AI Tool

Claude.ai — How to Use Claude

Claude is Anthropic's AI assistant — available at claude.ai and in the Claude app. This guide is for people using Claude through the consumer interface rather than the API. It covers everything Claude can do in practice: long documents, artefacts, projects, extended thinking, and the features that make Claude distinctively useful for professional and creative work.

AI Tool

What Claude is

Claude is an AI assistant made by Anthropic. You talk to it at claude.ai or in the Claude mobile app. It reads and writes text, understands and creates code, analyses documents, and helps with an enormous range of tasks — from drafting emails to reviewing contracts to writing software.

Claude is particularly known for three things: handling very long documents (it can read a full book or a large codebase in one conversation), following complex instructions carefully and consistently, and being genuinely useful for professional work rather than just answering questions.

Claude vs ChatGPT — the practical difference: Both are capable AI assistants. Claude tends to give more nuanced, careful responses and excels at long-context work. ChatGPT has a larger plugin ecosystem and is more widely known. Many professionals use both for different tasks.

The key features to know

  • Projects — persistent workspaces where Claude remembers your context across multiple conversations. Tell Claude once what you are working on, your role, and your preferences, and it carries this into every conversation in that project.
  • Artefacts — when Claude produces a document, code, or other substantial piece of content, it appears in a separate panel you can edit directly, copy, or download.
  • Long context window — Claude can handle very long inputs. Paste an entire research report, a full codebase, a lengthy contract, or a book chapter and ask questions about it.
  • Extended thinking — on complex problems, Claude can be instructed to think through a problem step by step before giving its final answer, producing more reliable results on difficult tasks.
  • Voice mode — speak to Claude and hear responses read back. Available in the Claude mobile app.

What Claude is best at

Reading and analysing documents — contracts, research papers, reports, datasets. Paste the document and ask questions, request summaries, or ask Claude to identify specific information.

Writing that requires careful instruction-following — style guides, specific tone requirements, structured formats, templates. Claude tends to follow detailed instructions more consistently than most alternatives.

Code review and explanation — paste code and ask Claude to explain it, find bugs, suggest improvements, or refactor it to meet specific requirements.

Extended professional work — multi-step projects like research synthesis, drafting documents with multiple sections, or iterating on complex creative work benefit from Projects and the long context window.

Setting up Projects effectively

Projects are the most underused feature in Claude. Create a project for each ongoing area of work (client, topic, or project type). In the project instructions, tell Claude: your role and context, any preferences or constraints, recurring tasks, and how you want it to respond. This context persists across every conversation in the project — no need to re-explain yourself each time.

Example project instructions: "I am a marketing manager at [company type]. I work on B2B content — blog posts, case studies, and email campaigns. Always use active voice. Avoid marketing jargon. When I ask for drafts, give me one version, not multiple options, unless I ask."

Prompts for Claude

Analyse a long document
Here is [document type — contract / research paper / report / transcript]. Please: (1) give a 3-paragraph summary covering the main points, (2) identify the 5 most important specific facts or figures, (3) flag anything unusual, concerning, or that I should pay particular attention to: [paste document]
Set up a Project system prompt
I want to set up a Claude Project for [describe your work]. Write a project instructions block that tells Claude: my role and context, the types of tasks I'll use it for, my preferred output format and tone, any constraints or things to avoid, and how to handle ambiguity.
Review and improve writing
Please review the following [document type]. First give me an overall assessment (1-2 sentences). Then provide specific suggestions for: clarity, structure, tone, and any factual or logical issues. Finally, rewrite the weakest paragraph to show what an improved version would look like: [paste text]
Extract structured information from a document
From the following [document type], extract all instances of [type of information — e.g. dates and deadlines / prices and fees / names and contact details / action items] and present them in a structured table. If any information is ambiguous or missing, flag it: [paste document]
Code review with specific criteria
Review the following code for: (1) bugs or logical errors, (2) security vulnerabilities, (3) performance issues, (4) readability and maintainability. For each issue found, explain the problem and provide a corrected version. Prioritise by severity: [paste code]
Explain extended thinking
I want Claude to think through this problem carefully before answering. Work through it step by step, show your reasoning, identify any assumptions you are making, and flag where you are uncertain: [complex question or problem]
Synthesise multiple sources
I have [number] documents on [topic]. Read all of them and produce a synthesis that: (1) identifies the main areas of agreement, (2) identifies significant differences or contradictions, (3) draws overall conclusions, (4) notes any important gaps. Documents: [paste all documents]
Draft with strict style requirements
Write [document type] on [topic]. Style requirements: [list specific requirements — length, tone, structure, vocabulary level, perspective, any phrases to include or avoid]. Show a draft, then wait for my feedback before revising.
Compare Claude Pro vs Free for my use
I currently use Claude Free. Describe exactly what additional capabilities I would get on Claude Pro, based on my typical use: [describe how you use Claude — types of tasks, frequency, document sizes]. Is the upgrade worth it for my use case?
Use artefacts for document creation
Create [document type] on [topic]. Format it as a proper document with headings, sections, and professional structure. I want to be able to edit it directly and download it.

The model family (April 2026)

Claude is available in three model tiers:

  • Claude Haiku — fastest, most efficient, used for quick tasks and high-volume applications
  • Claude Sonnet — the balanced default, best performance-to-speed ratio for most tasks. Claude 3.5 Sonnet is the primary model on the Free and Pro tiers.
  • Claude Opus — most capable, slowest. Pro and Team plans. For the most complex reasoning, analysis, and creative tasks.

On claude.ai, the Free tier uses Claude 3.5 Sonnet with usage limits. Pro unlocks higher usage and access to Opus. The specific models available update as new versions are released — check anthropic.com/claude for the current model lineup.

Constitutional AI — how Claude is trained

Anthropic trains Claude using a method called Constitutional AI (CAI), published in a 2022 research paper (Bai et al., arXiv:2212.08073). CAI involves training the model to evaluate and revise its own outputs against a set of principles (the "constitution") — covering helpfulness, harmlessness, and honesty — rather than relying solely on human feedback for every behaviour. This approach is designed to produce models that are more reliably aligned with intended values at scale. The full Anthropic model card and Constitutional AI paper are publicly available at anthropic.com/research.

Context window

Claude 3.5 Sonnet has a 200,000-token context window — approximately 150,000 words or roughly 500 pages of text. This is one of the largest context windows available in a consumer AI product and is the basis for Claude's document analysis and long-context capabilities. For comparison, a typical novel is 70,000-100,000 words; an entire codebase for a medium-sized application typically falls within this window.

Privacy and data handling

By default on claude.ai, conversations may be used by Anthropic to improve models. Users can opt out of this in Settings. On Claude Team plans, conversations are not used for model training by default. Full privacy policy at anthropic.com/legal/privacy.

Official resources

Source note: Pricing from claude.ai/upgrade. Technical specifications from Anthropic model documentation. Constitutional AI from Bai et al. (2022), arXiv:2212.08073. All verified April 2026.