diff --git a/internal/cloud/workbench-projection-writer.test.ts b/internal/cloud/workbench-projection-writer.test.ts
index d4c54a8c..5d4368d7 100644
--- a/internal/cloud/workbench-projection-writer.test.ts
+++ b/internal/cloud/workbench-projection-writer.test.ts
@@ -353,6 +353,9 @@ test("workbench projection writer seals failed AgentRun turns with failure final
   assert.equal(facts.turns[0].terminal, true);
   assert.equal(facts.turns[0].sealed, true);
   assert.match(facts.turns[0].finalResponse.text, /provider-stream-disconnected/u);
+  assert.equal(facts.turns[0].diagnostic.projectionStatus, "caught-up");
+  assert.equal(facts.turns[0].diagnostic.projectionHealth, "healthy");
+  assert.equal(facts.turns[0].diagnostic.blocker, null);
   assert.equal(facts.checkpoints[0].projectionStatus, "caught_up");
   assert.equal(facts.checkpoints[0].terminal, true);
   assert.equal(facts.checkpoints[0].sealed, true);
diff --git a/internal/cloud/workbench-turn-projection.ts b/internal/cloud/workbench-turn-projection.ts
index 84c7fb52..fc6221ad 100644
--- a/internal/cloud/workbench-turn-projection.ts
+++ b/internal/cloud/workbench-turn-projection.ts
@@ -119,22 +119,22 @@ export function createWorkbenchTurnTimingProjection({ result = null, session = n
 
 export function projectionDiagnostics({ traceId = null, projection = null, result = null, trace = null, refreshError = null } = {}) {
   const turn = projection ?? createWorkbenchTurnProjection({ traceId, result, trace });
-  const sealedCompleted = turn.terminal === true && turn.status === "completed" && Boolean(turn.finalResponse?.text);
+  const sealedTerminal = turn.terminal === true && Boolean(turn.finalResponse?.text);
   const waitingFor = textValue(turn.waitingFor) || null;
-  const source = sealedCompleted ? null : projectionDiagnosticSource(trace);
-  const rawBlocker = sealedCompleted ? null : refreshError ?? source?.blocker ?? trace?.blocker ?? result?.blocker ?? result?.error ?? null;
-  const retryingProviderInterruption = !sealedCompleted && turn.running === true ? retryableProviderInterruptionEvidence(rawBlocker) : null;
+  const source = sealedTerminal ? null : projectionDiagnosticSource(trace);
+  const rawBlocker = sealedTerminal ? null : refreshError ?? source?.blocker ?? trace?.blocker ?? result?.blocker ?? result?.error ?? null;
+  const retryingProviderInterruption = !sealedTerminal && turn.running === true ? retryableProviderInterruptionEvidence(rawBlocker) : null;
   const blocker = retryingProviderInterruption ? null : rawBlocker;
   const hasProjectionInput = hasTraceProjection(trace) || Boolean(result || result?.agentRun);
-  const sourceStatus = sealedCompleted ? null : normalizeProjectionStatus(source?.projectionStatus ?? trace?.projectionStatus);
+  const sourceStatus = sealedTerminal ? null : normalizeProjectionStatus(source?.projectionStatus ?? trace?.projectionStatus);
   const effectiveSourceStatus = retryingProviderInterruption && sourceStatus === "blocked" ? "projecting" : sourceStatus;
-  const status = sealedCompleted ? "caught-up" : waitingFor ? "projecting" : effectiveSourceStatus ?? (blocker ? "blocked" : turn.terminal ? "caught-up" : hasProjectionInput ? "projecting" : "unknown");
+  const status = sealedTerminal ? "caught-up" : waitingFor ? "projecting" : effectiveSourceStatus ?? (blocker ? "blocked" : turn.terminal ? "caught-up" : hasProjectionInput ? "projecting" : "unknown");
   const diagnostic = blocker ? diagnosticBlocker(blocker) : null;
-  const sourceHealth = sealedCompleted ? null : normalizeProjectionHealth(source?.projectionHealth ?? trace?.projectionHealth);
+  const sourceHealth = sealedTerminal ? null : normalizeProjectionHealth(source?.projectionHealth ?? trace?.projectionHealth);
   const effectiveSourceHealth = retryingProviderInterruption && (sourceHealth === "degraded" || sourceHealth === "unavailable" || sourceHealth === "stalled") ? "projecting" : sourceHealth;
-  const projectionHealth = sealedCompleted ? "healthy" : waitingFor ? "projecting" : effectiveSourceHealth
+  const projectionHealth = sealedTerminal ? "healthy" : waitingFor ? "projecting" : effectiveSourceHealth
     ?? projectionHealthFor({ status, turn, hasProjectionInput, blocker: diagnostic });
-  const staleMs = sealedCompleted ? null : projectionStaleMs(source?.staleMs ?? trace?.staleMs, turn.updatedAt ?? trace?.updatedAt ?? result?.updatedAt);
+  const staleMs = sealedTerminal ? null : projectionStaleMs(source?.staleMs ?? trace?.staleMs, turn.updatedAt ?? trace?.updatedAt ?? result?.updatedAt);
   return {
     projectionStatus: status,
     projectionHealth,
diff --git a/web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.test.ts b/web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.test.ts
index 895e189b..af2a300c 100644
--- a/web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.test.ts
+++ b/web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.test.ts
@@ -47,3 +47,22 @@ test("turn result merge seals completed result with final response", () => {
   assert.equal((patch?.finalResponse as any)?.text, "final answer");
   assert.equal(patch?.text, "final answer");
 });
+
+test("turn result merge seals failed result with failure final response", () => {
+  const traceId = "trc_frontend_terminal_failed_with_body";
+  const message = { id: "msg_frontend_terminal_failed_with_body", role: "agent", status: "running", traceId } as any;
+  const result = {
+    traceId,
+    status: "failed",
+    terminal: true,
+    finalResponse: { text: "Workbench terminal failed: provider-stream-disconnected", status: "failed" }
+  } as any;
+
+  const patch = terminalMessagePatchFromTurnResult(message, result);
+  assert.equal(turnResultStatusForMerge(result), "failed");
+  assert.equal(turnResultIsTerminalForMerge(result), true);
+  assert.equal(patch?.status, "failed");
+  assert.equal((patch?.finalResponse as any)?.status, "failed");
+  assert.equal((patch?.finalResponse as any)?.text, "Workbench terminal failed: provider-stream-disconnected");
+  assert.equal(patch?.text, "Workbench terminal failed: provider-stream-disconnected");
+});
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 2ddf2742..195373be 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
@@ -325,20 +325,21 @@ export function terminalMessagePatchFromTurnResult(message: ChatMessage, result:
 }
 
 function terminalMessageBodyPatchFromTurnResult(message: ChatMessage, result: AgentChatResultResponse, resultStatus: string | null): Partial<ChatMessage> {
-  if (normalizedStatusText(resultStatus) !== "completed") return {};
+  const status = normalizedStatusText(resultStatus);
+  if (!isTerminalMessageStatus(status)) 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",
+      status,
       traceId,
       sealed: true,
       source: "turn-result",
       valuesRedacted: true
     },
-    text: projectedAgentMessageText({ status: "completed", finalText })
+    text: projectedAgentMessageText({ status, finalText })
   };
 }
 
diff --git a/web/hwlab-cloud-web/src/stores/workbench-server-state.test.ts b/web/hwlab-cloud-web/src/stores/workbench-server-state.test.ts
index 57cc2af8..5ffa64ce 100644
--- a/web/hwlab-cloud-web/src/stores/workbench-server-state.test.ts
+++ b/web/hwlab-cloud-web/src/stores/workbench-server-state.test.ts
@@ -55,3 +55,20 @@ test("server state reducer keeps sealed terminal messages when a stale partial s
   assert.equal(terminal.finalResponse.text, "final answer");
   assert.equal(selectSessionStatusAuthority(state)[sessionId]?.status, "completed");
 });
+
+test("server state reducer promotes failed terminal message authority and ignores running list rollback", () => {
+  const sessionId = "ses_state_failed_terminal_authority";
+  const traceId = "trc_state_failed_terminal_authority";
+  let state = createWorkbenchServerState();
+  state = reduceWorkbenchServerState(state, { type: "session.detail", session: { sessionId, status: "running", lastTraceId: traceId, messages: [] } as any });
+  state = reduceWorkbenchServerState(state, { type: "session.messages", sessionId, messages: [
+    { id: "msg_state_failed_user", role: "user", status: "sent", text: "one", sessionId, traceId } as any,
+    { id: "msg_state_failed_agent", role: "agent", status: "failed", text: "Workbench terminal failed: provider-stream-disconnected", finalResponse: { text: "Workbench terminal failed: provider-stream-disconnected" }, sessionId, traceId, finishedAt: "2026-07-01T00:00:05.000Z", durationMs: 5000 } as any
+  ] });
+
+  assert.equal(selectSessionStatusAuthority(state)[sessionId]?.status, "failed");
+  state = reduceWorkbenchServerState(state, { type: "session.list", sessions: [{ sessionId, status: "running", lastTraceId: traceId, messages: [] } as any] });
+
+  assert.equal(selectSessionStatusAuthority(state)[sessionId]?.status, "failed");
+  assert.equal(selectActiveMessages(state, sessionId).find((message) => message.id === "msg_state_failed_agent")?.status, "failed");
+});
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 a26ef96d..68d7e639 100644
--- a/web/hwlab-cloud-web/src/stores/workbench-server-state.ts
+++ b/web/hwlab-cloud-web/src/stores/workbench-server-state.ts
@@ -400,11 +400,12 @@ function sessionStatusAuthorityFromDetail(session: WorkbenchSessionRecord): Sess
 }
 
 function sessionStatusAuthorityFromMessages(sessionId: string, messages: ChatMessage[]): SessionStatusAuthority | null {
-  const message = [...messages].reverse().find((item) => messageHasCompletedFinalResponse(item));
+  const message = [...messages].reverse().find((item) => messageHasTerminalResponse(item));
   if (!message) return null;
+  const status = canonicalTerminalMessageStatus(message.status);
   return {
     sessionId,
-    status: "completed",
+    status,
     updatedAt: textValue(message.updatedAt) ?? textValue(message.finishedAt) ?? textValue(message.lastEventAt),
     lastTraceId: textValue(message.traceId) ?? textValue(message.runnerTrace?.traceId),
     projection: projectionFromMessageRecord(message),
@@ -413,7 +414,7 @@ function sessionStatusAuthorityFromMessages(sessionId: string, messages: ChatMes
 }
 
 function mergeSessionStatusAuthority(existing: SessionStatusAuthority | undefined, incoming: SessionStatusAuthority): SessionStatusAuthority {
-  if (existing?.status === "completed" && incoming.status !== "completed" && isSameTraceAuthority(existing, incoming) && isRunningSessionStatus(incoming.status)) return existing;
+  if (isTerminalSessionStatusAuthority(existing) && !isTerminalSessionStatusAuthority(incoming) && isSameTraceAuthority(existing, incoming) && isRunningSessionStatus(incoming.status)) return existing;
   return {
     ...(existing ?? {}),
     ...incoming,
@@ -422,6 +423,11 @@ function mergeSessionStatusAuthority(existing: SessionStatusAuthority | undefine
   };
 }
 
+function isTerminalSessionStatusAuthority(session: SessionStatusAuthority | undefined): boolean {
+  if (!session) return false;
+  return isTerminalMessageStatus(session.status) && !isRunningSessionStatus(session.status);
+}
+
 function mergeTurnStatusAuthority(existing: TurnStatusAuthority | undefined, incoming: TurnStatusAuthority): TurnStatusAuthority {
   if (existing && isTerminalTurnStatusAuthority(existing) && !isTerminalTurnStatusAuthority(incoming) && isRunningSessionStatus(incoming.status)) return existing;
   return {
@@ -459,6 +465,19 @@ function messageHasCompletedFinalResponse(message: ChatMessage): boolean {
   return Boolean(messageFinalResponseText(message));
 }
 
+function messageHasTerminalResponse(message: ChatMessage): boolean {
+  if (message.role !== "agent") return false;
+  const status = normalizedMessageStatus(message.status);
+  if (!isTerminalMessageStatus(status)) return false;
+  if (status === "completed") return messageHasCompletedFinalResponse(message);
+  return Boolean(messageFinalResponseText(message));
+}
+
+function canonicalTerminalMessageStatus(value: unknown): string {
+  const status = normalizedMessageStatus(value);
+  return status === "cancelled" ? "canceled" : status;
+}
+
 function messageFinalResponseText(message: ChatMessage): string | null {
   return textValue(message.text) ?? textValue(message.content) ?? nestedTextValue((message as Record<string, unknown>).finalResponse);
 }