Claude Opus 4.6 Review: Better Code, Bigger Context, Stronger AI

Quick answer: Claude Opus 4.6 is an AI model from Anthropic, released on February 5, 2026. It was the first Opus model with a 1 million token context window (beta), handles up to 128,000 output tokens, and costs $5 per million input tokens and $25 per million output tokens. It is no longer the newest Opus, and Anthropic now recommends Opus 5.5 for new projects.

If you are searching for "Opus 4.6" today, you probably are looking for three answers: what it does, what it costs, and whether it still makes sense to start with it. This guide covers all three. Specs and prices come from Anthropic's launch post and the models overview in the docs.

Claude Opus 4.6 at a glance

What is Claude Opus 4.6?

Opus is Anthropic's most capable model. Opus 4.6 is built for coding, long-horizon reasoning, agentic workflows, and very large documents. You can reach it through Claude.ai, the Claude API, Amazon Bedrock, and Microsoft Foundry.

Key features

1 million token context (beta): One request can carry up to a million tokens. That is enough for a large codebase, a stack of contracts, or a full set of reports. The feature runs only on the Claude Developer Platform, and prompts above 200,000 tokens move to the higher price.

Adaptive thinking and effort levels: Rather than a simple on/off switch for reasoning, the model decides when deeper thinking pays off. Developers set the effort to low, medium, high, or max. Anthropic suggests medium if the model overthinks easy tasks.

Agent teams in Claude Code: Several agents split a job, work in parallel, and coordinate, for instance during a review across a whole repository. It is a research preview. For a concrete picture, see our piece on multi-agent code review in Claude Code.

128,000 output tokens and compaction: Long reports fit into a single answer. Compaction (beta) summarizes older parts of a conversation once a configurable threshold is hit, which keeps long sessions alive.

Benchmarks: what Anthropic reports

These numbers come from the vendor and reflect launch day, when GPT-5.2 was the yardstick. For a head-to-head with OpenAI's coding model, read GPT-5.3-Codex vs Claude Opus 4.6. OpenAI's current model is covered in our GPT-5.6 review.

Opus 4.6 vs Opus 4.7, 4.8, 5 and 5.5

Want more on the successors? Start with our Claude Opus 4.8 review and the guide to Claude Opus 5. The tier above Opus is explained in Claude Fable 5 and Mythos 5.

Heads-up for developers: from Opus 4.7 on, the API no longer accepts temperature, top_p, or top_k, so existing code needs a small update. Details are in Anthropic's model deprecations page.

How much does Claude Opus 4.6 cost?

The API bills per token: $5 per million input tokens and $25 per million output tokens. Prompts above 200,000 tokens cost $10 and $37.50, and only on the Claude Developer Platform. US-only inference costs 1.1 times the standard price. Prompt caching and batch processing cut the bill for suitable workloads.

These are worked examples at list price, before discounts and taxes. Using Opus inside Claude.ai means a subscription rather than per-token billing. Current plans are on the Claude pricing page.

Can you use Claude Opus 4.6 for free?

As far as we know, Opus 4.6 was available in Claude.ai on the Pro, Max, Team, and Enterprise plans, and through the API on a paid basis. We are not aware of permanent free access. The pricing page shows what the free plan includes today. For a first try, a smaller model like Sonnet is usually the cheaper route.

Claude Sonnet vs Opus: which one is worth it?

Sonnet is faster and cheaper, while Opus is the strongest line for hard, long tasks. Users often report that Opus burns through usage limits faster than smaller models.

What changed between Sonnet 4.5 and 4.6 is in our post on Claude Sonnet 4.6 vs Sonnet 4.5.

Opus 4.6 in Claude Code and in business

Inside Claude Code, Opus 4.6 handles programming, debugging, and refactoring across several files. For background, see our overview of agentic software development and the comparison Gemini CLI vs Claude Code.

Beyond development, teams use it for financial models, spreadsheet analysis, presentations, and legal research. For office workflows, Claude Cowork is the natural fit. How smaller firms put Claude to work is covered in Claude for small business in Germany.

Who should use Opus 4.6 today?

• Existing projects: keep them running. Retirement is no sooner than February 5, 2027, and will be announced at least 60 days ahead. Still, plan the move early.

• New projects: start with Opus 5.5. Anthropic recommends it for most workloads, and it costs less per token ($4 / $20).

• Very long documents: consider a newer model, since Opus 4.7 and 4.8 offer the 1M window without a premium.

• Benchmarking: Opus 4.6 is still a handy baseline for measuring how far its successors have come.

Safety and availability

Anthropic tested Opus 4.6 extensively before release, and the findings are in the vendor's system card. The model was offered in Claude.ai, the Claude API, and through the major cloud providers.

Conclusion

Claude Opus 4.6 was a big step in February 2026, with a 1 million token context in beta, agent teams, adaptive thinking, and strong results in coding and research. Today it suits running projects and comparisons, while new work is better built on Opus 5.5. If you want help matching a model to your budget, data protection needs, and tasks, talk to our AI consulting for businesses.

Frequently asked questions (FAQ)

What is Claude Opus 4.6? 

An AI model from Anthropic in the Opus class, built for coding, research, and agentic workflows with up to 1 million tokens of context (beta).

When was Claude Opus 4.6 released? 

On February 5, 2026. Its API model ID is claude-opus-4-6.

How much does Claude Opus 4.6 cost? 

In the API, it is $5 per million input tokens and $25 per million output tokens. Above 200,000 tokens, it is $10 and $37.50 on the Claude Developer Platform. On Claude.ai, it comes with a subscription.

Is Claude Opus 4.6 free? 

We are not aware of permanent free access. Opus 4.6 was offered on the Pro, Max, Team, and Enterprise plans. The pricing page shows what the free plan covers today.

What is Claude Opus 4.6 good for? 

Complex coding, long documents, research, and multi-step agent workflows where quality matters more than speed.

Is Sonnet or Opus better? 

It depends on the job. Sonnet is faster and cheaper and covers many everyday tasks, while Opus is the better pick for hard, long, or agentic work.

Is Opus 4.6 still current, or should I use Opus 5 or 5.5? 

It is no longer the newest model. For new projects, Anthropic recommends Opus 5.5. Existing applications keep working on Opus 4.6.

Is Claude Opus 4.6 being retired? 

Anthropic lists it as active. Retirement is planned no sooner than February 5, 2027, and will be announced at least 60 days in advance.