Anthropic logo, creators of Claude 4

Claude 4 / Opus 4: Frontier Reasoning

Product LaunchesThe Agentic Era
Impact

What Happened

Anthropic released Claude 4 Opus, a model with significantly enhanced reasoning, extended thinking capabilities, and the ability to sustain complex multi-step problem-solving over long contexts. It excelled at agentic tasks, code generation, and nuanced analysis.

Why It Mattered

Pushed the frontier of what AI assistants could accomplish autonomously. Extended thinking allowed the model to 'work through' complex problems systematically, approaching human expert-level performance on challenging tasks.

Organizations

Tags

Part of the The Agentic Era (2025–2026) era · Browse all product launches · View all 2025 milestones

Related Milestones

Anthropic logo, creators of Claude 4.5 Opus
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Claude 4.5 / 4.6 Opus: Frontier Agentic Capability

Anthropic released Claude 4.5 and 4.6 Opus, representing the frontier of AI capability in early 2026. These models demonstrated unprecedented reasoning depth, coding ability, and capacity for autonomous multi-step work. They could sustain complex agentic workflows, manage entire projects, and collaborate with other AI agents.

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Anthropic logo, creators of Claude 3
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Claude 3: Approaching Human-Level

Anthropic launched the Claude 3 family (Haiku, Sonnet, Opus), with Claude 3 Opus matching or exceeding GPT-4 on most benchmarks. It featured a 200K token context window, strong reasoning, nuanced instruction-following, and a 'personality' that users found distinctively thoughtful and careful.

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Anthropic logo
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Claude 3.5 Sonnet: A Leading Coding Model

Anthropic's Claude 3.5 Sonnet emerged as one of the strongest widely used models for coding tasks, with developers praising its code generation, debugging, and software engineering capabilities. It powered tools like Claude Code, enabling AI to work directly inside developer environments.

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OpenAI logo
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OpenAI o3: Advanced Reasoning at Scale

OpenAI released o3, the successor to o1, with markedly improved reasoning capabilities. It posted state-of-the-art results on many math and coding benchmarks and handled problems that previously required expert-level multi-step analysis.

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Anthropic logo, creators of Claude
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Claude: Constitutional AI

Anthropic released Claude, an AI assistant built with Constitutional AI (CAI) — a novel approach where the model is trained to follow a set of principles rather than just optimizing for human preference ratings. Anthropic, founded by former OpenAI researchers, positioned Claude as the safety-focused alternative.

Dario AmodeiDaniela AmodeiAnthropic

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