Anthropic just dropped Claude Opus 4.6—and it's not just an upgrade, it's a generational leap. Released February 5, 2026, this is the most capable AI model ever created for professional work, featuring revolutionary agent teams, a massive 1 million token context window, and coding capabilities that outperform every competitor.
But that's not all. Within hours of release, Opus 4.6 has already discovered over 500 zero-day security vulnerabilities in open-source software—a feat that would take human security researchers months or years.
Here's everything you need to know about Claude Opus 4.6.
Table of Contents
- What's New in Opus 4.6
- Agent Teams: Multi-Agent Orchestration
- 1 Million Token Context Window
- Coding Capabilities
- Benchmark Results
- 500 Zero-Day Vulnerabilities Discovered
- Opus 4.6 vs GPT-5.3-Codex
- New Developer Features
- Productivity Integrations
- Safety Improvements
- What Developers Are Saying
- Pricing and Availability
- Getting Started
What's New in Opus 4.6
Claude Opus 4.6 represents Anthropic's most significant model release to date. The improvements span every dimension of capability:
- Agent Teams — Multi-agent orchestration for parallel task execution
- 1M Token Context — First Opus-class model with million-token context (beta)
- Superior Coding — #1 on Terminal-Bench 2.0 and SWE-Bench Pro
- Better Planning — More careful reasoning on complex tasks
- Longer Sessions — Sustains agentic tasks for extended periods
- Self-Debugging — Catches its own mistakes during code review
- Compaction — Summarizes context to run longer without hitting limits
- Adaptive Thinking — Automatically adjusts reasoning depth
- PowerPoint & Excel — New productivity integrations
Agent Teams: Multi-Agent Orchestration
The headline feature of Opus 4.6 is agent teams—a revolutionary approach to AI-assisted development available in Claude Code.
How Agent Teams Work
Instead of a single agent working sequentially through tasks, Opus 4.6 can now:
- Analyze the task and identify independent subtasks
- Spawn specialized sub-agents for different components
- Run tools and agents in parallel
- Coordinate results back to the main agent
- Identify blockers with precision
Think of it like having a team of senior engineers working on your codebase simultaneously—one handling the frontend, another the API, another writing tests—all coordinating autonomously.
Real-World Impact
Early access partners reported dramatic improvements:
"Claude Opus 4.6 is a huge leap for agentic planning. It breaks complex tasks into independent subtasks, runs tools and subagents in parallel, and identifies blockers with real precision."
— Replit team
"Claude Opus 4.6 autonomously closed 13 issues and assigned 12 issues to the right team members in a single day, managing a ~50-person organization across 6 repositories."
— Enterprise partner
1 Million Token Context Window
For the first time, an Opus-class model gets the massive context window previously reserved for Sonnet models. This is currently in beta and represents a qualitative shift in what's possible.
What 1 Million Tokens Means
- ~750,000 words — Entire novels, complete codebases
- Full repositories — Load your entire project in one session
- Research papers — Analyze dozens of papers simultaneously
- Extended conversations — Days of context without losing thread
Reduced Context Rot
A common complaint about AI models is "context rot"—where performance degrades as conversations grow longer. Opus 4.6 shows dramatic improvement:
| Benchmark | Opus 4.6 | Sonnet 4.5 |
|---|---|---|
| MRCR v2 (8-needle, 1M) | 76% | 18.5% |
This is a 4x improvement in long-context performance. Opus 4.6 can find buried details that even Opus 4.5 would miss.
Coding Capabilities
Opus 4.6 was built for developers. The improvements in software engineering are substantial:
Planning and Execution
- More careful planning — Thinks deeply about architecture before writing code
- Better judgment — Handles ambiguous requirements with improved intuition
- Longer sessions — Stays productive over extended coding sessions
- Large codebase navigation — Reliably operates in massive repositories
Code Review and Debugging
- Self-debugging — Catches its own mistakes during review
- Better code review — More thorough analysis of potential issues
- Fewer tokens — Achieves better results with less context usage
Multi-Language Support
Opus 4.6 shows strong performance across programming languages, not just Python. SWE-Bench Pro tests span four languages with more contamination-resistant, diverse evaluations.
Benchmark Results
The numbers speak for themselves. Opus 4.6 leads or matches every frontier model on key evaluations:
| Benchmark | What It Measures | Opus 4.6 Result |
|---|---|---|
| Terminal-Bench 2.0 | Agentic coding capabilities | #1 (Highest Score) |
| Humanity's Last Exam | Complex multidisciplinary reasoning | #1 (Leads all models) |
| GDPval-AA | Knowledge work (finance, legal, etc.) | +144 Elo vs GPT-5.2 |
| BrowseComp | Finding hard-to-locate information | #1 (Best in industry) |
| BigLaw Bench | Legal reasoning | 90.2% (40% perfect scores) |
| SWE-Bench Pro | Real-world software engineering | State-of-the-art |
| OSWorld | Computer use / desktop tasks | Far stronger than previous GPT models |
GDPval-AA: The Knowledge Work Benchmark
GDPval-AA measures performance on economically valuable knowledge work tasks across finance, legal, and other professional domains. The results are striking:
- +144 Elo vs GPT-5.2 (OpenAI's best)
- +190 Elo vs Claude Opus 4.5
This is the largest gap between frontier models on a major benchmark.
500 Zero-Day Vulnerabilities Discovered
In a stunning demonstration of capability, Opus 4.6 has already discovered over 500 previously unknown high-severity security vulnerabilities in open-source software libraries—with little to no prompting.
Why This Matters
According to Axios, who broke the exclusive story:
"The advancement signals an inflection point for how AI tools can help cyber defenders, even as AI is also making attacks more dangerous."
This is unprecedented. Finding 500 zero-days would typically require:
- Teams of security researchers
- Months or years of work
- Millions of dollars in resources
Opus 4.6 did it autonomously.
Cybersecurity Performance
In controlled testing:
"Across 40 cybersecurity investigations, Claude Opus 4.6 produced the best results 38 of 40 times in a blind ranking against Claude 4.5 models. Each model ran end to end on the same agentic harness with up to 9 subagents and 100+ tool calls."
— Security testing partner
Anthropic is accelerating defensive use of the model to help patch vulnerabilities in open-source software.
Opus 4.6 vs GPT-5.3-Codex: The Same-Day Battle
In a remarkable coincidence, OpenAI released GPT-5.3-Codex on the exact same day as Opus 4.6. This sets up a direct competition for the title of best agentic coding model.
Head-to-Head Comparison
| Feature | Claude Opus 4.6 | GPT-5.3-Codex |
|---|---|---|
| Context Window | 1M tokens (beta) | Not disclosed |
| Agent Teams | Yes (native) | No (single agent) |
| Terminal-Bench 2.0 | #1 | #2 |
| GDPval-AA | +144 Elo vs GPT-5.2 | Matches GPT-5.2 |
| Self-Training | No | Yes (used to train itself) |
| Pricing (Input) | $5/M tokens | Not disclosed |
| Pricing (Output) | $25/M tokens | Not disclosed |
Key Differentiators
Opus 4.6 advantages:
- Agent teams for parallel execution
- 1M token context window
- Better long-context performance
- Lower context rot
- Transparent pricing
GPT-5.3-Codex advantages:
- Interactive steering while working
- 25% faster than 5.2-Codex
- Self-improvement capability
New Developer Features
Beyond the headline capabilities, Opus 4.6 introduces several features for developers building with the API:
Compaction
Claude can now summarize its own context to continue running without hitting token limits. This is essential for long-running agentic workflows.
Previously, extended tasks would fail when hitting context limits. Now, Claude compacts intelligently and keeps working.
Adaptive Thinking
Previously, developers had a binary choice: extended thinking on or off. Now, with adaptive thinking, Claude can decide when deeper reasoning would be helpful.
- Simple questions → Quick, efficient answers
- Complex problems → Deeper analysis and reasoning
The model picks up on contextual clues to adjust automatically.
Effort Controls
New /effort parameter gives fine-grained control over the intelligence/speed/cost tradeoff:
- High (default) — Maximum capability, may overthink simple tasks
- Medium — Balanced for most use cases
- Low — Fast responses for simple queries
If Opus 4.6 is overthinking on a given task, dial effort down to medium.
Productivity Integrations
Opus 4.6 isn't just for developers. New integrations bring Claude into everyday work:
Claude in PowerPoint (Research Preview)
Create and edit presentations with AI assistance. Claude can:
- Generate slide decks from descriptions
- Improve existing presentations
- Add visual elements and formatting
- Research and populate content
Claude in Excel (Upgraded)
Substantial upgrades to spreadsheet capabilities:
- Complex formula generation
- Data analysis and visualization
- Automated report creation
- Financial modeling assistance
Cowork: Autonomous Multitasking
Within Cowork, Claude can multitask autonomously on your behalf—running financial analyses, doing research, and creating documents simultaneously.
Safety Improvements
These intelligence gains do not come at the cost of safety. According to Anthropic's extensive system card:
- Low misaligned behavior — Deception, sycophancy, and misuse cooperation rates remain low
- Well-aligned — As aligned as Opus 4.5, previously the most-aligned frontier model
- Lowest over-refusals — Better at answering benign queries without false positives
New Safety Evaluations
Opus 4.6 received the most comprehensive safety testing of any Anthropic model:
- New user wellbeing evaluations
- More complex refusal testing
- Updated surreptitious action evaluations
- Interpretability experiments to understand behavior
Cybersecurity Safeguards
Given enhanced cybersecurity capabilities, Anthropic developed six new probes to detect potential misuse. Real-time intervention may be implemented to block abuse.
What Developers Are Saying
Early access partners are enthusiastic:
"Claude Opus 4.6 is the strongest model Anthropic has shipped. It takes complicated requests and actually follows through, breaking them into concrete steps, executing, and producing polished work even when the task is ambitious. For Notion users, it feels less like a tool and more like a capable collaborator."
— Notion team
"Claude Opus 4.6 feels noticeably better than Opus 4.5 in Windsurf, especially on tasks that require careful exploration like debugging and understanding unfamiliar codebases. We've noticed Opus 4.6 thinks longer, which pays off when deeper reasoning is needed."
— Windsurf team
"Claude Opus 4.6 handled a multi-million-line codebase migration like a senior engineer. It planned up front, adapted its strategy as it learned, and finished in half the time."
— Enterprise partner
"Claude Opus 4.6 is an uplift in design quality. It works beautifully with our design systems and it's more autonomous, which is core to Lovable's values. People should be creating things that matter, not micromanaging AI."
— Lovable team
"The performance jump with Claude Opus 4.6 feels almost unbelievable. Real-world tasks that were challenging for Opus 4.5 suddenly became easy. This feels like a watershed moment for spreadsheet agents."
— Shortcut team
"We only ship models in v0 when developers will genuinely feel the difference. Claude Opus 4.6 passed that bar with ease. Its frontier-level reasoning, especially with edge cases, helps v0 to deliver on our number-one aim: to let anyone elevate their ideas from prototype to production."
— Vercel v0 team
Pricing and Availability
Opus 4.6 maintains the same pricing as its predecessor:
| Tier | Price |
|---|---|
| Input tokens | $5 per million tokens |
| Output tokens | $25 per million tokens |
Model ID
Use claude-opus-4-6 in your API calls.
Availability
Claude Opus 4.6 is available now on:
- claude.ai — Web interface
- Claude API — Direct integration
- Amazon Bedrock — AWS integration
- Google Cloud Vertex AI — GCP integration
- Perplexity — Already added to model list
Getting Started with Opus 4.6
For Developers
- Update your API calls to use
claude-opus-4-6 - Explore agent teams in Claude Code
- Test compaction for long-running tasks
- Experiment with effort controls for cost optimization
For Teams
If you need AI automation with enterprise-grade security—without the complexity of managing local agents—consider Serenities AI. We offer:
- Claude integration — Access Opus 4.6 through your existing subscriptions
- No local execution — Secure, cloud-based automation
- 10-25x cheaper — Use AI subscriptions instead of expensive API pricing
The Bottom Line
Claude Opus 4.6 is the most capable AI model available for professional work. The combination of:
- Agent teams for parallel execution
- 1M token context for massive codebases
- State-of-the-art coding on every benchmark
- 500 zero-days discovered demonstrating security capabilities
...makes it the clear choice for developers, knowledge workers, and enterprises.
The same-day release of GPT-5.3-Codex signals we're in a new era of AI competition. For users, this means better tools, faster progress, and more capability than ever before.
Available now at claude.ai and the Claude API.