diff --git a/src/routes/chat.ts b/src/routes/chat.ts
index 08164ae..74cb94e 100644
--- a/src/routes/chat.ts
+++ b/src/routes/chat.ts
@@ -53,10 +53,139 @@ const sessionStateSchema = z.object({
   branch_groups: z.array(z.unknown()).default([]),
 });
 
+type RunStatus = "running" | "completed" | "error" | "aborted";
+
+type StreamSubscriber = {
+  write: (event: string, data: Record<string, unknown>) => void;
+  close: () => void;
+};
+
+type ActiveRun = {
+  clientSessionId: string;
+  controller: AbortController;
+  messages: unknown[];
+  status: RunStatus;
+  subscribers: Set<StreamSubscriber>;
+};
+
+const activeRuns = new Map<string, ActiveRun>();
+const lastRunStatuses = new Map<string, RunStatus>();
+
 const toSessionUiStateContext = (sessionRecord: SessionRecord) => ({
   sessionId: sessionRecord.sessionId,
 });
 
+const getSessionRunStatus = (sessionId: string) =>
+  activeRuns.get(sessionId)?.status ?? lastRunStatuses.get(sessionId);
+
+const isObjectRecord = (value: unknown): value is Record<string, unknown> =>
+  typeof value === "object" && value !== null && !Array.isArray(value);
+
+const createFrontendMessageId = () =>
+  `msg-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 8)}`;
+
+const createInitialStreamingMessages = (existingMessages: unknown[], userContent: string) => {
+  const userMessage = {
+    id: createFrontendMessageId(),
+    role: "user",
+    content: userContent,
+  };
+  return [
+    ...existingMessages,
+    {
+      ...userMessage,
+      branchRootId: userMessage.id,
+    },
+    {
+      id: createFrontendMessageId(),
+      role: "assistant",
+      content: "",
+      progress: [
+        {
+          id: "request-received",
+          phase: "start",
+          status: "running",
+          title: "已收到请求，正在启动 Agent 分析",
+          detail: "已接收用户消息，正在建立会话并准备进入分析、规划和工具调用阶段。",
+          startedAt: Date.now(),
+          elapsedMs: 0,
+          elapsedSnapshotAt: Date.now(),
+        },
+      ],
+    },
+  ];
+};
+
+const upsertBackendProgress = (
+  progress: unknown,
+  payload: Record<string, unknown>,
+) => {
+  const next = Array.isArray(progress) ? [...progress] : [];
+  const id = typeof payload.id === "string" ? payload.id : `progress-${Date.now()}`;
+  const index = next.findIndex((item) => isObjectRecord(item) && item.id === id);
+  const nextItem = {
+    id,
+    phase: typeof payload.phase === "string" ? payload.phase : "progress",
+    status:
+      payload.status === "completed" || payload.status === "error"
+        ? payload.status
+        : "running",
+    title: typeof payload.title === "string" ? payload.title : "正在处理",
+    detail: typeof payload.detail === "string" ? payload.detail : undefined,
+    startedAt: typeof payload.started_at === "number" ? payload.started_at : undefined,
+    endedAt: typeof payload.ended_at === "number" ? payload.ended_at : undefined,
+    elapsedMs: typeof payload.elapsed_ms === "number" ? payload.elapsed_ms : undefined,
+    elapsedSnapshotAt:
+      typeof payload.elapsed_ms === "number" ? Date.now() : undefined,
+    durationMs: typeof payload.duration_ms === "number" ? payload.duration_ms : undefined,
+  };
+  if (index >= 0) {
+    next[index] = nextItem;
+  } else {
+    next.push(nextItem);
+  }
+  return next;
+};
+
+const completeBackendProgress = (progress: unknown) =>
+  Array.isArray(progress)
+    ? progress.map((item) => {
+        if (!isObjectRecord(item) || item.status !== "running") {
+          return item;
+        }
+        const endedAt = Date.now();
+        const startedAt = typeof item.startedAt === "number" ? item.startedAt : undefined;
+        return {
+          ...item,
+          status: "completed",
+          endedAt,
+          elapsedMs: undefined,
+          elapsedSnapshotAt: undefined,
+          durationMs:
+            typeof item.durationMs === "number"
+              ? item.durationMs
+              : startedAt !== undefined
+                ? Math.max(0, endedAt - startedAt)
+                : item.elapsedMs,
+        };
+      })
+    : progress;
+
+const updateLastAssistantMessage = (
+  messages: unknown[],
+  updater: (message: Record<string, unknown>) => Record<string, unknown>,
+) => {
+  for (let index = messages.length - 1; index >= 0; index -= 1) {
+    const message = messages[index];
+    if (isObjectRecord(message) && message.role === "assistant") {
+      const next = [...messages];
+      next[index] = updater(message);
+      return next;
+    }
+  }
+  return messages;
+};
+
 export const buildChatRouter = (
   sessionBridge: ChatSessionBridge,
   runtime: OpencodeRuntimeAdapter,
@@ -124,6 +253,8 @@ export const buildChatRouter = (
         updated_at: record.updatedAt,
         status: record.status,
         parent_session_id: record.parentSessionId,
+        is_streaming: activeRuns.get(record.sessionId)?.status === "running",
+        run_status: getSessionRunStatus(record.sessionId),
       })),
     });
   });
@@ -167,9 +298,75 @@ export const buildChatRouter = (
       messages: state?.messages ?? [],
       branch_groups: state?.branchGroups ?? [],
       parent_session_id: sessionRecord.parentSessionId,
+      is_streaming: activeRuns.get(sessionRecord.sessionId)?.status === "running",
+      run_status: getSessionRunStatus(sessionRecord.sessionId),
     });
   });
 
+  chatRouter.get("/session/:sessionId/stream", async (req, res) => {
+    const sessionId = req.params.sessionId?.trim();
+    const projectId = req.header("x-project-id") ?? undefined;
+    const userId = req.header("x-user-id") ?? undefined;
+    const actorKey = toActorKey(userId);
+    const projectKey = toProjectKey(projectId);
+    if (!sessionId) {
+      res.status(400).json({ message: "session_id is required" });
+      return;
+    }
+
+    const sessionRecord = await sessionMetadataStore.get(
+      { actorKey, projectId, projectKey, userId },
+      sessionId,
+    );
+    if (!sessionRecord) {
+      res.status(404).json({ message: "session not found" });
+      return;
+    }
+
+    res.status(200);
+    res.setHeader("Content-Type", "text/event-stream; charset=utf-8");
+    res.setHeader("Cache-Control", "no-cache");
+    res.setHeader("Connection", "keep-alive");
+    res.setHeader("X-Accel-Buffering", "no");
+    res.flushHeaders?.();
+
+    const run = activeRuns.get(sessionRecord.sessionId);
+    const state = await sessionUiStateStore.read(toSessionUiStateContext(sessionRecord));
+    res.write(
+      toSse("state", {
+        session_id: sessionRecord.sessionId,
+        messages: state?.messages ?? run?.messages ?? [],
+        is_streaming: run?.status === "running",
+        run_status: getSessionRunStatus(sessionRecord.sessionId) ?? "completed",
+      }),
+    );
+
+    if (!run || run.status !== "running") {
+      res.end();
+      return;
+    }
+
+    const subscriber: StreamSubscriber = {
+      write: (event, data) => {
+        if (!res.writableEnded && !res.destroyed) {
+          res.write(toSse(event, data));
+        }
+      },
+      close: () => {
+        if (!res.writableEnded && !res.destroyed) {
+          res.end();
+        }
+      },
+    };
+    run.subscribers.add(subscriber);
+
+    const cleanup = () => {
+      run.subscribers.delete(subscriber);
+    };
+    req.on("close", cleanup);
+    res.on("close", cleanup);
+  });
+
   chatRouter.put("/session/:sessionId", async (req, res) => {
     const sessionId = req.params.sessionId?.trim();
     const parsed = sessionStateSchema.safeParse(req.body ?? {});
@@ -304,6 +501,8 @@ export const buildChatRouter = (
       clientSessionId: sessionRecord.sessionId,
       sessionId: sessionRecord.sessionId,
     });
+    activeRuns.delete(sessionRecord.sessionId);
+    lastRunStatuses.delete(sessionRecord.sessionId);
     await sessionMetadataStore.remove(sessionRecord);
     res.status(204).end();
   });
@@ -376,8 +575,42 @@ export const buildChatRouter = (
             sessionId: sessionRecord.sessionId,
           })
         : null;
+      const run = activeRuns.get(parsed.data.session_id);
+      if (run && run.status === "running") {
+        run.status = "aborted";
+        lastRunStatuses.set(parsed.data.session_id, "aborted");
+        run.controller.abort();
+        run.messages = updateLastAssistantMessage(run.messages, (message) => ({
+          ...message,
+          content:
+            typeof message.content === "string" && message.content.trim()
+              ? message.content
+              : "⚠️ **请求已中断**",
+          isError: true,
+          progress: completeBackendProgress(message.progress),
+        }));
+        if (sessionRecord) {
+          const currentState = await sessionUiStateStore.read(
+            toSessionUiStateContext(sessionRecord),
+          );
+          await sessionUiStateStore.write(toSessionUiStateContext(sessionRecord), {
+            sessionId: sessionRecord.sessionId,
+            isTitleManuallyEdited: currentState?.isTitleManuallyEdited ?? false,
+            messages: run.messages,
+            branchGroups: currentState?.branchGroups ?? [],
+          });
+        }
+        for (const subscriber of run.subscribers) {
+          subscriber.write("error", {
+            session_id: parsed.data.session_id,
+            message: "请求已中断",
+          });
+          subscriber.close();
+        }
+        run.subscribers.clear();
+      }
 
-      if (!binding) {
+      if (!binding && !run) {
         res.status(204).end();
         return;
       }
@@ -385,7 +618,7 @@ export const buildChatRouter = (
       logger.info(
         {
           clientSessionId: parsed.data.session_id,
-          sessionId: binding.sessionId,
+          sessionId: binding?.sessionId ?? parsed.data.session_id,
         },
         "aborted chat session by client request",
       );
@@ -545,6 +778,13 @@ export const buildChatRouter = (
       const initialSessionState = await sessionUiStateStore.read(
         toSessionUiStateContext(activeSessionRecord),
       );
+      if (activeRuns.get(activeSessionRecord.sessionId)?.status === "running") {
+        res.status(409).json({
+          message: "session is already streaming",
+          session_id: activeSessionRecord.sessionId,
+        });
+        return;
+      }
 
       logger.info(
         {
@@ -569,16 +809,95 @@ export const buildChatRouter = (
       let streamClosed = false;
       const abortController = new AbortController();
       sessionBridge.registerAbortController(clientSessionId, abortController);
+      const initialMessages = createInitialStreamingMessages(
+        initialSessionState?.messages ?? [],
+        parsed.data.message,
+      );
+      const branchGroups = initialSessionState?.branchGroups ?? [];
+      const activeRun: ActiveRun = {
+        clientSessionId,
+        controller: abortController,
+        messages: initialMessages,
+        status: "running",
+        subscribers: new Set(),
+      };
+      activeRuns.set(clientSessionId, activeRun);
+      lastRunStatuses.set(clientSessionId, "running");
+      await sessionUiStateStore.write(toSessionUiStateContext(activeSessionRecord), {
+        sessionId: activeSessionRecord.sessionId,
+        isTitleManuallyEdited: initialSessionState?.isTitleManuallyEdited ?? false,
+        messages: initialMessages,
+        branchGroups,
+      });
+      const primarySubscriber: StreamSubscriber = {
+        write: (event, data) => {
+          if (!streamClosed && !res.writableEnded && !res.destroyed) {
+            res.write(toSse(event, data));
+          }
+        },
+        close: () => {
+          if (!res.writableEnded && !res.destroyed) {
+            res.end();
+          }
+        },
+      };
+      activeRun.subscribers.add(primarySubscriber);
       const handleClientClose = () => {
-        if (streamClosed || abortController.signal.aborted) {
-          return;
-        }
-        abortController.abort();
+        streamClosed = true;
+        activeRun.subscribers.delete(primarySubscriber);
       };
 
       req.on("close", handleClientClose);
       res.on("close", handleClientClose);
 
+      const publish = async (event: string, data: Record<string, unknown>) => {
+        if (event === "token") {
+          activeRun.messages = updateLastAssistantMessage(activeRun.messages, (message) => ({
+            ...message,
+            content: `${typeof message.content === "string" ? message.content : ""}${typeof data.content === "string" ? data.content : ""}`,
+            isError: false,
+          }));
+        } else if (event === "progress") {
+          activeRun.messages = updateLastAssistantMessage(activeRun.messages, (message) => ({
+            ...message,
+            progress: upsertBackendProgress(message.progress, data),
+          }));
+        } else if (event === "done") {
+          activeRun.status = "completed";
+          lastRunStatuses.set(clientSessionId, "completed");
+          activeRun.messages = updateLastAssistantMessage(activeRun.messages, (message) => ({
+            ...message,
+            content:
+              typeof message.content === "string" && message.content.trim()
+                ? message.content
+                : "Agent 已完成处理，但没有生成文本回答。请查看过程记录，或换个更具体的问题重试。",
+            progress: completeBackendProgress(message.progress),
+          }));
+        } else if (event === "error") {
+          activeRun.status = activeRun.status === "aborted" ? "aborted" : "error";
+          lastRunStatuses.set(clientSessionId, activeRun.status);
+          activeRun.messages = updateLastAssistantMessage(activeRun.messages, (message) => ({
+            ...message,
+            content:
+              typeof message.content === "string" && message.content.trim()
+                ? message.content
+                : `⚠️ **错误：** ${typeof data.message === "string" ? data.message : "unknown error"}`,
+            isError: true,
+            progress: completeBackendProgress(message.progress),
+          }));
+        }
+
+        await sessionUiStateStore.write(toSessionUiStateContext(activeSessionRecord), {
+          sessionId: activeSessionRecord.sessionId,
+          isTitleManuallyEdited: initialSessionState?.isTitleManuallyEdited ?? false,
+          messages: activeRun.messages,
+          branchGroups,
+        });
+        for (const subscriber of activeRun.subscribers) {
+          subscriber.write(event, data);
+        }
+      };
+
       try {
         const preparedMessage = await buildPromptWithLearningContext(
           memoryStore,
@@ -601,10 +920,9 @@ export const buildChatRouter = (
           projectId: requestContext.projectId,
           signal: abortController.signal,
           write: (event, data) => {
-            if (streamClosed || res.writableEnded || res.destroyed) {
-              return;
-            }
-            res.write(toSse(event, data));
+            void publish(event, data).catch((error) => {
+              logger.warn({ err: error, sessionId: clientSessionId }, "failed to publish chat stream event");
+            });
           },
         });
 
@@ -642,23 +960,32 @@ export const buildChatRouter = (
               ? { title: sessionTitle }
               : {}),
           });
-          if (!streamClosed && !res.writableEnded && !res.destroyed) {
-            if (
-              shouldGenerateTitle &&
-              sessionTitle &&
-              sessionTitle !== existingSessionTitle
-            ) {
-              res.write(
-                toSse("session_title", {
-                  session_id: clientSessionId,
-                  title: sessionTitle,
-                }),
-              );
-            }
+          if (
+            shouldGenerateTitle &&
+            sessionTitle &&
+            sessionTitle !== existingSessionTitle
+          ) {
+            await publish("session_title", {
+              session_id: clientSessionId,
+              title: sessionTitle,
+            });
           }
         }
       } finally {
         sessionBridge.finalizeRequest(clientSessionId);
+        activeRun.status = abortController.signal.aborted
+          ? activeRun.status === "aborted"
+            ? "aborted"
+            : "aborted"
+          : activeRun.status === "running"
+            ? "completed"
+            : activeRun.status;
+        lastRunStatuses.set(clientSessionId, activeRun.status);
+        for (const subscriber of activeRun.subscribers) {
+          subscriber.close();
+        }
+        activeRun.subscribers.clear();
+        activeRuns.delete(clientSessionId);
         streamClosed = true;
         req.off("close", handleClientClose);
         res.off("close", handleClientClose);