project_id to get sandbox id

backend/agent/api.py

@@ -468,7 +468,6 @@ async def start_agent(
             thread_id=thread_id,
             instance_id=instance_id,
             project_id=project_id,
-            sandbox=sandbox,
             model_name=MODEL_NAME_ALIASES.get(body.model_name, body.model_name), 
             enable_thinking=body.enable_thinking,
             reasoning_effort=body.reasoning_effort,
@@ -606,7 +605,6 @@ async def run_agent_background(
     thread_id: str,
     instance_id: str,
     project_id: str,
-    sandbox,
     model_name: str,
     enable_thinking: Optional[bool],
     reasoning_effort: Optional[str],
@@ -737,7 +735,6 @@ async def run_agent_background(
             project_id=project_id,
             stream=stream,
             thread_manager=thread_manager,
-            sandbox=sandbox,
             model_name=model_name,
             enable_thinking=enable_thinking,
             reasoning_effort=reasoning_effort,
@@ -1118,7 +1115,6 @@ async def initiate_agent_with_files(
                 thread_id=thread_id,
                 instance_id=instance_id,
                 project_id=project_id,
-                sandbox=sandbox,
                 model_name=MODEL_NAME_ALIASES.get(model_name, model_name), 
                 enable_thinking=enable_thinking,
                 reasoning_effort=reasoning_effort,

backend/agent/run.py

@@ -27,7 +27,6 @@ load_dotenv()
 async def run_agent(
     thread_id: str,
     project_id: str,
-    sandbox,
     stream: bool,
     thread_manager: Optional[ThreadManager] = None,
     native_max_auto_continues: int = 25,
@@ -48,6 +47,19 @@ async def run_agent(
     if not account_id:
         raise ValueError("Could not determine account ID for thread")
 
+    # Get sandbox info from project
+    project = await client.table('projects').select('*').eq('project_id', project_id).execute()
+    if not project.data or len(project.data) == 0:
+        raise ValueError(f"Project {project_id} not found")
+    
+    project_data = project.data[0]
+    sandbox_info = project_data.get('sandbox', {})
+    if not sandbox_info.get('id'):
+        raise ValueError(f"No sandbox found for project {project_id}")
+    
+    # Get or start the sandbox
+    sandbox = await get_or_start_sandbox(sandbox_info['id'])
+    
     # Note: Billing checks are now done in api.py before this function is called
     
     thread_manager.add_tool(SandboxShellTool, sandbox=sandbox)