Claude

Claude is an AI assistant built by Anthropic. It runs in a browser at claude.ai and in matching desktop and mobile apps that share one account and one history, so a conversation started on a laptop can be picked up on a phone. There is nothing to install to try it and no configuration to work through: you type a request in plain language, read the answer, and refine from there.

What it handles best is anything made of language or information. Drafting and rewriting — emails, reports, documentation, applications. Summarising long or dense material down to the parts that actually matter. Explaining an unfamiliar subject at whatever level you ask for, from a one-line answer to a full walk-through. Reasoning through problems that have to be worked out step by step rather than looked up. It is also good at turning mess into structure: a wall of notes into a table, a transcript into action points, a vague idea into an outline you can argue with.

Files can be part of the conversation. PDFs, Word documents, spreadsheets, CSV exports, images, and source code can be uploaded and then questioned, summarised, compared, or used to check your own work. Projects group related conversations and reference files together, so ongoing work — a manuscript, a course, a codebase, a long research question — keeps its context instead of starting from nothing each session. Claude can also search the web when a question needs current information, and cites the pages it used so you can check them yourself.

Who is it for? Writers and editors who want a tireless second reader on a draft. Students and researchers moving through more source material than they have time for. Analysts and developers who paste in data, logs, or code and want structure, a bug found, or a plain explanation of what something does. Support, operations, and admin staff turning repetitive writing into a usable first draft. And anyone who would rather ask one careful question than open ten browser tabs.

No prompt-engineering skill is needed. Plain, specific requests work best, and the two things that improve an answer most are context and a stated goal: who the text is for, what you have already tried, what a good result would look like. Asking Claude to critique its own answer, or to give you the two strongest objections to it, is usually more productive than rephrasing the question.

The assistant runs on Anthropic's Claude model family, and which model you get depends on your plan. Claude Sonnet 5 is the default for free and Pro accounts — fast, and capable enough for most everyday work. Claude Opus 5 is the strongest option, meant for long, complex, or high-stakes tasks. Claude Haiku 4.5 is the lightweight one for short, quick requests. Paid plans let you switch between them from one conversation to the next.

Two limits are worth knowing before you lean on it. Claude can be fluent and wrong at the same time, so anything load-bearing — a figure, a citation, a legal or medical detail — needs checking against a real source; treat it as a well-read assistant, not a system of record. And every plan has usage limits: the free tier is the tightest, and a heavy session with large files can reach a cap before the day is out.

Getting started takes about a minute. Go to claude.ai, create a free account with an email address — no credit card — and start typing. A real task makes a better first test than a toy one: paste in something you actually have to write or read, and ask for a specific outcome. If the free plan runs out mid-task often enough to annoy you, that is the signal to consider Pro; if it never does, there is no reason to pay for it.

Developers who want Claude inside their own product use the Anthropic API instead. It is billed separately from claude.ai subscriptions and is not covered by a Pro or Max plan. Claude Code, Anthropic's terminal-based coding tool, is a separate product again, usable with a paid Claude plan or with API billing.