Implement

Convert a SPEC.md into implementation-ready artifacts and execute the iteration loop. This skill operates in three phases:

1. Convert — Transform SPEC.md into a structured spec.json
2. Prepare — Validate the spec.json, craft the implementation prompt, save it to a file
3. Execute — Run scripts/implement.sh to iterate through user stories via subprocess

Each phase can be entered independently. If you already have a spec.json, start at Phase 2. If artifacts are ready and you need execution, start at Phase 3. If you only need conversion, stop after Phase 1.

When composed by /ship, Ship invokes /implement for the full lifecycle and reviews the output afterward. When standalone, /implement runs end-to-end and reports results directly.

Ship working directory

All implementation artifacts are stored in tmp/ship/, derived dynamically from git rev-parse --show-toplevel. Override with CLAUDE_SHIP_DIR_OVERRIDE for Docker/CI/isolated envs. The implement.sh script resolves the directory automatically.

Inputs