diff --git a/.gitignore b/.gitignore
index ae5478e..5d9da4c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -40,3 +40,4 @@ node_modules
 logs
 dist
 .trae
+.opencode/
diff --git a/Cargo.lock b/Cargo.lock
index 25018ca..057944c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -466,6 +466,15 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d6914041f254d6e9176c01941b21115dcfb7089e55135a35411081bd106ef3f"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.21"
@@ -879,6 +888,25 @@ dependencies = [
  "yaml-rust2",
 ]
 
+[[package]]
+name = "h2"
+version = "0.4.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6cb093c84e8bd9b188d4c4a8cb6579fc016968d14c99882163cd3ff402a4f155"
+dependencies = [
+ "atomic-waker",
+ "bytes",
+ "fnv",
+ "futures-core",
+ "futures-sink",
+ "http",
+ "indexmap",
+ "slab",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.14.5"
@@ -937,6 +965,12 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
+[[package]]
+name = "hermit-abi"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc0fef456e4baa96da950455cd02c081ca953b141298e41db3fc7e36b1da849c"
+
 [[package]]
 name = "hex"
 version = "0.4.3"
@@ -1004,6 +1038,7 @@ dependencies = [
  "bytes",
  "futures-channel",
  "futures-core",
+ "h2",
  "http",
  "http-body",
  "httparse",
@@ -1024,7 +1059,9 @@ dependencies = [
  "http",
  "hyper",
  "hyper-util",
+ "log",
  "rustls",
+ "rustls-native-certs",
  "tokio",
  "tokio-rustls",
  "tower-service",
@@ -1441,6 +1478,52 @@ version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
 
+[[package]]
+name = "metrics"
+version = "0.23.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3045b4193fbdc5b5681f32f11070da9be3609f189a79f3390706d42587f46bb5"
+dependencies = [
+ "ahash",
+ "portable-atomic",
+]
+
+[[package]]
+name = "metrics-exporter-prometheus"
+version = "0.15.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4f0c8427b39666bf970460908b213ec09b3b350f20c0c2eabcbba51704a08e6"
+dependencies = [
+ "base64",
+ "http-body-util",
+ "hyper",
+ "hyper-rustls",
+ "hyper-util",
+ "indexmap",
+ "ipnet",
+ "metrics",
+ "metrics-util",
+ "quanta",
+ "thiserror 1.0.69",
+ "tokio",
+ "tracing",
+]
+
+[[package]]
+name = "metrics-util"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4259040465c955f9f2f1a4a8a16dc46726169bca0f88e8fb2dbeced487c3e828"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+ "hashbrown 0.14.5",
+ "metrics",
+ "num_cpus",
+ "quanta",
+ "sketches-ddsketch",
+]
+
 [[package]]
 name = "meval"
 version = "0.2.0"
@@ -1556,6 +1639,16 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "num_cpus"
+version = "1.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91df4bbde75afed763b708b7eee1e8e7651e02d97f6d5dd763e89367e957b23b"
+dependencies = [
+ "hermit-abi",
+ "libc",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -1654,6 +1747,8 @@ dependencies = [
  "iana-time-zone",
  "image",
  "libc",
+ "metrics",
+ "metrics-exporter-prometheus",
  "meval",
  "mime_guess",
  "parking_lot",
@@ -1710,6 +1805,12 @@ dependencies = [
  "miniz_oxide",
 ]
 
+[[package]]
+name = "portable-atomic"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05c8b63e8d9609db387f0324918f81d68fe27748f084ef092fb35954d0539a85"
+
 [[package]]
 name = "potential_utf"
 version = "0.1.5"
@@ -1796,6 +1897,21 @@ version = "0.1.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e0c5ccf5294c6ccd63a74f1565028353830a9c2f5eb0c682c355c471726a6e3f"
 
+[[package]]
+name = "quanta"
+version = "0.12.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3ab5a9d756f0d97bdc89019bd2e4ea098cf9cde50ee7564dde6b81ccc8f06c7"
+dependencies = [
+ "crossbeam-utils",
+ "libc",
+ "once_cell",
+ "raw-cpuid",
+ "wasi",
+ "web-sys",
+ "winapi",
+]
+
 [[package]]
 name = "quick-error"
 version = "2.0.1"
@@ -1947,6 +2063,15 @@ version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "63b8176103e19a2643978565ca18b50549f6101881c443590420e4dc998a3c69"
 
+[[package]]
+name = "raw-cpuid"
+version = "11.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "498cd0dc59d73224351ee52a95fee0f1a617a2eae0e7d9d720cc622c73a54186"
+dependencies = [
+ "bitflags",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.5.18"
@@ -2562,6 +2687,12 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8ee5873ec9cce0195efcb7a4e9507a04cd49aec9c83d0389df45b1ef7ba2e649"
 
+[[package]]
+name = "sketches-ddsketch"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85636c14b73d81f541e525f585c0a2109e6744e1565b5c1668e31c70c10ed65c"
+
 [[package]]
 name = "slab"
 version = "0.4.12"
diff --git a/Cargo.toml b/Cargo.toml
index 96a4553..d6e4ade 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -41,6 +41,8 @@ prost = "0.14"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter", "json"] }
 tracing-appender = "0.2"
+metrics = "0.23"
+metrics-exporter-prometheus = "0.15"
 anyhow = "1.0"
 chrono = { version = "0.4", features = ["serde"] }
 chrono-tz = "0.10"
diff --git a/src/agent/agent_loop.rs b/src/agent/agent_loop.rs
index 9dd73b2..13e9900 100644
--- a/src/agent/agent_loop.rs
+++ b/src/agent/agent_loop.rs
@@ -1068,13 +1068,13 @@ impl AgentLoop {
     /// - `compaction_sink`: 压缩结果回写端（可选）。配置 `compressor` 后，
     ///   当 LLM 压缩被触发时通过此 sink 把压缩结果持久化到 DB。
     ///   传 None 则即使配置了 compressor 也只改内存不回写。
+    #[tracing::instrument(skip(self, messages, system_prompt_context, compaction_sink), fields(history_len = messages.len(), max_iterations = self.max_iterations))]
     pub async fn process(
         &self,
         mut messages: Vec<ChatMessage>,
         system_prompt_context: Option<&SystemPromptContext>,
         compaction_sink: Option<&dyn CompactionSink>,
     ) -> Result<AgentProcessResult, AgentError> {
-        #[cfg(debug_assertions)]
         tracing::debug!(
             history_len = messages.len(),
             max_iterations = self.max_iterations,
@@ -1179,6 +1179,14 @@ impl AgentLoop {
                 )
                 .await;
 
+            // Emit AgentStart event for metrics (LLM 请求耗时/token 指标)
+            if let Some(ref observer) = self.observer {
+                observer.record_event(&ObserverEvent::AgentStart {
+                    provider: self.provider.name().to_string(),
+                    model: self.provider.model_id().to_string(),
+                });
+            }
+
             // Set up streaming delta consumer
             // Pre-generate the message ID so stream deltas and the final assistant
             // message share the same ID — this lets the front-end replace the
@@ -1190,9 +1198,12 @@ impl AgentLoop {
 
             let max_retries = self.runtime_config.max_retries as usize;
             let mut response: Option<crate::providers::ChatCompletionResponse> = None;
+            // 记录最后一次尝试的耗时（不含重试退避），用于 AgentEnd 指标
+            let mut last_attempt_duration = std::time::Duration::ZERO;
 
             'retry: for attempt in 0..=max_retries {
                 // 每次重试重建 channel + consumer：上次失败的 channel 可能已关闭。
+                let attempt_start = std::time::Instant::now();
                 let (delta_tx, mut delta_rx) = tokio::sync::mpsc::channel::<StreamDelta>(256);
                 let consumer_handler = self.emitted_message_handler.clone();
                 let consumer_task = tokio::spawn(async move {
@@ -1222,6 +1233,16 @@ impl AgentLoop {
                         _ = self.cancel_signal() => {
                             drop(stream_callback);
                             let _ = consumer_task.await;
+                            // cancel 路径补发 AgentEnd，保证指标配对闭合
+                            last_attempt_duration = attempt_start.elapsed();
+                            if let Some(ref observer) = self.observer {
+                                observer.record_event(&ObserverEvent::AgentEnd {
+                                    provider: self.provider.name().to_string(),
+                                    model: self.provider.model_id().to_string(),
+                                    duration: last_attempt_duration,
+                                    tokens_used: None,
+                                });
+                            }
                             let cancel = Self::build_cancel_result(iteration, emitted_messages);
                             self.emit_live_tool_call_message(cancel.final_response.clone()).await;
                             return Ok(cancel);
@@ -1242,10 +1263,12 @@ impl AgentLoop {
 
                 match llm_result {
                     Ok(resp) => {
+                        last_attempt_duration = attempt_start.elapsed();
                         response = Some(resp);
                         break 'retry;
                     }
                     Err(e) => {
+                        last_attempt_duration = attempt_start.elapsed();
                         let error_text = e.to_string();
                         let can_retry = attempt < max_retries
                             && !emitted.load(Ordering::SeqCst)
@@ -1265,6 +1288,16 @@ impl AgentLoop {
                             if self.cancel_token.is_some() {
                                 tokio::select! {
                                     _ = self.cancel_signal() => {
+                                        // cancel 路径补发 AgentEnd，保证指标配对闭合
+                                        last_attempt_duration = attempt_start.elapsed();
+                                        if let Some(ref observer) = self.observer {
+                                            observer.record_event(&ObserverEvent::AgentEnd {
+                                                provider: self.provider.name().to_string(),
+                                                model: self.provider.model_id().to_string(),
+                                                duration: last_attempt_duration,
+                                                tokens_used: None,
+                                            });
+                                        }
                                         let cancel = Self::build_cancel_result(iteration, emitted_messages);
                                         self.emit_live_tool_call_message(cancel.final_response.clone()).await;
                                         return Ok(cancel);
@@ -1283,6 +1316,15 @@ impl AgentLoop {
                             error_details = %format_error_chain(e.as_ref()),
                             "LLM request failed"
                         );
+                        // 错误分支补发 AgentEnd，保证指标配对闭合
+                        if let Some(ref observer) = self.observer {
+                            observer.record_event(&ObserverEvent::AgentEnd {
+                                provider: self.provider.name().to_string(),
+                                model: self.provider.model_id().to_string(),
+                                duration: last_attempt_duration,
+                                tokens_used: None,
+                            });
+                        }
                         let assistant_message =
                             ChatMessage::assistant(recoverable_llm_message(&error_text));
                         emitted_messages.push(assistant_message.clone());
@@ -1298,11 +1340,34 @@ impl AgentLoop {
                 }
             }
 
-            let response = response.ok_or_else(|| {
-                AgentError::Other(
-                    "retry loop exited without setting response or returning".to_string(),
-                )
-            })?;
+            // 防御性兜底：retry 循环异常退出（正常不应发生）。
+            // 补发 AgentEnd 保证指标配对闭合，再返回错误。
+            let response = match response {
+                Some(resp) => resp,
+                None => {
+                    if let Some(ref observer) = self.observer {
+                        observer.record_event(&ObserverEvent::AgentEnd {
+                            provider: self.provider.name().to_string(),
+                            model: self.provider.model_id().to_string(),
+                            duration: last_attempt_duration,
+                            tokens_used: None,
+                        });
+                    }
+                    return Err(AgentError::Other(
+                        "retry loop exited without setting response or returning".to_string(),
+                    ));
+                }
+            };
+
+            // Emit AgentEnd event for metrics (LLM 请求耗时/token 指标)
+            if let Some(ref observer) = self.observer {
+                observer.record_event(&ObserverEvent::AgentEnd {
+                    provider: self.provider.name().to_string(),
+                    model: self.provider.model_id().to_string(),
+                    duration: last_attempt_duration,
+                    tokens_used: Some(response.usage.total_tokens as u64),
+                });
+            }
 
             // Signal stream end if handler exists
             let had_streaming = self.emitted_message_handler.is_some();
@@ -1715,8 +1780,20 @@ impl AgentLoop {
             .await;
         let max_retries = self.runtime_config.max_retries as usize;
 
+        // Emit AgentStart for the summary LLM call
+        if let Some(ref observer) = self.observer {
+            observer.record_event(&ObserverEvent::AgentStart {
+                provider: self.provider.name().to_string(),
+                model: self.provider.model_id().to_string(),
+            });
+        }
+
+        // 记录最后一次尝试的耗时（不含重试退避）
+        let mut summary_last_attempt_duration = std::time::Duration::ZERO;
+
         for attempt in 0..=max_retries {
             // 最终 summary 调用也与取消信号竞速
+            let attempt_start = std::time::Instant::now();
             let final_result: Result<
                 crate::providers::ChatCompletionResponse,
                 Box<dyn std::error::Error + Send + Sync>,
@@ -1724,6 +1801,16 @@ impl AgentLoop {
             if self.cancel_token.is_some() {
                 tokio::select! {
                     _ = self.cancel_signal() => {
+                        // cancel 路径补发 AgentEnd，保证指标配对闭合
+                        summary_last_attempt_duration = attempt_start.elapsed();
+                        if let Some(ref observer) = self.observer {
+                            observer.record_event(&ObserverEvent::AgentEnd {
+                                provider: self.provider.name().to_string(),
+                                model: self.provider.model_id().to_string(),
+                                duration: summary_last_attempt_duration,
+                                tokens_used: None,
+                            });
+                        }
                         let cancel = Self::build_cancel_result(self.max_iterations, std::mem::take(emitted_messages));
                         self.emit_live_tool_call_message(cancel.final_response.clone()).await;
                         return cancel;
@@ -1738,6 +1825,16 @@ impl AgentLoop {
 
             match final_result {
                 Ok(response) => {
+                    summary_last_attempt_duration = attempt_start.elapsed();
+                    // Emit AgentEnd for the summary LLM call
+                    if let Some(ref observer) = self.observer {
+                        observer.record_event(&ObserverEvent::AgentEnd {
+                            provider: self.provider.name().to_string(),
+                            model: self.provider.model_id().to_string(),
+                            duration: summary_last_attempt_duration,
+                            tokens_used: Some(response.usage.total_tokens as u64),
+                        });
+                    }
                     let mut assistant_message = if let Some(reasoning_content) =
                         response.reasoning_content
                     {
@@ -1761,6 +1858,7 @@ impl AgentLoop {
                     };
                 }
                 Err(e) => {
+                    summary_last_attempt_duration = attempt_start.elapsed();
                     let error_text = e.to_string();
                     let can_retry = attempt < max_retries && is_recoverable_llm_error(&error_text);
                     if can_retry {
@@ -1776,6 +1874,16 @@ impl AgentLoop {
                         if self.cancel_token.is_some() {
                             tokio::select! {
                                 _ = self.cancel_signal() => {
+                                    // cancel 路径补发 AgentEnd，保证指标配对闭合
+                                    summary_last_attempt_duration = attempt_start.elapsed();
+                                    if let Some(ref observer) = self.observer {
+                                        observer.record_event(&ObserverEvent::AgentEnd {
+                                            provider: self.provider.name().to_string(),
+                                            model: self.provider.model_id().to_string(),
+                                            duration: summary_last_attempt_duration,
+                                            tokens_used: None,
+                                        });
+                                    }
                                     let cancel = Self::build_cancel_result(self.max_iterations, std::mem::take(emitted_messages));
                                     self.emit_live_tool_call_message(cancel.final_response.clone()).await;
                                     return cancel;
@@ -1794,6 +1902,15 @@ impl AgentLoop {
                         error_details = %format_error_chain(e.as_ref()),
                         "Failed to get summary from LLM"
                     );
+                    // 错误分支补发 AgentEnd，保证指标配对闭合
+                    if let Some(ref observer) = self.observer {
+                        observer.record_event(&ObserverEvent::AgentEnd {
+                            provider: self.provider.name().to_string(),
+                            model: self.provider.model_id().to_string(),
+                            duration: summary_last_attempt_duration,
+                            tokens_used: None,
+                        });
+                    }
                     let final_message =
                         ChatMessage::assistant(recoverable_llm_message(&error_text));
                     emitted_messages.push(final_message.clone());
@@ -1818,6 +1935,15 @@ impl AgentLoop {
             model = %self.provider.model_id(),
             "run_final_summary retry loop exited without returning"
         );
+        // 兜底也补发 AgentEnd
+        if let Some(ref observer) = self.observer {
+            observer.record_event(&ObserverEvent::AgentEnd {
+                provider: self.provider.name().to_string(),
+                model: self.provider.model_id().to_string(),
+                duration: summary_last_attempt_duration,
+                tokens_used: None,
+            });
+        }
         let final_message = ChatMessage::assistant(
             "Failed to generate final summary: retry loop exited unexpectedly.",
         );
@@ -1935,6 +2061,7 @@ impl AgentLoop {
     }
 
     /// Execute a single tool and return the outcome with event tracking.
+    #[tracing::instrument(skip(self, tool_call), fields(tool = %tool_call.name))]
     async fn execute_one_tool(&self, tool_call: &ToolCall) -> ToolExecutionOutcome {
         let start = Instant::now();
         let tool_name = tool_call.name.clone();
diff --git a/src/bus/message.rs b/src/bus/message.rs
index eea1843..b60d08b 100644
--- a/src/bus/message.rs
+++ b/src/bus/message.rs
@@ -502,6 +502,9 @@ pub struct InboundMessage {
     pub metadata: HashMap<String, String>,
     /// Data forwarded from inbound to outbound (copied to OutboundMessage.metadata by gateway).
     pub forwarded_metadata: HashMap<String, String>,
+    /// 端到端追踪 ID（由 channel 在构造消息时生成，贯穿 bus→processor→agent_loop→provider→tool 全链路）。
+    /// 基础设施层元数据，不进入 domain 层。
+    pub trace_id: String,
 }
 
 impl InboundMessage {
@@ -537,6 +540,9 @@ pub struct OutboundMessage {
     /// instead of generating a random UUID. Critical for stream delta → assistant_response
     /// ID matching on the front-end.
     pub message_id: Option<String>,
+    /// 端到端追踪 ID（从 InboundMessage 继承，用于 outbound dispatcher 日志关联）。
+    /// 非 agent 执行路径产生的消息（如 scheduler 通知）此字段为空。
+    pub trace_id: String,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -564,6 +570,12 @@ impl OutboundMessage {
         )
     }
 
+    /// 设置 trace_id（builder 模式，用于 agent 执行路径中从 InboundMessage 继承）。
+    pub fn with_trace_id(mut self, trace_id: impl Into<String>) -> Self {
+        self.trace_id = trace_id.into();
+        self
+    }
+
     pub fn assistant(
         channel: impl Into<String>,
         chat_id: impl Into<String>,
@@ -587,6 +599,7 @@ impl OutboundMessage {
             tool_arguments: None,
             reasoning_content: None,
             message_id: None,
+            trace_id: String::new(),
         }
     }
 
@@ -645,6 +658,7 @@ impl OutboundMessage {
             tool_arguments: Some(tool_arguments),
             reasoning_content: None,
             message_id: None,
+            trace_id: String::new(),
         }
     }
 
@@ -676,6 +690,7 @@ impl OutboundMessage {
             tool_arguments: None,
             reasoning_content: None,
             message_id: None,
+            trace_id: String::new(),
         }
     }
 
@@ -707,6 +722,7 @@ impl OutboundMessage {
             tool_arguments: None,
             reasoning_content: None,
             message_id: None,
+            trace_id: String::new(),
         }
     }
 
@@ -735,6 +751,7 @@ impl OutboundMessage {
             tool_arguments: None,
             reasoning_content: reasoning_delta,
             message_id: None,
+            trace_id: String::new(),
         }
     }
 
@@ -761,6 +778,7 @@ impl OutboundMessage {
             tool_arguments: None,
             reasoning_content: None,
             message_id: None,
+            trace_id: String::new(),
         }
     }
 
@@ -786,6 +804,7 @@ impl OutboundMessage {
             tool_arguments: None,
             reasoning_content: None,
             message_id: None,
+            trace_id: String::new(),
         }
     }
 
diff --git a/src/bus/mod.rs b/src/bus/mod.rs
index ef7e737..4a5abf9 100644
--- a/src/bus/mod.rs
+++ b/src/bus/mod.rs
@@ -35,8 +35,15 @@ impl MessageBus {
 
     /// Publish a message to the inbound queue
     pub async fn publish_inbound(&self, msg: InboundMessage) -> Result<(), BusError> {
-        #[cfg(debug_assertions)]
-        tracing::debug!(channel = %msg.channel, sender = %msg.sender_id, chat = %msg.chat_id, content_len = %msg.content.len(), media_count = %msg.media.len(), "Bus: publishing inbound message");
+        tracing::debug!(
+            channel = %msg.channel,
+            sender = %msg.sender_id,
+            chat_id = %msg.chat_id,
+            trace_id = %msg.trace_id,
+            content_len = %msg.content.len(),
+            media_count = %msg.media.len(),
+            "Bus: publishing inbound message"
+        );
         self.inbound_tx
             .send(msg)
             .await
@@ -47,8 +54,13 @@ impl MessageBus {
     /// Returns `None` when the channel is closed (all senders dropped).
     pub async fn consume_inbound(&self) -> Option<InboundMessage> {
         let msg = self.inbound_rx.lock().await.recv().await?;
-        #[cfg(debug_assertions)]
-        tracing::debug!(channel = %msg.channel, sender = %msg.sender_id, chat = %msg.chat_id, "Bus: consuming inbound message");
+        tracing::debug!(
+            channel = %msg.channel,
+            sender = %msg.sender_id,
+            chat_id = %msg.chat_id,
+            trace_id = %msg.trace_id,
+            "Bus: consuming inbound message"
+        );
         Some(msg)
     }
 
@@ -59,13 +71,20 @@ impl MessageBus {
     /// 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");
+        tracing::debug!(
+            channel = %msg.channel,
+            chat_id = %msg.chat_id,
+            trace_id = %msg.trace_id,
+            content_len = %msg.content.len(),
+            "Bus: publishing outbound message"
+        );
         match self.outbound_tx.try_send(msg) {
             Ok(()) => Ok(()),
             Err(tokio::sync::mpsc::error::TrySendError::Full(msg)) => {
                 tracing::warn!(
                     channel = %msg.channel,
+                    chat_id = %msg.chat_id,
+                    trace_id = %msg.trace_id,
                     "Outbound bus full, dropping message"
                 );
                 Err(BusError::Dropped)
diff --git a/src/channels/feishu.rs b/src/channels/feishu.rs
index 2b64666..efb2bc4 100644
--- a/src/channels/feishu.rs
+++ b/src/channels/feishu.rs
@@ -1327,6 +1327,7 @@ impl FeishuChannel {
                                                 media: parsed.media.map(|m| vec![m]).unwrap_or_default(),
                                                 metadata: std::collections::HashMap::new(),
                                                 forwarded_metadata,
+                                                trace_id: crate::observability::tracing_ctx::new_trace_id(),
                                             };
                                             if let Err(e) = channel.handle_and_publish(&bus, &msg).await {
                                                 tracing::error!(error = %e, open_id = %parsed.open_id, chat_id = %parsed.chat_id, "Failed to publish Feishu message to bus");
diff --git a/src/channels/wechat.rs b/src/channels/wechat.rs
index 1038d53..c3e3c31 100644
--- a/src/channels/wechat.rs
+++ b/src/channels/wechat.rs
@@ -247,6 +247,7 @@ impl Channel for WechatChannel {
                         media,
                         metadata,
                         forwarded_metadata: HashMap::new(),
+                        trace_id: crate::observability::tracing_ctx::new_trace_id(),
                     };
 
                     if let Err(error) = bus.publish_inbound(inbound).await {
diff --git a/src/cli/init.rs b/src/cli/init.rs
index b2b1563..933b61a 100644
--- a/src/cli/init.rs
+++ b/src/cli/init.rs
@@ -79,6 +79,7 @@ impl InitWizard {
             memory_maintenance: crate::config::MemoryMaintenanceConfig::default(),
             mcp_servers: HashMap::new(),
             mcp_tool_timeout_secs: 300,
+            observability: crate::config::ObservabilityConfig::default(),
             image_context: crate::config::ImageContextConfig::default(),
             subagents: crate::config::SubagentsConfig::default(),
             experts: crate::config::ExpertsConfig::default(),
@@ -845,6 +846,7 @@ impl InitWizard {
             memory_maintenance: existing.memory_maintenance.clone(),
             mcp_servers: existing.mcp_servers.clone(),
             mcp_tool_timeout_secs: existing.mcp_tool_timeout_secs,
+            observability: existing.observability.clone(),
             image_context: existing.image_context.clone(),
             subagents: existing.subagents.clone(),
             experts: existing.experts.clone(),
diff --git a/src/config/mod.rs b/src/config/mod.rs
index f7564e9..8d231e8 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -45,6 +45,8 @@ pub struct Config {
     pub experts: ExpertsConfig,
     #[serde(default)]
     pub compaction: CompactionConfig,
+    #[serde(default)]
+    pub observability: ObservabilityConfig,
 }
 
 /// 图片上下文限制配置
@@ -125,6 +127,34 @@ impl Default for CompactionConfig {
     }
 }
 
+/// 可观测性配置（日志格式、metrics 开关等）
+#[derive(Debug, Clone, Deserialize, Serialize)]
+pub struct ObservabilityConfig {
+    /// 日志输出格式：text（默认）或 json。
+    /// json 格式便于接入 ELK/Loki 等日志聚合系统。
+    #[serde(default)]
+    pub log_format: LogFormat,
+}
+
+impl Default for ObservabilityConfig {
+    fn default() -> Self {
+        Self {
+            log_format: LogFormat::default(),
+        }
+    }
+}
+
+/// 日志输出格式
+#[derive(Debug, Clone, Deserialize, Serialize, Default, PartialEq, Eq)]
+#[serde(rename_all = "lowercase")]
+pub enum LogFormat {
+    /// 纯文本格式（默认，便于人读）
+    #[default]
+    Text,
+    /// JSON 格式（便于机器解析和日志聚合）
+    Json,
+}
+
 #[derive(Debug, Clone, Deserialize, Serialize)]
 pub struct TimeConfig {
     #[serde(default = "default_timezone")]
diff --git a/src/gateway/agent_factory.rs b/src/gateway/agent_factory.rs
index e3d0c15..123e8b9 100644
--- a/src/gateway/agent_factory.rs
+++ b/src/gateway/agent_factory.rs
@@ -9,6 +9,7 @@ use crate::experts::ExpertRuntime;
 use crate::gateway::agent_prompt_provider::AgentPromptProvider;
 use crate::gateway::model_selection::ModelSelectionStore;
 use crate::gateway::tool_prompt_provider::ToolPromptProvider;
+use crate::observability::Observer;
 use crate::skills::{SkillPromptProvider, SkillRuntime};
 use crate::storage::PromptInjectionRepository;
 use crate::storage::persistent_session_id;
@@ -56,6 +57,8 @@ pub(crate) struct AgentFactory {
     model_selections: Arc<ModelSelectionStore>,
     /// 上下文压缩算法配置（所有 agent 共享）
     compaction_config: CompactionConfig,
+    /// 可观测性 Observer（依赖注入到 AgentLoop，业务层不感知具体实现）
+    observer: Option<Arc<dyn Observer>>,
     /// 实例创建时间戳（用于区分新旧 AgentFactory 实例）
     instance_id: u64,
 }
@@ -71,6 +74,8 @@ pub(crate) struct AgentBuildRequest<'a> {
     pub(crate) topic_id: Option<String>,
     /// 取消信号接收端（可选）：Agent 在每次迭代时检查是否被取消
     pub(crate) cancel_token: Option<tokio::sync::watch::Receiver<()>>,
+    /// 端到端追踪 ID（从 InboundMessage 继承，注入 ToolContext 供 tool 执行路径日志关联）
+    pub(crate) trace_id: Option<String>,
 }
 
 impl AgentFactory {
@@ -84,6 +89,7 @@ impl AgentFactory {
         model_resolver: Arc<ModelResolver>,
         model_selections: Arc<ModelSelectionStore>,
         compaction_config: CompactionConfig,
+        observer: Option<Arc<dyn Observer>>,
     ) -> Self {
         // 使用 Arc 指针地址作为实例标识符，用于区分新旧 AgentFactory 实例
         let instance_id = Arc::as_ptr(&tools) as u64;
@@ -102,6 +108,7 @@ impl AgentFactory {
             model_resolver,
             model_selections,
             compaction_config,
+            observer,
             instance_id,
         }
     }
@@ -245,8 +252,13 @@ impl AgentFactory {
                     tool_call_id: None,
                     // 注入专家 capability，TaskTool 据此强制校验子代理白/黑名单
                     parent_capability: expert_capability.clone(),
+                    trace_id: request.trace_id.clone(),
                 })
                 .with_compressor(Some(compressor));
+            // 注入观测器（依赖注入，agent_loop 只认 Observer trait）
+            if let Some(ref observer) = self.observer {
+                agent = agent.with_observer(observer.clone());
+            }
             // 如果有取消信号接收端，注入 Agent
             if let Some(token) = request.cancel_token {
                 agent = agent.with_cancel_token(token);
diff --git a/src/gateway/auth.rs b/src/gateway/auth.rs
index 7856e13..c748da6 100644
--- a/src/gateway/auth.rs
+++ b/src/gateway/auth.rs
@@ -84,9 +84,10 @@ pub fn extract_bearer_token(headers: &HeaderMap) -> Option<&str> {
         })
 }
 
-/// axum 中间件：对 `/api/*` 路由强制 Bearer token 校验。
+/// axum 中间件：对 `/api/*` 和 `/metrics` 路由强制 Bearer token 校验。
 /// 仅在 `requires_auth` 为 true 时挂载。
 /// `/health`、`/ws`、静态资源放行；`/ws` 的 token 校验在 ws_handler 内完成。
+/// `/metrics` 包含运行时指标（provider/model/耗时/token 用量），远程部署时需保护。
 pub async fn require_bearer_auth(
     headers: HeaderMap,
     request: Request,
@@ -94,8 +95,9 @@ pub async fn require_bearer_auth(
 ) -> Response {
     let path = request.uri().path();
 
-    // 仅对 /api/ 前缀的请求强制认证
-    if !path.starts_with("/api/") {
+    // /api/* 和 /metrics 需要认证；其余放行
+    let needs_auth = path.starts_with("/api/") || path == "/metrics";
+    if !needs_auth {
         return next.run(request).await;
     }
 
diff --git a/src/gateway/execution.rs b/src/gateway/execution.rs
index 6ce20d9..2e2010a 100644
--- a/src/gateway/execution.rs
+++ b/src/gateway/execution.rs
@@ -114,6 +114,8 @@ pub(crate) struct MessageExecutionRequest<'a> {
     pub(crate) live_emitter: Option<Arc<dyn EmittedMessageHandler>>,
     /// 消息接收时捕获的 topic_id，全程显式传递避免从共享状态重复读取竞态
     pub(crate) topic_id: Option<String>,
+    /// 端到端追踪 ID（从 InboundMessage 透传，贯穿 agent → tool → outbound）
+    pub(crate) trace_id: &'a str,
 }
 
 pub(crate) struct ScheduledExecutionRequest<'a> {
@@ -127,6 +129,8 @@ pub(crate) struct ScheduledExecutionRequest<'a> {
     pub(crate) system_prompt: Option<&'a str>,
     pub(crate) metadata: &'a HashMap<String, String>,
     pub(crate) fresh_session: bool,
+    /// 端到端追踪 ID（由 ScheduledAgentTaskService 生成）
+    pub(crate) trace_id: String,
 }
 
 impl AgentExecutionService {
@@ -341,6 +345,7 @@ impl AgentExecutionService {
                 Some(request.sender_id),
                 Some(&user_message.id),
                 original_topic_id.as_deref(),
+                request.trace_id,
             )?;
             if let Some(handler) = request.live_emitter.clone() {
                 agent = agent.with_emitted_message_handler(handler);
@@ -477,6 +482,7 @@ impl AgentExecutionService {
                 Some(&user_message.id),
                 request.provider_config.clone(),
                 original_topic_id.as_deref(),
+                &request.trace_id,
             )?;
 
             // 获取 store 和 session_id，用于构造消息持久化 handler
diff --git a/src/gateway/http.rs b/src/gateway/http.rs
index fbe95b6..6f1b380 100644
--- a/src/gateway/http.rs
+++ b/src/gateway/http.rs
@@ -240,6 +240,21 @@ pub async fn list_executions(State(state): State<Arc<GatewayState>>) -> Json<Exe
     Json(ExecutionsResponse { topic_ids })
 }
 
+/// GET /metrics — Prometheus metrics 端点
+///
+/// 返回 Prometheus 格式的 metrics 文本。若 recorder 未安装则返回 503。
+pub async fn metrics_handler(
+    State(state): State<Arc<GatewayState>>,
+) -> (StatusCode, String) {
+    match &state.prometheus_handle {
+        Some(handle) => (StatusCode::OK, handle.render()),
+        None => (
+            StatusCode::SERVICE_UNAVAILABLE,
+            "Metrics recorder not initialized".to_string(),
+        ),
+    }
+}
+
 /// GET /api/mcp/status — Return MCP server connection status
 pub async fn mcp_status(
     State(state): State<Arc<GatewayState>>,
diff --git a/src/gateway/mod.rs b/src/gateway/mod.rs
index e3cbd6d..5d86bdb 100644
--- a/src/gateway/mod.rs
+++ b/src/gateway/mod.rs
@@ -72,6 +72,9 @@ pub struct GatewayState {
     pub subagent_runtime: Arc<SubagentRuntime>,
     /// per-session 的用户模型选择（覆盖专家配置）
     pub model_selections: Arc<model_selection::ModelSelectionStore>,
+    /// Prometheus metrics handle（/metrics 端点渲染用）。
+    /// None 表示 recorder 安装失败；热重启时从 OnceLock 缓存复用，不会因重复安装而变为 None。
+    pub prometheus_handle: Option<metrics_exporter_prometheus::PrometheusHandle>,
 }
 
 impl GatewayState {
@@ -132,6 +135,9 @@ impl GatewayState {
 
         let cancel_manager = CancelManager::new();
 
+        // 安装 Prometheus recorder（幂等：首次安装并缓存 handle，热重启时返回缓存）
+        let prometheus_handle = crate::observability::metrics::init_recorder();
+
         Ok(Self {
             config: Arc::new(RwLock::new(config)),
             session_manager,
@@ -145,6 +151,7 @@ impl GatewayState {
             experts,
             subagent_runtime,
             model_selections,
+            prometheus_handle,
         })
     }
 
@@ -195,9 +202,10 @@ pub async fn run(
 ) -> Result<bool, Box<dyn std::error::Error>> {
     let config = Config::load_default()?;
     let timezone = config.time.parse_timezone()?;
+    let log_format = config.observability.log_format.clone();
 
     // Initialize logging
-    logging::init_logging(timezone);
+    logging::init_logging(timezone, log_format);
     tracing::info!("Starting PicoBot Gateway");
 
     // Restart signal channel
@@ -332,7 +340,8 @@ pub async fn run(
             "/api/session/selected-model",
             routing::get(http::session_selected_model),
         )
-        .route("/ws", routing::get(ws::ws_handler));
+        .route("/ws", routing::get(ws::ws_handler))
+        .route("/metrics", routing::get(http::metrics_handler));
 
     // 仅 fallback 按模式区分：嵌入资源 vs 磁盘目录。
     // fallback 必须在 with_state 之前调用，否则 handler 的 State 类型无法推断。
diff --git a/src/gateway/outbound_dispatcher.rs b/src/gateway/outbound_dispatcher.rs
index d05430b..d96cc74 100644
--- a/src/gateway/outbound_dispatcher.rs
+++ b/src/gateway/outbound_dispatcher.rs
@@ -171,6 +171,8 @@ impl OutboundDispatcher {
         channel_name: &str,
         msg: OutboundMessage,
     ) {
+        let msg_chat_id = msg.chat_id.clone();
+        let msg_trace_id = msg.trace_id.clone();
         match Self::send_with_retry(channel, msg).await {
             Ok(()) => {}
             Err(ChannelError::ChannelFull) => {
@@ -178,12 +180,16 @@ impl OutboundDispatcher {
                 // 记 warn 而非 error：这是预期的背压丢弃。
                 tracing::warn!(
                     channel = %channel_name,
+                    chat_id = %msg_chat_id,
+                    trace_id = %msg_trace_id,
                     "Message dropped: channel queue full"
                 );
             }
             Err(error) => {
                 tracing::error!(
                     channel = %channel_name,
+                    chat_id = %msg_chat_id,
+                    trace_id = %msg_trace_id,
                     error = %error,
                     "Failed to send message after retries"
                 );
diff --git a/src/gateway/processor.rs b/src/gateway/processor.rs
index 9e9696d..cd011e3 100644
--- a/src/gateway/processor.rs
+++ b/src/gateway/processor.rs
@@ -147,17 +147,15 @@ impl InboundProcessor {
                 }
             };
 
-            #[cfg(debug_assertions)]
-            {
-                tracing::debug!(
-                    channel = %inbound.channel,
-                    chat_id = %inbound.chat_id,
-                    sender = %inbound.sender_id,
-                    content_len = %inbound.content.len(),
-                    media_count = %inbound.media.len(),
-                    "Processing inbound message"
-                );
-            }
+            tracing::debug!(
+                channel = %inbound.channel,
+                chat_id = %inbound.chat_id,
+                trace_id = %inbound.trace_id,
+                sender = %inbound.sender_id,
+                content_len = %inbound.content.len(),
+                media_count = %inbound.media.len(),
+                "Processing inbound message"
+            );
 
             // 2. 获取 semaphore permit（控制并发）
             let permit = match self.semaphore.clone().acquire_owned().await {
@@ -172,18 +170,37 @@ impl InboundProcessor {
             let processor = self.clone();
 
             // 4. 独立任务处理（包含 permit，任务完成自动释放）
-            tokio::spawn(async move {
-                let _permit = permit; // 持有 permit 直到任务完成
-                if let Err(e) = processor.process_one(inbound).await {
-                    tracing::error!(error = %e, "Message processing failed");
-                }
-            });
+            // spawn 不自动传播父 span，用 traced() 重建 span 上下文，
+            // 使 process_one 内所有日志携带 trace_id/chat_id/session_id。
+            let trace_id = inbound.trace_id.clone();
+            let chat_id_for_span = inbound.chat_id.clone();
+            let session_id_for_span =
+                crate::storage::persistent_session_id(&inbound.channel, &inbound.chat_id);
+            tokio::spawn(
+                crate::observability::tracing_ctx::traced(
+                    &trace_id,
+                    &chat_id_for_span,
+                    &session_id_for_span,
+                    async move {
+                        let _permit = permit; // 持有 permit 直到任务完成
+                        if let Err(e) = processor.process_one(inbound).await {
+                            tracing::error!(
+                                error = %crate::utils::format_error_chain(&e),
+                                "Message processing failed"
+                            );
+                            crate::observability::metrics::record_message_processing_error();
+                        }
+                    },
+                ),
+            );
         }
     }
 
+    #[tracing::instrument(skip(self, inbound), fields(trace_id = %inbound.trace_id, chat_id = %inbound.chat_id, session_id))]
     async fn process_one(&self, inbound: InboundMessage) -> Result<(), AgentError> {
         // 计算正确的 session_id（根据 channel_name 和 chat_id）
         let session_id = persistent_session_id(&inbound.channel, &inbound.chat_id);
+        tracing::Span::current().record("session_id", tracing::field::display(&session_id));
 
         // 获取当前话题（封装了 session 创建逻辑）
         let current_topic = self
@@ -220,14 +237,17 @@ impl InboundProcessor {
                 for msg in &response.messages {
                     if let Err(error) = self
                         .bus
-                        .publish_outbound(OutboundMessage::assistant(
-                            inbound.channel.clone(),
-                            inbound.chat_id.clone(),
-                            response.metadata.get("session_id").cloned(),
-                            msg.content.clone(),
-                            None,
-                            inbound.forwarded_metadata.clone(),
-                        ))
+                        .publish_outbound(
+                            OutboundMessage::assistant(
+                                inbound.channel.clone(),
+                                inbound.chat_id.clone(),
+                                response.metadata.get("session_id").cloned(),
+                                msg.content.clone(),
+                                None,
+                                inbound.forwarded_metadata.clone(),
+                            )
+                            .with_trace_id(&inbound.trace_id),
+                        )
                         .await
                     {
                         match error {
@@ -243,14 +263,17 @@ impl InboundProcessor {
             } else if let Some(error) = response.error {
                 if let Err(e) = self
                     .bus
-                    .publish_outbound(OutboundMessage::assistant(
-                        inbound.channel.clone(),
-                        inbound.chat_id.clone(),
-                        response.metadata.get("session_id").cloned(),
-                        format!("Error [{}]: {}", error.code, error.message),
-                        None,
-                        inbound.forwarded_metadata.clone(),
-                    ))
+                    .publish_outbound(
+                        OutboundMessage::assistant(
+                            inbound.channel.clone(),
+                            inbound.chat_id.clone(),
+                            response.metadata.get("session_id").cloned(),
+                            format!("Error [{}]: {}", error.code, error.message),
+                            None,
+                            inbound.forwarded_metadata.clone(),
+                        )
+                        .with_trace_id(&inbound.trace_id),
+                    )
                     .await
                 {
                     match e {
@@ -279,6 +302,7 @@ impl InboundProcessor {
                 inbound.chat_id.clone(),
                 emitter_metadata,
                 self.session_manager.store(),
+                inbound.trace_id.clone(),
             ),
             self.session_manager.store(),
             &session_id,
@@ -307,6 +331,7 @@ impl InboundProcessor {
                 inbound.media,
                 Some(live_emitter),
                 current_topic.as_deref(),
+                &inbound.trace_id,
             )
             .await
         {
@@ -319,6 +344,8 @@ impl InboundProcessor {
                             .metadata
                             .insert("topic_id".to_string(), topic_id.clone());
                     }
+                    // 透传 trace_id 到出站消息，保持端到端追踪贯通
+                    outbound.trace_id = inbound.trace_id.clone();
                     if let Err(error) = self.bus.publish_outbound(outbound).await {
                         match error {
                             crate::bus::BusError::Dropped => {
@@ -414,19 +441,26 @@ impl InboundProcessor {
                 }
             }
             Err(error) => {
-                tracing::error!(error = %error, "Failed to handle message");
+                tracing::error!(
+                    error = %crate::utils::format_error_chain(&error),
+                    "Failed to handle message"
+                );
+                crate::observability::metrics::record_message_processing_error();
                 let mut metadata = inbound.forwarded_metadata.clone();
                 metadata.insert("error_kind".to_string(), "agent_execution".to_string());
                 if let Err(publish_error) = self
                     .bus
-                    .publish_outbound(OutboundMessage::error_notification(
-                        inbound.channel,
-                        inbound.chat_id,
-                        None, // session_id
-                        error.to_string(),
-                        None,
-                        metadata,
-                    ))
+                    .publish_outbound(
+                        OutboundMessage::error_notification(
+                            inbound.channel,
+                            inbound.chat_id,
+                            None, // session_id
+                            error.to_string(),
+                            None,
+                            metadata,
+                        )
+                        .with_trace_id(&inbound.trace_id),
+                    )
                     .await
                 {
                     match publish_error {
@@ -454,12 +488,15 @@ impl InboundProcessor {
         }
         if let Err(error) = self
             .bus
-            .publish_outbound(OutboundMessage::execution_completed(
-                channel,
-                chat_id,
-                Some(session_id),
-                completion_metadata,
-            ))
+            .publish_outbound(
+                OutboundMessage::execution_completed(
+                    channel,
+                    chat_id,
+                    Some(session_id),
+                    completion_metadata,
+                )
+                .with_trace_id(&inbound.trace_id),
+            )
             .await
         {
             match error {
diff --git a/src/gateway/runtime.rs b/src/gateway/runtime.rs
index 5165c7c..df3315f 100644
--- a/src/gateway/runtime.rs
+++ b/src/gateway/runtime.rs
@@ -312,6 +312,8 @@ pub(crate) fn build_session_manager_with_sender(
 
     let prompt_repository: Arc<dyn PromptInjectionRepository> = store.clone();
     let model_selections = Arc::new(ModelSelectionStore::new());
+    let observer: Arc<dyn crate::observability::Observer> =
+        crate::observability::metrics::default_observer();
     let agent_factory = AgentFactory::new(
         tools.clone(),
         skills.clone(),
@@ -322,6 +324,7 @@ pub(crate) fn build_session_manager_with_sender(
         model_resolver.clone(),
         model_selections.clone(),
         compaction_config,
+        Some(observer),
     );
     let session_factory = SessionFactory::new(
         provider_config.clone(),
diff --git a/src/gateway/scheduled_agent_task_service.rs b/src/gateway/scheduled_agent_task_service.rs
index 38e2359..281f764 100644
--- a/src/gateway/scheduled_agent_task_service.rs
+++ b/src/gateway/scheduled_agent_task_service.rs
@@ -47,7 +47,10 @@ impl ScheduledAgentTaskService {
             .unwrap_or_else(|| "scheduler".to_string());
         let provider_config = self.provider_configs.select(options.agent.as_deref())?;
 
-        AgentExecutionService::new(self.show_tool_results)
+        // 定时任务没有入站消息，在此生成独立 trace_id 以贯穿 agent → tool → outbound
+        let trace_id = crate::observability::tracing_ctx::new_trace_id();
+
+        let mut outbound_messages = AgentExecutionService::new(self.show_tool_results)
             .prepare_and_execute_scheduled_task(ScheduledExecutionRequest {
                 session,
                 channel_name,
@@ -59,7 +62,15 @@ impl ScheduledAgentTaskService {
                 system_prompt: options.system_prompt.as_deref(),
                 metadata: &options.metadata,
                 fresh_session: options.fresh_session,
+                trace_id: trace_id.clone(),
             })
-            .await
+            .await?;
+
+        // 将 trace_id 透传到出站消息，保持端到端追踪贯通
+        for msg in &mut outbound_messages {
+            msg.trace_id = trace_id.clone();
+        }
+
+        Ok(outbound_messages)
     }
 }
diff --git a/src/gateway/session.rs b/src/gateway/session.rs
index ef2c0c9..67fcd0e 100644
--- a/src/gateway/session.rs
+++ b/src/gateway/session.rs
@@ -61,6 +61,7 @@ pub struct BusToolCallEmitter {
     metadata: HashMap<String, String>,
     store: Arc<SessionStore>,
     stream_message_id: parking_lot::Mutex<Option<String>>,
+    trace_id: String,
 }
 
 impl BusToolCallEmitter {
@@ -70,6 +71,7 @@ impl BusToolCallEmitter {
         chat_id: impl Into<String>,
         metadata: HashMap<String, String>,
         store: Arc<SessionStore>,
+        trace_id: impl Into<String>,
     ) -> Self {
         Self {
             bus,
@@ -78,6 +80,7 @@ impl BusToolCallEmitter {
             metadata,
             store,
             stream_message_id: parking_lot::Mutex::new(None),
+            trace_id: trace_id.into(),
         }
     }
 }
@@ -85,7 +88,7 @@ impl BusToolCallEmitter {
 #[async_trait]
 impl EmittedMessageHandler for BusToolCallEmitter {
     async fn handle(&self, message: ChatMessage) {
-        for outbound in OutboundMessage::from_chat_message(
+        for mut outbound in OutboundMessage::from_chat_message(
             &self.channel_name,
             &self.chat_id,
             None, // session_id
@@ -93,6 +96,7 @@ impl EmittedMessageHandler for BusToolCallEmitter {
             &self.metadata,
             &message,
         ) {
+            outbound.trace_id = self.trace_id.clone();
             if let Err(error) = self.bus.publish_outbound(outbound).await {
                 match error {
                     crate::bus::BusError::Dropped => {
@@ -111,7 +115,7 @@ impl EmittedMessageHandler for BusToolCallEmitter {
         if let Some(ms) = duration_ms {
             metadata.insert("tool_duration_ms".to_string(), ms.to_string());
         }
-        for outbound in OutboundMessage::from_chat_message(
+        for mut outbound in OutboundMessage::from_chat_message(
             &self.channel_name,
             &self.chat_id,
             None, // session_id
@@ -119,6 +123,7 @@ impl EmittedMessageHandler for BusToolCallEmitter {
             &metadata,
             &message,
         ) {
+            outbound.trace_id = self.trace_id.clone();
             if let Err(error) = self.bus.publish_outbound(outbound).await {
                 match error {
                     crate::bus::BusError::Dropped => {
@@ -147,7 +152,7 @@ impl EmittedMessageHandler for BusToolCallEmitter {
         };
 
         // Empty content + no reasoning = stream end signal
-        let outbound = if delta.content.is_empty() && delta.reasoning_content.is_none() {
+        let mut outbound = if delta.content.is_empty() && delta.reasoning_content.is_none() {
             OutboundMessage::stream_end(
                 &self.channel_name,
                 &self.chat_id,
@@ -166,6 +171,7 @@ impl EmittedMessageHandler for BusToolCallEmitter {
                 self.metadata.clone(),
             )
         };
+        outbound.trace_id = self.trace_id.clone();
 
         if let Err(error) = self.bus.publish_outbound(outbound).await {
             match error {
@@ -302,6 +308,7 @@ impl Session {
             model_resolver,
             Arc::new(super::model_selection::ModelSelectionStore::new()),
             crate::config::CompactionConfig::default(),
+            None,
         );
         Self::with_factories(
             channel_name,
@@ -613,6 +620,7 @@ impl Session {
         sender_id: Option<&str>,
         message_id: Option<&str>,
         explicit_topic_id: Option<&str>,
+        trace_id: &str,
     ) -> Result<AgentLoop, AgentError> {
         self.create_agent_with_provider_config(
             chat_id,
@@ -621,6 +629,7 @@ impl Session {
             message_id,
             self.provider_config.clone(),
             explicit_topic_id,
+            trace_id,
         )
     }
 
@@ -632,6 +641,7 @@ impl Session {
         message_id: Option<&str>,
         provider_config: LLMProviderConfig,
         explicit_topic_id: Option<&str>,
+        trace_id: &str,
     ) -> Result<AgentLoop, AgentError> {
         // 优先使用显式传入的 topic_id；回退到当前 chat 的活跃 topic
         let topic_id = explicit_topic_id
@@ -657,6 +667,7 @@ impl Session {
             message_id,
             provider_config,
             cancel_token,
+            trace_id: Some(trace_id.to_string()),
         })
     }
 }
@@ -908,6 +919,7 @@ impl SessionManager {
         media: Vec<crate::bus::MediaItem>,
         live_emitter: Option<Arc<dyn EmittedMessageHandler>>,
         topic_id: Option<&str>,
+        trace_id: &str,
     ) -> Result<Vec<OutboundMessage>, AgentError> {
         self.messages
             .handle_message(
@@ -918,6 +930,7 @@ impl SessionManager {
                 media,
                 live_emitter,
                 topic_id,
+                trace_id,
             )
             .await
     }
@@ -1305,6 +1318,7 @@ mod tests {
                 Vec::new(),
                 None,
                 None,
+                "test-trace",
             )
             .await
             .unwrap();
@@ -2095,8 +2109,14 @@ mod tests {
     async fn test_bus_tool_call_emitter_emits_completed_tool_results() {
         let store = Arc::new(SessionStore::in_memory().unwrap());
         let bus = MessageBus::new(4);
-        let emitter =
-            BusToolCallEmitter::new(bus.clone(), "test-channel", "chat-1", HashMap::new(), store);
+        let emitter = BusToolCallEmitter::new(
+            bus.clone(),
+            "test-channel",
+            "chat-1",
+            HashMap::new(),
+            store,
+            "test-trace-id",
+        );
 
         emitter
             .handle(ChatMessage::tool("call-1", "calculator", "2"))
diff --git a/src/gateway/session_message_sender.rs b/src/gateway/session_message_sender.rs
index 75640ee..c1c7125 100644
--- a/src/gateway/session_message_sender.rs
+++ b/src/gateway/session_message_sender.rs
@@ -51,7 +51,8 @@ impl SessionMessageSender for BusSessionMessageSender {
                 text,
                 None,
                 metadata.clone(),
-            );
+            )
+            .with_trace_id(context.trace_id.as_deref().unwrap_or(""));
             if attachment_count > 0 {
                 outbound.media = request.attachments.clone();
             }
@@ -88,7 +89,8 @@ impl SessionMessageSender for BusSessionMessageSender {
                     String::new(),
                     None,
                     metadata.clone(),
-                );
+                )
+                .with_trace_id(context.trace_id.as_deref().unwrap_or(""));
                 outbound.media = vec![attachment];
                 match self.bus.publish_outbound(outbound).await {
                     Ok(()) => {
diff --git a/src/gateway/session_message_service.rs b/src/gateway/session_message_service.rs
index 4733e61..9704278 100644
--- a/src/gateway/session_message_service.rs
+++ b/src/gateway/session_message_service.rs
@@ -29,6 +29,7 @@ impl SessionMessageService {
         media: Vec<MediaItem>,
         live_emitter: Option<Arc<dyn EmittedMessageHandler>>,
         topic_id: Option<&str>,
+        trace_id: &str,
     ) -> Result<Vec<OutboundMessage>, AgentError> {
         #[cfg(debug_assertions)]
         {
@@ -56,6 +57,7 @@ impl SessionMessageService {
                 media,
                 live_emitter,
                 topic_id: topic_id.map(|s| s.to_string()),
+                trace_id,
             })
             .await?;
 
diff --git a/src/gateway/ws.rs b/src/gateway/ws.rs
index 0d79a4e..44782d2 100644
--- a/src/gateway/ws.rs
+++ b/src/gateway/ws.rs
@@ -397,6 +397,7 @@ async fn handle_inbound(
                     media,
                     metadata: HashMap::new(),
                     forwarded_metadata: HashMap::new(),
+                    trace_id: crate::observability::tracing_ctx::new_trace_id(),
                 })
                 .await
                 .map_err(|error| AgentError::Other(error.to_string()))?;
diff --git a/src/logging.rs b/src/logging.rs
index 485fc24..851fbc9 100644
--- a/src/logging.rs
+++ b/src/logging.rs
@@ -3,9 +3,11 @@ use chrono_tz::Tz;
 use std::path::PathBuf;
 use tracing_appender::rolling::{RollingFileAppender, Rotation};
 use tracing_subscriber::{
-    fmt, fmt::time::FormatTime, layer::SubscriberExt, util::SubscriberInitExt, EnvFilter,
+    fmt, fmt::time::FormatTime, layer::SubscriberExt, util::SubscriberInitExt, EnvFilter, Layer,
 };
 
+use crate::config::LogFormat;
+
 #[derive(Clone, Copy, Debug)]
 struct ConfiguredTimestamp {
     timezone: Tz,
@@ -40,7 +42,10 @@ pub fn get_default_config_path() -> PathBuf {
 
 /// Initialize logging with file appender
 /// Logs are written to ~/.picobot/logs/ with daily rotation
-pub fn init_logging(timezone: Tz) {
+///
+/// `log_format` 控制文件日志格式：Text（默认）或 Json（便于日志聚合）。
+/// 控制台始终使用文本格式（便于人读）。
+pub fn init_logging(timezone: Tz, log_format: LogFormat) {
     use std::sync::Once;
     static INIT: Once = Once::new();
 
@@ -72,14 +77,28 @@ pub fn init_logging(timezone: Tz) {
     // Build subscriber with both console and file output
     let env_filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info"));
 
-    let file_layer = fmt::layer()
-        .with_writer(file_appender)
-        .with_timer(ConfiguredTimestamp { timezone })
-        .with_ansi(false)
-        .with_target(true)
-        .with_level(true)
-        .with_thread_ids(true);
+    // 文件层：根据 log_format 选择 text 或 json
+    let file_layer = match log_format {
+        LogFormat::Json => fmt::layer()
+            .with_writer(file_appender)
+            .with_timer(ConfiguredTimestamp { timezone })
+            .with_ansi(false)
+            .with_target(true)
+            .with_level(true)
+            .with_thread_ids(true)
+            .json()
+            .boxed(),
+        LogFormat::Text => fmt::layer()
+            .with_writer(file_appender)
+            .with_timer(ConfiguredTimestamp { timezone })
+            .with_ansi(false)
+            .with_target(true)
+            .with_level(true)
+            .with_thread_ids(true)
+            .boxed(),
+    };
 
+    // 控制台层：始终文本格式
     let console_layer = fmt::layer()
         .with_timer(ConfiguredTimestamp { timezone })
         .with_target(true)
@@ -91,7 +110,11 @@ pub fn init_logging(timezone: Tz) {
         .with(file_layer)
         .init();
 
-    tracing::info!("Logging initialized. Log directory: {}", log_dir.display());
+    tracing::info!(
+        log_format = ?log_format,
+        log_dir = %log_dir.display(),
+        "Logging initialized"
+    );
 }
 
 /// Initialize logging without file output (console only)
diff --git a/src/observability/metrics.rs b/src/observability/metrics.rs
new file mode 100644
index 0000000..4d0008a
--- /dev/null
+++ b/src/observability/metrics.rs
@@ -0,0 +1,157 @@
+//! Metrics 基础设施：基于 `metrics` + `metrics-exporter-prometheus`。
+//!
+//! 提供 `MetricsObserver`（实现 `Observer` trait，桥接 agent_loop 事件到 metrics），
+//! 以及 Prometheus recorder 初始化。
+//!
+//! 设计原则：
+//! - 业务层（agent_loop）只认 `dyn Observer` trait，不感知 metrics 实现。
+//! - 具体指标名和 label 约定集中于此模块。
+//! - metrics 后端可替换（换掉 recorder + Observer 实现即可）。
+
+use std::sync::Arc;
+
+use metrics_exporter_prometheus::{PrometheusBuilder, PrometheusHandle};
+
+use super::{Observer, ObserverEvent};
+
+// ============================================================================
+// 指标名常量
+// ============================================================================
+
+/// LLM 请求耗时（直方图，秒）。Labels: provider, model
+pub const LLM_REQUEST_DURATION: &str = "picobot_llm_request_duration_seconds";
+/// LLM token 使用量（计数器）。Labels: provider, model, type (prompt/completion/total)
+pub const LLM_TOKENS_USED: &str = "picobot_llm_tokens_used_total";
+/// 工具执行耗时（直方图，秒）。Labels: tool
+pub const TOOL_EXECUTION_DURATION: &str = "picobot_tool_execution_duration_seconds";
+/// 工具执行总数（计数器）。Labels: tool, success (true/false)
+pub const TOOL_EXECUTION_TOTAL: &str = "picobot_tool_execution_total";
+/// Agent 迭代总数（计数器）
+pub const AGENT_ITERATIONS: &str = "picobot_agent_iterations_total";
+/// 消息处理错误总数（计数器）
+pub const MESSAGE_PROCESSING_ERRORS: &str = "picobot_message_processing_errors_total";
+
+// ============================================================================
+// Recorder 初始化
+// ============================================================================
+
+/// 安装 Prometheus recorder，返回 handle 供 `/metrics` 端点渲染。
+///
+/// 幂等：首次调用安装 recorder 并缓存 handle；后续调用（含热重启）返回缓存的 handle。
+/// 这避免了热重启后 `install_recorder()` 因 recorder 已安装而失败、导致 `/metrics` 返回 503 的问题。
+/// 返回 None 表示安装失败（非致命，metrics 静默降级）。
+static PROMETHEUS_HANDLE: std::sync::OnceLock<Option<PrometheusHandle>> = std::sync::OnceLock::new();
+
+pub fn init_recorder() -> Option<PrometheusHandle> {
+    PROMETHEUS_HANDLE
+        .get_or_init(|| {
+            let builder = PrometheusBuilder::new();
+            match builder.install_recorder() {
+                Ok(handle) => {
+                    tracing::info!("Prometheus metrics recorder installed");
+                    Some(handle)
+                }
+                Err(e) => {
+                    tracing::warn!(error = %e, "Failed to install Prometheus recorder (metrics will be no-op)");
+                    None
+                }
+            }
+        })
+        .clone()
+}
+
+// ============================================================================
+// MetricsObserver — 桥接 ObserverEvent 到 metrics 宏
+// ============================================================================
+
+/// 将 `ObserverEvent` 转换为 metrics 指标的 Observer 实现。
+///
+/// 通过 `AgentFactory` 依赖注入到 `AgentLoop`，agent_loop 不感知 metrics 实现。
+pub struct MetricsObserver;
+
+impl MetricsObserver {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl Default for MetricsObserver {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Observer for MetricsObserver {
+    fn record_event(&self, event: &ObserverEvent) {
+        match event {
+            ObserverEvent::ToolCallStart { tool, .. } => {
+                // 工具开始：不记录指标，仅 span 日志已覆盖
+                let _ = tool;
+            }
+            ObserverEvent::ToolCall {
+                tool,
+                duration,
+                success,
+            } => {
+                let duration_secs = duration.as_secs_f64();
+                metrics::histogram!(TOOL_EXECUTION_DURATION, "tool" => tool.clone())
+                    .record(duration_secs);
+                metrics::counter!(
+                    TOOL_EXECUTION_TOTAL,
+                    "tool" => tool.clone(),
+                    "success" => success.to_string()
+                )
+                .increment(1);
+            }
+            ObserverEvent::AgentStart { provider, model } => {
+                metrics::counter!(
+                    AGENT_ITERATIONS,
+                    "provider" => provider.clone(),
+                    "model" => model.clone()
+                )
+                .increment(1);
+            }
+            ObserverEvent::AgentEnd {
+                provider,
+                model,
+                duration,
+                tokens_used,
+            } => {
+                let duration_secs = duration.as_secs_f64();
+                metrics::histogram!(
+                    LLM_REQUEST_DURATION,
+                    "provider" => provider.clone(),
+                    "model" => model.clone()
+                )
+                .record(duration_secs);
+                if let Some(tokens) = tokens_used {
+                    metrics::counter!(
+                        LLM_TOKENS_USED,
+                        "provider" => provider.clone(),
+                        "model" => model.clone(),
+                        "type" => "total"
+                    )
+                    .increment(*tokens);
+                }
+            }
+        }
+    }
+
+    fn name(&self) -> &str {
+        "metrics_observer"
+    }
+}
+
+/// 创建默认的 `Arc<dyn Observer>`（供 AgentFactory 注入）。
+pub fn default_observer() -> Arc<dyn Observer> {
+    Arc::new(MetricsObserver::new())
+}
+
+// ============================================================================
+// 辅助函数：供非 agent_loop 路径直接记录指标
+// ============================================================================
+
+/// 记录消息处理错误（供 processor 错误路径调用）。
+pub fn record_message_processing_error() {
+    metrics::counter!(MESSAGE_PROCESSING_ERRORS).increment(1);
+}
diff --git a/src/observability/mod.rs b/src/observability/mod.rs
index da04a42..e063d76 100644
--- a/src/observability/mod.rs
+++ b/src/observability/mod.rs
@@ -3,6 +3,9 @@
 //! This module provides an Observer pattern for emitting and collecting
 //! telemetry events during agent execution.
 
+pub mod metrics;
+pub mod tracing_ctx;
+
 use std::time::Duration;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
diff --git a/src/observability/tracing_ctx.rs b/src/observability/tracing_ctx.rs
new file mode 100644
index 0000000..444ac5d
--- /dev/null
+++ b/src/observability/tracing_ctx.rs
@@ -0,0 +1,43 @@
+//! 观测上下文辅助：trace_id 生成与 span 创建。
+//!
+//! 集中管理 trace_id 的生成和 span 字段命名，避免散落在各模块。
+//! 业务代码调用此模块的辅助函数，不直接拼 span 字段。
+
+use tracing::Instrument;
+
+use std::future::Future;
+
+/// 生成新的 trace_id（UUID v4）。
+pub fn new_trace_id() -> String {
+    uuid::Uuid::new_v4().to_string()
+}
+
+/// 在携带 trace_id/chat_id/session_id 的 span 内执行 future。
+///
+/// 用于 `tokio::spawn` 边界：spawn 不自动传播父 span，
+/// 调用此函数在 spawn 的 async block 内重建 span 上下文。
+///
+/// # 示例
+/// ```ignore
+/// tokio::spawn(
+///     traced(&trace_id, &chat_id, &session_id, async move {
+///         // 此处所有 tracing 日志自动携带 trace_id/chat_id/session_id
+///         process_one(inbound).await
+///     })
+/// );
+/// ```
+pub fn traced<F>(trace_id: &str, chat_id: &str, session_id: &str, f: F) -> Instrumented<F>
+where
+    F: Future,
+{
+    let span = tracing::info_span!(
+        "request",
+        trace_id = %trace_id,
+        chat_id = %chat_id,
+        session_id = %session_id
+    );
+    f.instrument(span)
+}
+
+/// tracing::Instrumented 的重新导出，便于调用方使用。
+pub type Instrumented<F> = tracing::instrument::Instrumented<F>;
diff --git a/src/providers/anthropic.rs b/src/providers/anthropic.rs
index 518a523..6a47003 100644
--- a/src/providers/anthropic.rs
+++ b/src/providers/anthropic.rs
@@ -252,6 +252,7 @@ struct AnthropicUsage {
 
 #[async_trait]
 impl LLMProvider for AnthropicProvider {
+    #[tracing::instrument(skip(self, request), fields(provider = %self.name, model = %self.model_id))]
     async fn chat(
         &self,
         request: ChatCompletionRequest,
@@ -259,6 +260,14 @@ impl LLMProvider for AnthropicProvider {
         let url = format!("{}/v1/messages", self.base_url);
         let max_tokens = request.max_tokens.or(self.max_tokens).unwrap_or(1024);
 
+        tracing::info!(
+            provider = %self.name,
+            model = %self.model_id,
+            message_count = request.messages.len(),
+            has_tools = request.tools.is_some(),
+            "Anthropic: sending chat completion request"
+        );
+
         let tools = request.tools.map(|tools| {
             tools
                 .iter()
@@ -304,7 +313,16 @@ impl LLMProvider for AnthropicProvider {
             req_builder = req_builder.header(key.as_str(), value.as_str());
         }
 
-        let resp = req_builder.json(&body).send().await?;
+        let resp = req_builder.json(&body).send().await.map_err(|e| {
+            tracing::error!(
+                provider = %self.name,
+                model = %self.model_id,
+                url = %url,
+                error = %format_error_chain(&e),
+                "Anthropic: HTTP request failed"
+            );
+            e
+        })?;
         let status = resp.status();
         let text = resp.text().await?;
 
@@ -321,11 +339,13 @@ impl LLMProvider for AnthropicProvider {
             return Err(format!("API error {}: {}", status, text).into());
         }
 
-        #[cfg(debug_assertions)]
-        {
-            let resp_preview: String = text.chars().take(100).collect();
-            tracing::debug!(status = %status, response_preview = %resp_preview, response_len = %text.len(), timeout_secs = self.llm_timeout_secs, "Anthropic response (first 100 chars shown)");
-        }
+        tracing::debug!(
+            provider = %self.name,
+            model = %self.model_id,
+            status = %status,
+            response_len = text.len(),
+            "Anthropic response received"
+        );
 
         let anthropic_resp: AnthropicResponse = serde_json::from_str(&text).map_err(|e| {
             tracing::error!(
@@ -364,18 +384,29 @@ impl LLMProvider for AnthropicProvider {
             }
         }
 
+        let usage = Usage {
+            prompt_tokens: anthropic_resp.usage.input_tokens,
+            completion_tokens: anthropic_resp.usage.output_tokens,
+            total_tokens: anthropic_resp.usage.input_tokens + anthropic_resp.usage.output_tokens,
+        };
+
+        tracing::info!(
+            provider = %self.name,
+            model = %self.model_id,
+            prompt_tokens = usage.prompt_tokens,
+            completion_tokens = usage.completion_tokens,
+            total_tokens = usage.total_tokens,
+            has_tool_calls = !tool_calls.is_empty(),
+            "Anthropic: chat completion completed"
+        );
+
         Ok(ChatCompletionResponse {
             id: anthropic_resp.id,
             model: anthropic_resp.model,
             content,
             reasoning_content: None,
             tool_calls,
-            usage: Usage {
-                prompt_tokens: anthropic_resp.usage.input_tokens,
-                completion_tokens: anthropic_resp.usage.output_tokens,
-                total_tokens: anthropic_resp.usage.input_tokens
-                    + anthropic_resp.usage.output_tokens,
-            },
+            usage,
         })
     }
 
diff --git a/src/tools/task/runtime.rs b/src/tools/task/runtime.rs
index c2ac449..72f46f0 100644
--- a/src/tools/task/runtime.rs
+++ b/src/tools/task/runtime.rs
@@ -115,12 +115,13 @@ struct SubAgentEmitter {
     /// 子/孙智能体自身的 task_id，用于持久化时作为 scope_key
     task_id: String,
     stream_message_id: parking_lot::Mutex<Option<String>>,
+    trace_id: Option<String>,
 }
 
 #[async_trait]
 impl EmittedMessageHandler for SubAgentEmitter {
     async fn handle(&self, message: ChatMessage) {
-        for outbound in OutboundMessage::from_chat_message(
+        for mut outbound in OutboundMessage::from_chat_message(
             &self.channel_name,
             &self.chat_id,
             None,
@@ -128,6 +129,9 @@ impl EmittedMessageHandler for SubAgentEmitter {
             &self.metadata,
             &message,
         ) {
+            if let Some(ref tid) = self.trace_id {
+                outbound.trace_id = tid.clone();
+            }
             if let Err(error) = self.bus.publish_outbound(outbound).await {
                 match error {
                     crate::bus::BusError::Dropped => {
@@ -146,7 +150,7 @@ impl EmittedMessageHandler for SubAgentEmitter {
         if let Some(ms) = duration_ms {
             metadata.insert("tool_duration_ms".to_string(), ms.to_string());
         }
-        for outbound in OutboundMessage::from_chat_message(
+        for mut outbound in OutboundMessage::from_chat_message(
             &self.channel_name,
             &self.chat_id,
             None,
@@ -154,6 +158,9 @@ impl EmittedMessageHandler for SubAgentEmitter {
             &metadata,
             &message,
         ) {
+            if let Some(ref tid) = self.trace_id {
+                outbound.trace_id = tid.clone();
+            }
             if let Err(error) = self.bus.publish_outbound(outbound).await {
                 match error {
                     crate::bus::BusError::Dropped => {
@@ -180,7 +187,7 @@ impl EmittedMessageHandler for SubAgentEmitter {
                 .clone()
         };
 
-        let outbound = if delta.content.is_empty() && delta.reasoning_content.is_none() {
+        let mut outbound = if delta.content.is_empty() && delta.reasoning_content.is_none() {
             OutboundMessage::stream_end(
                 &self.channel_name,
                 &self.chat_id,
@@ -199,6 +206,9 @@ impl EmittedMessageHandler for SubAgentEmitter {
                 self.metadata.clone(),
             )
         };
+        if let Some(ref tid) = self.trace_id {
+            outbound.trace_id = tid.clone();
+        }
 
         if let Err(error) = self.bus.publish_outbound(outbound).await {
             match error {
@@ -306,16 +316,23 @@ fn build_subagent_event_metadata(session: &TaskSession) -> HashMap<String, Strin
 }
 
 /// 发布子智能体执行完成事件（ExecutionCompleted），metadata 含 subagent_task_id。
-async fn publish_subagent_completion(bus: &Option<Arc<MessageBus>>, session: &TaskSession) {
+async fn publish_subagent_completion(
+    bus: &Option<Arc<MessageBus>>,
+    session: &TaskSession,
+    trace_id: &str,
+) {
     if let Some(bus) = bus {
         let metadata = build_subagent_event_metadata(session);
         if let Err(e) = bus
-            .publish_outbound(OutboundMessage::execution_completed(
-                session.parent_channel_name.clone(),
-                session.parent_chat_id.clone(),
-                Some(session.parent_session_id.clone()),
-                metadata,
-            ))
+            .publish_outbound(
+                OutboundMessage::execution_completed(
+                    session.parent_channel_name.clone(),
+                    session.parent_chat_id.clone(),
+                    Some(session.parent_session_id.clone()),
+                    metadata,
+                )
+                .with_trace_id(trace_id),
+            )
             .await
         {
             tracing::warn!(error = %e, task_id = %session.id, "Failed to publish subagent execution_completed");
@@ -328,18 +345,22 @@ async fn publish_subagent_error(
     bus: &Option<Arc<MessageBus>>,
     session: &TaskSession,
     error_msg: &str,
+    trace_id: &str,
 ) {
     if let Some(bus) = bus {
         let metadata = build_subagent_event_metadata(session);
         if let Err(e) = bus
-            .publish_outbound(OutboundMessage::error_notification(
-                session.parent_channel_name.clone(),
-                session.parent_chat_id.clone(),
-                Some(session.parent_session_id.clone()),
-                error_msg.to_string(),
-                None,
-                metadata,
-            ))
+            .publish_outbound(
+                OutboundMessage::error_notification(
+                    session.parent_channel_name.clone(),
+                    session.parent_chat_id.clone(),
+                    Some(session.parent_session_id.clone()),
+                    error_msg.to_string(),
+                    None,
+                    metadata,
+                )
+                .with_trace_id(trace_id),
+            )
             .await
         {
             tracing::warn!(error = %e, task_id = %session.id, "Failed to publish subagent error notification");
@@ -480,6 +501,7 @@ impl DefaultSubAgentRuntime {
         def: Option<&SubagentDef>,
         parent_nesting_depth: u32,
         parent_task_id: Option<String>,
+        trace_id: Option<String>,
     ) -> Result<AgentLoop, TaskError> {
         let prompt_provider = Arc::new(StaticSystemPromptProvider::new(system_prompt));
 
@@ -529,6 +551,8 @@ impl DefaultSubAgentRuntime {
                 // 子代理自身的 capability 作为孙代理的 parent_capability，
                 // 使孙代理的 TaskTool 能按此策略校验（与主 agent 注入专家 capability 同构）
                 parent_capability: def.map(|d| d.capability.clone()),
+                // 从父 ToolContext 继承 trace_id，保持端到端追踪贯通子代理
+                trace_id: trace_id.clone(),
             });
 
             // 如果有 MessageBus，附加实时广播 emitter
@@ -550,6 +574,7 @@ impl DefaultSubAgentRuntime {
                         store: self.store.clone(),
                         task_id: session.id.clone(),
                         stream_message_id: parking_lot::Mutex::new(None),
+                        trace_id: trace_id.clone(),
                     },
                     self.conversation_repository.clone(),
                     session.session_id.clone(),
@@ -658,6 +683,7 @@ impl DefaultSubAgentRuntime {
         &self,
         session: TaskSession,
         error: TaskError,
+        trace_id: &str,
     ) -> Result<TaskToolResult, TaskError> {
         let status = error.as_status();
         tracing::warn!(
@@ -674,7 +700,7 @@ impl DefaultSubAgentRuntime {
             session.mark_failed(error.to_string());
         }
         self.task_repository.save_task_session(&session).await?;
-        publish_subagent_error(&self.bus, &session, &error.to_string()).await;
+        publish_subagent_error(&self.bus, &session, &error.to_string(), trace_id).await;
         Ok(TaskToolResult {
             status: status.to_string(),
             summary: error.to_string(),
@@ -791,6 +817,7 @@ impl SubAgentRuntime for DefaultSubAgentRuntime {
                 tool_arguments: None,
                 reasoning_content: None,
                 message_id: None,
+                trace_id: parent_context.trace_id.clone().unwrap_or_default(),
             };
 
             if let Err(e) = bus.publish_outbound(event).await {
@@ -844,6 +871,7 @@ impl SubAgentRuntime for DefaultSubAgentRuntime {
                 Some(&def),
                 parent_context.nesting_depth,
                 parent_context.task_id.clone(),
+                parent_context.trace_id.clone(),
             )?;
 
             // 8. 执行任务
@@ -852,6 +880,7 @@ impl SubAgentRuntime for DefaultSubAgentRuntime {
         };
 
         // 9. 更新会话状态并保存
+        let trace_id = parent_context.trace_id.as_deref().unwrap_or("");
         match result {
             Ok(tool_result) => {
                 let mut session = session;
@@ -863,13 +892,13 @@ impl SubAgentRuntime for DefaultSubAgentRuntime {
                 );
                 self.task_repository.save_task_session(&session).await?;
                 // 发布子智能体 ExecutionCompleted，metadata 注入 subagent_task_id 供前端路由到对应子智能体层
-                publish_subagent_completion(&self.bus, &session).await;
+                publish_subagent_completion(&self.bus, &session, trace_id).await;
                 Ok(tool_result)
             }
             Err(e) => {
                 // 会话创建后的任何失败（含 AgentCreationFailed、Timeout、ExecutionFailed）
                 // 统一返回结构化结果，携带 task_id 供前端导航
-                self.handle_task_failure(session, e).await
+                self.handle_task_failure(session, e, trace_id).await
             }
         }
     }
@@ -939,24 +968,26 @@ impl SubAgentRuntime for DefaultSubAgentRuntime {
                 Some(&def),
                 parent_context.nesting_depth,
                 parent_context.task_id.clone(),
+                parent_context.trace_id.clone(),
             )?;
             self.execute_task_with_history(agent, &session, additional_prompt)
                 .await
         };
 
         // 7. 更新会话状态
+        let trace_id = parent_context.trace_id.as_deref().unwrap_or("");
         match result {
             Ok(tool_result) => {
                 let mut session = session;
                 session.mark_completed(tool_result.summary.clone());
                 self.task_repository.save_task_session(&session).await?;
                 // 发布子智能体 ExecutionCompleted，metadata 注入 subagent_task_id 供前端路由到对应子智能体层
-                publish_subagent_completion(&self.bus, &session).await;
+                publish_subagent_completion(&self.bus, &session, trace_id).await;
                 Ok(tool_result)
             }
             Err(e) => {
                 // 修复：原代码一律 mark_failed，未处理 timeout；现统一走 handle_task_failure
-                self.handle_task_failure(session, e).await
+                self.handle_task_failure(session, e, trace_id).await
             }
         }
     }
diff --git a/src/tools/todo_read.rs b/src/tools/todo_read.rs
index 7b44f6e..6892dbb 100644
--- a/src/tools/todo_read.rs
+++ b/src/tools/todo_read.rs
@@ -184,6 +184,7 @@ mod tests {
             parent_task_id: None,
             tool_call_id: None,
             parent_capability: None,
+            trace_id: None,
         }
     }
 
diff --git a/src/tools/todo_write.rs b/src/tools/todo_write.rs
index 9c17c47..25d6f70 100644
--- a/src/tools/todo_write.rs
+++ b/src/tools/todo_write.rs
@@ -486,6 +486,7 @@ mod tests {
             parent_task_id: None,
             tool_call_id: None,
             parent_capability: None,
+            trace_id: None,
         }
     }
 
diff --git a/src/tools/traits.rs b/src/tools/traits.rs
index dc90b80..630f6df 100644
--- a/src/tools/traits.rs
+++ b/src/tools/traits.rs
@@ -32,6 +32,9 @@ pub struct ToolContext {
     /// TaskTool 据此强制校验子代理加载（白/黑名单），与 spawn/resume 安全范式一致。
     /// 以数据形式传递，避免 task 模块反向依赖 experts 模块。
     pub parent_capability: Option<CapabilityPolicy>,
+    /// 端到端追踪 ID（从 InboundMessage 继承，用于 tool 执行路径的日志关联）。
+    /// None 表示无追踪上下文（如子代理独立执行或测试环境）。
+    pub trace_id: Option<String>,
 }
 
 #[async_trait]