ATDD (Acceptance Test-Driven Development) workflow that generates @AC-N-tagged Gherkin scenarios from a signed-off acceptance-criteria list, scaffolds NotImplementedError step stubs, and produces an AC-to-test traceability table, all before implementation begins, in the team's BDD framework (Cucumber / Behave / Reqnroll). Use when devs are gated on green acceptance tests and failures must map back to a specific criterion. For story-narrative-to-Gherkin without prior ACs, use gherkin-from-stories. For BDD scenario authoring without the ATDD test-first gate, use a general BDD scenario-authoring workflow.