A conversation can be enough
If you perform the job infrequently or its requirements change every time, a well-written prompt may be the right system. Save your instructions, keep examples, and review the result. You do not need to justify another integration.
A schedule adds a start condition
A recurring reminder or research brief has a defined time to run. It still needs accessible inputs, an output destination, and a way to stop. OpenAI’s task documentation describes account-specific scheduling and event support; do not assume that every task can read every file.
A connected workflow moves data
A connected workflow has a trigger and explicit steps across tools. Use it for repeated, sufficiently stable work. Treat field mappings, credentials, duplicate events, and failures as part of the product rather than details you will solve later.
An assistant with tools can act
MCP can expose permitted tool actions to a compatible assistant. That access may enable real changes in an application. It does not remove the need to establish authorization, scope, and review. Giving an assistant a tool is not the same as building a well-tested recurring workflow.
Use the simplest sufficient version
Try a reusable prompt first, a scheduled task second when timing is the real problem, and an app workflow when repeatable handoffs are the bottleneck. These are suggested choices, not a universal ranking of tools. The best answer depends on the task and its consequences.
Make it practical.
Choose a task you already do. Work through one original recipe and check the result.
Find a workflow