How do you understand that a task is ready for a sprint?

A task is ready for a sprint when it is fully elaborated and meets the Definition of Ready. This means that:

• Requirements are clearly described and understood by the team.
• Acceptance criteria are defined.
• The task has been estimated and agreed upon.
• Dependencies are identified and considered.
• Technical details are worked out if necessary.
• The task is broken down into sub-tasks if it is large.

Thus, the team can start working without additional clarifications and blockers.