core-onboarding

core-onboarding is a skill for Claude Code, Codex from j4flmao/agent-skills. It costs 73 tokens per session (7,903 once invoked), scanned A, original, MIT.

A structured guide for helping a new developer join a team and become productive. It covers environment setup, the system's architecture, development workflow, team roles, and delivery practices.

In plain words
What is it for?
Use it to create Day 1 and Week 1 onboarding plans, configure a development environment, explain the codebase, and guide a first code change.
Why use it?
It reduces the time new team members spend discovering setup steps, project context, and who handles different responsibilities.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Codex.

Good fit Use it to create Day 1 and Week 1 onboarding plans, configure a development environment, explain the codebase, and guide a first code change.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/j4flmao/agent-skills/onboarding
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add j4flmao/agent-skills --skill onboarding
Clone the repo
git clone --depth 1 https://github.com/j4flmao/agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for core-onboarding

README.md
[![agentmods](https://agentmods.dev/badge/skills/j4flmao/agent-skills/onboarding/github.svg)](https://agentmods.dev/skills/j4flmao/agent-skills/onboarding)
Your own site
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/onboarding"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/onboarding/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for core-onboarding

Your own site · 80×15
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/onboarding"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/onboarding.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 7,903 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. ✓ AI security review Sonnet 5 · 7 Sept 2026 📄 Read the review
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00073 $0.07903
Opus 5 $0.00036 $0.03952
Sonnet 5 $0.00015 $0.01581
Haiku 4.5 $0.00007 $0.00790

Measured 8d ago against content hash d36294ab536b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

core-onboarding scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/core/onboarding/SKILL.md · 635 lines

How it starts

The opening of the file, as written. The whole thing — 635 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Core Onboarding

Purpose

Accelerate new team member ramp-up through structured Day 1 / Week 1 onboarding. Covers environment setup, architecture overview, development workflow, and team practices so new joiners ship their first code change by end of week one.

Great onboarding is a competitive advantage for engineering organizations. New hires who ship their first PR within the first week reach full productivity faster and are retained at higher rates. Every hour invested in onboarding saves dozens of hours across future new hires. The feedback loop: every new hire who finds missing documentation and fixes it as their first PR creates a self-improving system.

Agent Protocol

Trigger

"onboarding", "new developer", "new team member", "setup guide", "getting started", "dev environment setup", "new joiner", "ramp up"

Input Context

  • Project repository URL and default branch (main, master, develop)
  • Technology stack: primary language(s) and versions, framework(s), database(s), queue, cache, cloud platform
  • Team structure: EM, tech lead, assigned buddy, DevOps contact, PM, designer
  • CI/CD details: provider (GitHub Actions, GitLab CI, CircleCI, Jenkins), lint/typecheck/test/build commands, deployment targets and environments
  • Development workflow: branch naming convention, PR template, required reviewers, CI checks, merge strategy, release cadence
  • Environment requirements: supported host OS, minimum hardware, reserved ports, system dependencies
  • Documentation paths: ADRs, API docs, runbooks, incident response guides, architecture diagrams

Output Artifact

Onboarding plan with day-by-day checklist, environment setup commands in executable order, architecture overview with key directories and request flow, and team practices reference guide.

Response Format

  • Day 1-5 checklist with time estimates, expected outcomes, verification steps
  • Environment setup as ordered copy-paste-ready command blocks
  • Architecture overview: key directories table, request flow diagram, deployment pipeline map
  • Team practices: standup format, communication channels, documentation conventions, on-call rotation
  • No preamble. No postamble. No explanations. No filler/hedging/transitions.

Read the full file on GitHub · 635 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 635 lines · 73 tokens per session scan F d36294ab536b

Subscribe to this mod's changes

core-onboarding is a skill published in the GitHub repository j4flmao/agent-skills (23 stars, last pushed 5d ago), licensed MIT. It adds 73 tokens to every session and 7,903 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Related

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