diff --git a/Cargo.lock b/Cargo.lock
index 7dfddb9..253fb7e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1635,7 +1635,7 @@ dependencies = [
 
 [[package]]
 name = "picobot"
-version = "0.2.0"
+version = "0.3.0"
 dependencies = [
  "anyhow",
  "async-trait",
diff --git a/Cargo.toml b/Cargo.toml
index 2a5699d..c9a9901 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "picobot"
-version = "0.2.0"
+version = "0.3.0"
 edition = "2024"
 
 [lints.rust]
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 661a389..094b53e 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -2,6 +2,70 @@
 
 本文件记录 Picobot 各版本的显著变更，遵循 [Keep a Changelog](https://keepachangelog.com/zh-CN/1.1.0/) 风格。
 
+## [0.3.0] - 2026-08-04
+
+较 [0.2.0] 的 14 个已提交 commit + 本次版本一并提交的锁屏冻结架构修复（12 文件），聚焦 **Agent 执行与显示层解耦**、**工程化基线**、**并发持久化稳定性** 与 **安全加固** 四大方向。架构修复经五轮对抗性审查验证。
+
+### 新增功能
+
+#### 话题重命名
+- 新增 `RenameTopic` 命令与 `TopicRenamed` 协议消息，复用存储层已有的 `update_topic_title` 方法。后端响应携带刷新后的完整 topic 列表，前端零额外往返同步侧边栏。
+- 前端 `TopicList` 侧边栏增加内联编辑入口：悬停显示铅笔图标，Enter 提交 / Esc 取消 / blur 取消，通过 `onMouseDown preventDefault` 防止按钮点击时 input 提前失焦。
+
+#### 前端自动构建集成
+- 新增 `build.rs`，`cargo build` 时自动执行 `npm install + npm run build`，消除前后端构建割裂。支持 `SKIP_FRONTEND_BUILD` 环境变量跳过。
+
+#### 工程化基线
+- `rustfmt.toml` 固化 `max_width=100` / 4 空格缩进；`Cargo.toml` 配置 `[lints.rust]` 与 `[lints.clippy]` 渐进式规则。
+- `.github/workflows/ci.yml`：Rust（fmt + clippy + test）+ 前端（eslint + tsc + test + prettier format:check）双平台 CI。
+- `Makefile` 新增 `check` / `fmt` / `fix` 目标，clippy 对齐 `--all-targets --all-features`。
+- 前端 eslint flat config + prettier 配置，对 47 个前端文件统一格式化并在 CI 强制 `format:check`。
+
+#### 默认迭代上限调整
+- `max_tool_iterations` 默认值调整为 1000，匹配长任务子代理的实际需求。
+
+### 架构修复
+
+#### Agent 执行与显示层解耦（锁屏冻结根因修复）
+根因：浏览器锁屏导致 WebSocket 半死，`ws_sender.send().await` 永久阻塞，级联阻塞 dispatcher → MessageBus → Agent Loop，后端停止执行直到解锁。
+
+基于第一性原理建立"执行-显示解耦"原则：agent 执行只依赖 SQLite 持久化，实时广播是可丢弃的最佳努力通道。
+
+- `MessageBus::publish_outbound` 由 `send().await` 改为 `try_send()`：bus 满时丢弃消息并告警，agent 不再被显示层阻塞。新增 `BusError::Dropped` 变体。
+- WebSocket writer task 包裹 `tokio::time::timeout(30s)`：半死连接超时即关闭。使用每连接独立的 `CancellationToken`（非共享的 CliChannel 级 token），避免一个连接超时关闭所有连接。writer 退出时 cancel 通知主 loop 退出，确保 `unregister_connection` 执行。
+- `CliChannel::send` 由 `send().await` 改为 `try_send()`：dispatcher 单线程顺序处理，原阻塞式发送在 writer 卡住时会阻塞所有连接 37s，改后立即返回。
+- 全仓 13 处 `publish_outbound` 调用统一区分 `Dropped`（warn，预期背压）/ `Closed`（error，异常）日志级别，消除监控噪音。scheduler 的 3 处 `?` 改为 warn，避免 `Dropped` 触发 misfire 重试风暴。
+- 前端 WebSocket 添加 25s 客户端 ping + 指数退避重连（3s→6s→12s→24s→60s 封顶，上限 999 次）。重连后区分"重连恢复"与"首次/切换通道"：前者保留断连前 messages 并刷新 topic 列表，后者清空数据避免污染。
+
+### 安全加固
+
+#### SSRF 重定向绕过修复
+- `web_fetch` 工具禁用 HTTP 重定向（`redirect::Policy::none()`）：原 `validate_url` 只校验初始 URL 的 host，跟随 302 跳转可重定向到 `169.254.169.254`（云元数据）或 `127.0.0.1` 等内网地址，绕过 `is_private_host` 的 SSRF 防护。与 `http_request` 工具保持一致。
+
+#### Safety Guard 正则收紧
+- `format` 正则收紧为 `\bformat\s+.*[a-z]:`，要求出现盘符才拦截，避免误伤 `dart format`、`buf format`、`pytest --format` 等合法命令。
+- 按平台分组注入规则，Unix 不再注入 Windows 专用规则；`Remove-Item` 正则改为小写，与 `guard_command` 的大小写处理一致。
+
+### 稳定性修复
+
+#### SQLite 并发写入死锁
+- 7 个写事务从 `BEGIN DEFERRED` 改为 `BEGIN IMMEDIATE`：在事务开始即获取写锁，消除多 sub-agent 并发写入时的死锁路径。`busy_timeout` 从 5s 提升至 30s。
+- 根因：`BEGIN DEFERRED` 下多个事务可同时读 `MAX(seq)` 不持写锁，提交时互相阻塞，5s timeout 耗尽后返回 `SQLITE_BUSY`。`BEGIN IMMEDIATE` 强制写者串行排队，顺带消除 `MAX(seq)+1` 竞态导致的 UNIQUE 约束冲突。
+
+#### 测试与代码质量
+- 修复 `anthropic` 错误链嵌套测试为真正的 `#[source]` 链（原测试是无效的，inner 变量被 `let _` 抑制）。
+- 补充 `anthropic` provider 15 个纯函数单测（原 396 行零测试），覆盖 data URL 解析、图片过滤、字段过滤、响应反序列化、错误链格式化。
+- 修复 3 个失败测试：`agent_md_template` 写入模板内容 / `StreamingAccumulator` BTreeMap 保序 / `source_order` 断言补全。
+- 清理未使用的 dead code 函数与方法。
+- 新增 `ARCHITECTURE.md` 架构文档，聚焦数据流与 7 个关键设计决策。
+
+#### CI 覆盖范围扩大
+- `cargo build --lib` 改为 `cargo build`，确保 `main.rs` 二进制入口被编译验证。
+- `cargo test --lib` 改为 `cargo test`，纳入 `tests/` 目录集成测试。`test_request_format.rs` 的 8 个序列化测试此前从未在 CI 中运行。
+
+#### 跨平台构建修复
+- 修正依赖分类错误：`rmcp` / `schemars` / `http` / `tower-http` / `rust-embed` 均为跨平台 crate，错放在 `[target.'cfg(windows)'.dependencies]` 下导致 Linux 构建失败，移出 target 段。
+
 ## [0.2.0] - 2026-07-31
 
 较 [0.1.2] 的 47 个 commit 迭代，聚焦 **能力策略**、**模型独立配置**、**话题级并发隔离** 与 **Agent Loop 性能优化** 四大方向。
diff --git a/src/bus/mod.rs b/src/bus/mod.rs
index de0d507..ef7e737 100644
--- a/src/bus/mod.rs
+++ b/src/bus/mod.rs
@@ -52,14 +52,26 @@ impl MessageBus {
         Some(msg)
     }
 
-    /// Publish a message to the outbound queue
+    /// Publish a message to the outbound queue.
+    ///
+    /// Uses `try_send` (non-blocking): if the queue is full, the message is
+    /// dropped immediately with a warning. This ensures the agent loop is never
+    /// blocked by slow or disconnected display consumers. Persistent state is
+    /// unaffected — messages are stored in SQLite independently.
     pub async fn publish_outbound(&self, msg: OutboundMessage) -> Result<(), BusError> {
         #[cfg(debug_assertions)]
         tracing::debug!(channel = %msg.channel, chat_id = %msg.chat_id, content_len = %msg.content.len(), "Bus: publishing outbound message");
-        self.outbound_tx
-            .send(msg)
-            .await
-            .map_err(|_| BusError::Closed)
+        match self.outbound_tx.try_send(msg) {
+            Ok(()) => Ok(()),
+            Err(tokio::sync::mpsc::error::TrySendError::Full(msg)) => {
+                tracing::warn!(
+                    channel = %msg.channel,
+                    "Outbound bus full, dropping message"
+                );
+                Err(BusError::Dropped)
+            }
+            Err(tokio::sync::mpsc::error::TrySendError::Closed(_)) => Err(BusError::Closed),
+        }
     }
 
     /// Consume an outbound message from the outbound queue.
@@ -76,12 +88,14 @@ impl MessageBus {
 #[derive(Debug)]
 pub enum BusError {
     Closed,
+    Dropped,
 }
 
 impl std::fmt::Display for BusError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             BusError::Closed => write!(f, "Bus channel closed"),
+            BusError::Dropped => write!(f, "Bus full, message dropped"),
         }
     }
 }
diff --git a/src/channels/cli.rs b/src/channels/cli.rs
index b103f41..1c18ede 100644
--- a/src/channels/cli.rs
+++ b/src/channels/cli.rs
@@ -100,12 +100,15 @@ impl Channel for CliChannel {
             )));
         };
 
+        // 使用 try_send 避免阻塞 dispatcher——dispatcher 是单线程顺序处理，
+        // 若 writer task 卡在 ws_sender.send() 上，send().await 会阻塞，
+        // 导致所有连接的实时消息被阻塞。try_send 满时立即返回错误，
+        // dispatcher 记录后继续处理下一条消息。
         for outbound in ws_outbound_from_outbound_message(&msg) {
             connection
                 .sender
-                .send(outbound)
-                .await
-                .map_err(|_| ChannelError::SendError("CLI websocket sender closed".to_string()))?;
+                .try_send(outbound)
+                .map_err(|_| ChannelError::SendError("CLI websocket sender closed or full".to_string()))?;
         }
 
         Ok(())
diff --git a/src/gateway/processor.rs b/src/gateway/processor.rs
index 53d8ec2..1156e20 100644
--- a/src/gateway/processor.rs
+++ b/src/gateway/processor.rs
@@ -229,7 +229,14 @@ impl InboundProcessor {
                         ))
                         .await
                     {
-                        tracing::error!(error = %error, "Failed to publish command response");
+                        match error {
+                            crate::bus::BusError::Dropped => {
+                                tracing::warn!(error = %error, "Outbound dropped (bus full)");
+                            }
+                            crate::bus::BusError::Closed => {
+                                tracing::error!(error = %error, "Failed to publish command response");
+                            }
+                        }
                     }
                 }
             } else if let Some(error) = response.error {
@@ -245,7 +252,14 @@ impl InboundProcessor {
                     ))
                     .await
                 {
-                    tracing::error!(error = %e, "Failed to publish error response");
+                    match e {
+                        crate::bus::BusError::Dropped => {
+                            tracing::warn!(error = %e, "Outbound dropped (bus full)");
+                        }
+                        crate::bus::BusError::Closed => {
+                            tracing::error!(error = %e, "Failed to publish error response");
+                        }
+                    }
                 }
             }
             return Ok(());
@@ -305,7 +319,14 @@ impl InboundProcessor {
                             .insert("topic_id".to_string(), topic_id.clone());
                     }
                     if let Err(error) = self.bus.publish_outbound(outbound).await {
-                        tracing::error!(error = %error, "Failed to publish outbound");
+                        match error {
+                            crate::bus::BusError::Dropped => {
+                                tracing::warn!(error = %error, "Outbound dropped (bus full)");
+                            }
+                            crate::bus::BusError::Closed => {
+                                tracing::error!(error = %error, "Failed to publish outbound");
+                            }
+                        }
                     }
                 }
 
@@ -407,7 +428,14 @@ impl InboundProcessor {
                     ))
                     .await
                 {
-                    tracing::error!(error = %publish_error, "Failed to publish execution error outbound");
+                    match publish_error {
+                        crate::bus::BusError::Dropped => {
+                            tracing::warn!(error = %publish_error, "Outbound dropped (bus full)");
+                        }
+                        crate::bus::BusError::Closed => {
+                            tracing::error!(error = %publish_error, "Failed to publish execution error outbound");
+                        }
+                    }
                 }
             }
         }
@@ -433,7 +461,14 @@ impl InboundProcessor {
             ))
             .await
         {
-            tracing::error!(error = %error, "Failed to publish execution_completed");
+            match error {
+                crate::bus::BusError::Dropped => {
+                    tracing::warn!(error = %error, "Outbound dropped (bus full)");
+                }
+                crate::bus::BusError::Closed => {
+                    tracing::error!(error = %error, "Failed to publish execution_completed");
+                }
+            }
         }
 
         Ok(())
diff --git a/src/gateway/session.rs b/src/gateway/session.rs
index 1dfd678..d442186 100644
--- a/src/gateway/session.rs
+++ b/src/gateway/session.rs
@@ -94,7 +94,14 @@ impl EmittedMessageHandler for BusToolCallEmitter {
             &message,
         ) {
             if let Err(error) = self.bus.publish_outbound(outbound).await {
-                tracing::error!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Failed to publish live outbound tool call");
+                match error {
+                    crate::bus::BusError::Dropped => {
+                        tracing::warn!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Outbound dropped (bus full)");
+                    }
+                    crate::bus::BusError::Closed => {
+                        tracing::error!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Failed to publish live outbound tool call");
+                    }
+                }
             }
         }
     }
@@ -113,7 +120,14 @@ impl EmittedMessageHandler for BusToolCallEmitter {
             &message,
         ) {
             if let Err(error) = self.bus.publish_outbound(outbound).await {
-                tracing::error!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Failed to publish live outbound tool call");
+                match error {
+                    crate::bus::BusError::Dropped => {
+                        tracing::warn!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Outbound dropped (bus full)");
+                    }
+                    crate::bus::BusError::Closed => {
+                        tracing::error!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Failed to publish live outbound tool call");
+                    }
+                }
             }
         }
 
@@ -154,7 +168,14 @@ impl EmittedMessageHandler for BusToolCallEmitter {
         };
 
         if let Err(error) = self.bus.publish_outbound(outbound).await {
-            tracing::error!(error = %error, channel = %self.channel_name, "Failed to publish stream delta");
+            match error {
+                crate::bus::BusError::Dropped => {
+                    tracing::warn!(error = %error, channel = %self.channel_name, "Outbound dropped (bus full)");
+                }
+                crate::bus::BusError::Closed => {
+                    tracing::error!(error = %error, channel = %self.channel_name, "Failed to publish stream delta");
+                }
+            }
         }
     }
 
diff --git a/src/gateway/session_message_sender.rs b/src/gateway/session_message_sender.rs
index 5bcaf2c..75640ee 100644
--- a/src/gateway/session_message_sender.rs
+++ b/src/gateway/session_message_sender.rs
@@ -3,7 +3,7 @@ use std::sync::Arc;
 
 use async_trait::async_trait;
 
-use crate::bus::{MessageBus, OutboundMessage};
+use crate::bus::{BusError, MessageBus, OutboundMessage};
 use crate::tools::{SessionMessageSender, SessionSendOutcome, SessionSendRequest, ToolContext};
 
 pub(crate) struct BusSessionMessageSender {
@@ -55,15 +55,28 @@ impl SessionMessageSender for BusSessionMessageSender {
             if attachment_count > 0 {
                 outbound.media = request.attachments.clone();
             }
-            self.bus.publish_outbound(outbound).await?;
-            published_messages += 1;
-            tracing::info!(
-                channel = %channel_name,
-                chat_id = %chat_id,
-                content_len = content_len,
-                attachment_count = attachment_count,
-                "Published session text message to outbound bus"
-            );
+            match self.bus.publish_outbound(outbound).await {
+                Ok(()) => {
+                    published_messages += 1;
+                    tracing::info!(
+                        channel = %channel_name,
+                        chat_id = %chat_id,
+                        content_len = content_len,
+                        attachment_count = attachment_count,
+                        "Published session text message to outbound bus"
+                    );
+                }
+                Err(BusError::Dropped) => {
+                    tracing::warn!(
+                        channel = %channel_name,
+                        chat_id = %chat_id,
+                        "Outbound bus full, dropping session text message"
+                    );
+                }
+                Err(BusError::Closed) => {
+                    return Err(anyhow::anyhow!("Outbound bus closed"));
+                }
+            }
         } else {
             for attachment in request.attachments {
                 let media_path = attachment.path.clone();
@@ -77,15 +90,28 @@ impl SessionMessageSender for BusSessionMessageSender {
                     metadata.clone(),
                 );
                 outbound.media = vec![attachment];
-                self.bus.publish_outbound(outbound).await?;
-                published_messages += 1;
-                tracing::info!(
-                    channel = %channel_name,
-                    chat_id = %chat_id,
-                    media_type = %media_type,
-                    media_path = %media_path,
-                    "Published session attachment to outbound bus"
-                );
+                match self.bus.publish_outbound(outbound).await {
+                    Ok(()) => {
+                        published_messages += 1;
+                        tracing::info!(
+                            channel = %channel_name,
+                            chat_id = %chat_id,
+                            media_type = %media_type,
+                            media_path = %media_path,
+                            "Published session attachment to outbound bus"
+                        );
+                    }
+                    Err(BusError::Dropped) => {
+                        tracing::warn!(
+                            channel = %channel_name,
+                            chat_id = %chat_id,
+                            "Outbound bus full, dropping session attachment"
+                        );
+                    }
+                    Err(BusError::Closed) => {
+                        return Err(anyhow::anyhow!("Outbound bus closed"));
+                    }
+                }
             }
         }
 
diff --git a/src/gateway/ws.rs b/src/gateway/ws.rs
index a5ddcd3..960040d 100644
--- a/src/gateway/ws.rs
+++ b/src/gateway/ws.rs
@@ -40,6 +40,7 @@ use std::collections::HashMap;
 use std::path::PathBuf;
 use std::sync::Arc;
 use tokio::sync::mpsc;
+use tokio_util::sync::CancellationToken;
 
 const WS_CHANNEL_NAME: &str = "websocket";
 
@@ -221,13 +222,34 @@ async fn handle_socket(ws: WebSocket, state: Arc<GatewayState>) {
 
     let mut receiver = receiver;
     let session_id_for_sender = runtime_session_id.clone();
+    // 每连接独立的关闭信号：writer 超时/错误时 cancel，通知主 loop 退出
+    // 不能用共享的 shutdown_token——那是 CliChannel 级别的，cancel 会关闭所有连接
+    let writer_closed = CancellationToken::new();
+    let writer_closed_clone = writer_closed.clone();
     tokio::spawn(async move {
         while let Some(msg) = receiver.recv().await {
             if let Ok(text) = serialize_outbound(&msg) {
-                if ws_sender.send(WsMessage::Text(text.into())).await.is_err() {
-                    #[cfg(debug_assertions)]
-                    tracing::debug!(session_id = %session_id_for_sender, "WebSocket send error");
-                    break;
+                let send_result = tokio::time::timeout(
+                    std::time::Duration::from_secs(30),
+                    ws_sender.send(WsMessage::Text(text.into())),
+                )
+                .await;
+                match send_result {
+                    Ok(Ok(())) => {}
+                    Ok(Err(_)) => {
+                        #[cfg(debug_assertions)]
+                        tracing::debug!(session_id = %session_id_for_sender, "WebSocket send error");
+                        writer_closed_clone.cancel();
+                        break;
+                    }
+                    Err(_) => {
+                        tracing::warn!(
+                            session_id = %session_id_for_sender,
+                            "WebSocket send timed out after 30s, closing connection"
+                        );
+                        writer_closed_clone.cancel();
+                        break;
+                    }
                 }
             }
         }
@@ -235,11 +257,16 @@ async fn handle_socket(ws: WebSocket, state: Arc<GatewayState>) {
 
     loop {
         tokio::select! {
-            // 监听 shutdown 信号（来自 CliChannel::stop()）
+            // 监听全局 shutdown 信号（来自 CliChannel::stop()）
             _ = shutdown_token.cancelled() => {
                 tracing::info!(session_id = %current_session_id, "WebSocket shutdown signal received, closing connection");
                 break;
             }
+            // 监听 writer 退出信号（writer 超时或错误，仅关闭当前连接）
+            _ = writer_closed.cancelled() => {
+                tracing::info!(session_id = %current_session_id, "WebSocket writer closed, shutting down connection");
+                break;
+            }
             // 监听 WebSocket 消息
             msg = ws_receiver.next() => {
                 let Some(msg) = msg else {
diff --git a/src/scheduler/mod.rs b/src/scheduler/mod.rs
index 5c46f03..f8255aa 100644
--- a/src/scheduler/mod.rs
+++ b/src/scheduler/mod.rs
@@ -298,7 +298,11 @@ impl Scheduler {
         match job.kind {
             SchedulerJobKind::OutboundMessage => {
                 let message = build_outbound_message(job)?;
-                self.bus.publish_outbound(message).await?;
+                // publish_outbound 失败（bus 满或关闭）不视为 job 失败：
+                // 通知丢弃是预期的背压行为，标记 job 失败会触发 misfire 重试风暴
+                if let Err(e) = self.bus.publish_outbound(message).await {
+                    tracing::warn!(error = %e, job_id = %job.id, "Dropping outbound for scheduler job");
+                }
             }
             SchedulerJobKind::InternalEvent => {
                 execute_internal_event(self.maintenance_executor.as_ref(), job).await?;
@@ -311,7 +315,9 @@ impl Scheduler {
                 )
                 .await?;
                 for message in outbound_messages {
-                    self.bus.publish_outbound(message).await?;
+                    if let Err(e) = self.bus.publish_outbound(message).await {
+                        tracing::warn!(error = %e, job_id = %job.id, "Dropping outbound for scheduler agent task");
+                    }
                 }
             }
             SchedulerJobKind::SilentAgentTask => {
@@ -407,7 +413,8 @@ impl Scheduler {
             "silent_agent_task".to_string(),
         );
 
-        self.bus
+        if let Err(e) = self
+            .bus
             .publish_outbound(OutboundMessage::error_notification(
                 channel,
                 chat_id,
@@ -421,7 +428,10 @@ impl Scheduler {
                 metadata,
             ))
             .await
-            .map_err(|error| anyhow::anyhow!(error.to_string()))
+        {
+            tracing::warn!(error = %e, job_id = %job.id, "Dropping silent agent task failure notification");
+        }
+        Ok(())
     }
 }
 
diff --git a/src/tools/shell_session.rs b/src/tools/shell_session.rs
index a495aee..98419a3 100644
--- a/src/tools/shell_session.rs
+++ b/src/tools/shell_session.rs
@@ -140,20 +140,17 @@ impl ShellSessionManager {
 
         // Wait for new output or process exit
         let deadline = Instant::now() + Duration::from_millis(OUTPUT_WAIT_MS);
-        loop {
-            tokio::select! {
-                status = session.child.wait() => {
-                    // Process exited — collect final output
-                    let stdout = session.stdout_buf.lock().await.clone();
-                    let stderr = session.stderr_buf.lock().await.clone();
-                    let code = status.ok().and_then(|s| s.code());
-                    drop(sessions);
-                    return Ok(Self::format_output(&stdout, &stderr, code));
-                }
-                _ = tokio::time::sleep_until(deadline) => {
-                    // Timeout — return current output
-                    break;
-                }
+        tokio::select! {
+            status = session.child.wait() => {
+                // Process exited — collect final output
+                let stdout = session.stdout_buf.lock().await.clone();
+                let stderr = session.stderr_buf.lock().await.clone();
+                let code = status.ok().and_then(|s| s.code());
+                drop(sessions);
+                return Ok(Self::format_output(&stdout, &stderr, code));
+            }
+            _ = tokio::time::sleep_until(deadline) => {
+                // Timeout — fall through to return current output
             }
         }
 
diff --git a/src/tools/task/runtime.rs b/src/tools/task/runtime.rs
index d64a2de..3acf74c 100644
--- a/src/tools/task/runtime.rs
+++ b/src/tools/task/runtime.rs
@@ -128,12 +128,14 @@ impl EmittedMessageHandler for SubAgentEmitter {
             &message,
         ) {
             if let Err(error) = self.bus.publish_outbound(outbound).await {
-                tracing::error!(
-                    error = %error,
-                    channel = %self.channel_name,
-                    chat_id = %self.chat_id,
-                    "Failed to publish live sub-agent tool call"
-                );
+                match error {
+                    crate::bus::BusError::Dropped => {
+                        tracing::warn!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Outbound dropped (bus full)");
+                    }
+                    crate::bus::BusError::Closed => {
+                        tracing::error!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Failed to publish live sub-agent tool call");
+                    }
+                }
             }
         }
     }
@@ -152,12 +154,14 @@ impl EmittedMessageHandler for SubAgentEmitter {
             &message,
         ) {
             if let Err(error) = self.bus.publish_outbound(outbound).await {
-                tracing::error!(
-                    error = %error,
-                    channel = %self.channel_name,
-                    chat_id = %self.chat_id,
-                    "Failed to publish live sub-agent tool call"
-                );
+                match error {
+                    crate::bus::BusError::Dropped => {
+                        tracing::warn!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Outbound dropped (bus full)");
+                    }
+                    crate::bus::BusError::Closed => {
+                        tracing::error!(error = %error, channel = %self.channel_name, chat_id = %self.chat_id, "Failed to publish live sub-agent tool call");
+                    }
+                }
             }
         }
 
@@ -196,7 +200,14 @@ impl EmittedMessageHandler for SubAgentEmitter {
         };
 
         if let Err(error) = self.bus.publish_outbound(outbound).await {
-            tracing::error!(error = %error, channel = %self.channel_name, "Failed to publish sub-agent stream delta");
+            match error {
+                crate::bus::BusError::Dropped => {
+                    tracing::warn!(error = %error, channel = %self.channel_name, "Outbound dropped (bus full)");
+                }
+                crate::bus::BusError::Closed => {
+                    tracing::error!(error = %error, channel = %self.channel_name, "Failed to publish sub-agent stream delta");
+                }
+            }
         }
     }
 
diff --git a/web/src/hooks/chat/useSessions.ts b/web/src/hooks/chat/useSessions.ts
index a41e31c..e7b69dc 100644
--- a/web/src/hooks/chat/useSessions.ts
+++ b/web/src/hooks/chat/useSessions.ts
@@ -1,4 +1,4 @@
-import { useState, useCallback, useMemo, type Dispatch, type SetStateAction } from 'react';
+import { useState, useCallback, useMemo, useEffect, useRef, type Dispatch, type SetStateAction, type MutableRefObject } from 'react';
 import type { SessionSummary, Command } from '../../types/protocol';
 
 export interface UseSessionsReturn {
@@ -6,6 +6,7 @@ export interface UseSessionsReturn {
   setSessions: Dispatch<SetStateAction<SessionSummary[]>>;
   selectedSessionId: string | null;
   setSelectedSessionId: Dispatch<SetStateAction<string | null>>;
+  selectedSessionIdRef: MutableRefObject<string | null>;
   session: SessionSummary | null;
   sessionId: string | null;
   chatId: string;
@@ -22,6 +23,11 @@ export function useSessions(options?: UseSessionsOptions): UseSessionsReturn {
   const [sessions, setSessions] = useState<SessionSummary[]>([]);
   const [selectedSessionId, setSelectedSessionId] = useState<string | null>(null);
 
+  const selectedSessionIdRef = useRef<string | null>(null);
+  useEffect(() => {
+    selectedSessionIdRef.current = selectedSessionId;
+  }, [selectedSessionId]);
+
   const selectedSession = useMemo(
     () => sessions.find((s) => s.session_id === selectedSessionId) ?? null,
     [sessions, selectedSessionId],
@@ -50,6 +56,7 @@ export function useSessions(options?: UseSessionsOptions): UseSessionsReturn {
     setSessions,
     selectedSessionId,
     setSelectedSessionId,
+    selectedSessionIdRef,
     session: selectedSession,
     sessionId,
     chatId,
diff --git a/web/src/hooks/useChat.ts b/web/src/hooks/useChat.ts
index ef166f5..d96cb35 100644
--- a/web/src/hooks/useChat.ts
+++ b/web/src/hooks/useChat.ts
@@ -159,22 +159,42 @@ export function useChat(): UseChatReturn {
         conn.setConnectionId(message.session_id);
         return;
 
-      case 'session_list':
-        // 清空旧数据（切换通道时避免数据污染）
-        topics.setTopics([]);
-        topics.setSelectedTopic(null);
-        messages.setMessages([]);
+      case 'session_list': {
+        // 重连恢复：重连前已有选中 topic，且原 session 仍存在于新列表中
+        // 保留断连前的 messages（用户仍可查看之前的对话），仅刷新 session/topic 列表
+        // 注意：不发 load_chat_messages——历史消息不带 topic_id（ChatMessage 结构无此字段），
+        // 前端无法按 topic 过滤，会导致跨 topic 消息污染 + 与残留消息重复
+        // 断连期间的新消息在 SQLite 中，需后端新增按 topic 加载的命令才能恢复（既有限制）
+        const prevSid = sessions.selectedSessionIdRef.current;
+        const prevSessionExists =
+          prevSid !== null && message.sessions.some((s) => s.session_id === prevSid);
+        const isReconnect =
+          topics.selectedTopicRef.current !== null && prevSessionExists;
         sessions.setSessions(message.sessions);
-        // 自动选中：优先保持当前选中，否则选第一个
-        sessions.setSelectedSessionId((prev) =>
-          prev && message.sessions.some((s) => s.session_id === prev)
-            ? prev
-            : message.sessions.length > 0
-              ? message.sessions[0].session_id
-              : null,
-        );
-        messages.setIsLoading(false);
+        if (isReconnect) {
+          // 原 session 仍在，保持选中
+          sessions.setSelectedSessionId(prevSid);
+          // 刷新 topic 列表（断连期间可能新建了 topic）
+          const topicCmd = topics.requestTopicList(prevSid!);
+          if (topicCmd) conn.sendCommand(topicCmd);
+          // 重置 loading 状态（断连时可能卡在 loading）
+          messages.setIsLoading(false);
+        } else {
+          // 首次连接、切换通道、或原 session 已被删除：清空旧数据避免污染
+          topics.setTopics([]);
+          topics.setSelectedTopic(null);
+          messages.setMessages([]);
+          sessions.setSelectedSessionId((prev) =>
+            prev && message.sessions.some((s) => s.session_id === prev)
+              ? prev
+              : message.sessions.length > 0
+                ? message.sessions[0].session_id
+                : null,
+          );
+          messages.setIsLoading(false);
+        }
         return;
+      }
 
       case 'session_created':
       case 'session_loaded':
diff --git a/web/src/hooks/useWebSocket.ts b/web/src/hooks/useWebSocket.ts
index 5ba2a63..c2b19ff 100644
--- a/web/src/hooks/useWebSocket.ts
+++ b/web/src/hooks/useWebSocket.ts
@@ -18,6 +18,11 @@ interface UseWebSocketReturn {
   disconnect: () => void;
 }
 
+// 客户端 ping 间隔（ms）：小于典型代理/NAT 60s 空闲超时
+const PING_INTERVAL_MS = 25000;
+// 指数退避重连上限（ms）
+const MAX_RECONNECT_DELAY_MS = 60000;
+
 export function useWebSocket({
   url,
   onMessage,
@@ -25,13 +30,21 @@ export function useWebSocket({
   onDisconnect,
   onError,
   reconnectInterval = 3000,
-  maxReconnectAttempts = 5,
+  maxReconnectAttempts = 999,
 }: UseWebSocketOptions): UseWebSocketReturn {
   const [status, setStatus] = useState<ConnectionStatus>('disconnected');
   const wsRef = useRef<WebSocket | null>(null);
   const reconnectAttemptsRef = useRef(0);
   const reconnectTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const isManualDisconnectRef = useRef(false);
+  const pingIntervalRef = useRef<ReturnType<typeof setInterval> | null>(null);
+
+  const clearPing = useCallback(() => {
+    if (pingIntervalRef.current) {
+      clearInterval(pingIntervalRef.current);
+      pingIntervalRef.current = null;
+    }
+  }, []);
 
   const connect = useCallback(() => {
     if (wsRef.current?.readyState === WebSocket.OPEN) {
@@ -48,6 +61,18 @@ export function useWebSocket({
       ws.onopen = () => {
         setStatus('connected');
         reconnectAttemptsRef.current = 0;
+        // 启动客户端 ping：定期写数据保持连接活性，写失败会触发 onclose 检测半死连接
+        clearPing();
+        pingIntervalRef.current = setInterval(() => {
+          if (wsRef.current?.readyState === WebSocket.OPEN) {
+            try {
+              wsRef.current.send(JSON.stringify({ type: 'ping' }));
+            } catch {
+              // 极端时序下 send 可能抛 InvalidStateError，忽略即可
+              // onclose 会随后触发，进入重连流程
+            }
+          }
+        }, PING_INTERVAL_MS);
         onConnect?.();
       };
 
@@ -67,21 +92,24 @@ export function useWebSocket({
 
       ws.onclose = () => {
         setStatus('disconnected');
+        clearPing();
         onDisconnect?.();
 
-        // Auto reconnect if not manually disconnected
+        // 指数退避自动重连：3s → 6s → 12s → 24s → 60s 封顶
         if (!isManualDisconnectRef.current && reconnectAttemptsRef.current < maxReconnectAttempts) {
           reconnectAttemptsRef.current += 1;
+          const attempts = reconnectAttemptsRef.current;
+          const delay = Math.min(reconnectInterval * Math.pow(2, attempts - 1), MAX_RECONNECT_DELAY_MS);
           reconnectTimerRef.current = setTimeout(() => {
             connect();
-          }, reconnectInterval);
+          }, delay);
         }
       };
     } catch (error) {
       setStatus('error');
       console.error('WebSocket connection error:', error);
     }
-  }, [url, onMessage, onConnect, onDisconnect, onError, reconnectInterval, maxReconnectAttempts]);
+  }, [url, onMessage, onConnect, onDisconnect, onError, reconnectInterval, maxReconnectAttempts, clearPing]);
 
   const disconnect = useCallback(() => {
     isManualDisconnectRef.current = true;
@@ -91,13 +119,15 @@ export function useWebSocket({
       reconnectTimerRef.current = null;
     }
 
+    clearPing();
+
     if (wsRef.current) {
       wsRef.current.close();
       wsRef.current = null;
     }
 
     setStatus('disconnected');
-  }, []);
+  }, [clearPing]);
 
   const sendMessage = useCallback((message: WsInbound): boolean => {
     if (wsRef.current?.readyState === WebSocket.OPEN) {