# AILesson

> AILesson provides short, interactive lessons that help beginners build practical AI skills without requiring a programming background.

English is the default language. Simplified Chinese translations use the `/zh` URL prefix. To retrieve any public HTML page below as Markdown, request the same URL with `Accept: text/markdown`; do not append a `.md` suffix. Public Lesson pages contain a preview, and the Markdown representation preserves that access boundary. Continuing beyond the preview may require sign-in and an AILesson Pro membership.

## Start here

- [AILesson home](https://ailesson.io/): Product overview, learning approach, featured Courses, and membership options.
- [Course catalog](https://ailesson.io/courses): Browse the complete public Course catalog.
- [Lesson library](https://ailesson.io/lessons): Find public Lesson previews by topic, category, and duration.
- [AI concept Flashcards](https://ailesson.io/flashcards): Read concise definitions of reusable AI concepts and review them as interactive Flashcards.
- [About and editorial standards](https://ailesson.io/about): How AILesson creates, reviews, updates, and corrects learning content.

## Courses

- [AI for Beginners](https://ailesson.io/courses/ai-for-beginners): Start a useful AI conversation, make the answer better, check what matters, and know when the next move is yours.
- [ChatGPT Fundamentals](https://ailesson.io/courses/chatgpt-fundamentals): Learn ChatGPT through three practical workflows: complete a first chat, work from a file, then use Projects to carry a checked plan into a new chat.
- [How Generative AI Works](https://ailesson.io/courses/how-generative-ai-works): Understand how common AI chats learn language patterns, use current messages, build replies, and add sources and tools.
- [Plan a Trip with AI](https://ailesson.io/courses/plan-a-trip-with-ai): Plan your own trip with AI: turn travel needs into a researched, flexible plan with checks for destinations, transport, stays, budget, and booking.
- [Agent Skills for Beginners](https://ailesson.io/courses/agent-skills-for-beginners): Learn when reusable AI instructions deserve an Agent Skill, then inspect and test a complete SKILL.md.
- [Research a Topic with AI](https://ailesson.io/courses/research-a-topic-with-ai): Research one real decision with AI: define the question, find and verify sources, preserve uncertainty, and produce a brief another person can audit.
- [Vibe Coding for Beginners](https://ailesson.io/courses/vibe-coding-for-beginners): Build your first small App with AI, then test, improve, review, and hand off only what the evidence supports.
- [Make Product Decisions with AI](https://ailesson.io/courses/make-product-decisions-with-ai): Turn mixed product feedback, metrics, and team claims into an evidence-bounded recommendation that a real decision owner can review.

## AI concepts

- [AI Agent](https://ailesson.io/flashcards/ai-agent): An AI agent is an AI that can do more than answer. It can break a goal into steps and use tools, such as search or files, to carry them out. Give it clear limits and check important steps, because it can still do something you did not expect.
- [AI Bias](https://ailesson.io/flashcards/ai-bias): AI bias happens when an AI treats similar people or situations differently in a way that is unfair. This can come from the information used to build it or from how it is designed. A confident answer is not proof that it treated everyone fairly.
- [AI with Your Documents](https://ailesson.io/flashcards/ai-with-your-documents): AI with your documents uses selected files or other provided sources alongside your request to help form an answer. Systems built this way are often called retrieval-augmented generation, or RAG. The answer is only as dependable as the relevant material it finds and uses, so the documents and important claims still need checking.
- [Context](https://ailesson.io/flashcards/context): Context is the information an AI can use when it answers you. This can include your goal, useful facts, limits, examples, files, the result you want, and earlier messages in the chat. Giving the right context helps the AI give a more relevant answer, but something does not become true just because it was included.
- [Context Window](https://ailesson.io/flashcards/context-window): An AI can only look at a certain amount of information at one time. That amount is called its context window. If a chat or file is very long, earlier parts may not fit, so the AI may miss them.
- [Conversation Context](https://ailesson.io/flashcards/conversation-context): Conversation context is what has already been said in the same chat. When earlier messages remain available, the AI can often use them in its next answer. You can add a detail, ask for a change, or try again—but you may need to repeat important information in another tool or a long chat.
- [Generative AI](https://ailesson.io/flashcards/generative-ai): Generative AI can produce content such as words, pictures, sounds, or video. It uses what you ask or show it to produce that content. Its answer can be helpful, but important details can still be wrong, so check them.
- [AI Hallucination](https://ailesson.io/flashcards/hallucination): An AI hallucination is an answer that sounds believable but states something false or unsupported as if it were true. It can include made-up facts, sources, quotations, or details, so important claims still need checking.
- [Human Oversight](https://ailesson.io/flashcards/human-oversight): Human oversight means people set the goal and limits for AI, review important output, and approve decisions or actions that matter. AI can assist with work, but it does not take over human responsibility.
- [Large Language Model (LLM)](https://ailesson.io/flashcards/llm): A large language model, or LLM, is the technology that lets tools such as ChatGPT understand and write everyday language. It builds a reply by choosing words based on what it learned and what you shared in the chat. Its answers can be useful, but they can also be wrong, and it will not know your goal unless you explain it.
- [Multimodal AI](https://ailesson.io/flashcards/multimodal-ai): Multimodal AI can work with more than one kind of content, such as words, pictures, sound, or video. A particular tool may not handle every kind, and it can still misunderstand what you give it.
- [Prompt](https://ailesson.io/flashcards/prompt): A prompt is what you say or send to an AI when you ask for help. It can be as simple as a question or an instruction. You do not need special words: say what you need, then add useful details when they matter.
- [Prompt Injection](https://ailesson.io/flashcards/prompt-injection): Prompt injection is when text in a webpage, file, or message tries to tell an AI what to do, even though those instructions are not yours. Treat that text as something to check, not as an instruction the AI should follow.
- [Token](https://ailesson.io/flashcards/token): A token is a small piece of text that an AI reads or writes. One word can be one token or several, and punctuation can count too. AI products use tokens to set limits and measure use, so tokens are not the same as words.

## Languages

- [简体中文首页](https://ailesson.io/zh): AI 小课的简体中文产品介绍。
- [简体中文课程目录](https://ailesson.io/zh/courses): 浏览提供简体中文内容的公开课程。
- [简体中文闪卡目录](https://ailesson.io/zh/flashcards): 阅读常用 AI 概念的简明解释。
- [关于 AI 小课与编辑规范](https://ailesson.io/zh/about): 了解内容创作、审核、更新与纠错原则。

## Optional

- [Meet AI](https://ailesson.io/courses/ai-for-beginners/lessons/meet-ai): Learn how generative AI chats work and where AI can help with an everyday task. Estimated learning time: 7 minutes.
- [Start a Chat](https://ailesson.io/courses/ai-for-beginners/lessons/start-a-chat): Use ordinary language to ask AI for a simple, useful result. Estimated learning time: 7 minutes.
- [Improve and Check](https://ailesson.io/courses/ai-for-beginners/lessons/improve-and-check): Refine an answer for real use and check its important details in the same chat. Estimated learning time: 8 minutes.
- [Share What Matters](https://ailesson.io/courses/ai-for-beginners/lessons/share-what-matters): Give AI the details that shape a plan while keeping human decisions clear. Estimated learning time: 8 minutes.
- [Compare Possible Plans](https://ailesson.io/courses/ai-for-beginners/lessons/compare-possible-plans): Compare two AI plans, verify their claims, and find a real mismatch. Estimated learning time: 8 minutes.
- [Adjust It with Real Feedback](https://ailesson.io/courses/ai-for-beginners/lessons/adjust-it-with-real-feedback): Revise an AI plan with real feedback while keeping the final decision human. Estimated learning time: 7 minutes.
- [Find What Is Missing](https://ailesson.io/courses/ai-for-beginners/lessons/find-what-is-missing): Sort confirmed facts, proposals, conflicts, and gaps before continuing with AI. Estimated learning time: 7 minutes.
- [Ask Instead of Guessing](https://ailesson.io/courses/ai-for-beginners/lessons/ask-instead-of-guessing): Identify what a draft cannot answer and prepare questions for the right people. Estimated learning time: 8 minutes.
- [Update with Confirmed Answers](https://ailesson.io/courses/ai-for-beginners/lessons/update-with-confirmed-answers): Turn confirmed replies into usable materials without hiding estimates or unfinished actions. Estimated learning time: 7 minutes.
- [Find Pages to Check](https://ailesson.io/courses/ai-for-beginners/lessons/find-pages-to-check): Use AI to find official pages without mistaking its answer for proof. Estimated learning time: 7 minutes.
- [Open the Right Page](https://ailesson.io/courses/ai-for-beginners/lessons/open-the-right-page): Check whether an official page fits your situation and preserve any disagreements. Estimated learning time: 8 minutes.
- [Make a Checked Visit Note](https://ailesson.io/courses/ai-for-beginners/lessons/make-a-checked-visit-note): Turn checked facts into a useful note with open choices, rechecks, and links. Estimated learning time: 7 minutes.
- [See What Happened](https://ailesson.io/courses/ai-for-beginners/lessons/see-what-happened): Compare a plan with actual use without guessing why things changed. Estimated learning time: 7 minutes.
- [Ask Before You Change](https://ailesson.io/courses/ai-for-beginners/lessons/ask-before-you-change): Ask neutral questions when a repeated change reveals a problem but not its cause. Estimated learning time: 7 minutes.
- [Make One Useful Change](https://ailesson.io/courses/ai-for-beginners/lessons/make-one-useful-change): Keep what works, try one supported change, and prepare a focused recheck. Estimated learning time: 7 minutes.
- [Start Your First Useful Chat](https://ailesson.io/courses/chatgpt-fundamentals/lessons/start-your-first-useful-chat): Send a safe first request to ChatGPT as a guest and recognize its response. Estimated learning time: 12 minutes.
- [Improve the Answer with Follow-Ups](https://ailesson.io/courses/chatgpt-fundamentals/lessons/improve-the-answer-with-follow-ups): Continue the same ChatGPT conversation and use a follow-up to revise the result. Estimated learning time: 11 minutes.
- [Search the Web and Check Sources](https://ailesson.io/courses/chatgpt-fundamentals/lessons/search-the-web-and-check-sources): Search with ChatGPT and verify what each cited source actually supports. Estimated learning time: 13 minutes.
- [Review and Finish the Result](https://ailesson.io/courses/chatgpt-fundamentals/lessons/review-and-finish-the-result): Use a targeted ChatGPT audit to correct and save a finished result. Estimated learning time: 14 minutes.
- [Upload a File to ChatGPT](https://ailesson.io/courses/chatgpt-fundamentals/lessons/upload-a-file-to-chatgpt): Upload a safe practice PDF, confirm the attachment, and ask a focused file question. Estimated learning time: 13 minutes.
- [Analyze a File with ChatGPT](https://ailesson.io/courses/chatgpt-fundamentals/lessons/analyze-a-file-with-chatgpt): Check important file claims and compare verified requirements with an existing plan. Estimated learning time: 15 minutes.
- [Use a File to Update a Plan](https://ailesson.io/courses/chatgpt-fundamentals/lessons/use-a-file-to-update-a-plan): Apply checked file requirements and save a traceable approval work pack. Estimated learning time: 16 minutes.
- [Create a Project in ChatGPT](https://ailesson.io/courses/chatgpt-fundamentals/lessons/create-a-project-in-chatgpt): Create a ChatGPT Project with reusable sources and instructions for a weekly dinner plan. Estimated learning time: 12 minutes.
- [Make a Weekly Meal Plan with ChatGPT](https://ailesson.io/courses/chatgpt-fundamentals/lessons/make-a-weekly-meal-plan-with-chatgpt): Use Project sources to make, check, repair, and save a five-day meal plan. Estimated learning time: 18 minutes.
- [Create a Shopping List with ChatGPT](https://ailesson.io/courses/chatgpt-fundamentals/lessons/create-a-shopping-list-with-chatgpt): Reuse a saved Project plan in a new chat to make a checked shopping list. Estimated learning time: 12 minutes.
- [Learn from Examples](https://ailesson.io/courses/how-generative-ai-works/lessons/learn-from-examples): See how training examples shape a model before it answers new requests. Estimated learning time: 10 minutes.
- [Predict What Comes Next](https://ailesson.io/courses/how-generative-ai-works/lessons/predict-what-comes-next): Learn how text AI predicts what comes next and why that is not fact-checking. Estimated learning time: 9 minutes.
- [Use Context](https://ailesson.io/courses/how-generative-ai-works/lessons/use-context): Distinguish AI’s limited current context from permanent memory. Estimated learning time: 10 minutes.
- [Build a Response](https://ailesson.io/courses/how-generative-ai-works/lessons/build-a-response): See how AI builds a fluent reply piece by piece without checking its facts. Estimated learning time: 9 minutes.
- [Follow Instructions](https://ailesson.io/courses/how-generative-ai-works/lessons/follow-instructions): See how training feedback, product rules, and your request shape an AI assistant. Estimated learning time: 10 minutes.
- [Use Tools and Sources](https://ailesson.io/courses/how-generative-ai-works/lessons/use-tools-and-sources): Distinguish model-generated text from external sources, tools, and real actions. Estimated learning time: 11 minutes.
- [Know the Limits](https://ailesson.io/courses/how-generative-ai-works/lessons/know-the-limits): Map evidence, conclusions, unknowns, and human actions in an AI answer. Estimated learning time: 12 minutes.
- [Create a Trip Brief](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/turn-a-travel-idea-into-a-trip-brief): Turn a travel idea into a clear brief before asking AI to plan. Estimated learning time: 14 minutes.
- [Compare Destinations](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/choose-a-destination-with-ai): Search with AI and decide whether the evidence supports a destination. Estimated learning time: 15 minutes.
- [Check Entry Requirements](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/check-entry-requirements-with-ai): Build an entry checklist from official rules without guessing missing personal facts. Estimated learning time: 18 minutes.
- [Compare Travel Options](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/compare-travel-options-with-ai): Compare exact-date travel options with a corrected budget and fair live checkout. Estimated learning time: 17 minutes.
- [Compare Places to Stay](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/choose-where-to-stay-with-ai): Choose where to stay without declaring a winner the evidence cannot support. Estimated learning time: 17 minutes.
- [Choose Experiences](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/choose-experiences-and-reservations-with-ai): Choose travel experiences without inventing dates or overcommitting the plan. Estimated learning time: 17 minutes.
- [Build a Trip Budget](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/build-and-stress-test-a-trip-budget-with-ai): Build a transparent trip budget and correct a false affordability claim. Estimated learning time: 19 minutes.
- [Build an Itinerary](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/build-a-day-by-day-itinerary-with-ai): Build a realistic itinerary without invented precision or a disconnected budget. Estimated learning time: 18 minutes.
- [Audit Your Travel Plan](https://ailesson.io/courses/plan-a-trip-with-ai/lessons/audit-and-finalize-a-travel-plan-with-ai): Audit a travel plan for unsafe purchases and turn it into an action list. Estimated learning time: 21 minutes.
- [What Is an Agent Skill?](https://ailesson.io/courses/agent-skills-for-beginners/lessons/agent-skills-basics): Distinguish AI, AI agents, and Agent Skills through a simple comparison. Estimated learning time: 10 minutes.
- [Why Save Instructions as a Skill?](https://ailesson.io/courses/agent-skills-for-beginners/lessons/benefits-of-agent-skills): Judge a Skill’s benefits and limits from real quiz behavior. Estimated learning time: 8 minutes.
- [When Is a Skill the Right Fit?](https://ailesson.io/courses/agent-skills-for-beginners/lessons/when-to-use-agent-skills): Define a Skill’s boundary by separating similar requests with different outcomes. Estimated learning time: 8 minutes.
- [How Does an Agent Find a Skill?](https://ailesson.io/courses/agent-skills-for-beginners/lessons/agent-skills-in-action): See how a Skill’s name and description tell an Agent when to open it. Estimated learning time: 8 minutes.
- [What Goes in SKILL.md?](https://ailesson.io/courses/agent-skills-for-beginners/lessons/build-your-first-agent-skill): Choose essential instructions and inspect a complete single-file Skill. Estimated learning time: 12 minutes.
- [How Do You Know It Works?](https://ailesson.io/courses/agent-skills-for-beginners/lessons/test-an-agent-skill): Evaluate a Skill with complete quiz records and three kinds of checks. Estimated learning time: 20 minutes.
- [Turn a Decision into a Research Brief](https://ailesson.io/courses/research-a-topic-with-ai/lessons/turn-a-decision-into-a-research-brief): Define the decision, context, and boundaries before asking AI to research. Estimated learning time: 12 minutes.
- [Plan the Questions and Evidence](https://ailesson.io/courses/research-a-topic-with-ai/lessons/plan-the-questions-and-evidence): Turn a decision into research questions, evidence needs, and a stopping rule. Estimated learning time: 11 minutes.
- [Find Sources with AI](https://ailesson.io/courses/research-a-topic-with-ai/lessons/find-sources-with-ai): Use AI to find sources, then verify citations before using them as evidence. Estimated learning time: 15 minutes.
- [Check What the Sources Actually Support](https://ailesson.io/courses/research-a-topic-with-ai/lessons/check-what-the-sources-actually-support): Compare AI extraction with original sources and correct claims that go too far. Estimated learning time: 15 minutes.
- [Compare Evidence and Preserve Uncertainty](https://ailesson.io/courses/research-a-topic-with-ai/lessons/compare-evidence-and-preserve-uncertainty): Compare sources without erasing disagreement, limits, or unknowns. Estimated learning time: 12 minutes.
- [Produce a Decision-Ready Research Brief](https://ailesson.io/courses/research-a-topic-with-ai/lessons/produce-a-decision-ready-research-brief): Turn verified evidence into a conditional recommendation and clear next step. Estimated learning time: 16 minutes.
- [What Is Vibe Coding?](https://ailesson.io/courses/vibe-coding-for-beginners/lessons/what-is-vibe-coding): Decide whether a small software task fits Vibe Coding and identify the decisions that still belong to you. Estimated learning time: 8 minutes.
- [Choose a Vibe Coding Tool](https://ailesson.io/courses/vibe-coding-for-beginners/lessons/choose-a-vibe-coding-tool): Choose an AI coding starting point from the task's current state, setup needs, and required level of control. Estimated learning time: 10 minutes.
- [Plan Your First App](https://ailesson.io/courses/vibe-coding-for-beginners/lessons/plan-your-first-app): Turn a vague App idea into a bounded brief with a complete user path and observable success conditions. Estimated learning time: 12 minutes.
- [Build Your First App with Replit](https://ailesson.io/courses/vibe-coding-for-beginners/lessons/build-your-first-app-with-replit): Follow a bounded Replit build and inspect the first runnable Preview without treating it as a finished product. Estimated learning time: 10 minutes.
- [Test Your Replit App](https://ailesson.io/courses/vibe-coding-for-beginners/lessons/test-your-replit-app): Run observable checks against the original brief and record what passed, failed, or remains unverified. Estimated learning time: 12 minutes.
- [Fix One Problem with Replit](https://ailesson.io/courses/vibe-coding-for-beginners/lessons/fix-one-problem-with-replit): Turn one observed Reset failure into a focused repair request, then retest the repaired path without hiding what remains unknown. Estimated learning time: 12 minutes.
- [Hand Off a Replit Project to Codex](https://ailesson.io/courses/vibe-coding-for-beginners/lessons/move-your-replit-project-to-codex): Inspect project evidence, identify a genuine file-level need, and prepare a bounded Replit-to-Codex handoff. Estimated learning time: 14 minutes.
- [Verify and Hand Off a Codex Change](https://ailesson.io/courses/vibe-coding-for-beginners/lessons/make-verify-and-hand-off-a-change-with-codex): Approve one exact Codex change, review its diff and checks, and hand off the working state with honest limitations. Estimated learning time: 16 minutes.
- [Frame the Product Decision](https://ailesson.io/courses/make-product-decisions-with-ai/lessons/frame-the-product-decision): Turn a rushed feature request into a clear, evidence-aware next decision. Estimated learning time: 16 minutes.
- [Analyze Feedback without Losing the Evidence](https://ailesson.io/courses/make-product-decisions-with-ai/lessons/analyze-feedback-without-losing-the-evidence): Organize product feedback without losing its sources, exceptions, or uncertainty. Estimated learning time: 14 minutes.
- [Reconcile Feedback, Metrics, and Team Claims](https://ailesson.io/courses/make-product-decisions-with-ai/lessons/reconcile-feedback-metrics-and-team-claims): Compare feedback, metrics, and team input without inventing cause or intent. Estimated learning time: 13 minutes.
- [Define the Problem and Compare Responses](https://ailesson.io/courses/make-product-decisions-with-ai/lessons/define-the-problem-and-compare-responses): Define a bounded product problem and compare realistic responses. Estimated learning time: 13 minutes.
- [Make a Conditional Product Recommendation](https://ailesson.io/courses/make-product-decisions-with-ai/lessons/make-a-conditional-product-recommendation): Turn options into a traceable recommendation with clear limits and ownership. Estimated learning time: 12 minutes.
- [Challenge and Revise the Product Decision](https://ailesson.io/courses/make-product-decisions-with-ai/lessons/challenge-and-revise-the-product-decision): Audit a recommendation independently and revise it into an accountable handoff. Estimated learning time: 21 minutes.
- [Changelog](https://ailesson.io/changelog): User-visible changes in each AILesson release.
- [Privacy policy](https://ailesson.io/privacy): How AILesson handles personal information.
- [Terms of service](https://ailesson.io/terms): Terms for using AILesson.
- [Subscription terms](https://ailesson.io/subscription-terms): Terms specific to paid memberships.