Skill: scaffold

The materialization step between survey's greenfield foundation and the first feature. survey fixes the foundation (stack / structure / conventions in docs/architecture-map.md, marked mode: greenfield-bootstrap) and emits the scaffold plan (docs/features/_scaffold/tasks.json, tasks S1–S5 per ../survey/references/foundation.md); scaffold turns that plan into a repo that builds, boots, tests and migrates — then the normal per-feature flow (specify → … → implement) builds into it. This skill exists so the greenfield handoff is a real gate, not a wave of the hand: _scaffold is not a feature (no .size, no .route, no ACs), so it never enters implement's engine or its team/workflow decision tree.

The skeleton smoke test is the TDD anchor (canonical here). Scaffold tasks have no feature ACs, so red→green anchors on the structural smoke test: RED = the project does not build / boot / the tooling doesn't run; GREEN = build + boot + the empty test suite + the migration tool all succeed. That keeps the discipline meaningful for structural work — no per-folder TDD theatre.

Owner

Architect / Tech Lead — the same person who fixed the foundation in survey.

Inputs

• docs/architecture-map.md with mode: greenfield-bootstrap — the decided stack, module structure, conventions, and the machine keys (build_cmd, test_cmd, lint_cmd, migration_tool, frontend).
• docs/features/_scaffold/tasks.json — the S1–S5 scaffold plan (layer: scaffold, slug: "_scaffold").

Protocol

1. Hard gate. Both inputs must exist: docs/architecture-map.md whose frontmatter says mode: greenfield-bootstrap, AND docs/features/_scaffold/tasks.json parsing as the scaffold contract (slug: "_scaffold", layer: scaffold tasks with id/title/deps/dod/files_hint). Either missing → refuse: «run survey first — its greenfield session fixes the foundation and emits the scaffold plan». A map without the greenfield marker means the repo is already real — refuse too and point at /sdd:specify <slug>. If the skeleton already exists (every S-task's output present and the smoke test green), say so and STOP — nothing to materialize.
2. Ensure the settings file (first thing, after this skill's own gate). If .claude/sdd.local.md is absent, create it now from the canonical template — documented defaults + the self-documenting body — and patch .gitignore; if it exists, read it and never overwrite. The one procedure lives in ../_shared/settings-file.md. Creating is unconditional; changing values is only ever offered by config. Say one line: «.claude/sdd.local.md created with documented defaults — /sdd:config to tune it». Then read the foundation. From the map: stack, folder/module structure, conventions catalog, the machine keys. From tasks.json: the S-tasks in dependency order. The map is the only source of decisions — scaffold never re-litigates stack/style choices (that was survey's session).
3. Materialize sequentially inline. Execute the S-tasks one by one in dependency order, in this session — deliberately no agent team, no Workflow, no implement decision tree: _scaffold has no .size/.route, and five structural tasks need no orchestration. Per task: create the files its files_hint names, to the map's conventions; verify its dod; record it done. A task that genuinely doesn't apply (e.g. no datastore → the migration task) is explicitly dropped with a stated reason — never silently skipped.
4. Drive the smoke test green. Write the smoke test as part of the harness task, then run the full anchor with the map's machine-key commands: build + boot + the empty test suite + the migration tool (apply + revert). Iterate until GREEN — a red skeleton is not done.
5. Reconcile the map's machine keys. If the commands that actually worked differ from the map's frontmatter (build_cmd / test_cmd / lint_cmd / migration_tool), update the map — implement's command-detection cascade reads these keys; stale keys poison every later feature.
6. Structural self-check — per ../_shared/self-check.md, before any commit: verify 4 items: (1) the smoke test was actually executed and is green (build + boot + empty suite + migration tool — command output in hand, not assumed); (2) every S-task is done or explicitly dropped with a reason; (3) the map's machine keys match the commands that just ran (updated if they diverged); (4) every file the S-tasks' files_hint names exists on disk and is not gitignored. Fix + re-check ≤2 cycles; surface anything unresolved — an unresolved item means no commits.
7. Commit per ../_shared/write-and-commit.md — the skeleton is one indivisible commit (scaffold: materialize skeleton, paths = the materialized files + the settings .gitignore patch); the map, if step 5 changed it, is a separate commit (scaffold: architecture-map.md machine keys).
8. Handoff. Emit the stage-handoff block per ../_shared/handoff.md — What I did (tasks materialized, smoke-test result, «self-check: 4/4 pass», the commits with short SHAs) + Review before continuing (the committed skeleton diff + docs/architecture-map.md) + Run next: /clear, then /sdd:specify <slug> — the first real feature, with a real repo to build into.

Definition of Done

• Every S-task from docs/features/_scaffold/tasks.json is materialized (or explicitly dropped with a reason), to the conventions the map fixes.
• The skeleton smoke test is green: the project builds, boots, the empty test suite runs, the migration tool applies + reverts.
• The map's machine keys reflect the commands that actually work; the skeleton is committed.

Anti-patterns

• Orchestrating five structural tasks. No team mode, no Workflow, no DAG engine — _scaffold is repo-level bootstrap, not a feature; sequential inline is the design, not a fallback.
• Per-folder TDD theatre. The smoke test is the one anchor; writing a failing test per directory is ceremony without information.
• Re-deciding the foundation. Stack/structure/convention choices live in the map + its ADRs (survey's session); scaffold materializes, it never re-litigates. A gap in the map goes back to survey, not into an improvised decision here.
• Handing off red. «Skeleton written but doesn't boot» is not done — GREEN is the exit condition.
• Treating _scaffold as a feature. No .size/.route, no spec, no ACs — it never enters the per-feature pipeline or its size/route machinery.