intent = router.route(context,
                 new IntentRouterInput("那退款服务呢？", IntentType.DIAGNOSIS, "订单支付为什么超时？"));
@@ -72,6 +76,9 @@ class ApplicationExecutorsTest {
         assertTrue(model.prompts.get(0).contains("那退款服务呢？"));
         assertFalse(model.prompts.get(0).contains("tool_call_id"));
         assertEquals(2, attempts.size());
+        assertEquals(List.of(TraceEventType.ROUTING_ATTEMPT, TraceEventType.ROUTING_ATTEMPT),
+                trace.stream().map(DiagnosisTraceAuditEvent::eventType).toList());
+        assertEquals("INVALID_OUTPUT", trace.get(0).details().get("failure"));
     }
 
     @Test
@@ -118,6 +125,10 @@ class ApplicationExecutorsTest {
 
         assertEquals(1, lookupCalls.get());
         assertEquals(1, model.calls.get());
+        assertTrue(model.prompts.get(0).contains("answer_items"));
+        assertTrue(model.prompts.get(0).contains("tool_call_id"));
+        assertTrue(model.prompts.get(0).contains("document_ids"));
+        assertTrue(model.prompts.get(0).contains("limitations"));
         assertEquals("doc-1", content.references().get(0).documentId());
         assertFalse(objectMapper.writeValueAsString(content).contains("knowledge-1"));
         assertFalse(objectMapper.writeValueAsString(content).contains("tool_call_id"));
@@ -144,12 +155,18 @@ class ApplicationExecutorsTest {
     }
 
     private IntentRouter router(DiagnosisHarnessCore core, ChatModel model,
-                                java.util.function.Consumer<RetryAttempt> recorder) {
+                                 java.util.function.Consumer<RetryAttempt> recorder) {
+        return router(core, model, recorder, DiagnosisTraceRecorder.noop());
+    }
+
+    private IntentRouter router(DiagnosisHarnessCore core, ChatModel model,
+                                 java.util.function.Consumer<RetryAttempt> recorder,
+                                 DiagnosisTraceRecorder traceRecorder) {
         return new IntentRouter(
                 core, new HarnessRetryExecutor(core),
                 new GuardModelCall(core, model, executor), objectMapper,
                 new IntentRouterLimits(20_000, 2_000,
-                        Duration.ofSeconds(2), Duration.ofSeconds(3)), recorder);
+                        Duration.ofSeconds(2), Duration.ofSeconds(3)), recorder, traceRecorder);
     }
 
     private KnowledgeQueryExecutor knowledge(DiagnosisHarnessCore core,

src/test/java/com/superbiz/agent/harness/application/ChatApplicationUseCaseTest.java

@@ -3,6 +3,9 @@ package com.superbiz.agent.harness.application;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.harness.application.persistence.ChatRunStore;
 import com.superbiz.agent.harness.application.persistence.RoutingHistory;
+import com.superbiz.agent.harness.audit.DiagnosisTraceAuditEvent;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceEventType;
 import com.superbiz.agent.harness.application.routing.IntentRoutingException;
 import com.superbiz.agent.harness.contract.AnalysisKind;
 import com.superbiz.agent.harness.contract.DiagnosisDraft;
@@ -72,6 +75,29 @@ class ChatApplicationUseCaseTest {
         }
     }
 
+    @Test
+    void unifiedTraceRecordsRunRoutingAndTerminalEvents() {
+        FakeStore store = new FakeStore();
+        List<DiagnosisTraceAuditEvent> trace = new ArrayList<>();
+        ChatApplicationUseCase useCase = useCase(
+                store,
+                (context, input) -> IntentType.SYSTEM_CHAT,
+                (context, query) -> new SystemChatContent("ok"),
+                (context, query) -> new KnowledgeContent("unused", List.of(), List.of()),
+                (context, query, previous, status) -> diagnosisSuccess(query),
+                trace::add);
+
+        useCase.execute(new ChatApplicationRequest("hello", "session-trace"));
+
+        assertEquals(List.of(
+                        TraceEventType.RUN_STARTED,
+                        TraceEventType.ROUTING_DECISION,
+                        TraceEventType.RUN_FINISHED),
+                trace.stream().map(DiagnosisTraceAuditEvent::eventType).toList());
+        assertEquals("SYSTEM_CHAT", trace.get(1).details().get("intent"));
+        assertEquals("SUCCESS", trace.get(2).details().get("release_outcome"));
+    }
+
     @Test
     void priorSafeTurnIsReadBeforeCurrentRunAndOnlyDiagnosisReceivesIt() {
         FakeStore store = new FakeStore();
@@ -168,8 +194,18 @@ class ChatApplicationUseCaseTest {
     private ChatApplicationUseCase useCase(FakeStore store,
                                            IntentRouting routing,
                                            SystemChatOperation system,
-                                           KnowledgeQueryOperation knowledge,
-                                           DiagnosisOperation diagnosis) {
+                                            KnowledgeQueryOperation knowledge,
+                                            DiagnosisOperation diagnosis) {
+        return useCase(store, routing, system, knowledge, diagnosis,
+                DiagnosisTraceRecorder.noop());
+    }
+
+    private ChatApplicationUseCase useCase(FakeStore store,
+                                            IntentRouting routing,
+                                            SystemChatOperation system,
+                                            KnowledgeQueryOperation knowledge,
+                                            DiagnosisOperation diagnosis,
+                                            DiagnosisTraceRecorder traceRecorder) {
         AtomicInteger ids = new AtomicInteger();
         DiagnosisHarnessCore core = new DiagnosisHarnessCore(
                 Clock.systemUTC(), () -> "run-app-" + ids.incrementAndGet(), Duration.ofMinutes(5),
@@ -177,7 +213,7 @@ class ChatApplicationUseCaseTest {
                 HarnessRetryPolicies.strict());
         return new ChatApplicationUseCase(
                 core, () -> "generated-session", store, routing,
-                system, knowledge, diagnosis, objectMapper);
+                system, knowledge, diagnosis, objectMapper, traceRecorder);
     }
 
     private DiagnosisExecutionResult diagnosisSuccess(String query) {

src/test/java/com/superbiz/agent/harness/audit/HarnessAgentAuditHookTest.java

@@ -3,8 +3,10 @@ package com.superbiz.agent.harness.audit;
 import com.alibaba.cloud.ai.graph.RunnableConfig;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.domain.entity.AgentStep;
+import com.superbiz.agent.domain.entity.AgentReasoningAudit;
 import com.superbiz.agent.harness.agent.DiagnosisAgentFactory;
 import com.superbiz.agent.repository.AgentStepRepository;
+import com.superbiz.agent.repository.AgentReasoningAuditRepository;
 import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
 import org.springframework.ai.chat.messages.AssistantMessage;
@@ -12,10 +14,13 @@ import org.springframework.ai.chat.messages.UserMessage;
 
 import java.util.List;
 import java.util.Optional;
+import java.util.concurrent.atomic.AtomicReference;
 
 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.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
@@ -25,13 +30,16 @@ import static org.mockito.Mockito.when;
 class HarnessAgentAuditHookTest {
 
     @Test
-    void persistsExactIdentityAndMetadataWithoutContentOrArguments() {
+    void persistsMetadataAndReasoningInSeparateAudit() {
         AgentStepRepository repository = mock(AgentStepRepository.class);
+        AgentReasoningAuditRepository reasoningRepository = mock(AgentReasoningAuditRepository.class);
         AgentStep persisted = AgentStep.builder().id(7L).build();
         when(repository.save(any(AgentStep.class))).thenReturn(persisted);
         when(repository.findById(7L)).thenReturn(Optional.of(persisted));
+        AtomicReference<DiagnosisTraceAuditEvent> trace = new AtomicReference<>();
         HarnessAgentAuditHook hook = new HarnessAgentAuditHook(
-                repository, new ObjectMapper(), DiagnosisAgentFactory.AGENT_NAME);
+                repository, new ObjectMapper(), DiagnosisAgentFactory.AGENT_NAME,
+                trace::set, reasoningRepository);
         RunnableConfig config = RunnableConfig.builder()
                 .addMetadata("sessionId", "session-audit")
                 .addMetadata("runId", "run-audit")
@@ -40,6 +48,8 @@ class HarnessAgentAuditHookTest {
         hook.beforeModel(List.of(new UserMessage("secret-query")), config);
         AssistantMessage response = AssistantMessage.builder()
                 .content("secret-model-output")
+                .properties(java.util.Map.of(
+                        "reasoning_content", "inspect bounded evidence before selecting query_logs"))
                 .toolCalls(List.of(new AssistantMessage.ToolCall(
                         "call-1", "function", "query_logs", "{\"query\":\"secret-argument\"}")))
                 .build();
@@ -54,8 +64,28 @@ class HarnessAgentAuditHookTest {
         assertFalse(started.getModelInput().contains("secret-query"));
         assertFalse(completed.getModelOutput().contains("secret-model-output"));
         assertFalse(completed.getModelOutput().contains("secret-argument"));
-        assertEquals("{\"has_text\":true,\"tool_names\":[\"query_logs\"]}", completed.getModelOutput());
+        assertEquals("{\"has_text\":true,\"tool_names\":[\"query_logs\"],"
+                + "\"reasoning_available\":true,\"reasoning_bytes\":52}",
+                completed.getModelOutput());
         assertNull(completed.getThought());
+        ArgumentCaptor<AgentReasoningAudit> reasoningCaptor =
+                ArgumentCaptor.forClass(AgentReasoningAudit.class);
+        verify(reasoningRepository).save(reasoningCaptor.capture());
+        AgentReasoningAudit reasoning = reasoningCaptor.getValue();
+        assertEquals("session-audit", reasoning.getSessionId());
+        assertEquals("run-audit", reasoning.getRunId());
+        assertEquals(0, reasoning.getStepIndex());
+        assertTrue(reasoning.getReasoningAvailable());
+        assertEquals("inspect bounded evidence before selecting query_logs",
+                reasoning.getReasoningContent());
+        assertNotNull(trace.get());
+        assertEquals(TraceEventType.AGENT_MODEL_STEP, trace.get().eventType());
+        String traceText = trace.get().details().toString();
+        assertFalse(traceText.contains("secret-query"));
+        assertFalse(traceText.contains("secret-model-output"));
+        assertFalse(traceText.contains("secret-argument"));
+        assertFalse(traceText.contains("inspect bounded evidence"));
+        assertTrue(traceText.contains("reasoning_available=true"));
     }
 
     @Test

src/test/java/com/superbiz/agent/harness/audit/JpaDiagnosisTraceRecorderTest.java

@@ -0,0 +1,78 @@
+package com.superbiz.agent.harness.audit;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.superbiz.agent.domain.entity.DiagnosisTraceEvent;
+import com.superbiz.agent.repository.DiagnosisTraceEventRepository;
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
+import org.springframework.core.io.ClassPathResource;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+class JpaDiagnosisTraceRecorderTest {
+
+    @Test
+    void persistsIndependentMonotonicSafeEvents() {
+        DiagnosisTraceEventRepository repository = mock(DiagnosisTraceEventRepository.class);
+        when(repository.findMaxSequenceNoByRunId("run-1")).thenReturn(7);
+        JpaDiagnosisTraceRecorder recorder = new JpaDiagnosisTraceRecorder(
+                repository, new ObjectMapper());
+
+        recorder.record(event(TraceEventType.RUN_STARTED, TraceEventStatus.STARTED));
+        recorder.record(event(TraceEventType.RELEASE_DECISION, TraceEventStatus.FALLBACK));
+
+        ArgumentCaptor<DiagnosisTraceEvent> captor =
+                ArgumentCaptor.forClass(DiagnosisTraceEvent.class);
+        verify(repository, times(2)).save(captor.capture());
+        assertEquals(8, captor.getAllValues().get(0).getSequenceNo());
+        assertEquals(9, captor.getAllValues().get(1).getSequenceNo());
+        assertEquals("{\"failure\":\"SCHEMA_INVALID\"}",
+                captor.getAllValues().get(0).getDetails());
+        assertFalse(captor.getAllValues().get(0).getDetails().contains("prompt"));
+    }
+
+    @Test
+    void persistenceFailureNeverChangesMainFlow() {
+        DiagnosisTraceEventRepository repository = mock(DiagnosisTraceEventRepository.class);
+        when(repository.findMaxSequenceNoByRunId("run-1")).thenReturn(0);
+        doThrow(new IllegalStateException("database unavailable"))
+                .when(repository).save(any(DiagnosisTraceEvent.class));
+        JpaDiagnosisTraceRecorder recorder = new JpaDiagnosisTraceRecorder(
+                repository, new ObjectMapper());
+
+        assertDoesNotThrow(() -> recorder.record(
+                event(TraceEventType.RUN_STARTED, TraceEventStatus.STARTED)));
+    }
+
+    @Test
+    void migrationCreatesIndependentAppendOnlyTraceTable() throws Exception {
+        String sql;
+        try (var input = new ClassPathResource(
+                "db/migration/V014__create_diagnosis_trace_event.sql").getInputStream()) {
+            sql = new String(input.readAllBytes(), StandardCharsets.UTF_8);
+        }
+
+        assertTrue(sql.contains("CREATE TABLE diagnosis_trace_event"));
+        assertTrue(sql.contains("details JSON NOT NULL"));
+        assertTrue(sql.contains("idx_trace_event_run_sequence"));
+        assertFalse(sql.toUpperCase().contains("FOREIGN KEY"));
+    }
+
+    private DiagnosisTraceAuditEvent event(TraceEventType type, TraceEventStatus status) {
+        return new DiagnosisTraceAuditEvent(
+                "session-1", "run-1", TracePhase.RUN, type, status,
+                null, null, Map.of("failure", "SCHEMA_INVALID"));
+    }
+}

src/test/java/com/superbiz/agent/harness/audit/JpaToolInvocationAuditSinkTest.java

@@ -18,7 +18,9 @@ class JpaToolInvocationAuditSinkTest {
     @Test
     void persistsOnlyBoundedStableMetadata() {
         ToolInvocationRepository repository = mock(ToolInvocationRepository.class);
-        JpaToolInvocationAuditSink sink = new JpaToolInvocationAuditSink(repository, new ObjectMapper());
+        DiagnosisTraceRecorder traceRecorder = mock(DiagnosisTraceRecorder.class);
+        JpaToolInvocationAuditSink sink = new JpaToolInvocationAuditSink(
+                repository, new ObjectMapper(), traceRecorder);
 
         sink.record(new ToolInvocationAuditEvent(
                 "session-1", "run-1", "call-1", "query_logs",
@@ -37,5 +39,11 @@ class JpaToolInvocationAuditSinkTest {
         String serialized = saved.getInputParams() + saved.getOutputPreview() + saved.getRetrievalDetails();
         assertFalse(serialized.contains("query"));
         assertFalse(serialized.contains("raw_response"));
+        ArgumentCaptor<DiagnosisTraceAuditEvent> traceCaptor =
+                ArgumentCaptor.forClass(DiagnosisTraceAuditEvent.class);
+        verify(traceRecorder).record(traceCaptor.capture());
+        assertEquals(TraceEventType.TOOL_INVOCATION, traceCaptor.getValue().eventType());
+        assertEquals("call-1", traceCaptor.getValue().details().get("tool_call_id"));
+        assertFalse(traceCaptor.getValue().details().toString().contains("raw_response"));
     }
 }

src/test/java/com/superbiz/agent/harness/contract/HarnessContractTest.java

@@ -92,5 +92,7 @@ class HarnessContractTest {
                 previousJson.path("source_documents").get(0).path("document_id").asText());
         assertFalse(previousJson.toString().contains("tool_call_id"));
         assertFalse(previousJson.toString().contains("raw_response"));
+        assertTrue(fallbackJson.path("observed_facts").isArray());
+        assertTrue(fallbackJson.path("validation_issues").isArray());
     }
 }

src/test/java/com/superbiz/agent/harness/release/DiagnosisReleaseUseCaseTest.java

@@ -2,6 +2,9 @@ package com.superbiz.agent.harness.release;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.harness.contract.AnalysisKind;
+import com.superbiz.agent.harness.audit.DiagnosisTraceAuditEvent;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceEventType;
 import com.superbiz.agent.harness.contract.DiagnosisDraft;
 import com.superbiz.agent.harness.contract.EvidenceStatus;
 import com.superbiz.agent.harness.contract.FallbackType;
@@ -46,6 +49,7 @@ 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.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class DiagnosisReleaseUseCaseTest {
 
@@ -127,7 +131,21 @@ class DiagnosisReleaseUseCaseTest {
                 fixture.context, "Why did payment fail?", duplicateDraft());
 
         assertFallback(result, FallbackType.EVIDENCE_VALIDATION_FAILED, 0);
+        assertEquals("EVIDENCE_VALIDATION", result.fallback().failureStage());
+        assertFalse(result.fallback().validationIssues().isEmpty());
+        assertTrue(result.fallback().validationIssues().stream()
+                .anyMatch(issue -> "ANALYSIS_ID_DUPLICATE".equals(issue.code())));
         assertEquals(1, fixture.model.calls.get());
+        assertEquals(List.of(
+                        TraceEventType.EVIDENCE_GUARD_INITIAL,
+                        TraceEventType.EVIDENCE_REPAIR_ATTEMPT,
+                        TraceEventType.EVIDENCE_GUARD_RECHECK,
+                        TraceEventType.RELEASE_DECISION),
+                fixture.trace.events.stream().map(DiagnosisTraceAuditEvent::eventType).toList());
+        String trace = fixture.trace.events.toString();
+        assertTrue(trace.contains("ANALYSIS_ID_DUPLICATE"));
+        assertTrue(trace.contains("call-rag-1"));
+        assertFalse(trace.contains("Pool reached its limit"));
     }
 
     @Test
@@ -140,10 +158,18 @@ class DiagnosisReleaseUseCaseTest {
                 fixture.context, "Why did payment fail?", draft);
 
         assertFallback(result, FallbackType.SEMANTIC_UNSUPPORTED, 1);
+        assertEquals("SEMANTIC_VALIDATION", result.fallback().failureStage());
+        assertEquals(1, result.fallback().observedFacts().size());
+        assertTrue(result.fallback().observedFacts().get(0).summary().contains("active=50"));
         String json = objectMapper.writeValueAsString(result);
         assertFalse(json.contains("Pool exhausted"));
         assertFalse(json.contains("secret-audit-reason"));
         assertEquals(1, fixture.model.calls.get());
+        String trace = fixture.trace.events.toString();
+        assertTrue(trace.contains("SEMANTIC_GUARD_DECISION"));
+        assertTrue(trace.contains("UNSUPPORTED"));
+        assertFalse(trace.contains("secret-audit-reason"));
+        assertFalse(trace.contains("Pool exhausted"));
     }
 
     @Test
@@ -167,15 +193,18 @@ class DiagnosisReleaseUseCaseTest {
         ScriptedChatModel model = new ScriptedChatModel(responses);
         HarnessRetryExecutor retries = new HarnessRetryExecutor(core);
         GuardModelCall modelCall = new GuardModelCall(core, model, executor);
+        RecordingTraceRecorder trace = new RecordingTraceRecorder();
         DiagnosisReleaseUseCase useCase = new DiagnosisReleaseUseCase(
                 new EvidenceGuard(store, new ToolCallKeyFactory(PREFIX), objectMapper),
                 new EvidenceRepair(core, retries, modelCall, objectMapper,
-                        new EvidenceRepairLimits(100_000, 20_000, Duration.ofSeconds(2)), ignored -> { }),
+                        new EvidenceRepairLimits(100_000, 20_000, Duration.ofSeconds(2)),
+                        ignored -> { }, trace),
                 new SemanticGuard(core, retries, modelCall, objectMapper,
                         new SemanticGuardLimits(100_000, 20_000,
-                                Duration.ofSeconds(2), Duration.ofSeconds(3)), ignored -> { }),
-                new SafeFallbackFactory());
-        return new Fixture(context, model, useCase);
+                                Duration.ofSeconds(2), Duration.ofSeconds(3)),
+                        ignored -> { }, trace),
+                new SafeFallbackFactory(), trace);
+        return new Fixture(context, model, useCase, trace);
     }
 
     private DiagnosisDraft duplicateDraft() {
@@ -309,6 +338,16 @@ class DiagnosisReleaseUseCaseTest {
     private record Fixture(
             RunContext context,
             ScriptedChatModel model,
-            DiagnosisReleaseUseCase useCase) {
+            DiagnosisReleaseUseCase useCase,
+            RecordingTraceRecorder trace) {
+    }
+
+    private static final class RecordingTraceRecorder implements DiagnosisTraceRecorder {
+        private final List<DiagnosisTraceAuditEvent> events = new ArrayList<>();
+
+        @Override
+        public void record(DiagnosisTraceAuditEvent event) {
+            events.add(event);
+        }
     }
 }

src/test/java/com/superbiz/agent/service/DiagnosisTraceServiceTest.java

@@ -2,17 +2,23 @@ package com.superbiz.agent.service;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.domain.entity.AgentStep;
+import com.superbiz.agent.domain.entity.AgentReasoningAudit;
 import com.superbiz.agent.domain.entity.ChatSession;
 import com.superbiz.agent.domain.entity.DiagnosisRun;
 import com.superbiz.agent.domain.entity.DiagnosisSession;
+import com.superbiz.agent.domain.entity.DiagnosisTraceEvent;
 import com.superbiz.agent.domain.entity.ToolInvocation;
 import com.superbiz.agent.dto.DiagnosisTraceResponse;
 import com.superbiz.agent.exception.SessionNotFoundException;
 import com.superbiz.agent.repository.AgentStepRepository;
+import com.superbiz.agent.repository.AgentReasoningAuditRepository;
 import com.superbiz.agent.repository.ChatSessionRepository;
 import com.superbiz.agent.repository.DiagnosisRunRepository;
 import com.superbiz.agent.repository.DiagnosisSessionRepository;
+import com.superbiz.agent.repository.DiagnosisTraceEventRepository;
 import com.superbiz.agent.repository.ToolInvocationRepository;
+import com.superbiz.agent.harness.contract.IntentType;
+import com.superbiz.agent.harness.contract.ReleaseOutcome;
 import org.junit.jupiter.api.Test;
 
 import java.time.LocalDateTime;
@@ -36,16 +42,50 @@ class DiagnosisTraceServiceTest {
     private final ChatSessionRepository chatSessionRepository = mock(ChatSessionRepository.class);
     private final DiagnosisRunRepository diagnosisRunRepository = mock(DiagnosisRunRepository.class);
     private final AgentStepRepository agentStepRepository = mock(AgentStepRepository.class);
+    private final AgentReasoningAuditRepository agentReasoningAuditRepository =
+            mock(AgentReasoningAuditRepository.class);
     private final ToolInvocationRepository toolInvocationRepository = mock(ToolInvocationRepository.class);
+    private final DiagnosisTraceEventRepository diagnosisTraceEventRepository =
+            mock(DiagnosisTraceEventRepository.class);
     private final DiagnosisTraceService service = new DiagnosisTraceService(
             diagnosisSessionRepository,
             chatSessionRepository,
             diagnosisRunRepository,
             agentStepRepository,
+            agentReasoningAuditRepository,
             toolInvocationRepository,
+            diagnosisTraceEventRepository,
             new ObjectMapper()
     );
 
+    @Test
+    void reasoningAuditRequiresExactRunAndReturnsRestrictedContent() {
+        String sessionId = "trace-session-reasoning";
+        String runId = "run-reasoning";
+        LocalDateTime createdAt = LocalDateTime.of(2026, 7, 23, 10, 0);
+        when(diagnosisRunRepository.findBySessionIdAndRunId(sessionId, runId))
+                .thenReturn(Optional.of(run(9L, sessionId, runId, "question", createdAt)));
+        when(agentReasoningAuditRepository.findByRunIdOrderByStepIndex(runId))
+                .thenReturn(List.of(AgentReasoningAudit.builder()
+                        .id(11L)
+                        .sessionId(sessionId)
+                        .runId(runId)
+                        .stepIndex(0)
+                        .agentName("diagnosis_agent")
+                        .reasoningAvailable(true)
+                        .reasoningContent("bounded reasoning")
+                        .contentBytes(17)
+                        .createdAt(createdAt)
+                        .build()));
+
+        List<DiagnosisTraceResponse.AgentReasoningTrace> result =
+                service.getReasoning(sessionId, runId);
+
+        assertEquals(1, result.size());
+        assertEquals("bounded reasoning", result.get(0).getReasoningContent());
+        assertTrue(result.get(0).getReasoningAvailable());
+    }
+
     @Test
     void getTraceWithoutRunIdResolvesLatestRun() {
         String sessionId = "trace-session-latest";
@@ -53,12 +93,16 @@ class DiagnosisTraceServiceTest {
         DiagnosisRun latest = run(2L, sessionId, "run-latest", "second question", base.plusMinutes(1));
         AgentStep step = step(20L, sessionId, "run-latest", 0, "composer", base.plusMinutes(1));
         ToolInvocation invocation = invocation(30L, sessionId, "run-latest", "query_metrics", base.plusMinutes(1));
+        DiagnosisTraceEvent event = traceEvent(40L, sessionId, "run-latest", 1,
+                "RUN", "RUN_STARTED", "STARTED", base.plusMinutes(1));
 
         when(diagnosisRunRepository.findFirstBySessionIdOrderByCreatedAtDescIdDesc(sessionId))
                 .thenReturn(Optional.of(latest));
         when(chatSessionRepository.findBySessionId(sessionId)).thenReturn(Optional.of(chatSession(sessionId)));
         when(agentStepRepository.findByRunIdOrderByStepIndex("run-latest")).thenReturn(List.of(step));
         when(toolInvocationRepository.findByRunIdOrderByIdAsc("run-latest")).thenReturn(List.of(invocation));
+        when(diagnosisTraceEventRepository.findByRunIdOrderBySequenceNoAscIdAsc("run-latest"))
+                .thenReturn(List.of(event));
 
         DiagnosisTraceResponse response = service.getTrace(sessionId);
 
@@ -69,6 +113,10 @@ class DiagnosisTraceServiceTest {
         assertEquals("run-latest", response.getSteps().get(0).getRunId());
         assertEquals("run-latest", response.getToolInvocations().get(0).getRunId());
         assertEquals(1, response.getChatSession().getMessagePairCount());
+        assertEquals("DIAGNOSIS", response.getRun().getIntent());
+        assertEquals("SUCCESS", response.getRun().getReleaseOutcome());
+        assertEquals("RUN_STARTED", response.getTimeline().get(0).getEventType());
+        assertEquals(1, response.getSummary().getReturnedTraceEventCount());
     }
 
     @Test
@@ -216,6 +264,8 @@ class DiagnosisTraceServiceTest {
                 .query(query)
                 .status("SUCCESS")
                 .agentFlow("CHAT")
+                .intent(IntentType.DIAGNOSIS)
+                .releaseOutcome(ReleaseOutcome.SUCCESS)
                 .answer("answer for " + runId)
                 .selfEvaluation("{\"verifier_evaluation\":{\"verdict\":\"PASS\"}}")
                 .feedback("useful")
@@ -226,6 +276,22 @@ class DiagnosisTraceServiceTest {
                 .build();
     }
 
+    private DiagnosisTraceEvent traceEvent(
+            Long id, String sessionId, String runId, int sequenceNo,
+            String phase, String eventType, String status, LocalDateTime createdAt) {
+        return DiagnosisTraceEvent.builder()
+                .id(id)
+                .sessionId(sessionId)
+                .runId(runId)
+                .sequenceNo(sequenceNo)
+                .phase(phase)
+                .eventType(eventType)
+                .status(status)
+                .details("{\"safe\":true}")
+                .createdAt(createdAt)
+                .build();
+    }
+
     private ChatSession chatSession(String sessionId) {
         return ChatSession.builder()
                 .id(99L)