Claude is an AI assistant built by Anthropic PBC. It runs on Anthropic's Claude models, such as Opus, Sonnet and Haiku, which are large language models: neural networks trained on large amounts of text that generate text in reply to a prompt. Anthropic trains Claude with a method it calls Constitutional AI.
A user writes a request in a chat, on the web, in the iOS and Android apps or in the desktop app, and Claude answers. It writes and edits text, generates code, explains subjects, searches the web, analyzes data and makes charts, and it can create files and run code. It keeps a memory across conversations, and connectors, which use the Model Context Protocol (MCP), let it read and act in other apps such as Slack and Google Workspace. Paid plans add Claude Code, a coding tool, projects for organizing chats and documents, and more models.
Claude has five plans: Free with limited use, Pro and Max for individuals, and Team and Enterprise for organizations. Paid plans are monthly or yearly subscriptions with usage limits.