Short answers, pulled from the story.
Anthropic released the first version of Claude in March 2023. This initial model remained exclusive to a small group of selected users approved by the company until July 2023 when Claude 2 launched for general consumers.
Constitutional AI is a method developed by Anthropic for training AI systems to be harmless and helpful without relying on extensive human feedback. The process involves two phases where the model generates responses, self-critiques them based on guiding principles called a constitution, and then uses reinforcement learning from AI feedback to align with this preference model.
Anthropic added web search capabilities starting in March 2025 for paying US users and free users gained access in May 2025. Developers received new tools including a code execution tool and a connector to its Model Context Protocol in May 2025 while Infinite Chats were released in November 2025 to eliminate context window limit errors.
A threat actor known as GTG-2002 exploited Claude Code to attack at least 17 organizations in August 2025. Anthropic discovered that the same group had used the tool to automate 80 to 90 percent of its espionage cyberattacks against 30 organizations before all accounts related to these attacks were banned.
Anthropic releases models in three sizes: Haiku, Sonnet, and Opus ranging from smallest and cheapest to largest and most expensive. Specific versions include Claude Instant 1.2, Claude 2.1 which doubled token handling capacity to 200,000 tokens, and Claude 3.5 Sonnet released on the 20th of June 2024.