Anthropic Launches Claude Opus 4.6

Anthropic has released Claude Opus 4.6, an upgraded version of its most advanced artificial intelligence model, significantly intensifying competition with OpenAI’s ChatGPT and Google’s Gemini. The launch comes as rivalry among frontier AI models accelerates, with companies racing to deliver stronger reasoning, coding, and long-context capabilities.

The new model brings major improvements over its predecessor, particularly in coding, reasoning, and autonomous task execution, positioning Claude Opus 4.6 as a powerful option for developers and enterprises working with large, complex systems.

Major Upgrade: 1 Million Token Context Window

For the first time in the Opus lineup, Anthropic has introduced a 1 million token context window in beta. This allows Claude Opus 4.6 to process and retain vastly larger amounts of information within a single session, making it well-suited for:

• Large codebase analysis

• Long-running autonomous agents

• Deep research and financial analysis

• Complex document and knowledge workflows

Anthropic says the expanded context window directly addresses challenges like “context rot”, where models lose accuracy or coherence as context grows.

Stronger Agentic Coding and Autonomous Workflows

Improved Planning and Error Detection

According to Anthropic, Claude Opus 4.6:

• Plans more carefully

• Sustains agentic workflows for longer durations

• Performs stronger code review and debugging

• Can catch and correct its own errors

Beyond software development, the model is designed for complex knowledge work, including financial modelling, legal analysis, research tasks, and the creation of documents, spreadsheets, and presentations.

Claude Opus 4.6 Inside Cowork

Within Cowork, Anthropic’s autonomous multitasking environment, Opus 4.6 can combine these capabilities to execute multi-step tasks with minimal human oversight, further reinforcing its positioning as an agent-first model.

Benchmark Performance: Claude Takes the Lead

Anthropic claims state-of-the-art results across multiple evaluations.

Key Benchmark Highlights

• Terminal-Bench 2.0: Opus 4.6 leads this agentic coding benchmark

• Humanity’s Last Exam: Tops the multidisciplinary reasoning test

• GDPval-AA: Outperforms OpenAI’s GPT-5.2 by roughly 144 Elo points and its own predecessor by 190 points

• BrowseComp: Achieves the best results in locating difficult-to-find information online

Anthropic argues that these results demonstrate a broader leap in long-context reasoning and retrieval, an area where many AI models still struggle.

Needle-in-a-Haystack Test With 1M Tokens

On MRCR v2, a needle-in-a-haystack benchmark using a 1 million token context:

• Claude Opus 4.6 scored 76%

• Claude Sonnet 4.5 scored 18.5%

Anthropic describes this gap as a qualitative shift in how effectively large contexts can be used without performance degradation.

Safety and Alignment Remain a Focus

Anthropic says performance gains did not come at the expense of safety. According to the system card:

• Opus 4.6 shows low rates of misaligned behaviour

• Reduced instances of deception or over-compliance

• Fewer unnecessary refusals compared to earlier Claude models

The company has also introduced new cybersecurity probes in response to the model’s stronger defensive and offensive security capabilities.

Product and API Updates Alongside the Model

Developer-Focused Enhancements

Alongside Claude Opus 4.6, Anthropic rolled out several updates:

• Adaptive thinking with adjustable reasoning effort

• Context compaction for longer-running agents

• Maximum output length increased to 128,000 tokens

• US-only inference option available at a premium

Agent Teams and Productivity Tools

• Agent teams in Claude Code allow multiple AI agents to work in parallel on large codebases

• Claude for Excel has received upgrades

• A research preview of Claude in PowerPoint is now available for Max, Team, and Enterprise users

Availability and Pricing

Claude Opus 4.6 is available:

• On claude.ai

• Via the Claude API

• Across major cloud platforms

Pricing remains unchanged at $5 per million input tokens and $25 per million output tokens.

Why Claude Opus 4.6 Matters

With a massive context window, benchmark-leading performance, and stronger agentic capabilities, Claude Opus 4.6 signals a major step forward for Anthropic as competition with OpenAI and Google intensifies. The release highlights how frontier AI models are shifting from simple chatbots toward long-running, autonomous systems capable of handling real-world complexity at scale.