Claude Code From Scratch is a step-by-step learning project that recreates the core architecture of a coding agent in roughly 5,000 lines of TypeScript and Python. It is for developers who want to understand how coding agents work without reading a much larger codebase.
Borrowing it
Nothing to install: this file belongs to Windy3f3f3f3f/claude-code-from-scratch. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/Windy3f3f3f3f/claude-code-from-scratch/main/.claude/skills/greet/SKILL.mdgit clone --depth 1 https://github.com/Windy3f3f3f3f/claude-code-from-scratchWrote 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.
[](https://agentmods.dev/skills/windy3f3f3f3f/claude-code-from-scratch/greet)<a href="https://agentmods.dev/skills/windy3f3f3f3f/claude-code-from-scratch/greet"><img src="https://agentmods.dev/badge/skills/windy3f3f3f3f/claude-code-from-scratch/greet/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.
<a href="https://agentmods.dev/skills/windy3f3f3f3f/claude-code-from-scratch/greet"><img src="https://agentmods.dev/badge/skills/windy3f3f3f3f/claude-code-from-scratch/greet.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00010 | $0.00064 |
| Opus 5.5 | $0.00004 | $0.00026 |
| Sonnet 5.5 | $0.00002 | $0.00013 |
| Haiku 4.5 | $0.00001 | $0.00006 |
Grade A, and why
greet 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 1mo 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.
What it actually says
Greet Skill
Generate a short, friendly, creative greeting. If an argument (name) is provided, address that person by name. Keep it to 1-2 sentences.
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.
- 1mo ago First seen · 11 lines · 10 tokens per session scan A 692c6e76e81f
greet is a skill published in the GitHub repository Windy3f3f3f3f/claude-code-from-scratch (2,796 stars, last pushed 3mo ago), licensed MIT. It adds 10 tokens to every session and 64 once invoked, about $0.0000 per session on Opus 5.5. 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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