feat(recovery): persist active_task_id to project.json for browser-refresh reconnection

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/api/graph.py

@@ -489,6 +489,7 @@ def build_graph():
         # Update project status
         project.status = ProjectStatus.GRAPH_BUILDING
         project.graph_build_task_id = task_id
+        project.active_task_id = task_id
         ProjectManager.save_project(project)
 
         # Capture locale before spawning background thread
@@ -592,6 +593,7 @@ def build_graph():
                 
                 # Update project status
                 project.status = ProjectStatus.GRAPH_COMPLETED
+                project.active_task_id = None
                 ProjectManager.save_project(project)
 
                 node_count = graph_data.get("node_count", 0)
@@ -620,6 +622,7 @@ def build_graph():
                 
                 project.status = ProjectStatus.FAILED
                 project.error = str(e)
+                project.active_task_id = None
                 ProjectManager.save_project(project)
                 
                 task_manager.update_task(

backend/app/models/project.py

@@ -52,6 +52,9 @@ class Project:
     # Error info
     error: Optional[str] = None
 
+    # Persisted so the frontend can reconnect after a page refresh
+    active_task_id: Optional[str] = None
+
     def to_dict(self) -> Dict[str, Any]:
         """Convert to dictionary"""
         return {
@@ -69,7 +72,8 @@ class Project:
             "simulation_requirement": self.simulation_requirement,
             "chunk_size": self.chunk_size,
             "chunk_overlap": self.chunk_overlap,
-            "error": self.error
+            "error": self.error,
+            "active_task_id": self.active_task_id,
         }
     
     @classmethod
@@ -94,7 +98,8 @@ class Project:
             simulation_requirement=data.get('simulation_requirement'),
             chunk_size=data.get('chunk_size', 500),
             chunk_overlap=data.get('chunk_overlap', 50),
-            error=data.get('error')
+            error=data.get('error'),
+            active_task_id=data.get('active_task_id'),
         )
 
 

backend/tests/test_project_task_recovery.py

@@ -0,0 +1,31 @@
+def test_project_serializes_active_task_id():
+    """active_task_id is included in Project.to_dict()."""
+    from app.models.project import Project, ProjectStatus
+    p = Project(
+        project_id="proj-1", name="Test",
+        status=ProjectStatus.GRAPH_BUILDING,
+        created_at="2026-01-01", updated_at="2026-01-01",
+        active_task_id="task-abc-123",
+    )
+    assert p.to_dict()["active_task_id"] == "task-abc-123"
+
+
+def test_project_deserializes_active_task_id():
+    """Project.from_dict() restores active_task_id from JSON."""
+    from app.models.project import Project
+    data = {
+        "project_id": "proj-1", "name": "Test", "status": "graph_building",
+        "created_at": "2026-01-01", "updated_at": "2026-01-01",
+        "active_task_id": "task-abc-123",
+    }
+    assert Project.from_dict(data).active_task_id == "task-abc-123"
+
+
+def test_project_active_task_id_defaults_none():
+    """active_task_id defaults to None for projects without it (backward compat)."""
+    from app.models.project import Project
+    data = {
+        "project_id": "proj-1", "name": "Test", "status": "created",
+        "created_at": "2026-01-01", "updated_at": "2026-01-01",
+    }
+    assert Project.from_dict(data).active_task_id is None

frontend/src/views/MainView.vue

@@ -257,10 +257,14 @@ const loadProject = async () => {
       
       if (res.data.status === 'ontology_generated' && !res.data.graph_id) {
         await startBuildGraph()
-      } else if (res.data.status === 'graph_building' && res.data.graph_build_task_id) {
-        currentPhase.value = 1
-        startPollingTask(res.data.graph_build_task_id)
-        startGraphPolling()
+      } else if (res.data.status === 'graph_building') {
+        const taskId = res.data.active_task_id || res.data.graph_build_task_id
+        if (taskId) {
+          currentPhase.value = 1
+          addLog(t('log.reconnectingToTask', { taskId }))
+          startPollingTask(taskId)
+          startGraphPolling()
+        }
       } else if (res.data.status === 'graph_completed' && res.data.graph_id) {
         currentPhase.value = 2
         await loadGraph(res.data.graph_id)

locales/ca.json

@@ -596,7 +596,8 @@
     "getReportInfoFailed": "Error en obtenir la informació de l'informe: {error}",
     "enterStep": "Entrant al pas {step}: {name}",
     "returnToStep": "Tornant al pas {step}: {name}",
-    "customSimRounds": "Rondes de simulació personalitzades: {rounds} rondes"
+    "customSimRounds": "Rondes de simulació personalitzades: {rounds} rondes",
+    "reconnectingToTask": "Reconnectant a la tasca activa {taskId}…"
   },
   "report": {
     "taskStarted": "Tasca de generació de l'informe iniciada",

locales/en.json

@@ -597,7 +597,8 @@
     "getReportInfoFailed": "Failed to get report info: {error}",
     "enterStep": "Entering Step {step}: {name}",
     "returnToStep": "Returning to Step {step}: {name}",
-    "customSimRounds": "Custom simulation rounds: {rounds} rounds"
+    "customSimRounds": "Custom simulation rounds: {rounds} rounds",
+    "reconnectingToTask": "Reconnecting to active task {taskId}…"
   },
   "report": {
     "taskStarted": "Report generation task started",

locales/es.json

@@ -596,7 +596,8 @@
     "getReportInfoFailed": "Error al obtener información del informe: {error}",
     "enterStep": "Entrando al Paso {step}: {name}",
     "returnToStep": "Volviendo al Paso {step}: {name}",
-    "customSimRounds": "Rondas de simulación personalizadas: {rounds} rondas"
+    "customSimRounds": "Rondas de simulación personalizadas: {rounds} rondas",
+    "reconnectingToTask": "Reconectando a la tarea activa {taskId}…"
   },
   "report": {
     "taskStarted": "Tarea de generación de informe iniciada",

locales/zh.json

@@ -597,7 +597,8 @@
     "getReportInfoFailed": "获取报告信息失败: {error}",
     "enterStep": "进入 Step {step}: {name}",
     "returnToStep": "返回 Step {step}: {name}",
-    "customSimRounds": "自定义模拟轮数: {rounds} 轮"
+    "customSimRounds": "自定义模拟轮数: {rounds} 轮",
+    "reconnectingToTask": "重新连接到活动任务 {taskId}…"
   },
   "report": {
     "taskStarted": "报告生成任务开始",