AI Engineering from Scratch is a free, open-source curriculum that teaches people to build AI systems through lessons and reusable artifacts such as prompts, skills, agents, and MCP servers. It is for learners who want practical foundations or want to create AI applications, and the catalogue skills support parts of that curriculum.
Borrowing it
Nothing to install: this file belongs to rohitg00/ai-engineering-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/rohitg00/ai-engineering-from-scratch/main/.claude/skills/lesson-screen/SKILL.mdgit clone --depth 1 https://github.com/rohitg00/ai-engineering-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/rohitg00/ai-engineering-from-scratch/lesson-screen)<a href="https://agentmods.dev/skills/rohitg00/ai-engineering-from-scratch/lesson-screen"><img src="https://agentmods.dev/badge/skills/rohitg00/ai-engineering-from-scratch/lesson-screen/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/rohitg00/ai-engineering-from-scratch/lesson-screen"><img src="https://agentmods.dev/badge/skills/rohitg00/ai-engineering-from-scratch/lesson-screen.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00137 | $0.02837 |
| Opus 5.5 | $0.00055 | $0.01135 |
| Sonnet 5.5 | $0.00027 | $0.00567 |
| Haiku 4.5 | $0.00014 | $0.00284 |
Grade A, and why
lesson-screen 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 7d 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 — 186 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Lesson screen
The lesson screen is a small local web server and one browser tab. The tutor keeps teaching in the terminal. At each step it writes one screen into a folder, and the browser shows the newest screen. The learner can press options and click parts. Those clicks go to an event log that the tutor reads before its next reply.
Use this skill with Claude, Cursor, Codex, OpenClaw, Hermes, or any agent that reads SKILL.md. It needs Node.js 20 or later and a browser on the same machine. It installs no packages.
When to use
- A course tutor teaches a lesson, and the learner accepts the screen. The tutors are learn, learn-mcp, learn-agent-skills, learn-reverse-engineering, claude-certification, and mcpa-certification.
- The learner asks to see a lesson, a concept, or a system: "show me", "draw it", "in 3D".
- A concept has a structure, a flow, or a number that changes. Seeing it helps more than reading it.
When not to use
- The learner declined the screen. Do not offer it again this session.
- The learner cannot reach a browser page from the host: a chat app, or a remote machine without port forwarding. Give the lesson page on aiengineeringfromscratch.com.
references/hosts.mdlists the cases. - The step is words only: a clarifying question, a tradeoff, or a definition. Keep it in the terminal and show the waiting screen.
- You need a permanent figure for a lesson file. Use the figure skills directly. This skill makes screens for one learner.
Paths
SKILL_ROOT is the folder that holds this SKILL.md. In this file, CLI means node "$SKILL_ROOT/scripts/lesson-screen.mjs".
Run every command from the learner's working folder. Screens go to .lesson-screen/screens/, and builds go to .lesson-screen/builds/. If the folder is a git repository, ask the learner to add .lesson-screen/ to .gitignore.
Start
- Run
CLI start --open. It prints one JSON line withurl,screens,state, andnext. - Give the learner the full
urlwith its query string. The key in it protects the page. - Run
CLI startagain at any time. It reuses a running server and keeps the same port. - If the start fails, say so in one line. Give the lesson page link and keep teaching.
What ships with it
9 files 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.
- 7d ago First seen · 186 lines · 137 tokens per session scan A 4013cf83446c
lesson-screen is a skill published in the GitHub repository rohitg00/ai-engineering-from-scratch (77,007 stars, last pushed yesterday), licensed MIT. It adds 137 tokens to every session and 2,837 once invoked, about $0.0005 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 2026-10-30.
lesson-screen compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| lesson-screenrohitg00/ai-engineering-from-scratch | Skill | 77k | yesterday | MIT | A | 137 | Claude Code, Codex |
| playwrightopenai/openai-agents-python | Skill | 31k | today | MIT | A | 19 | Claude Code, Codex |
| show-mehumanlayer/humanlayer | Skill | 13k | yesterday | Apache-2.0 | A | 25 | Claude Code |
| computer-usekirodotdev/KiroCrew | Skill | 4.8k | today | Apache-2.0 | A | 62 | Claude Code, Codex |
| browser-recordingkirodotdev/KiroCrew | Skill | 4.8k | today | Apache-2.0 | A | 64 | Claude Code, Codex |
| web-verifykirodotdev/KiroCrew | Skill | 4.8k | today | Apache-2.0 | A | 0 | Claude Code, Codex |
| web-previewkirodotdev/KiroCrew | Skill | 4.8k | today | Apache-2.0 | A | 68 | Claude Code, Codex |