Claude is an advanced large language model developed by Anthropic, a company founded in 2021 by former OpenAI researchers Dario and Daniela Amodei. Positioned as a safety-first AI assistant, Claude is built on Constitutional AI principles and has evolved through multiple generations from a basic chatbot to a powerful coding, reasoning, and agentic AI platform. 1)
| Date | Model | Key Innovation | Status |
|---|---|---|---|
| Mar 2023 | Claude 1 | First public model by Anthropic | Retired |
| Jul 2023 | Claude 2 | Improved performance, longer responses, API access | Retired |
| Mar 2024 | Claude 3 (Haiku, Sonnet, Opus) | Three-tier family, vision, 200K context window | Retired |
| Jun 2024 | Claude 3.5 Sonnet | Mid-tier model that beat the flagship | Superseded |
| Oct 2024 | Claude 3.5 Sonnet v2 | Computer Use capability, upgraded Sonnet and Haiku | Superseded |
| Feb 2025 | Claude 3.7 Sonnet | Hybrid reasoning with extended thinking | Superseded |
| Feb 2025 | Claude Code | First agentic coding tool | Active |
| May 2025 | Claude 4 (Sonnet 4, Opus 4) | Claude Code goes mainstream | Active |
| Sep 2025 | Claude Sonnet 4.5 | Best coding model, 1M beta context | Superseded |
| Oct 2025 | Claude Haiku 4.5 | Smart model switching, budget tier | Active |
| Nov 2025 | Claude Opus 4.5 | 67 percent cheaper, best for coding and agents | Active |
| Feb 2026 | Claude Opus 4.6 | 1M context, Agent Teams, Adaptive Thinking | Active |
| Feb 2026 | Claude Sonnet 4.6 | Opus-level coding at lower cost, 94 percent computer use | Active |
Haiku is engineered for ultra-fast, low-latency responses, making it the model of choice for high-volume, real-time assistant applications and customer service bots.
Sonnet is Anthropic recommended default for most use cases, balancing cost, intelligence, context window size, and agentic capabilities. Sonnet 4.6 delivers 98 percent of Opus coding performance at one-fifth the cost. 3)
Opus is the premium flagship, designed for deep reasoning, expert science, multi-step planning, and large-scale code refactoring. Opus 4.6 features a 1M token context window in beta, Agent Teams for parallel workflows, and Adaptive Thinking that autonomously determines reasoning depth. 4)
Coding: Coding is the most common use case, accounting for 35 percent of conversations on Claude.ai. Opus 4.6 scores 80.8 percent on SWE-bench Verified, while Sonnet 4.6 scores 79.6 percent. 5)
Context Windows: Claude Enterprise offers 500K to 1M token context windows, enabling analysis of entire codebases and long documents. 6)
Agentic Workflows: Claude supports autonomous task completion with Claude Code, Cowork plugins for role-specific AI agents (launched January 2026), Agent Skills, and Agent Teams allowing multiple Claude-based agents to collaborate on end-to-end workflows. 7)
Multimodal Input: All modern Claude models (version 3 and later) support text and image understanding with 200K token context windows. 8)
Anthropic foundational approach emphasizes Constitutional AI principles, which guide controlled behavior including safeguards against hallucinations and sensitive content. The company implements hard-coded refusal patterns, bias audits, and human-in-the-loop review mechanisms. 9)
Claude has the lowest hallucination rate among major AI assistants, more likely to acknowledge uncertainty than provide incorrect answers with confidence. 10)
| Model | Input per 1M Tokens | Output per 1M Tokens |
|---|---|---|
| Sonnet 4.6 | $3 | $15 | |
| Opus 4.6 | $5 | $25 | |
| Haiku 4.5 | Budget tier | Budget tier |
Subscription tiers include Claude Free, Claude Pro ($20/month), Claude Max, Claude Team, and Claude Enterprise. 11)
Between November 2025 and February 2026, Claude usage diversified significantly. Approximately 49 percent of job categories have incorporated Claude for at least a quarter of their tasks. Directive conversations, where users delegate tasks entirely to Claude, rose from 27 percent in January 2025 to 39 percent in August 2025, reflecting growing trust in autonomous AI workflows. 12)
Claude popularity among paying U.S. consumers is growing significantly, though it remains behind ChatGPT in overall market penetration. 13)