TDD workflow from acceptance criteria to pull request

engineering

engineering is a Claude Code skill that handles the implementation phase between two gates in a structured spine loop — from frozen acceptance criteria through to handing control back to driving-work-to-done. It applies when a ticket already has a frozen assertion block, whether starting fresh or picking up mid-session work: reading the frozen block and the live document is enough to resume. The skill ships bash scripts for frozen-assertion-fence verification, loop-state recording, and a measurement-ledger that tracks command changes with old-hash, new-hash, and mandatory red-evidence proving the new command failed before any implementation. Measurement discipline is strict: a command that cannot go red measures nothing, and a preflight check must confirm the target exists before any verdict is recorded. Teams running a spine-based delivery workflow use this skill to automate the engineering cycle without manual gate management.