onboard-session

onboard-session is a skill for Claude Code from TimboGP/timbogp-marketplace. It costs 194 tokens per session (1,297 once invoked), scanned A, original, MIT.

An onboarding guide for understanding an existing codebase, document collection, or group of papers. It surveys the material, explains it in parts, checks your understanding, and helps you reproduce a recent change.

In plain words
What is it for?
Use it when joining a project, inheriting a service, exploring an open-source repository, or studying an existing body of writing.
Why use it?
It shortens the time needed to understand work created by someone else and builds confidence before making changes.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions CLAUDE.md; mentions AGENTS.md.

Part of the agentic-study-environment plugin — 7 skills, 1 command shipped together

Good fit Use it when joining a project, inheriting a service, exploring an open-source repository, or studying an existing body of writing.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/timbogp/timbogp-marketplace/onboard-session
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 TimboGP/timbogp-marketplace --skill onboard-session
Clone the repo
git clone --depth 1 https://github.com/TimboGP/timbogp-marketplace

Made for: Claude Code.

Or install agentic-study-environment, the plugin that ships this one along with the rest of its 7 skills, 1 command.

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 onboard-session

README.md
[![agentmods](https://agentmods.dev/badge/skills/timbogp/timbogp-marketplace/onboard-session/github.svg)](https://agentmods.dev/skills/timbogp/timbogp-marketplace/onboard-session)
Your own site
<a href="https://agentmods.dev/skills/timbogp/timbogp-marketplace/onboard-session"><img src="https://agentmods.dev/badge/skills/timbogp/timbogp-marketplace/onboard-session/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 onboard-session

Your own site · 80×15
<a href="https://agentmods.dev/skills/timbogp/timbogp-marketplace/onboard-session"><img src="https://agentmods.dev/badge/skills/timbogp/timbogp-marketplace/onboard-session.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 194 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,297 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.
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 $0.00194 $0.01297
Opus 5 $0.00097 $0.00648
Sonnet 5 $0.00039 $0.00259
Haiku 4.5 $0.00019 $0.00130

Measured 12d ago against content hash e7a59aef44fd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

onboard-session 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 12d 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.

plugin/agentic-study-environment/skills/onboard-session/SKILL.md · 50 lines

How it starts

The opening of the file, as written. The whole thing — 50 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Begin an onboarding session

This skill begins a bracketed onboarding session: getting up to speed on an existing artifact — a codebase, a document corpus, a body of papers — that the user did not author. The artifact is the source material; the goal is a working mental model and the confidence to make changes, not learning a topic from first principles.

Onboarding is one of the harness's four core session types, alongside theory, practice, and role-play. The other three are proposed and run through start-session; onboarding gets its own skill because its shape differs enough to warrant it — a read-only pass over an artifact outside the usual source-materials flow, its own three-phase protocol, and its own artifact tree under work/onboarding/.

When to use

The user wants to get familiar with something someone else built or wrote — a new job's codebase, an open-source project, a teammate's service, an inherited body of papers, a legal corpus. Phrases like "onboard me on this codebase", "walk me through this repo", "help me get up to speed on X", or "I just joined this project" should match.

If the user has not bootstrapped a sub-project yet, redirect them to the bootstrap skill first.

If the user instead wants theory, practice, or role-play, redirect to start-session — this skill only runs onboarding.

What to read before doing anything else

Before proposing or conducting anything, load context — the same up-front reads as start-session:

  1. The harness's optional .studyenv/AGENTS.md if present, otherwise .studyenv/CLAUDE.md if present (for cross-project conventions and any global Language:), and .studyenv/PROGRESS.md. Both are optional context; if either is missing, continue without it.
  2. The sub-project's .studyenv/<name>/AGENTS.md, falling back to .studyenv/<name>/CLAUDE.md for older projects (for Domain:, Language:, goals, Tools & Materials), and .studyenv/<name>/PROGRESS.md (for what's been covered and at what status).
  3. The sub-project's .studyenv/<name>/ai-agent-materials/ — especially curriculum.md, which may already name an onboarding topic entry — and work/onboarding/map.md if a prior onboarding session left one (so you resume where the last one left off, rather than re-surveying from scratch).
  4. If the sub-project declares Domain:, load the matching overlay at ../../domains/<domain>.md (relative to this SKILL.md). The overlay supplies the four onboarding parameters below; if no Domain: is set, the generic protocol applies over a flat corpus.

Read the full file on GitHub · 50 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. 12d ago First seen · 50 lines · 194 tokens per session scan A e7a59aef44fd

Subscribe to this mod's changes

onboard-session is a skill published in the GitHub repository TimboGP/timbogp-marketplace (3 stars, last pushed 2mo ago), licensed MIT. It adds 194 tokens to every session and 1,297 once invoked, about $0.0010 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 2026-08-31.

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