Claude is a series of large language models (LLMs) developed by the American software company Anthropic. The first Claude model was released as an AI-based chatbot in March 2023, and the system has since expanded into a range of products for conversation, software development, and enterprise automation. Claude is trained using a constitution, a technique created by Anthropic to improve ethical and legal compliance, and since Claude 3 each generation has typically been offered in three sizes: Haiku (least capable), Sonnet, and Opus (most capable). In 2026, Anthropic released Claude Mythos to a limited set of organizations, followed by Claude Fable, a version with stricter safeguards, to the general public.
Claude operates as a Generative AI assistant built on Large language model architecture, using techniques from Machine learning and Deep learning research. The models employ Transformer (architecture)-based designs with Multi-Head Attention and Positional Encoding mechanisms, and are optimized through methods such as Reinforcement Learning from AI Feedback (RLAIF) (reinforcement learning from AI feedback) and Temperature Scaling for response variability.
Products
Claude is available as a chatbot with features such as artifacts, introduced in June 2024, which allow the model to generate and interact with code snippets and documents. A web search feature was added in 2025. Subscription tiers include Claude Pro and Claude Max for individual users, with Max offering higher usage limits, and Claude Team and Claude Enterprise for organizations. According to card-spend data from Ramp, the share of businesses on its platform paying for Anthropic products rose 4.9 percentage points in February 2026 to 24.4%, the largest monthly gain recorded for the company.
A chat sharing feature lets users share conversations with anyone who has a link. In September 2025, Forbes reported that hundreds of shared Claude chats had appeared in Google Search results, following similar incidents with OpenAI's ChatGPT and xAI's Grok. In July 2026, shared chats and artifacts were again indexed by Google, with the BBC counting more than 200 instances, some containing health records and corporate documents. Technical analysis suggested that a robots.txt rule blocking crawlers from shared-chat pages also prevented them from reading the noindex directive. Anthropic said the listings were removed.
Application Programming Interface
Claude is also provided through an application programming interface (API). In October 2024, the "computer use" feature was introduced, allowing an application to call the Claude API to gain navigational control of the application via Claude's interpretation of screen content and simulation of keyboard and mouse input.
Claude Code
Claude Code, released in February 2025, is an agentic command line tool for delegating coding tasks from the terminal using natural language prompts. It was made generally available in May 2025 alongside Claude 4. Based on enterprise adoption, Anthropic reported a 5.5x increase in Claude Code revenue by July. On October 20, 2025, Anthropic launched a web version and a sandboxing feature. Coinciding with performance improvements tied to Claude Opus 4.5, Claude Code went viral during the 2025-2026 winter holidays, attracting many non-programmers who used it for vibe coding.
In August 2025, Anthropic reported that cybercriminals it designated "GTG-2002" had used Claude Code in a data-extortion campaign against at least 17 organizations. In November 2025, Anthropic said a China-based cybercrime group had used Claude Code to automate 80-90% of its espionage cyberattacks against 30 organizations. Claude Code is used by Microsoft and Google, and was used by OpenAI employees until August 2025, when Anthropic revoked OpenAI's API access, calling it a violation of its terms of service. In February 2026, Anthropic introduced Claude Code Security, which reviews codebases for vulnerabilities. In March 2026, the source code for the Claude Code command-line interface was leaked, revealing upcoming features and models. In May 2026, Anthropic introduced "Dreaming", a research-preview feature of its Managed Agents API that consolidates an agent's persistent memory between sessions.
Claude in Chrome and Claude Cowork
In August 2025, Anthropic released Claude for Chrome, a Google Cloud-adjacent browser extension for google-chrome that lets Claude browse websites and fill forms on the user's behalf. It launched as a pilot for 1,000 Max subscribers, with prompt-injection attacks succeeding 11.2% of the time after mitigations, and became generally available in August 2026.
Claude Cowork, released in January 2026 as a research preview, is a graphical tool aimed at non-technical users. It is available as a desktop application for Mac and Windows and through a web interface, providing Claude with access to a sandboxed shell and user-selected folders. A Wall Street Journal reporter noted user concerns about granting an AI agent broad access to a personal computer, and one early user reported that Cowork deleted all family photos when asked to organize a desktop, requiring restoration from an iCloud backup. In February 2026, Anthropic announced a wider enterprise release with connectors for Google Drive, Gmail, Docusign, and FactSet. In March 2026, Anthropic added Dispatch, which lets users send tasks from a phone to their computer. In August 2026, Cowork was made available in a sidebar of the Chrome browser.
Regulatory and Security Issues
In February 2026, the United States Department of Defense designated Anthropic a "supply chain risk" and ordered federal agencies to phase out Claude after the company refused to remove contractual prohibitions on using Claude for mass domestic surveillance and fully autonomous weapons. A federal judge blocked the designation in March 2026 and permanently set it aside in August 2026 as unconstitutional retaliation.