# Implement > Plan-then-implement workflow — sketches a hypothesis, explores targeted areas, creates a concrete plan, gets user approval, then implements in parallel subagents. Use for non-trivial features or changes. Use when this capability is needed. - Skill: `tomevault-io/implement` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/implement` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/implement/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Productivity - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/implement --- # Plan-Then-Implement Workflow You are executing a structured implementation workflow for: **$ARGUMENTS** Follow these phases strictly in order. ## Phase 1: Sketch Before exploring the codebase, form a rough hypothesis based on what you already know (skills, CLAUDE.md, conversation context, the request itself): - What areas of the codebase likely need to change? - What is the rough approach? - What specific questions need answering before you can make a concrete plan? Write this sketch down briefly. It does NOT need to be correct — its purpose is to give exploration direction, not to commit to an approach. ## Phase 2: Explore Use the `Explore` subagent (or multiple in parallel) to validate and refine the sketch. Focus exploration on: - Answering the specific questions from the sketch - Verifying that the files and patterns you hypothesized actually exist - Discovering anything the sketch missed — dependencies, constraints, edge cases - Checking existing patterns and conventions to follow - Identifying test patterns used for similar features Do NOT start writing code yet. ## Phase 3: Plan Enter plan mode. Based on what exploration confirmed or revised, create a concrete implementation plan: - List every file that needs to be created or modified - Describe the specific changes for each file - Identify which changes are independent (can be parallelized) vs sequential - Note any risks or decisions that need user input - Include a test plan Present the plan to the user and wait for approval before proceeding. Do not continue until the user confirms. ## Phase 4: Implement After user approval: 1. Create tasks for each piece of work 2. Exit plan mode 3. Launch implementation subagents in parallel for independent work items (use `isolation: worktree` for parallel file edits to the same files) 4. Handle sequential work items in order after parallel work completes 5. Mark tasks as completed as each finishes ## Phase 5: Verify After all implementation is done: 1. Run the linter: `pixi run pre-commit run -a` 2. Run relevant tests: `pixi run python -m pytest tests -m "unit or integration"` (adjust markers based on what was changed) 3. Fix any issues found 4. Summarize what was done --- > Source: [ymahlau/bonni](https://github.com/ymahlau/bonni) — distributed by [TomeVault](https://tomevault.io).