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Codebase Onboarding Guide

Maps an unfamiliar codebase and drafts a starter CLAUDE.md for new contributors

Repository
affaan-m/ECC
Stars
295,127
Licence
MIT
Files
1 file

What it does

When installed, the agent systematically scans an unfamiliar project: it checks package manifests, framework config files, entry points, directory layout, lint and build config, and test structure. It then produces a structured onboarding guide covering an architecture map, the main entry points and flow, the coding conventions and style, and a starter CLAUDE.md file that tells future Claude Code sessions how the project works. The skill is written in Japanese and is aimed at developers joining a new team or setting up Claude Code in a repository for the first time.

Great for

  • Developers joining a new team or inheriting an unfamiliar repository
  • Anyone setting up Claude Code in an existing project for the first time
  • Teams that want a starter CLAUDE.md generated from the existing code

Skip it if

  • Very large monorepos where a shallow scan will miss important modules (the skill only reads top-level structure and key files)
  • Projects where you need verified, up-to-date docs, since the output is inferred from the code and may be wrong or incomplete

Try asking

  • “このコードベースを理解する手助けをしてください”
  • “このプロジェクトのCLAUDE.mdを生成してください”
  • “このリポを説明してください”
  • “Claude Codeでこのプロジェクトを初めて開いたので、オンボードしてください”
Step-by-step guide: how to use Codebase Onboarding GuideInstall, first run, examples, tips and FAQs

Install in 3 steps

  1. 1

    Download the skill

    The ZIP contains the 1 original files, the MIT licence and an attribution note.

    codebase-onboarding.zip
  2. 2

    Add it to your agent

    Claude Code (all projects)

    mkdir -p ~/.claude/skills && unzip codebase-onboarding.zip -d ~/.claude/skills/

    Claude Code / Agent SDK (this project only)

    mkdir -p .claude/skills && unzip codebase-onboarding.zip -d .claude/skills/

    Claude apps (web/desktop): Settings → Capabilities → Skills → Upload skill, and choose the ZIP.

  3. 3

    Ask for the task

    No special command needed — the agent reads the skill's description and loads it when your request matches. Try one of the prompts above.

Get better results

  • Run it from the repository root so the agent can see the top-level layout and manifests.
  • Review the generated CLAUDE.md before committing it, since it is inferred and may include wrong assumptions.
  • Ask follow-up questions on specific modules to deepen the architecture map.

What's inside

  • SKILL.md

Redistributed unmodified from affaan-m/ECC under the MIT licence. The assessment was drafted with AI from the skill's files on 2026-10-29. Skills can instruct your agent to run code — read SKILL.md and any scripts before installing.