diff --git a/.gitignore b/.gitignore
index 4fcf4b1a..656cfe90 100644
--- a/.gitignore
+++ b/.gitignore
@@ -95,7 +95,3 @@ deploy/.env
 CLAUDE.md
 .claude/settings.local.json
 .claude/plans/
-
-# Private internal dirs
-.codex/
-openspec/
diff --git a/mateclaw-server/src/main/java/vip/mate/tool/builtin/DelegateAgentTool.java b/mateclaw-server/src/main/java/vip/mate/tool/builtin/DelegateAgentTool.java
index f72742f9..4eed4446 100644
--- a/mateclaw-server/src/main/java/vip/mate/tool/builtin/DelegateAgentTool.java
+++ b/mateclaw-server/src/main/java/vip/mate/tool/builtin/DelegateAgentTool.java
@@ -40,7 +40,7 @@ public class DelegateAgentTool {
     private static final int MAX_DELEGATION_DEPTH = 3;
     private static final int MAX_RESULT_LENGTH = 4000;
     private static final int MAX_PARALLEL_CHILDREN = 3;
-    private static final int PARALLEL_TIMEOUT_SECONDS = 300; // 5 分钟
+    private static final int PARALLEL_TIMEOUT_SECONDS = 60;
 
     /** 子 Agent 禁用的工具：防递归 + 防副作用 */
     private static final Set<String> CHILD_DENIED_TOOLS = Set.of(
diff --git a/mateclaw-server/src/main/java/vip/mate/tool/builtin/DelegationContext.java b/mateclaw-server/src/main/java/vip/mate/tool/builtin/DelegationContext.java
index 840b2fa6..c0b81b10 100644
--- a/mateclaw-server/src/main/java/vip/mate/tool/builtin/DelegationContext.java
+++ b/mateclaw-server/src/main/java/vip/mate/tool/builtin/DelegationContext.java
@@ -1,62 +1,65 @@
 package vip.mate.tool.builtin;
 
+import java.util.ArrayDeque;
+import java.util.Deque;
 import java.util.Set;
 
 /**
- * 跟踪 Agent 委派调用的上下文信息，防止无限递归并传递父会话信息。
+ * Tracks Agent delegation call context to prevent infinite recursion and carry parent session info.
  * <p>
- * 使用 ThreadLocal 存储当前线程的委派层级、父会话 ID 和子 Agent 禁用工具集。
- * 每次 {@link DelegateAgentTool} 发起委派时调用 enter()，返回后调用 exit()。
+ * Uses a ThreadLocal stack so that nested delegations correctly restore the previous layer's
+ * parentConversationId and childDeniedTools on exit.
+ * Each {@link DelegateAgentTool} delegation calls enter() before and exit() after execution.
  *
  * @author MateClaw Team
  */
 public final class DelegationContext {
 
-    private static final ThreadLocal<Integer> DEPTH = ThreadLocal.withInitial(() -> 0);
-    private static final ThreadLocal<String> PARENT_CONVERSATION_ID = new ThreadLocal<>();
-    private static final ThreadLocal<Set<String>> CHILD_DENIED_TOOLS = new ThreadLocal<>();
+    /**
+     * Snapshot of one delegation layer's state.
+     */
+    private record Frame(String parentConversationId, Set<String> childDeniedTools) {}
+
+    private static final ThreadLocal<Deque<Frame>> STACK = ThreadLocal.withInitial(ArrayDeque::new);
 
     private DelegationContext() {}
 
-    /** 获取当前委派深度（0 = 顶层调用） */
+    /** Current delegation depth (0 = top-level call, not inside any delegation) */
     public static int currentDepth() {
-        return DEPTH.get();
+        return STACK.get().size();
     }
 
-    /** 获取父会话 ID（用于事件 relay） */
+    /** Parent conversation ID for event relay (from the current frame) */
     public static String parentConversationId() {
-        return PARENT_CONVERSATION_ID.get();
+        Frame top = STACK.get().peek();
+        return top != null ? top.parentConversationId : null;
     }
 
-    /** 获取子 Agent 禁用的工具集 */
+    /** Denied tools set for the child Agent (from the current frame) */
     public static Set<String> childDeniedTools() {
-        Set<String> denied = CHILD_DENIED_TOOLS.get();
-        return denied != null ? denied : Set.of();
+        Frame top = STACK.get().peek();
+        return top != null && top.childDeniedTools != null ? top.childDeniedTools : Set.of();
     }
 
-    /** 进入下一层委派（带父会话 ID 和子 Agent 工具限制） */
+    /** Enter the next delegation layer (with parent conversation ID and child tool restrictions) */
     public static void enter(String parentConversationId, Set<String> deniedTools) {
-        DEPTH.set(DEPTH.get() + 1);
-        PARENT_CONVERSATION_ID.set(parentConversationId);
-        if (deniedTools != null) {
-            CHILD_DENIED_TOOLS.set(deniedTools);
-        }
+        STACK.get().push(new Frame(parentConversationId, deniedTools));
     }
 
-    /** 进入下一层委派（兼容旧调用） */
+    /** Enter the next delegation layer (backward-compatible overload) */
     public static void enter() {
         enter(null, null);
     }
 
-    /** 退出当前委派层 */
+    /** Exit the current delegation layer, restoring the previous layer's context */
     public static void exit() {
-        int current = DEPTH.get();
-        if (current <= 1) {
-            DEPTH.remove();
-            PARENT_CONVERSATION_ID.remove();
-            CHILD_DENIED_TOOLS.remove();
-        } else {
-            DEPTH.set(current - 1);
+        Deque<Frame> stack = STACK.get();
+        if (!stack.isEmpty()) {
+            stack.pop();
+        }
+        // Clean up ThreadLocal entirely when the stack is empty to prevent memory leaks
+        if (stack.isEmpty()) {
+            STACK.remove();
         }
     }
 }
diff --git a/mateclaw-server/src/main/java/vip/mate/workspace/conversation/ConversationService.java b/mateclaw-server/src/main/java/vip/mate/workspace/conversation/ConversationService.java
index 5112b53d..b2c1f589 100644
--- a/mateclaw-server/src/main/java/vip/mate/workspace/conversation/ConversationService.java
+++ b/mateclaw-server/src/main/java/vip/mate/workspace/conversation/ConversationService.java
@@ -431,7 +431,9 @@ public class ConversationService {
             return objectMapper.readValue(message.getContentParts(), new TypeReference<List<MessageContentPart>>() {});
         } catch (Exception e) {
             log.warn("Failed to parse content_parts for message {}: {}", message.getId(), e.getMessage());
-            return List.of();
+            return List.of(MessageContentPart.parseError(
+                    message.getId() != null ? message.getId().toString() : "unknown",
+                    e.getMessage() != null ? e.getMessage() : "unknown error"));
         }
     }
 
@@ -449,6 +451,7 @@ public class ConversationService {
             switch (part.getType()) {
                 case "text" -> appendSegment(text, part.getText());
                 case "thinking", "tool_call" -> { /* skip — frontend reads these from contentParts directly */ }
+                case "parse_error" -> appendSegment(text, part.getText());
                 case "file" -> appendSegment(text, "[附件] " + safe(part.getFileName()));
                 default -> appendSegment(text, part.getText());
             }
diff --git a/mateclaw-server/src/main/java/vip/mate/workspace/conversation/model/MessageContentPart.java b/mateclaw-server/src/main/java/vip/mate/workspace/conversation/model/MessageContentPart.java
index 34477876..237e1126 100644
--- a/mateclaw-server/src/main/java/vip/mate/workspace/conversation/model/MessageContentPart.java
+++ b/mateclaw-server/src/main/java/vip/mate/workspace/conversation/model/MessageContentPart.java
@@ -100,4 +100,15 @@ public class MessageContentPart {
         part.setText(jsonPayload);
         return part;
     }
+
+    /**
+     * Create a parse_error content part to surface content_parts deserialization failures
+     * instead of silently returning an empty list.
+     */
+    public static MessageContentPart parseError(String messageId, String cause) {
+        MessageContentPart part = new MessageContentPart();
+        part.setType("parse_error");
+        part.setText("[Message content parse failed] Message ID: " + messageId + " | Cause: " + cause);
+        return part;
+    }
 }
diff --git a/mateclaw-ui/src/components/chat/MessageBubble.vue b/mateclaw-ui/src/components/chat/MessageBubble.vue
index 98ecc323..62c2d3e9 100644
--- a/mateclaw-ui/src/components/chat/MessageBubble.vue
+++ b/mateclaw-ui/src/components/chat/MessageBubble.vue
@@ -143,6 +143,12 @@
           <span>{{ status === 'interrupted' ? $t('chat.interrupted') : $t('chat.stopped') }}</span>
         </div>
 
+        <!-- parse_error content block -->
+        <div v-if="parseErrorText" class="parse-error-card">
+          <el-icon class="parse-error-card__icon"><WarningFilled /></el-icon>
+          <span class="parse-error-card__text">{{ parseErrorText }}</span>
+        </div>
+
         <!-- 错误卡片 -->
         <div v-if="status === 'failed'" class="error-card">
           <div class="error-card__header">
@@ -440,6 +446,12 @@ const displayContent = computed(() => {
   return text
 })
 
+// --- parse_error detection ---
+const parseErrorText = computed(() => {
+  const errorPart = props.message.contentParts?.find(p => p.type === 'parse_error')
+  return errorPart?.text || ''
+})
+
 const renderedContent = computed(() => {
   if (!displayContent.value) return ''
   return renderMarkdown(displayContent.value)
@@ -1082,6 +1094,31 @@ watch(isGenerating, (generating) => {
   to { transform: rotate(360deg); }
 }
 
+/* ==================== parse_error card ==================== */
+.parse-error-card {
+  display: flex;
+  align-items: flex-start;
+  gap: 8px;
+  padding: 10px 14px;
+  margin-bottom: 8px;
+  border-radius: 8px;
+  background: color-mix(in srgb, var(--mc-warning, #f59e0b) 8%, var(--mc-bg-elevated, #f8fafc));
+  border: 1px solid color-mix(in srgb, var(--mc-warning, #f59e0b) 25%, transparent);
+  font-size: 13px;
+  line-height: 1.5;
+  color: var(--mc-text-secondary, #64748b);
+}
+
+.parse-error-card__icon {
+  flex-shrink: 0;
+  color: var(--mc-warning, #f59e0b);
+  margin-top: 1px;
+}
+
+.parse-error-card__text {
+  word-break: break-word;
+}
+
 /* ==================== 审批面板 ==================== */
 /* 极简审批状态（一行式） */
 .approval-inline {