PRP Implement

Execute a plan file step-by-step with continuous validation. Every change is verified immediately — never accumulate broken state.

Core Philosophy: Validation loops catch mistakes early. Run checks after every change. Fix issues immediately.

Golden Rule: If a validation fails, fix it before moving on. Never accumulate broken state.

---

Phase 0 — DETECT

Package Manager Detection

File Exists	Package Manager	Runner
bun.lockb	bun	bun run
pnpm-lock.yaml	pnpm	pnpm run
yarn.lock	yarn	yarn
package-lock.json	npm	npm run
pyproject.toml or requirements.txt	uv / pip	uv run or python -m
Cargo.toml	cargo	cargo
go.mod	go	go

Validation Scripts

Check package.json (or equivalent) for available scripts:

# For Node.js projects
cat package.json | grep -A 20 '"scripts"'

Note available commands for: type-check, lint, test, build.

---

Phase 1 — LOAD

Read the plan file:

cat "$ARGUMENTS"

Extract these sections from the plan:

• Summary — What is being built
• Patterns to Mirror — Code conventions to follow
• Files to Change — What to create or modify
• Step-by-Step Tasks — Implementation sequence
• Validation Commands — How to verify correctness
• Acceptance Criteria — Definition of done

If the file doesn't exist or isn't a valid plan:

Error: Plan file not found or invalid.