What Is Claude? How to Use Anthropic's AI Assistant and What It Can Do in 2026
機械翻訳 / Machine-translated
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AI Friends
2026年4月22日・20分で読める
機械翻訳 / Machine-translated
@aifriends
AI Friends（https://aifriends.jp）のクロスポスト公式アカウント。AIツールの紹介・使い方・できることを、中学生でもわかるやさしい日本語で届けます。
Claude is a next-generation AI assistant developed by Anthropic.
Like ChatGPT (an AI you can have conversations with), Claude lets you chat naturally — but what sets Claude apart is that it is designed with a strong emphasis on safety and accuracy.
It has an exceptionally high ability to understand long texts all at once, and can process up to one million tokens (equivalent to several typical business books' worth of information).
As of April 2026, Claude has three main models:
The most capable Opus 4.6, the well-balanced Sonnet 4.6, and the fastest and most economical Haiku 4.5.
It fully supports Japanese, and a free plan is available, so anyone can try it easily.
Its high reading comprehension and text generation quality have made it particularly popular among business professionals, researchers, and engineers.
On April 17, 2026, Claude Design — a feature that automatically generates designs — was also newly released, making Claude even more versatile.
Claude is packed with features that make everyday life and work more convenient. Here are five standout capabilities as of 2026.
Claude is an AI assistant capable of natural conversation.
It supports a wide range of text-related tasks, including drafting emails, creating presentation materials, and summarizing papers.
In particular, because it can read and understand long texts all at once, it excels at analyzing hundreds of pages of PDFs or legal documents and distilling the key points.
Compared to ChatGPT, it is especially strong at delivering factually grounded, accurate answers, making it well-suited for business use.
Its Japanese-language quality is also high, producing natural-sounding text.
Claude Code is a powerful tool for people who write programs.
Simply give it an instruction in natural language — such as "Build this feature" — and it will automatically generate code spanning multiple files.
It can also find and fix bugs (errors in a program) and automatically run Git commands (a tool for managing program versions).
In the April 2026 update, a /loop command for repeating tasks on a schedule and an Agent Teams feature enabling multiple AIs to collaborate on work were added.
There is also a UI called Cowork that even non-engineers can use — just say "Organize the files on my desktop" and it will automate the task.
Claude Design is the latest feature, released on April 17, 2026.
Simply give it a text instruction, and it will automatically generate website designs, presentation materials, slides, and UI prototypes (mockups) for product specifications.
For example, tell it "Create a landing page to introduce our company" in Japanese, and it will produce a usable webpage design in about 15 minutes.
It is sometimes compared to Figma (a design tool), but the key difference is that Claude Design requires no specialist knowledge.
Even non-designers can create professional-quality materials and websites.
Claude can retain up to one million tokens (approximately 750,000 words — equivalent to several typical business books) of information at once.
This is because its context window (the amount of information an AI can hold in memory at one time) is extremely large.
You can upload long papers, contracts, or manuals all at once and ask it to "summarize this" or "explain what this says about ○○."
Tasks that used to be difficult for conventional AI — such as cross-referencing and analyzing large volumes of documents — can now be carried out smoothly.
It is particularly useful for analyzing months of meeting minutes in one go, or identifying inconsistencies in legal documents.
Claude can understand not only text but also images.
For example, you can upload an image of a chart or graph and ask "Explain what this shows," and it will read the data and provide an explanation.
Send it a photo of handwritten notes or a whiteboard, and it can convert the content to text.
You can also show it a screenshot of a webpage and ask "Suggest improvements to this design."
The ability to combine text and images in your questions greatly expands how you can use it.
Claude is easy to get started with in just three steps, even for beginners. Here is a guide to the basics.
On a computer, go to Claude's official website (claude.ai).
On a smartphone, download the Claude app from the App Store (iPhone) or Google Play (Android).
Log in with your Google account (Gmail address) or email address, and you can start right away.
If you don't have an account, you can register for free with just an email address.
In the text input field at the bottom of the screen, type your question or instruction directly in Japanese.
For example, type something like "What is AI?", "Write a reply to this email," or "Summarize this document" — just speak naturally as if you were talking to someone.
Press the Enter key or click the send button, and your answer will appear within seconds.
To upload a file, click the paperclip button and select a PDF or image.
Once Claude displays its response, review the content.
If you want to know more, you can follow up with questions like "Tell me more" or "Give me a specific example."
Claude remembers the flow of the conversation, so you don't need to repeat the same explanations over and over.
If you're not satisfied with the response, you can ask it to "Try again" and receive a different answer.
To use Claude Code, go to code.claude.com and log in with the same account.
Claude has both convenient aspects and points to be aware of. Before you start using it, take a look at the pros and cons.
Claude is especially well-suited for people who need to handle long documents or who prioritize accuracy. Specifically, it is recommended for:
On the other hand, other AI tools may be better suited for people who want to look up the latest news or enjoy free-form creative writing.
Also, if you want to use the most capable Opus model, you will need to subscribe to a paid plan, which increases costs.
If you value privacy, please note that content you input may be stored by Anthropic.
Claude is an AI assistant developed by Anthropic, designed with a focus on safety and accuracy, and can significantly improve efficiency in both daily life and work. Here is a summary of the key points in this article, including the latest information as of April 2026.
/loop command and Agent Teams feature in April 2026Claude is an extremely powerful tool, especially for people who need to handle long documents or who prioritize accuracy.
A free plan is available, so we recommend visiting the official site (claude.ai) and giving it a try yourself.
Try talking to it naturally in Japanese, as if you were asking a friend — something like "Write a reply to this email" or "Summarize this document."
It should make your daily life and work much more convenient.
This article is a cross-post from AI Friends.