diff --git a/backend/packages/harness/deerflow/sandbox/tools.py b/backend/packages/harness/deerflow/sandbox/tools.py
index acd661db0..cad88dc93 100644
--- a/backend/packages/harness/deerflow/sandbox/tools.py
+++ b/backend/packages/harness/deerflow/sandbox/tools.py
@@ -801,7 +801,8 @@ def sandbox_from_runtime(runtime: ToolRuntime[ContextT, ThreadState] | None = No
     if sandbox is None:
         raise SandboxNotFoundError(f"Sandbox with ID '{sandbox_id}' not found", sandbox_id=sandbox_id)
 
-    runtime.context["sandbox_id"] = sandbox_id  # Ensure sandbox_id is in context for downstream use
+    if runtime.context is not None:
+        runtime.context["sandbox_id"] = sandbox_id  # Ensure sandbox_id is in context for downstream use
     return sandbox
 
 
@@ -836,7 +837,8 @@ def ensure_sandbox_initialized(runtime: ToolRuntime[ContextT, ThreadState] | Non
         if sandbox_id is not None:
             sandbox = get_sandbox_provider().get(sandbox_id)
             if sandbox is not None:
-                runtime.context["sandbox_id"] = sandbox_id  # Ensure sandbox_id is in context for releasing in after_agent
+                if runtime.context is not None:
+                    runtime.context["sandbox_id"] = sandbox_id  # Ensure sandbox_id is in context for releasing in after_agent
                 return sandbox
             # Sandbox was released, fall through to acquire new one
 
@@ -858,7 +860,8 @@ def ensure_sandbox_initialized(runtime: ToolRuntime[ContextT, ThreadState] | Non
     if sandbox is None:
         raise SandboxNotFoundError("Sandbox not found after acquisition", sandbox_id=sandbox_id)
 
-    runtime.context["sandbox_id"] = sandbox_id  # Ensure sandbox_id is in context for releasing in after_agent
+    if runtime.context is not None:
+        runtime.context["sandbox_id"] = sandbox_id  # Ensure sandbox_id is in context for releasing in after_agent
     return sandbox