Planning is the process by which an agent breaks a goal into smaller steps before or during execution. Task decomposition might decide which tools are needed, what information to retrieve, what order to perform actions in, and when to ask for clarification.
Planning should be evaluated when the path matters. A correct final answer may hide an inefficient, unsafe, or brittle plan. Plan quality evals can check whether steps are necessary, ordered correctly, grounded in available information, and aligned with policy.