diff --git a/internal/server/sse.go b/internal/server/sse.go
index fb167e8f..5804aa77 100644
--- a/internal/server/sse.go
+++ b/internal/server/sse.go
@@ -9,9 +9,18 @@ import (
 	"time"
 
 	"chat-agent-system/internal/bizdev"
+	"chat-agent-system/internal/squad"
 	"chat-agent-system/internal/stream"
 )
 
+// taskStreamRequest 任务/阶段流式运行请求：在 handlers.go 的 TaskRunRequestDTO 基础上
+// 增量扩展 resume 能力（work_dir 非空 → 续跑既有工作区），不改动既有 DTO 定义（向后兼容）。
+type taskStreamRequest struct {
+	TaskRunRequestDTO
+	WorkDir  string           `json:"work_dir,omitempty"`
+	AddSteps []squad.StepSpec `json:"add_steps,omitempty"`
+}
+
 // StreamChatRequest SSE流式请求参数
 type StreamChatRequest struct {
 	SessionID      string `json:"session_id"`
@@ -136,7 +145,7 @@ func (s *Server) handleRunTaskStream(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	var req TaskRunRequestDTO
+	var req taskStreamRequest
 	includeDetails := false
 	if r.Method == http.MethodPost {
 		_ = json.NewDecoder(r.Body).Decode(&req)
@@ -150,22 +159,33 @@ func (s *Server) handleRunTaskStream(w http.ResponseWriter, r *http.Request) {
 		req.IntendedUse = q.Get("intended_use")
 		req.TargetMarket = q.Get("target_market")
 		req.Backend = q.Get("backend")
+		req.WorkDir = q.Get("work_dir")
 		req.AutoRepair, _ = strconv.ParseBool(q.Get("auto_repair"))
 		if inc := q.Get("include_details"); inc != "" {
 			includeDetails, _ = strconv.ParseBool(inc)
 		}
 	}
 
+	// 请求追踪 ID：与 chat stream 对齐，注入 ctx 并回写响应头
+	requestID := fmt.Sprintf("req_%d", time.Now().UnixNano())
+	w.Header().Set("X-Request-Id", requestID)
 	w.Header().Set("Content-Type", "text/event-stream")
 	w.Header().Set("Cache-Control", "no-cache")
 	w.Header().Set("Connection", "keep-alive")
 	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("X-Accel-Buffering", "no") // 禁用 Nginx 等反代缓冲
 	flusher.Flush()
 
 	var writeMu sync.Mutex
+	// lastPhaseID 记录最近一次 phase 事件，失败时用于 error_info.phase_id。
+	// Streamer.Emit 为同步分发，listener 与后续读取同处 handler goroutine。
+	lastPhaseID := ""
 	listener := func(ev stream.StreamEvent) {
 		writeMu.Lock()
 		defer writeMu.Unlock()
+		if ev.Type == stream.EventPhase && ev.Phase != nil && ev.Phase.PhaseID != "" {
+			lastPhaseID = ev.Phase.PhaseID
+		}
 		data, err := json.Marshal(ev)
 		if err != nil {
 			return
@@ -174,11 +194,40 @@ func (s *Server) handleRunTaskStream(w http.ResponseWriter, r *http.Request) {
 		flusher.Flush()
 	}
 
-	ctxWithS, streamer := stream.WithListener(r.Context(), includeDetails, listener)
+	// 分类失败并发射结构化错误：phaseID 为空时回落到流中最近一次 phase
+	ctxWithS, streamer := stream.WithListener(stream.WithRequestID(r.Context(), requestID), includeDetails, listener)
+	classifyAndEmitError := func(err error, phaseID, workspaceID string) {
+		if phaseID == "" {
+			writeMu.Lock()
+			phaseID = lastPhaseID
+			writeMu.Unlock()
+		}
+		streamer.EmitErrorInfo(stream.ClassifyError(err, phaseID, requestID, "", workspaceID))
+	}
 	start := time.Now()
 
+	// resume 模式：work_dir 非空时续跑既有工作区（P2：「继续任务」后端入口），优先于 stage/task 新任务
+	if req.WorkDir != "" {
+		res, err := s.svc.ResumeOrModifyWorkspace(ctxWithS, squad.ModifyWorkflowRequest{
+			WorkDir:    req.WorkDir,
+			AddSteps:   req.AddSteps,
+			Backend:    req.Backend,
+			AutoRepair: req.AutoRepair,
+		})
+		if err != nil {
+			wsID := req.WorkDir
+			if res != nil && res.WorkDir != "" {
+				wsID = res.WorkDir
+			}
+			classifyAndEmitError(err, "task_resume", wsID)
+		} else {
+			streamer.EmitDoneWithWorkspace("task_resume", req.WorkDir, time.Since(start))
+		}
+		return
+	}
+
 	if req.Stage != "" {
-		_, err := s.svc.ExecuteStage(ctxWithS, bizdev.StageRunRequest{
+		res, err := s.svc.ExecuteStage(ctxWithS, bizdev.StageRunRequest{
 			Stage:           bizdev.MaturityStage(req.Stage),
 			ProjectName:     req.ProjectName,
 			CustomerName:    req.CustomerName,
@@ -200,9 +249,17 @@ func (s *Server) handleRunTaskStream(w http.ResponseWriter, r *http.Request) {
 			ForceDirectEdit: req.ForceDirectEdit,
 		})
 		if err != nil {
-			streamer.EmitError(err)
+			wsID := ""
+			if res != nil && res.WorkDir != "" {
+				wsID = res.WorkDir
+			}
+			classifyAndEmitError(err, "stage_run", wsID)
 		} else {
-			streamer.EmitDone("stage_run", time.Since(start))
+			wsID := ""
+			if res != nil {
+				wsID = res.WorkDir
+			}
+			streamer.EmitDoneWithWorkspace("stage_run", wsID, time.Since(start))
 		}
 		return
 	}
@@ -211,7 +268,7 @@ func (s *Server) handleRunTaskStream(w http.ResponseWriter, r *http.Request) {
 		req.TaskKey = "intake"
 	}
 
-	_, err := s.svc.ExecuteTask(ctxWithS, bizdev.TaskRunRequest{
+	res, err := s.svc.ExecuteTask(ctxWithS, bizdev.TaskRunRequest{
 		TaskKey:         req.TaskKey,
 		ProjectName:     req.ProjectName,
 		CustomerName:    req.CustomerName,
@@ -233,8 +290,18 @@ func (s *Server) handleRunTaskStream(w http.ResponseWriter, r *http.Request) {
 		ForceDirectEdit: req.ForceDirectEdit,
 	})
 	if err != nil {
-		streamer.EmitError(err)
+		// 软失败（执行器返回带 WorkDir 的 result，如 docgov 锁定 / squad 层任务中断）→ resumable；
+		// 硬失败（工作区未建立）→ workspaceID 为空，按超时/网络/默认规则分类
+		wsID := ""
+		if res != nil && res.WorkDir != "" {
+			wsID = res.WorkDir
+		}
+		classifyAndEmitError(err, "", wsID)
 	} else {
-		streamer.EmitDone("task_run", time.Since(start))
+		wsID := ""
+		if res != nil {
+			wsID = res.WorkDir
+		}
+		streamer.EmitDoneWithWorkspace("task_run", wsID, time.Since(start))
 	}
 }
diff --git a/internal/stream/stream.go b/internal/stream/stream.go
index cd956d95..a9c495de 100644
--- a/internal/stream/stream.go
+++ b/internal/stream/stream.go
@@ -226,6 +226,22 @@ func (s *Streamer) EmitDone(sessionID string, duration time.Duration) {
 	})
 }
 
+// EmitDoneWithWorkspace 发送流结束事件并携带任务工作区目录（P2：供前端「继续任务」续跑）
+func (s *Streamer) EmitDoneWithWorkspace(sessionID, workspaceID string, duration time.Duration) {
+	if s == nil {
+		return
+	}
+	s.Emit(StreamEvent{
+		Type: EventDone,
+		Done: &DonePayload{
+			SessionID:   sessionID,
+			WorkspaceID: workspaceID,
+			DurationMs:  duration.Milliseconds(),
+			TotalEvents: int(atomic.LoadInt64(&s.eventCount)),
+		},
+	})
+}
+
 // EventCount 获取已发射事件总数
 func (s *Streamer) EventCount() int {
 	if s == nil {
diff --git a/internal/stream/stream_test.go b/internal/stream/stream_test.go
index f3c8fd1c..134a30d3 100644
--- a/internal/stream/stream_test.go
+++ b/internal/stream/stream_test.go
@@ -2,7 +2,9 @@ package stream
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -165,3 +167,36 @@ func TestStreamer_Concurrency(t *testing.T) {
 		t.Fatalf("expected %d events, got %d", expected, total)
 	}
 }
+
+func TestStreamer_EmitDoneWithWorkspace(t *testing.T) {
+	var received StreamEvent
+
+	streamer := NewStreamer(true, func(ev StreamEvent) {
+		received = ev
+	})
+
+	streamer.EmitDoneWithWorkspace("task_run", "/tmp/ws-demo", 1200*time.Millisecond)
+
+	if received.Type != EventDone {
+		t.Fatalf("type=%s", received.Type)
+	}
+	if received.Done == nil {
+		t.Fatal("Done payload is nil")
+	}
+	if received.Done.WorkspaceID != "/tmp/ws-demo" {
+		t.Fatalf("WorkspaceID=%q want %q", received.Done.WorkspaceID, "/tmp/ws-demo")
+	}
+	if received.Done.DurationMs != 1200 {
+		t.Fatalf("DurationMs=%d want 1200", received.Done.DurationMs)
+	}
+
+	// workspace_id 为空时 omitempty 不应出现在 JSON 中
+	streamer.EmitDone("task_run", 100*time.Millisecond)
+	data, err := json.Marshal(received)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	if strings.Contains(string(data), "workspace_id") {
+		t.Fatalf("expected workspace_id omitted, got %s", data)
+	}
+}
diff --git a/internal/stream/types.go b/internal/stream/types.go
index 8b924556..e1894088 100644
--- a/internal/stream/types.go
+++ b/internal/stream/types.go
@@ -87,6 +87,7 @@ type DonePayload struct {
 	SessionID   string `json:"session_id,omitempty"`
 	DurationMs  int64  `json:"duration_ms"`
 	TotalEvents int    `json:"total_events"`
+	WorkspaceID string `json:"workspace_id,omitempty"` // P2: 任务工作区目录（供前端「继续任务」续跑）
 }
 
 type ErrorClass string