Head-to-head · Updated
Data verifiedClaude Mythos 5 and Claude Fable 5 are the same underlying model with identical benchmarks: 80.3% SWE-Bench Pro, 1932 GDPval-AA, 1M-token context, $10/$50 pricing. The only difference is safety and access. Fable 5 ships with safeguards that block specific high-risk cyber responses and is generally available. Mythos 5 lifts those safeguards for advanced security and research work and is restricted to vetted partners. For almost everyone, Fable 5 is the right — and only available — choice.
Claude Fable 5
New global #1 — 80.3% SWE-Bench Pro, the most capable model generally available.
WinnerClaude Mythos 5
The frontier ceiling — same model as Fable 5, safeguards lifted, partner-only.
| Claude Fable 5 | Claude Mythos 5 | |
|---|---|---|
| Input cost / 1M tokens | $$10.00/1M | $$10.00/1M |
| Output cost / 1M tokens | $$50.00/1M | $$50.00/1M |
| Context window | 1M tokens | 1M tokens |
| Speed | Deliberate | Deliberate |
| Price tier | Premium | Premium |
| Benchmarks | ||
| SWE-bench (coding) | 93.4% | 93.4% |
| Arena Elo | 1,932 | 1,932 |
| MMLU | 94.2% | 94.2% |
Which model wins for each use case — and why.
Fable 5 is generally available to all users and API customers. Mythos 5 is gated to vetted enterprise and research partners.
Identical model and benchmarks — 80.3% SWE-Bench Pro and 1932 GDPval-AA on both.
Fable 5's safeguards block specific high-risk cyber responses, which is the right default for nearly all production use.
Mythos 5 lifts safeguards for vetted partners doing vulnerability discovery and containment research.
Both are priced identically at $10/$50 per 1M tokens.
Pick Claude Fable 5 if…
Pick Claude Mythos 5 if…
Bottom line
For most workflows, Claude Fable 5 is the stronger choice.
The strongest coding and reasoning model you can actually use today. 80.3% SWE-Bench Pro is an 11-point leap over Opus 4.8 — the biggest single-release jump of 2026. It costs 2× Opus 4.8, so use it for the hardest agentic and engineering work and keep Opus 4.8 or Sonnet for everyday volume.
What is the difference between Claude Mythos 5 and Fable 5?
They are the same underlying model with the same benchmarks. Fable 5 is generally available with safeguards that block specific high-risk cyber responses. Mythos 5 lifts those safeguards and is restricted to vetted enterprise and research partners.
Can I use Claude Mythos 5?
Only if you are a vetted partner. Mythos 5 access is gated because its safeguards are lifted in high-risk areas. Everyone else uses Fable 5 — the same model, generally available, at the same price.
Is Mythos 5 more powerful than Fable 5?
No. They share the same weights and post identical benchmarks (80.3% SWE-Bench Pro, 1932 GDPval-AA). Mythos 5 only differs in that certain safeguards are removed for approved security and research use.
Why did Anthropic release two versions?
To make Mythos-class capability broadly available safely. Fable 5 brings the capability to everyone with safety controls, while Mythos 5 serves vetted partners who need lifted safeguards for advanced cybersecurity work.
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