scaffold

name	scaffold
description	Greenfield project architecture + harness scaffolding for AI Agent productivity. Interview-driven decisions -> markdown spec output. Produces: Code Structure (vertical slice exemplar), Test Infrastructure, Guard Rails, conditional extensions, AND Harness (CLAUDE.md with domain/team context, rules, skills, hooks). L2: architecture decisions, L3: harness setup, L4: unified plan (requirements + tasks). Use when: "/scaffold", "scaffold", "new project", "set up project", "프로젝트 세팅", "초기 구조"
allowed-tools	["Read","Grep","Glob","Task","Bash","Write","Edit","Agent","AskUserQuestion"]

/scaffold — Greenfield Architecture Scaffolding

Generate a scaffold spec through an architecture-focused derivation chain. Produces a complete development foundation that AI agents can extend consistently.

All outputs are written as markdown files — no external CLI dependencies.

---

Core Identity

scaffold is specify's architecture variant. Same structure, different weight center.

	specify	scaffold
Focus	What to build (features)	How to structure (architecture + harness)
L2 weight	Moderate (feature decisions)	Heavy (tech stack, patterns, infra)
L3	Requirements (behavioral)	Harness (domain, team, skills, hooks, rules)
L4	Tasks	Plan (requirements + tasks unified)
Tasks	Feature implementation	Project initialization + exemplar + harness
Output	Code changes	Complete development environment + AI harness
When	Feature on existing codebase	Greenfield or major restructure

---

Output Format

All layer results are written as sections in a single markdown file:

{project_dir}/scaffold-spec.md

The file accumulates as each layer completes. Structure:

# Scaffold Spec: {project name}

Created: {date}
Goal: {one-line goal}

## L0: Goal
...

## L1: Environment
...

## L2: Architecture Decisions
...

## L3: Harness Setup
...

## L4: Plan
...

---

Layer Flow

Layer	What	Gate
L0	Mirror -> confirmed_goal, non_goals	User confirms mirror
L1	Environment scan (greenfield detection)	Auto-advance
L2	Architecture interview -> decisions + constraints (HEAVY)	User approval
L3	Harness setup -> domain, team, rules, skills, hooks	User approval
L4	Plan -> requirements + tasks (unified from L2+L3)	User approval

Session Init (before L0)

Determine the project name from the user's goal. Create the output file:

touch {project_dir}/scaffold-spec.md

---

L0: Goal

Output: Goal section in scaffold-spec.md

Mirror Protocol

Mirror the user's goal with scaffold-specific framing:

"I understand you want to build [product/system].
 Architecture scope: [what the scaffold will set up].
 NOT in scaffold scope: [features, business logic -- those come later via /specify].
 Done when: [agent can extend the codebase consistently].
 Does this match?"

Key distinction: scaffold's goal is the foundation, not the product. If user says "I want to build a todo app", the scaffold goal is "Set up a web application foundation (server + client + DB) that an agent can extend to build features like a todo app."

Write to spec

After user confirms, write the L0 section:

## L0: Goal

**Confirmed Goal**: Set up a [framework] foundation with [key patterns] that an agent can extend to build [product] features

**Non-Goals**:
- Feature implementation
- Production deployment
- [other non-goals from discussion]

Gate

User confirms mirror -> advance to L1.

---

L1: Environment Scan

Output: Environment section in scaffold-spec.md

Unlike specify's L1 (which scans existing code), scaffold's L1 scans the environment:

Scan Targets

Target	How	Why
Working directory	ls -la, check for existing files	Greenfield confirmation
Package managers	which npm, which yarn, which pnpm, which bun	Available tooling
Runtime versions	node -v, python3 --version, go version, etc.	Compatibility constraints
Docker	docker --version, docker compose version	Infra capability
Git	git status	Repo state
OS/platform	uname -a	Platform constraints

Write to spec

## L1: Environment

- **Directory**: empty (greenfield confirmed) / has existing files
- **Node**: v22.x, pnpm available
- **Docker**: installed, compose v2
- **Git**: initialized, clean
- **Platform**: macOS ARM64

Gate

Auto-advance to L2 (no user approval needed).

---

L2: Architecture Decisions (HEAVY)

Output: Decisions section in scaffold-spec.md

This is scaffold's core. The interview determines the entire project architecture.

Step 0: Checkpoint Generation

Read L1 environment scan + confirmed goal, then generate checkpoints per architecture dimension.

Complexity classification -- based on confirmed goal:

Signal	Examples
Client-server boundary	web app, mobile + API, microservices
Multiple data stores	DB + cache + queue
Real-time communication	WebSocket, SSE, polling
External service integration	payment, auth provider, AI API
Multi-environment deployment	dev/staging/prod, Docker
Background processing	workers, cron, queues

• Simple (0-1 signals) -> 2-3 per dimension
• Medium (2-3 signals) -> 4-5 per dimension
• Complex (4+ signals) -> 6-8 per dimension

Architecture Dimensions

#	Dimension	Weight	Example Checkpoints
1	Tech Stack	25%	Language/runtime, framework, package manager
2	Communication	20%	Client-server protocol, API style, type safety strategy
3	Data & State	20%	Database choice, ORM/query builder, migration strategy, caching
4	Testing	15%	Test framework, test patterns, coverage strategy
5	DevOps & Environment	20%	Containerization, CI/CD, env config, deployment target

L1 Auto-Resolve: Check each checkpoint against environment scan. Node installed -> resolve "runtime" checkpoint. Docker available -> partially resolve containerization.

Interview Loop (score-driven)

Each round:

1. Score -- coverage per dimension
2. Target -- lowest-scoring dimension(s)
3. Ask -- 2 scenario questions targeting those checkpoints (via AskUserQuestion)
4. Resolve -- mark covered, record decisions
5. Scan -- detect cross-decision tensions
6. Display -- scoreboard

Question format -- RIGHT (concrete scenario):

AskUserQuestion(
  question: "Your API needs to serve both a React frontend and a future mobile app. How should client-server communication work?",
  options: [
    { label: "REST + OpenAPI + code-gen", description: "OpenAPI spec -> Orval/openapi-typescript. Type-safe, well-tooled." },
    { label: "tRPC", description: "End-to-end type safety, no code-gen. TypeScript only." },
    { label: "GraphQL", description: "Flexible queries, schema-first. Higher complexity." },
    { label: "Agent decides", description: "Let scaffold choose based on project context" }
  ]
)

"Agent decides" handling: When user selects this, scaffold makes an opinionated choice based on:

1. L1 environment capabilities
2. Decisions already made (consistency)
3. Project complexity (simpler for simple projects)
4. Agent productivity criteria (prefer type-safe, convention-over-config)

Record as decision with assumed: true.

Agent Productivity Bias

When making or recommending decisions, bias toward the 4 quality criteria:

Criteria	Bias
Agent extensibility	Prefer convention-over-config, clear naming, predictable patterns
Testability	Prefer dependency injection, pure functions, mockable boundaries
Drift resistance	Prefer strict linting, type checking, boundary enforcement
Type-safe communication	Prefer code-gen over manual types, schema-first over code-first

Conditional Extension Detection

During the interview, detect which conditional extensions to activate:

Signal from Interview	Extension Activated
Client-server boundary detected	Type Contracts (OpenAPI/tRPC/GraphQL schema)
Database mentioned or implied	Data Layer (migrations, connection, seed)
Docker available + multi-service	Docker/Infra (compose, Dockerfile)
Long-running server process	Runtime Patterns (health check, graceful shutdown)

Termination

Composite score uses weighted average across dimensions (weights from the table above). Terminate when: composite >= 0.80, every dimension >= 0.60, unknowns == 0.

Inversion Probe

Two architecture-specific questions:

1. Inversion: "Given these architecture decisions, what scenario would cause a complete restructure even if every component works individually?"
2. Implication: "You chose [most impactful decision]. Does that also mean [architectural consequence]?"

If the probe reveals a critical issue (e.g., contradictory decisions, missing dimension coverage):

• Record the issue as a known_gap
• Re-enter the interview loop targeting the affected dimension(s)
• Continue until termination criteria are met again

L2 Approval

Present all decisions + constraints + activated extensions, then ask user to approve via AskUserQuestion (Approve / Revise / Abort).

Write to spec

## L2: Architecture Decisions

### Decisions

| ID | Decision | Rationale | Assumed? |
|----|----------|-----------|----------|
| D1 | TypeScript + Node.js runtime | User preference, team familiarity | No |
| D2 | REST + OpenAPI for API | Multi-client support, code-gen | No |
| ... | ... | ... | ... |

### Constraints

- C1: pnpm workspace -- always use pnpm, never npm/yarn
- C2: ...

### Activated Extensions

- [x] Type Contracts (OpenAPI + Orval)
- [x] Data Layer (PostgreSQL + Prisma)
- [ ] Docker/Infra (not needed)
- [ ] Runtime Patterns (not needed)

### Known Gaps

- (none, or list gaps found during inversion probe)

---

L3: Harness Setup

Output: Harness section in scaffold-spec.md

L3 determines the AI work environment for this project.

3-1. Domain Context (interactive)

AskUserQuestion(
  question: "Does this project have domain-specific terms or business rules?",
  options: [
    { label: "Yes, I'll describe them", description: "You'll provide domain terms and key business rules" },
    { label: "None yet", description: "Skip -- can add later to CLAUDE.md" },
    { label: "Agent decides", description: "Infer from project goal if possible" }
  ]
)

3-2. Team Context (interactive)

AskUserQuestion(
  question: "Are there team conventions for commits, PRs, branching, or code review?",
  options: [
    { label: "Conventional Commits + GitHub Flow", description: "feat/fix/chore prefixes, feature branches, squash merge" },
    { label: "Trunk-based development", description: "Short-lived branches, no long-running feature branches" },
    { label: "Custom -- I'll describe", description: "You'll specify your team's rules" },
    { label: "Solo project, no conventions", description: "Skip team context" }
  ]
)

3-3. Constraints -> Rules (auto + confirm)

Scan L2 constraints and propose converting them to .claude/rules/ files:

AskUserQuestion(
  question: "Convert these constraints to .claude/rules/ for automatic enforcement?",
  options: [
    { label: "Yes, all of them", description: "All constraints become rules files" },
    { label: "Let me pick", description: "Choose which constraints to enforce" },
    { label: "Skip", description: "Keep constraints in spec only" }
  ]
)

3-3.5. CLAUDE.md Structure (Progressive Disclosure)

CLAUDE.md should stay lean — put stable rules in docs/ and load conditionally with @ refs.

# {project}

{3-5 lines: purpose, stack, directory map}

## Context (loaded on demand)
@docs/domain.md       # business terms, invariants
@docs/policies.md     # team conventions, commit style
@docs/architecture.md # decisions, boundaries

Rationale: monolithic CLAUDE.md inflates context every turn. check-harness axis 2 (C6) checks conditional_load_evidence ≥ 1. Keep the root file under ~80 lines.

3-4. Skills Detection (auto-suggest + ask)

Start minimal. Only scaffold skills that the L2 tech stack directly requires — dead skills pollute trigger matching (check-harness axis 1). Rule of thumb: if you can't name 3 times you'd call it next week, don't scaffold it.

Scan L2 decisions for recurring task patterns and suggest project-specific skills:

L2 Decision Signal	Auto-Suggested Skill	Description
DB + ORM (Prisma, Drizzle, SQLAlchemy)	/migrate	Run migration + regenerate types
DB detected	/seed-data	Generate development seed data
Docker / docker-compose	/deploy	Build, push, run with health check
API server (REST, GraphQL, tRPC)	/api-test	Test endpoint with curl/httpie
Async workers (Celery, BullMQ)	/worker-test	Dispatch test task + verify result
CLI binary (Rust, Go)	/release	Version bump + build + tag + publish
Frontend framework	/new-component	Scaffold component + test + story
Payment integration (Stripe, etc.)	/test-webhook	Forward + trigger webhook locally

AskUserQuestion(
  question: "These skills will be scaffolded based on your tech stack. Any other tasks you'll repeat frequently?",
  options: [
    { label: "These are enough", description: "Proceed with auto-suggested skills only" },
    { label: "Add more", description: "I'll describe additional recurring tasks" },
    { label: "Skip all skills", description: "Don't generate any project skills" }
  ]
)

3-5. Hooks Detection (auto + confirm)

Auto-detect hooks from L2 tech stack decisions:

L2 Decision	Auto-Detected Hook	Type
TypeScript (tsconfig.json)	tsc --noEmit on Edit/Write to .ts	PostToolUse
Prettier configured	prettier --write on Edit/Write	PostToolUse
ESLint configured	eslint --fix on Edit/Write	PostToolUse
Ruff / Black (Python)	ruff format on Edit/Write	PostToolUse
rustfmt (Rust)	rustfmt on Edit/Write	PostToolUse
gofmt (Go)	gofmt -w on Edit/Write	PostToolUse
.env files will exist	Block Edit/Write to .env*	PreToolUse
Lock files will exist	Block Edit/Write to lock files	PreToolUse

AskUserQuestion(
  question: "These hooks will be added to .claude/settings.json. Approve?",
  options: [
    { label: "Approve all", description: "Add all detected hooks" },
    { label: "Let me pick", description: "Choose which hooks to enable" },
    { label: "Skip hooks", description: "Don't set up any hooks" }
  ]
)

Write to spec

## L3: Harness Setup

### Domain Context
{domain terms and rules, or "None"}

### Team Conventions
{commit style, branching strategy, or "Solo project"}

### Rules (from Constraints)
| Constraint | Rule File | Status |
|-----------|-----------|--------|
| C1: pnpm only | `.claude/rules/pnpm-only.md` | Approved |
| ... | ... | ... |

### Skills
| Skill | Description | Source |
|-------|-------------|--------|
| `/migrate` | Run migration + regenerate types | D3 (Prisma) |
| ... | ... | ... |

### Hooks
| Hook | Type | Trigger |
|------|------|---------|
| `tsc --noEmit` | PostToolUse | Edit/Write .ts files |
| ... | ... | ... |

L3 Gate

Present harness summary -> AskUserQuestion (Approve / Revise / Abort).

---

L4: Plan (Requirements + Tasks)

Output: Plan section in scaffold-spec.md

L4 unifies requirements derivation and task generation in one step.

Step 1: Derive Requirements

Code Requirements (from L2):

R1: "Code Structure -- Project directories, base configs, and a complete vertical slice exemplar"
  R1.1: "Directory structure follows [framework] conventions with clear layer separation"
  R1.2: "Vertical slice exemplar implements one complete flow (route -> service -> data -> test) with importable utilities (logger, config, errors)"
  R1.3: "All exemplar utilities are importable modules, not inline code"

R2: "Test Infrastructure -- Framework setup with patterns matching the exemplar"
  R2.1: "[Test framework] configured with [runner] and example test matching exemplar flow"
  R2.2: "Test directory structure mirrors source structure"

R3: "Guard Rails -- CLAUDE.md + enforcement mechanisms for drift resistance"
  R3.1: "CLAUDE.md (lean — under ~80 lines) with architectural rules, domain context, team conventions, dependency direction, file placement conventions, available project skills summary, and active hooks summary. Stable long-form content lives in `docs/` and loads via Progressive Disclosure `@docs/*.md` references."
  R3.2: "Linter + formatter configured with project-specific rules"
  R3.3: "CI pipeline running lint + typecheck + test"
  R3.4: ".env.example with all required environment variables documented"

Conditional Code Extensions (from L2):

R4: "Type Contracts -- Schema-driven type safety across client-server boundary" (if activated)
R5: "Data Layer -- Database connection, schema management, and seed data" (if activated)
R6: "Docker/Infra -- Containerized local development environment" (if activated)
R7: "Runtime Patterns -- Production-readiness baseline for long-running server" (if activated)

Harness Requirements (from L3):

R8: "Project Rules -- Constraints converted to .claude/rules/" (if approved)
R9: "Domain Skills -- Project-specific repeatable task recipes" (if approved)
R10: "Project Hooks -- Automated code quality enforcement" (if approved)

Step 2: Derive Tasks

Task DAG:

T1: Project initialization (package.json, tsconfig, base configs)
    fulfills: [R1]

T2: Guard Rails setup (CLAUDE.md, lint, format, CI, .env.example, .claude/rules/)
    fulfills: [R3] + [R8 if approved]
    depends_on: [T1]

T4: Test infrastructure (test config, test dirs, path aliases -- framework setup only)
    fulfills: [R2]
    depends_on: [T1]

T3: Vertical slice exemplar (THE reference implementation + exemplar test)
    fulfills: [R1]
    depends_on: [T2, T4]
    <-- THIS IS THE MOST IMPORTANT TASK

--- Conditional code tasks (parallel where possible) ---

T5: Type Contracts setup (if R4)     fulfills: [R4]  depends_on: [T3]
T6: Data Layer setup (if R5)         fulfills: [R5]  depends_on: [T1]
T7: Docker/Infra setup (if R6)       fulfills: [R6]  depends_on: [T1]
T8: Runtime Patterns (if R7)         fulfills: [R7]  depends_on: [T3]

--- Harness tasks ---

T_SKILL: Domain Skills generation (if R9)
    fulfills: [R9]  depends_on: [T3]

T_HOOK: Project Hooks setup (if R10)
    fulfills: [R10] depends_on: [T1]

TF: Scaffold verification
    depends_on: all above

T3: Vertical Slice Exemplar (Critical Task)

The exemplar is the scaffold's highest-value output. It must demonstrate:

1. The complete flow -- from entry point to data layer and back
2. Importable utilities -- lib/logger.ts, lib/config.ts, lib/errors.ts (not inline)
3. The naming convention -- how files, functions, and variables are named
4. The test pattern -- how to test this flow
5. Error handling -- how errors propagate through layers
6. Type safety -- how types flow across boundaries

The exemplar answers: "If an agent reads only this one feature, can it build the next feature correctly?"

TF: Scaffold Verification

Steps:
- Build: all build/lint/typecheck commands pass
- Tests: all exemplar tests pass
- CLAUDE.md: includes architectural rules + domain context + team conventions + available skills + active hooks
- Rules: .claude/rules/ files match selected constraints from L3
- Exemplar: vertical slice is complete (entry -> data -> response -> test)
- Utilities: logger, config, errors are importable and used in exemplar
- Skills: each generated skill has valid SKILL.md with project-specific commands
- Hooks: .claude/settings.json hooks reference correct tool commands
- Agent test: could an agent read this codebase AND its harness and build a new feature consistently?

Write to spec

## L4: Plan

### Requirements

| ID | Requirement | Source | Conditional? |
|----|------------|--------|-------------|
| R1 | Code Structure | L2 | No |
| R2 | Test Infrastructure | L2 | No |
| R3 | Guard Rails | L2 | No |
| R4 | Type Contracts | L2 | If activated |
| ... | ... | ... | ... |

### Task DAG

| ID | Task | Fulfills | Depends On | Status |
|----|------|----------|------------|--------|
| T1 | Project init | R1 | - | pending |
| T2 | Guard Rails | R3, R8 | T1 | pending |
| T4 | Test infra | R2 | T1 | pending |
| T3 | Vertical slice exemplar | R1 | T2, T4 | pending |
| ... | ... | ... | ... | ... |
| TF | Verification | - | all | pending |

### Quality Criteria

- Agent extensibility: vertical slice exemplar (T3)
- Testability: test infrastructure + exemplar tests (T4)
- Drift resistance: CLAUDE.md + rules + lint + CI (T2)
- Type safety: [type contract strategy] (T5)
- Cross-session continuity: CLAUDE.md with domain/team context (T2)
- Task automation: domain skills (T_SKILL)
- Code quality enforcement: project hooks (T_HOOK)

L4 Gate

Present full plan summary, then:

AskUserQuestion(
  question: "Review the scaffold plan above.",
  options: [
    { label: "Approve", description: "Plan looks good" },
    { label: "Revise architecture (L2)", description: "Change architecture decisions" },
    { label: "Revise harness (L3)", description: "Change harness setup" },
    { label: "Revise plan (L4)", description: "Adjust requirements or tasks" },
    { label: "Abort", description: "Stop" }
  ]
)

---

Final Step: Next Action

After the user approves the full plan at L4, ask:

AskUserQuestion(
  question: "scaffold-spec.md is ready. What would you like to do?",
  options: [
    { label: "Implement now", description: "Start scaffolding the project based on this spec" },
    { label: "Later", description: "Save the spec and implement in a future session" }
  ]
)

• If Implement now: proceed with task execution following the Task DAG order.
• If Later: confirm the spec file location and end.

After Implementation: Establish Harness Baseline

Once TF (verification) passes, suggest running /check-harness to establish a maturity baseline for the new project. This closes the scaffold → audit → compound loop.

AskUserQuestion(
  question: "Run /check-harness now to baseline the new harness?",
  options: [
    { label: "Yes, baseline now", description: "Audit axes 1-6 and save report to .harness/check-reports/" },
    { label: "Skip", description: "Baseline later" }
  ]
)

---

User Approval Protocol

Three approval gates (L2, L3, L4). Same pattern at each:

AskUserQuestion(
  question: "Review the {items} above. Ready to proceed?",
  options: [
    { label: "Approve", description: "Looks good -- proceed to next layer" },
    { label: "Revise", description: "I want to change something" },
    { label: "Abort", description: "Stop specification" }
  ]
)

---

Checklist Before Stopping

• scaffold-spec.md exists in project directory
• confirmed_goal is architecture-framed (not feature-framed)
• Non-goals include "feature implementation" or similar
• L2: decisions cover all 5 architecture dimensions
• L2: Conditional extensions detected and recorded
• L3: Applicable harness decisions (domain, team, rules, skills, hooks)
• L3: Constraints -> rules conversion offered to user
• L3: Skills auto-suggested from tech stack + user input
• L3: Hooks auto-detected from formatter/linter choices
• L4: Requirements include Code (R1-R3) + Conditional (R4-R7) + Harness (R8-R10)
• R1 includes mandatory vertical slice exemplar requirement
• R3.1 CLAUDE.md includes domain context, team conventions, available skills, active hooks
• T3 (exemplar) includes importable utilities (logger, config, errors)
• T_SKILL produces skills with project-specific commands (not generic placeholders)
• T_HOOK produces hooks matching actual L2 tooling decisions
• TF includes agent extensibility + harness check
• Plan Summary presented to user
• Final AskUserQuestion: "Implement now" vs "Later"