Definition of Ready
Definition of Ready is a team's shared checklist for whether a piece of work is sufficiently well-defined to actually start — clear acceptance criteria, no unresolved dependencies, estimated effort — preventing a team from beginning work on something too vague or blocked to make real progress on.
Where Definition of Done gates the end of work, Definition of Ready gates the beginning — a story that's vague, missing acceptance criteria, or blocked on an external dependency shouldn't enter a sprint at all, since starting on it usually just produces wasted, thrashing effort and mid-sprint surprises.
For QA specifically, Definition of Ready often includes testability as an explicit criterion — can this story actually be tested with the environment, data, and access available, a question worth answering before committing to it, not discovering partway through the sprint.
