diff --git a/internal/cloud/server-workbench-http.test.ts b/internal/cloud/server-workbench-http.test.ts
index fbe58075..815f0a42 100644
--- a/internal/cloud/server-workbench-http.test.ts
+++ b/internal/cloud/server-workbench-http.test.ts
@@ -1164,13 +1164,18 @@ test("workbench read model projects terminal result atomically across session, m
     assert.equal(assistant.text, finalText);
     assert.equal(assistant.parts[0].status, "completed");
     assert.equal(assistant.parts[0].type, "final_response");
+    assert.equal(assistant.parts[0].messageId, assistant.messageId);
+    assert.equal(assistant.parts[0].traceId, traceId);
     assert.equal(assistant.parts[0].text, finalText);
 
     const turn = await getJson(port, `/v1/workbench/turns/${encodeURIComponent(traceId)}`);
     assert.equal(turn.status, 200);
     assert.equal(turn.body.turn.status, "completed");
     assert.equal(turn.body.turn.terminal, true);
+    assert.equal(turn.body.turn.assistantMessageId, assistant.messageId);
     assert.equal(turn.body.turn.assistantText, finalText);
+    assert.equal(turn.body.turn.finalResponse.source, "message-part");
+    assert.equal(turn.body.turn.finalResponse.sealed, true);
     assert.equal(turn.body.turn.finalResponse.text, finalText);
   } finally {
     await new Promise((resolve, reject) => server.close((error) => error ? reject(error) : resolve()));
diff --git a/web/hwlab-cloud-web/scripts/workbench-message-projection-runtime.test.ts b/web/hwlab-cloud-web/scripts/workbench-message-projection-runtime.test.ts
index d4089409..dc7a787b 100644
--- a/web/hwlab-cloud-web/scripts/workbench-message-projection-runtime.test.ts
+++ b/web/hwlab-cloud-web/scripts/workbench-message-projection-runtime.test.ts
@@ -83,6 +83,87 @@ test("message timing and terminal status patches stay independent from store sta
   assert.equal(terminalPatch.durationMs, 3500);
 });
 
+test("terminal turn result seals completed final response body", () => {
+  const restored = {
+    role: "agent",
+    status: "running",
+    text: "",
+    traceAutoLifecycle: "running",
+    traceId: "trc_unit_final",
+    runnerTrace: { traceId: "trc_unit_final", status: "running" }
+  } as ChatMessage;
+
+  const terminal = terminalMessagePatchFromTurnResult(restored, {
+    traceId: "trc_unit_final",
+    status: "completed",
+    terminal: true,
+    finalResponse: { text: "final answer" },
+    startedAt: "2026-01-01T00:00:00.000Z",
+    finishedAt: "2026-01-01T00:00:04.000Z",
+    durationMs: 4000
+  } as AgentChatResultResponse);
+
+  assert.equal(terminal?.status, "completed");
+  assert.equal(terminal?.traceAutoLifecycle, "terminal");
+  assert.equal(terminal?.text, "final answer");
+  assert.equal((terminal?.finalResponse as { text?: string } | undefined)?.text, "final answer");
+});
+
+test("terminal turn result accepts authoritative assistant trace final", () => {
+  const restored = {
+    role: "agent",
+    status: "running",
+    text: "",
+    traceId: "trc_trace_final",
+    runnerTrace: { traceId: "trc_trace_final", status: "running" }
+  } as ChatMessage;
+
+  const terminal = terminalMessagePatchFromTurnResult(restored, {
+    traceId: "trc_trace_final",
+    status: "completed",
+    terminal: true,
+    runnerTrace: {
+      traceId: "trc_trace_final",
+      status: "completed",
+      events: [
+        { seq: 1, type: "assistant_message", status: "running", message: "progress only" },
+        { seq: 2, type: "assistant_message", status: "completed", message: "final from trace", replyAuthority: true, final: true }
+      ]
+    }
+  } as unknown as AgentChatResultResponse);
+
+  assert.equal(terminal?.status, "completed");
+  assert.equal(terminal?.text, "final from trace");
+  assert.equal((terminal?.finalResponse as { text?: string } | undefined)?.text, "final from trace");
+});
+
+test("terminal failure does not synthesize completed final response from progress text", () => {
+  const restored = {
+    role: "agent",
+    status: "running",
+    text: "",
+    traceId: "trc_failed_progress",
+    runnerTrace: { traceId: "trc_failed_progress", status: "running" }
+  } as ChatMessage;
+
+  const terminal = terminalMessagePatchFromTurnResult(restored, {
+    traceId: "trc_failed_progress",
+    status: "failed",
+    terminal: true,
+    runnerTrace: {
+      traceId: "trc_failed_progress",
+      status: "failed",
+      events: [{ seq: 1, type: "assistant_message", status: "running", message: "progress only" }]
+    },
+    error: { message: "provider failed" }
+  } as unknown as AgentChatResultResponse);
+
+  assert.equal(terminal?.status, "failed");
+  assert.equal(terminal?.text, undefined);
+  assert.equal(terminal?.finalResponse, undefined);
+  assert.equal(terminal?.error?.message, "provider failed");
+});
+
 test("terminal seal blocks stale running snapshots after session restore", () => {
   const sealed = {
     role: "agent",
diff --git a/web/hwlab-cloud-web/scripts/workbench-server-state.test.ts b/web/hwlab-cloud-web/scripts/workbench-server-state.test.ts
index 7fc76569..cf1cb772 100644
--- a/web/hwlab-cloud-web/scripts/workbench-server-state.test.ts
+++ b/web/hwlab-cloud-web/scripts/workbench-server-state.test.ts
@@ -168,6 +168,50 @@ test("Workbench session messages keep sealed terminal timing on bulk refresh", (
   assert.equal(agent?.finishedAt, "2026-06-24T00:00:12.000Z");
 });
 
+test("Workbench sealed completed final body survives stale running session messages", () => {
+  let state = createWorkbenchServerState();
+  state = reduceWorkbenchServerState(state, {
+    type: "session.status",
+    session: { sessionId: "ses_final_seal", status: "running", lastTraceId: "trc_final_seal" }
+  });
+  state = reduceWorkbenchServerState(state, {
+    type: "session.messages",
+    sessionId: "ses_final_seal",
+    messages: [
+      { id: "msg_user", messageId: "msg_user", role: "user", title: "用户", text: "ping", status: "sent", createdAt: "2026-06-24T00:00:00.000Z", sessionId: "ses_final_seal", traceId: "trc_final_seal" },
+      { id: "msg_agent", messageId: "msg_agent", role: "agent", title: "Code Agent", text: "", status: "running", createdAt: "2026-06-24T00:00:01.000Z", sessionId: "ses_final_seal", traceId: "trc_final_seal", traceAutoLifecycle: "running", timing: { startedAt: "2026-06-24T00:00:01.000Z", lastEventAt: "2026-06-24T00:00:02.000Z", durationMs: null, valuesRedacted: true }, startedAt: "2026-06-24T00:00:01.000Z", lastEventAt: "2026-06-24T00:00:02.000Z", durationMs: null }
+    ]
+  });
+
+  state = reduceWorkbenchServerState(state, {
+    type: "message.snapshot",
+    sessionId: "ses_final_seal",
+    message: { id: "msg_agent", messageId: "msg_agent", role: "agent", title: "Code Agent", text: "final answer", finalResponse: { text: "final answer", sealed: true }, status: "completed", createdAt: "2026-06-24T00:00:01.000Z", updatedAt: "2026-06-24T00:00:06.000Z", sessionId: "ses_final_seal", traceId: "trc_final_seal", traceAutoLifecycle: "terminal", timing: { startedAt: "2026-06-24T00:00:01.000Z", finishedAt: "2026-06-24T00:00:06.000Z", durationMs: 5_000, valuesRedacted: true }, startedAt: "2026-06-24T00:00:01.000Z", finishedAt: "2026-06-24T00:00:06.000Z", durationMs: 5_000 }
+  });
+  state = reduceWorkbenchServerState(state, {
+    type: "session.messages",
+    sessionId: "ses_final_seal",
+    messages: [
+      { id: "msg_user", messageId: "msg_user", role: "user", title: "用户", text: "ping", status: "sent", createdAt: "2026-06-24T00:00:00.000Z", sessionId: "ses_final_seal", traceId: "trc_final_seal" },
+      { id: "msg_agent", messageId: "msg_agent", role: "agent", title: "Code Agent", text: "", status: "running", createdAt: "2026-06-24T00:00:01.000Z", sessionId: "ses_final_seal", traceId: "trc_final_seal", traceAutoLifecycle: "running", timing: { startedAt: "2026-06-24T00:00:01.000Z", lastEventAt: "2026-06-24T00:00:04.000Z", durationMs: null, valuesRedacted: true }, startedAt: "2026-06-24T00:00:01.000Z", lastEventAt: "2026-06-24T00:00:04.000Z", durationMs: null }
+    ]
+  });
+
+  const agent = selectActiveMessages(state, "ses_final_seal").find((message) => message.role === "agent");
+  assert.equal(agent?.status, "completed");
+  assert.equal(agent?.text, "final answer");
+  assert.equal((agent?.finalResponse as { text?: string } | undefined)?.text, "final answer");
+  assert.equal(selectSessionStatusAuthority(state).ses_final_seal?.status, "completed");
+
+  state = reduceWorkbenchServerState(state, {
+    type: "session.list",
+    sessions: [{ sessionId: "ses_final_seal", threadId: "thr_final_seal", status: "running", lastTraceId: "trc_final_seal", updatedAt: "2026-06-24T00:00:07.000Z" }]
+  });
+
+  assert.equal(selectSessionStatusAuthority(state).ses_final_seal?.status, "completed");
+  assert.equal(selectActiveSession(state, "ses_final_seal")?.status, "completed");
+});
+
 test("Workbench session messages repair terminal zero timing from running projection", () => {
   let state = createWorkbenchServerState();
   state = reduceWorkbenchServerState(state, {
diff --git a/web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.ts b/web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.ts
index e1d20e72..fb70db95 100644
--- a/web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.ts
+++ b/web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.ts
@@ -282,9 +282,11 @@ export function terminalMessagePatchFromTurnResult(message: ChatMessage, result:
   const error = resultError ?? (clearCompletedDiagnostics ? null : normalizeAgentError(runnerTrace?.error ?? message.error));
   const projection = clearCompletedDiagnostics ? nonBlockingProjection(resultProjection) : resultProjection ?? runnerTrace.projection ?? message.projection ?? null;
   const agentRun = agentRunFromResult(result, runnerTrace) ?? agentRunFromMessage(message);
+  const bodyPatch = terminalMessageBodyPatchFromTurnResult(message, result, resultStatus);
   return {
     ...messageTimingPatchForMerge(message, result),
     ...messageStatusPatchForTerminalMerge(message, resultStatus, terminal),
+    ...bodyPatch,
     runnerTrace,
     error,
     projection,
@@ -297,6 +299,87 @@ export function terminalMessagePatchFromTurnResult(message: ChatMessage, result:
   };
 }
 
+function terminalMessageBodyPatchFromTurnResult(message: ChatMessage, result: AgentChatResultResponse, resultStatus: string | null): Partial<ChatMessage> {
+  if (normalizedStatusText(resultStatus) !== "completed") return {};
+  const finalText = terminalFinalResponseTextFromTurnResult(result);
+  if (!finalText) return {};
+  const traceId = firstNonEmptyString(result.traceId, message.traceId, message.runnerTrace?.traceId) ?? null;
+  return {
+    finalResponse: {
+      text: finalText,
+      status: "completed",
+      traceId,
+      sealed: true,
+      source: "turn-result",
+      valuesRedacted: true
+    },
+    text: projectedAgentMessageText({ status: "completed", finalText })
+  };
+}
+
+function terminalFinalResponseTextFromTurnResult(result: AgentChatResultResponse): string | null {
+  const record = recordValue(result);
+  const direct = firstNonEmptyString(
+    finalResponseText(record?.finalResponse),
+    messageText(record?.assistantText),
+    messageText(record?.finalText),
+    messageText(record?.reply),
+    messageText(record?.text),
+    messageText(record?.content),
+    messageText(record?.message)
+  );
+  if (direct) return direct;
+  const resultTrace = recordValue(record?.runnerTrace);
+  return firstNonEmptyString(
+    terminalEvidenceFinalText(record?.terminalEvidence),
+    terminalEvidenceFinalText(resultTrace?.terminalEvidence),
+    terminalAssistantFinalEventText(firstArray(record?.events, record?.traceEvents, resultTrace?.events))
+  ) ?? null;
+}
+
+function terminalEvidenceFinalText(value: unknown): string | null {
+  const record = recordValue(value);
+  if (!record) return null;
+  return firstNonEmptyString(
+    finalResponseText(record.finalResponse),
+    messageText(record.assistantText),
+    messageText(record.finalText),
+    messageText(record.reply),
+    messageText(record.text),
+    messageText(record.content),
+    messageText(record.message),
+    terminalEvidenceFinalText(record.evidence),
+    terminalEvidenceFinalText(record.payload)
+  ) ?? null;
+}
+
+function terminalAssistantFinalEventText(events: TraceEvent[]): string | null {
+  for (const event of [...events].reverse()) {
+    if (!traceEventHasTerminalEvidence(event)) continue;
+    const record = recordValue(event);
+    if (!record) continue;
+    const payload = recordValue(record.payload);
+    const text = firstNonEmptyString(
+      finalResponseText(record.finalResponse),
+      messageText(record.assistantText),
+      messageText(record.finalText),
+      messageText(record.reply),
+      messageText(record.text),
+      messageText(record.content),
+      messageText(record.message),
+      finalResponseText(payload?.finalResponse),
+      messageText(payload?.assistantText),
+      messageText(payload?.finalText),
+      messageText(payload?.reply),
+      messageText(payload?.text),
+      messageText(payload?.content),
+      messageText(payload?.message)
+    );
+    if (text) return text;
+  }
+  return null;
+}
+
 export function firstPositiveFiniteNumber(...values: unknown[]): number | null {
   for (const value of values) {
     const number = firstFiniteNumber(value);
diff --git a/web/hwlab-cloud-web/src/stores/workbench-server-state.ts b/web/hwlab-cloud-web/src/stores/workbench-server-state.ts
index bf75ef88..90abd21d 100644
--- a/web/hwlab-cloud-web/src/stores/workbench-server-state.ts
+++ b/web/hwlab-cloud-web/src/stores/workbench-server-state.ts
@@ -110,14 +110,15 @@ function reduceSessionDetail(state: WorkbenchServerState, session: WorkbenchSess
   const existing = state.sessionsById[sessionId];
   const existingMessages = state.messagesBySessionId[sessionId] ?? existing?.messages ?? [];
   const messages = Array.isArray(session.messages) ? mergeMessageList(existingMessages, session.messages) : existingMessages;
-  const merged = mergeSessionRecord(existing, { ...session, messages });
-  const sessionStatus = sessionStatusAuthorityFromDetail(session);
+  const messageStatus = sessionStatusAuthorityFromMessages(sessionId, messages);
+  const merged = mergeSessionRecord(existing, { ...session, status: messageStatus?.status ?? session.status, messages });
+  const sessionStatus = messageStatus ?? sessionStatusAuthorityFromDetail(session);
   return {
     ...state,
     sessionOrder: state.sessionOrder.includes(sessionId) ? state.sessionOrder : [sessionId, ...state.sessionOrder],
     sessionsById: { ...state.sessionsById, [sessionId]: merged },
     sessionStatusById: sessionStatus
-      ? { ...state.sessionStatusById, [sessionId]: sessionStatus }
+      ? { ...state.sessionStatusById, [sessionId]: mergeSessionStatusAuthority(state.sessionStatusById[sessionId], sessionStatus) }
       : state.sessionStatusById,
     messagesBySessionId: {
       ...state.messagesBySessionId,
@@ -138,13 +139,14 @@ function reduceSessionListItem(state: WorkbenchServerState, session: WorkbenchSe
   const existing = state.sessionsById[sessionId];
   const existingMessages = state.messagesBySessionId[sessionId] ?? existing?.messages;
   const messages = Array.isArray(existingMessages) ? existingMessages : Array.isArray(session.messages) ? session.messages : [];
-  const merged = mergeSessionRecord(existing, { ...session, messages });
-  const sessionStatus = sessionStatusAuthorityFromDetail(session);
+  const messageStatus = sessionStatusAuthorityFromMessages(sessionId, messages);
+  const merged = mergeSessionRecord(existing, { ...session, status: messageStatus?.status ?? session.status, messages });
+  const sessionStatus = messageStatus ?? sessionStatusAuthorityFromDetail(session);
   return {
     ...state,
     sessionsById: { ...state.sessionsById, [sessionId]: merged },
     sessionStatusById: sessionStatus
-      ? { ...state.sessionStatusById, [sessionId]: sessionStatus }
+      ? { ...state.sessionStatusById, [sessionId]: mergeSessionStatusAuthority(state.sessionStatusById[sessionId], sessionStatus) }
       : state.sessionStatusById
   };
 }
@@ -154,10 +156,14 @@ function reduceSessionMessages(state: WorkbenchServerState, sessionId: string |
   const existing = state.sessionsById[sessionId];
   const existingMessages = state.messagesBySessionId[sessionId] ?? existing?.messages ?? [];
   const mergedMessages = mergeMessageList(existingMessages, messages);
-  const session = existing ? { ...existing, messages: mergedMessages, messageCount: mergedMessages.length } : null;
+  const reconciledStatus = sessionStatusAuthorityFromMessages(sessionId, mergedMessages);
+  const session = existing ? { ...existing, status: reconciledStatus?.status ?? existing.status, messages: mergedMessages, messageCount: mergedMessages.length } : null;
   return {
     ...state,
     sessionsById: session ? { ...state.sessionsById, [sessionId]: session } : state.sessionsById,
+    sessionStatusById: reconciledStatus
+      ? { ...state.sessionStatusById, [sessionId]: mergeSessionStatusAuthority(state.sessionStatusById[sessionId], reconciledStatus) }
+      : state.sessionStatusById,
     messagesBySessionId: { ...state.messagesBySessionId, [sessionId]: mergedMessages }
   };
 }
@@ -224,18 +230,26 @@ function sealExistingRunningMessageTiming(existing: ChatMessage, incoming: ChatM
 function sealExistingTerminalMessageTiming(existing: ChatMessage, incoming: ChatMessage): ChatMessage {
   if (!isTerminalMessageStatus(existing.status)) return incoming;
   const timing = sealedTerminalTimingProjection(existing, incoming);
-  if (!timing || timing.durationMs == null) return incoming;
-  const patch: Partial<ChatMessage> = {
-    status: existing.status,
+  const patch: Partial<ChatMessage> = sealedTerminalMessagePatch(existing);
+  if (timing && timing.durationMs != null) Object.assign(patch, {
     timing,
     startedAt: timing.startedAt ?? null,
     lastEventAt: timing.lastEventAt ?? null,
     finishedAt: timing.finishedAt ?? null,
-    durationMs: timing.durationMs ?? null,
+    durationMs: timing.durationMs ?? null
+  });
+  return { ...incoming, ...patch };
+}
+
+function sealedTerminalMessagePatch(existing: ChatMessage): Partial<ChatMessage> {
+  const patch: Partial<ChatMessage> = {
+    status: existing.status,
     traceAutoLifecycle: existing.traceAutoLifecycle ?? "terminal"
   };
   if (typeof existing.text === "string" && existing.text.trim()) patch.text = existing.text;
-  return { ...incoming, ...patch };
+  const finalResponse = (existing as Record<string, unknown>).finalResponse;
+  if (finalResponse) patch.finalResponse = finalResponse;
+  return patch;
 }
 
 function sealTerminalTransitionMessageTiming(existing: ChatMessage, incoming: ChatMessage): ChatMessage {
@@ -360,6 +374,72 @@ function sessionStatusAuthorityFromDetail(session: WorkbenchSessionRecord): Sess
   };
 }
 
+function sessionStatusAuthorityFromMessages(sessionId: string, messages: ChatMessage[]): SessionStatusAuthority | null {
+  const message = [...messages].reverse().find((item) => messageHasCompletedFinalResponse(item));
+  if (!message) return null;
+  return {
+    sessionId,
+    status: "completed",
+    updatedAt: textValue(message.updatedAt) ?? textValue(message.finishedAt) ?? textValue(message.lastEventAt),
+    lastTraceId: textValue(message.traceId) ?? textValue(message.runnerTrace?.traceId),
+    projection: projectionFromMessageRecord(message),
+    loadedAt: new Date().toISOString()
+  };
+}
+
+function mergeSessionStatusAuthority(existing: SessionStatusAuthority | undefined, incoming: SessionStatusAuthority): SessionStatusAuthority {
+  if (existing?.status === "completed" && incoming.status !== "completed" && isSameTraceAuthority(existing, incoming) && isRunningSessionStatus(incoming.status)) return existing;
+  return {
+    ...(existing ?? {}),
+    ...incoming,
+    projection: incoming.projection ?? existing?.projection ?? null,
+    loadedAt: incoming.loadedAt ?? existing?.loadedAt ?? null
+  };
+}
+
+function isSameTraceAuthority(left: SessionStatusAuthority, right: SessionStatusAuthority): boolean {
+  const leftTrace = textValue(left.lastTraceId);
+  const rightTrace = textValue(right.lastTraceId);
+  return Boolean(leftTrace && rightTrace && leftTrace === rightTrace);
+}
+
+function isRunningSessionStatus(value: unknown): boolean {
+  return ["", "pending", "running", "accepted", "queued", "dispatching", "streaming", "processing", "retrying", "busy", "creating"].includes(normalizedMessageStatus(value));
+}
+
+function messageHasCompletedFinalResponse(message: ChatMessage): boolean {
+  if (message.role !== "agent") return false;
+  if (normalizedMessageStatus(message.status) !== "completed") return false;
+  return Boolean(messageFinalResponseText(message));
+}
+
+function messageFinalResponseText(message: ChatMessage): string | null {
+  return textValue(message.text) ?? nestedTextValue((message as Record<string, unknown>).finalResponse);
+}
+
+function projectionFromMessageRecord(message: ChatMessage): ProjectionDiagnostic | null {
+  const direct = message.projection && typeof message.projection === "object" ? message.projection : null;
+  if (direct) return direct;
+  const trace = message.runnerTrace && typeof message.runnerTrace === "object" ? message.runnerTrace as Record<string, unknown> : null;
+  const traceProjection = trace?.projection && typeof trace.projection === "object" ? trace.projection as ProjectionDiagnostic : null;
+  return traceProjection ?? null;
+}
+
+function nestedTextValue(value: unknown): string | null {
+  const direct = textValue(value);
+  if (direct) return direct;
+  if (Array.isArray(value)) return value.map(nestedTextValue).filter((item): item is string => Boolean(item)).join("\n") || null;
+  if (!value || typeof value !== "object") return null;
+  const record = value as Record<string, unknown>;
+  return textValue(record.text) ?? textValue(record.content) ?? textValue(record.message) ?? textValue(record.summary) ?? textValue(record.preview);
+}
+
+function textValue(value: unknown): string | null {
+  if (typeof value !== "string") return null;
+  const text = value.trim();
+  return text || null;
+}
+
 function projectionFromSessionRecord(session: WorkbenchSessionRecord): ProjectionDiagnostic | null {
   const turnSummary = session.turnSummary && typeof session.turnSummary === "object" ? session.turnSummary as Record<string, unknown> : null;
   const direct = session.projection && typeof session.projection === "object" ? session.projection : null;