Claude Mythos Model Comparison
Analyzing the Anthropic 'Capybara' lineage from the efficiency of Haiku to the step-change reasoning of the Mythos class — now confirmed with official benchmarks.
— Anthropic Internal Memo
Haiku
Sub-second latency. Optimized for high-volume routing and lightweight task processing.
Sonnet
The production workhorse. Balanced performance-to-cost ratio for everyday workloads.
Opus
Flagship frontier reasoning. Complex multi-step planning and deep-context synthesis.
Mythos
New Capybara tier. SWE-bench 93.9%, USAMO 97.6%, CyberGym 83.1% — dominating Opus 4.6 across all benchmarks.
The Nature of the 'Step Change'
The April 8 official release confirmed everything. Mythos Preview scored 93.9% on SWE-bench Verified (Opus 4.6: 80.8%), 97.6% on USAMO 2026 (Opus 4.6: 42.3%), and 83.1% on CyberGym. Not qualitative claims — hard numbers.
Claude Mythos Comparative Metrics
A cross-dimensional analysis of capabilities based on official benchmarks and public information.
| Metric | Haiku | Sonnet | Opus | Mythos (Est.) |
|---|---|---|---|---|
| Inference Latency (TTFT) | 120ms | 450ms | 1.2s | ~2.5s |
| Context Window | 200K | 200K | 1M+ | — |
| Coding Capability | Baseline | Good | Excellent | "Dramatically higher" |
| Reasoning Capability | Baseline | Good | Excellent | "Dramatically higher" |
| Cybersecurity | — | — | Strong | "Far ahead of any AI" |
| Cost Tier | $1/$5 | $3/$15 | $5/$25 | $25/$125 |
Why Claude Mythos Matters
'The shift from Opus to Mythos is not about more data, it's about better internal models of the world. Mythos doesn't predict the next token; it predicts the consequence of the thought.'
View Full Analysis arrow_forwardA New Model Tier
Capybara is not an Opus version upgrade — it's an entirely new tier: larger, more intelligent, more expensive. A structural expansion of Anthropic's model family.
Cybersecurity Capabilities
Anthropic internally describes Mythos as 'far ahead of any other AI model in cyber capabilities.' For context: even Opus 4.6, with no specialized tooling, discovered 500+ high-severity zero-days in production open-source code. Mythos took this further — cracking a 20-year-old Linux kernel vulnerability in under 90 minutes during Frontier Red Team testing.
Restricted Access Strategy
Mythos is limited to select early access customers, with priority given to cyber defenders. Anthropic says it needs to become 'much more efficient before any general release.'
Claude Mythos Comparison FAQ
chevron_right Is Claude Mythos (Capybara) an upgrade to Opus?
No. Capybara is an entirely new model tier alongside Haiku, Sonnet, and Opus — a structural expansion of Anthropic's model family.
chevron_right How expensive is Claude Mythos to run?
Priced at 5x Opus 4.6: $25/M input tokens, $125/M output tokens. Currently restricted to approved organizations.
chevron_right Are the Claude Mythos metrics reliable?
Data marked 'speculative' comes from qualitative descriptions in the March leak. 'Confirmed' data comes from the April 8 official release benchmarks.
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