While the Prefect documentation doesn't explicitly mention a limit to the size or amount of parameters for a flow, it does mention rate limits for API requests, including flow and task creation. These limits are in place to ensure the stability of Prefect Cloud.
However, it's important to note that large parameters might affect the performance of your flow, especially if they are being passed around between tasks. If you're dealing with large data, it might be more efficient to store it in a database or a file and pass around a reference to the data instead.
If you're unsure or if you're experiencing issues, I would recommend reaching out to Prefect support at
help@prefect.io for more specific guidance.