generate-tasks decomposes a PRD or spec into shippable stories, each scoped to a single deployable unit with Given/When/Then acceptance criteria. It produces an ordered story set, a dependency graph, and an implementation sequence — plus a list of items flagged for PM input: edge cases the spec didn't resolve, data requirements that need explicit instrumentation, and product decisions embedded in acceptance criteria that only the PM can make.
The transition from spec to backlog is where scope and quality erode. Stories get written without acceptance criteria, data requirements get forgotten until after launch, and engineers make product decisions because the spec didn't make them. generate-tasks closes that gap systematically — and is explicit about what remains unresolved. Every flag it raises is a conversation you'd otherwise have mid-sprint.
Day 3 follows Day 2 because the PRD you wrote and reviewed is the natural input. You'll see how a document you authored translates into implementation units — and where the spec's gaps become story-level ambiguities. The stories you generate today are what a sprint plan would draw from on Day 4.