Translate PRD intent, roadmap asks, or product discussions into an implementation-ready capability plan that exposes constraints, invariants, interfaces, and unresolved decisions before multi-service work starts. This skill turns product intent into explicit engineering constraints and a durable capability manifest. Use it when the user needs an ECC-native PRD-to-SRS lane instead of vague planning prose, ensuring engineering review has a durable artifact instead of relying on memory.