01What Claude Miphos Is and How It Works

Claude Miphos is a new AI model from Anthropic that was accidentally leaked to the public. It is by far the most powerful AR model they have ever developed, according to their own internal documents.

Miphos sits above the current three tiers: Haiku, Sonnet, and Opus. It is a fourth tier with the internal code name Capybara. The leaked draft says Capybara is a new name for a new tier of model that is larger and more intelligent than Opus models, which were previously Anthropic's most powerful.

A configuration error in Anthropic's content management system left nearly 3,000 unpublished documents in a public searchable data store with no password or authentication. Security researcher Roy Paz from Layer X Security and Alex Powles from the University of Cambridge discovered the leak. Fortune later reviewed the documents.

02Main Features of Claude Miphos

Claude Miphos has several key features that set it apart from previous models. The most important is its ability to plan and execute sequences of actions on its own. This makes it a much more autonomous AI agent.

  • It can move across systems and make decisions without waiting for step-by-step instructions.
  • It completes operations on its own, without hand-holding.
  • It extends the extended thinking feature from Claude 3.7 Sonnet, allowing it to think through complex problems step-by-step, backtrack, and self-correct.
  • It scores dramatically higher than Opus 4.6 across coding, academic reasoning, and problem solving.
  • Anthropic internally described Miphos as being currently far ahead of any other AI model in cyber capabilities.

03How the Claude Miphos Leak Happened

Anthropic accidentally leaked their most powerful AR model, Claude Miphos, due to a configuration error. The error left nearly 3,000 unpublished documents in a public searchable data store with no password or authentication.

  1. A configuration error in Anthropic's content management system left the documents exposed.
  2. Security researcher Roy Paz from Layer X Security and Alex Powles from the University of Cambridge discovered the leak.
  3. Fortune reviewed the documents and reported on them.
  4. Anthropic later confirmed the model exists, with a spokesperson saying they are developing a general purpose model with meaningful advances in reasoning, coding, and cybersecurity.

04How to Use Claude Miphos in Your Business

While Claude Miphos is not yet public, you can prepare to use it by understanding its autonomous workflow capabilities. For example, a freelancer running client outreach can set a goal, and Miphos works through the steps without hand-holding.

To use Miphos effectively when it launches:

  • Describe what you want to know or achieve, and the agent figures out how to get it.
  • Use it for competitive research, where it can pull multiple steps and sources without you needing to prompt at each step.
  • Automate business tasks like proposal writing, client onboarding, and SEO content pipelines.

05Benchmark Results and Comparisons for Claude Miphos

The leaked documents show that Claude Miphos achieves dramatically higher scores than Claude Opus 4.6 across coding, academic reasoning, and problem solving. Claude Opus 4.6 already leads the industry with 76.8% on SWE Bench Verified, a benchmark that tests real software engineering tasks, and it beat GPT-5 Codex.

Miphos is described in the leaked documents as being in a totally different league. Anthropic's spokesperson called it a step change and the most capable model they have built to date.

The leak caused immediate market movement. CrowdStrike, Palo Alto Networks, Zscaler, and Fortinet all saw their share prices drop after the Miphos news. Investors questioned if Frontier AI could outperform entire security teams.

06Tips, Limits, and Mistakes to Avoid with Claude Miphos

Claude Miphos is extremely powerful, but there are important limits and mistakes to avoid. First, it is very expensive to run at scale. Anthropic is working on making it more efficient, but you should be prepared for high compute costs.

  • Do not assume Miphos is ready for public use yet. There is no release date, and Anthropic is testing it only with a small group of early access customers.
  • Be aware that Anthropic is being deliberate about release due to safety concerns. They warned senior US government officials that Miphos makes large-scale attacks significantly more likely in 2026.
  • Understand that Miphos's autonomous capabilities mean it can plan and carry out complex operations with very little human involvement. You must use it responsibly.

07Who Claude Miphos Is For and Why It Matters

Claude Miphos is for business owners, freelancers, and agency owners who want to automate complex workflows without constant prompting. If you are already using Claude to automate proposal writing, client onboarding, or SEO content, Miphos will make those workflows dramatically more powerful.

It matters because it represents a new class of AI that can act autonomously. The businesses that move first on every new Claude tier are the ones that compound their results. When Miphos drops, those who have already learned how to build Claude-based automations can plug it in immediately and get better results overnight.

The leaked documents also revealed plans for an invite-only CEO summit in Europe, where Anthropic is actively selling enterprise access to Miphos. The gap between being prepared and unprepared is growing with each new model release.