The frontier ceiling — same model as Fable 5, safeguards lifted, partner-only.
100
Coding
97
Writing
99
Research
87
Images
12
Value
98
Long Context
Published benchmarks
93.4%
SWE-bench
1,932
Arena Elo
94.2%
MMLU
83.5%
GPQA
97.4%
MATH
Use this when
Frontier cybersecurity research, autonomous vulnerability discovery, and the absolute capability ceiling
Skip this if
You don't have vetted-partner access or don't need lifted safeguards — Fable 5 is the same model, generally available, at the same price.
Pricing
$10.00/1M in
$50.00/1M out
→0%since Jun 2026
Context
1M tokens
Speed
Deliberate
Launched June 9, 2026 alongside Fable 5, following the April Project Glasswing private preview on Google Cloud. Restricted to vetted enterprise and research partners due to advanced cybersecurity capabilities. Same underlying model and benchmarks as Claude Fable 5.
Claude 3.5 Sonnet is Anthropic's mid-cycle flagship model, balancing strong reasoning, coding, and instruction-following with a 200K context window. It sits between Haiku and Opus in Anthropic's lineup, offering near-flagship quality at a lower cost than top-tier models.
Verdict
One of the best models for coding and complex instruction-following, but its premium pricing demands premium use cases.
Quality score
81%
Pricing
$6.00/1M in
$30.00/1M out
Speed
Balanced
Best for complex coding tasks, multi-step reasoning, and long-document analysis where gpt-4o-class quality is needed without paying for the absolute top tier.
Context
200k tokens
Pricing at $6 input / $30 output per million tokens is significantly higher than GPT-4o ($2.50/$10). Best accessed via Anthropic API or Amazon Bedrock. Claude 3.5 Sonnet (October 2024 version) supersedes the June 2024 release with improved performance.
Claude 3.7 Sonnet with extended thinking enabled — Anthropic's hybrid reasoning model that explicitly deliberates before responding, surfacing its chain-of-thought for complex multi-step problems. It sits between standard Sonnet and full reasoning-only models, balancing depth with practical usability.
Verdict
The most transparent reasoning model on the market — ideal when you need to see and trust the thought process, not just the answer.
Quality score
73%
Pricing
$3.00/1M in
$15.00/1M out
Speed
Deliberate
Best for tackling complex coding challenges, mathematical proofs, and multi-step logical problems where visible reasoning and higher accuracy matter more than speed.
Context
200k tokens
Thinking tokens (the internal reasoning trace) count toward output token billing, which can significantly increase costs on complex queries. The thinking budget can often be configured via the API. Best used selectively for tasks that genuinely benefit from deliberation rather than as a default model.
ReasoningExtended ThinkingCodingAgenticAnthropic
Best for
Tackling complex coding challenges, mathematical proofs, and multi-step logical problems where visible reasoning and higher accuracy matter more than speed.
Claude Opus 4 is Anthropic's most capable flagship model, designed for complex reasoning, nuanced writing, and sophisticated multi-step tasks. It sits at the top of the Claude 4 family, prioritizing depth and quality over speed.
Verdict
Anthropic's best model for when quality matters more than speed or cost.
Quality score
84%
Pricing
$10.00/1M in
$50.00/1M out
Speed
Deliberate
Best for demanding professional tasks requiring deep reasoning, nuanced judgment, and high-quality long-form output.
Context
200k tokens
At $15 input / $75 output per 1M tokens, Opus 4 is one of the most expensive models available. Anthropic recommends using Claude Sonnet 4 for most production use cases and reserving Opus 4 for tasks explicitly requiring maximum capability.
FlagshipPremiumReasoningLong ContextAgentic
Best for
Demanding professional tasks requiring deep reasoning, nuanced judgment, and high-quality long-form output.
Claude Mythos 5 is best for frontier cybersecurity research, autonomous vulnerability discovery, and the absolute capability ceiling. It is a strong fit when that workflow matters more than the tradeoffs around premium pricing and deliberate speed.
When should I avoid Claude Mythos 5?
You don't have vetted-partner access or don't need lifted safeguards — Fable 5 is the same model, generally available, at the same price.
What is a cheaper alternative to Claude Mythos 5?
Mistral: Mistral Nemo is the lower-cost option to compare first when you want a similar workflow fit with less token spend.
What is a faster alternative to Claude Mythos 5?
Anthropic: Claude 3.5 Sonnet is the better pick when response time matters more than maximum depth or premium quality.
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