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.
npx agentmods add skills/marcusrbrown/systematic/onboardingnpx skills add marcusrbrown/systematic --skill onboardinggit clone --depth 1 https://github.com/marcusrbrown/systematicWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00114 | $0.05264 |
| Opus 5 | $0.00057 | $0.02632 |
| Sonnet 5 | $0.00023 | $0.01053 |
| Haiku 4.5 | $0.00011 | $0.00526 |
Grade A, and why
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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 401 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Generate Onboarding Document
Crawl a repository and generate ONBOARDING.md at the repo root -- a document that helps new contributors understand the codebase without requiring the creator to explain it.
Onboarding is a general problem in software, but it is more acute in fast-moving codebases where code is written faster than documentation -- whether through AI-assisted development, rapid prototyping, or simply a team that ships faster than it documents. This skill reconstructs the mental model from the code itself.
This skill always regenerates the document from scratch. It does not read or diff a previous version. If ONBOARDING.md already exists, it is overwritten.
Core Principles
- Write for humans first -- Clear prose that a new developer can read and understand. Agent utility is a side effect of good human writing, not a separate goal.
- Show, don't just tell -- Use ASCII diagrams for architecture and flow, markdown tables for structured information, and backtick formatting for all file paths, commands, and code references.
- Six sections, each earning its place -- Every section answers a question a new contributor will ask in their first hour. No speculative sections. Section 2 may be skipped for pure infrastructure with no consuming audience, producing five sections.
- State what you can observe, not what you must infer -- Do not fabricate design rationale or assess fragility. If the code doesn't reveal why a decision was made, don't guess.
- Never include secrets -- The onboarding document is committed to the repository. Never include API keys, tokens, passwords, connection strings with credentials, or any other secret values. Reference environment variable names (
STRIPE_SECRET_KEY), never their values. If a.envfile contains actual secrets, extract only the variable names. - Link, don't duplicate -- When existing documentation covers a topic well, link to it inline rather than re-explaining.
Execution Flow
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 2d ago First seen · 401 lines · 114 tokens per session scan A 2faee3cc3af8
onboarding is a skill published in the GitHub repository marcusrbrown/systematic (24 stars, last pushed 3d ago), licensed MIT. It adds 114 tokens to every session and 5,264 once invoked, about $0.0006 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 2026-08-30.
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