Claude Mythos
A Possible Tier Above Opus
Based on late-March leaked draft materials and public reporting, Capybara may be Anthropic's next model tier, with Claude Mythos as the first surfaced model name.
What Are Capybara and Claude Mythos
Current public knowledge comes mainly from Fortune reporting, the CMS exposure discovered by LayerX / Cambridge researchers, and follow-up media coverage. The overall picture suggests Capybara is a possible new tier above Haiku, Sonnet, and Opus, while Claude Mythos is the first leaked model name within that tier.
"the most capable we've built to date"
What The Leak Claims
Stronger coding
The leaked draft says its software coding performance is materially higher than Claude Opus 4.6.
Deeper reasoning
Public descriptions point to clear gains in academic reasoning and complex knowledge synthesis.
Cybersecurity focus
The draft repeatedly emphasizes cyber offense and defense capability as the main reason for a cautious rollout.
Higher-tier positioning
If Capybara launches as a real tier, Anthropic's product ladder would extend beyond Opus for the first time.
Relative Positioning vs Released Models
| Dimension | Claude Mythos / Capybara | Claude Opus 4.6 | GPT-5.4 |
|---|---|---|---|
| Coding | Leak says clearly above Opus 4.6 | Anthropic's current released flagship | Top competing model |
| Reasoning | Leak says meaningful step-up | Current strength | Current strength |
| Cybersecurity | Described as the highest-risk capability jump | Already strong | Industry capabilities also rising |
| Context / spec | Not publicly confirmed | 1M context available | Await official product details |
| Pricing | Rumored to be above Opus, unconfirmed | Officially published | Depends on official product tier |
| Status | Early testing / unreleased | Released | Released |
This page is based on public-source synthesis and should not be treated as Anthropic's final naming, pricing, API availability, or capability commitment.
Public Timeline
The sequence below is based on public reports, leaked draft materials, and cross-checkable sources.
March 26-27, 2026: An Anthropic CMS configuration mistake exposed unpublished draft assets, and Fortune first reported the Mythos / Capybara references.
Current status: Anthropic has confirmed it is testing a stronger general-purpose model with a small set of early-access customers.
Possible rollout path: the leaked draft suggests a cautious release focused first on security defenders and enterprise-style evaluation.
Positioning takeaway: existing signals look more like a new tier above Opus than a routine minor-version refresh.
What This Means For Developers
The coding ceiling keeps rising
If Mythos ships, complex refactors, long-horizon agent coding, and high-stakes code review workflows could improve again.
Security becomes the main battleground
Anthropic's strongest caution is not chat quality but cyber capability, which matters directly for red-teaming, auditing, and vuln remediation.
Enterprise pilots matter more
High cost, high capability, and cautious release language all point to an enterprise-first evaluation pattern.
Preparing early pays off
Teams already organized around Claude Code, Opus 4.6, and long-context workflows will be able to adopt stronger models faster later.
Further Reading
Get familiar with the currently released Claude models, developer APIs, and QCode.cc workflows first.
Use the best Claude available today, watch Mythos next
QCode.cc already supports today's main Claude models and developer workflows. If a new model launches officially, it will fit more naturally into your existing setup.