diff --git a/backend/agent/runtime.py b/backend/agent/runtime.py
index f659b06..7c24afb 100644
--- a/backend/agent/runtime.py
+++ b/backend/agent/runtime.py
@@ -596,6 +596,8 @@ class WorkflowRuntime:
         db = self.db_factory()
         try:
             run = db.query(WorkflowRun).filter(WorkflowRun.id == run_id).first()
+            if run is None or not run.session_id:
+                return
             session = db.query(chat_models.ChatSession).filter(chat_models.ChatSession.session_id == run.session_id).first()
             if session is None:
                 raise RuntimeError("Chat session no longer exists.")
diff --git a/src/workflows/WorkflowEditor.jsx b/src/workflows/WorkflowEditor.jsx
index 8787853..53b484b 100644
--- a/src/workflows/WorkflowEditor.jsx
+++ b/src/workflows/WorkflowEditor.jsx
@@ -63,7 +63,11 @@ export default function WorkflowEditor({ apiBase, model, onChanged, tools, workf
   React.useEffect(() => {
     const graph = workflow?.graph || {}
     setNodes((graph.nodes || []).map(toCanvasNode))
-    setEdges(graph.edges || [])
+    setEdges((graph.edges || []).map(edge => ({
+      ...edge,
+      sourceHandle: edge.sourceHandle || edge.source_handle || 'output',
+      targetHandle: edge.targetHandle || edge.target_handle || 'input',
+    })))
     setInputsText(JSON.stringify(graph.inputs || {}, null, 2))
     setOutputsText(JSON.stringify(graph.outputs || {}, null, 2))
     setLimits(graph.limits || {})