A FastAPI Agent Template Is Not Production-Ready Until Task Ownership Crosses Every Layer

Vercel published an OpenAI Agents SDK with FastAPI template on July 17, 2026. A template can remove setup work, but successful generation is not the production boundary that usually breaks. Task ownership is. Primary source: Vercel template, “OpenAI Agents SDK with FastAPI” . Before adopting any agent starter, I would add one vertical test: Alice must be able to create and cancel her task; Bob must not be able to read, stream, or cancel it—even if he guesses the task ID. State the cross-layer contract UI -> POST /tasks -> ownership row -> worker UI <- GET /tasks/:id <- authorization <- state UI <- event stream <- authorization <- events UI -> POST /tasks/:id/cancel -> authorization -> cancellation Use explicit states: queued -> running -> succeeded -> failed queued|running -> cancelling -> cancelled The database, API response, stream, and UI must agree on the same task and owner. Minimal schema create table tasks ( id text primary key , owner_id text not null , state text not null check ( state in ( 'queued' , 'running' , 'succeeded' , 'failed' , 'cancelling' , 'cancelled' )), created_at text not null , updated_at text not null , revision integer not null default 0 ); create table task_events ( task_id text not null , revision integer not null , kind text not null , payload text not null , primary key ( task_id , revision ) ); Do not derive ownership from a browser-supplied field. Resolve the authenticated principal on the server and store it when creating the task. FastAPI authorization seam from fastapi import Depends , FastAPI , HTTPException app = FastAPI () def current_user (): # Replace with verified session/JWT middleware. return { " id " : " alice " } def load_owned_task ( task_id : str , user = Depends ( current_user )): task = db_get_task ( task_id ) # application function if task is None or task [ " owner_id " ] != user [ " id " ]: # Avoid revealing whether another user's task exists. raise HTTPException ( status_code = 404 , detail = " task not found " )