Claude 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.
AnthropicPremium
Claude Fable 5
New global #1 — 80.3% SWE-Bench Pro, the most capable model generally available.
Winner
VS
AnthropicPremium
Claude Mythos 5
The frontier ceiling — same model as Fable 5, safeguards lifted, partner-only.
At a glance
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)
95%
95.5%
Arena Elo
1,932
1,932
MMLU
94.2%
94.2%
How they compare
Which model wins for each use case — and why.
AvailabilityClaude Fable 5 wins
Fable 5 is generally available to all users and API customers. Mythos 5 is gated to vetted enterprise and research partners.
Raw capabilityTie
Identical model and benchmarks — 80.3% SWE-Bench Pro and 1932 GDPval-AA on both.
Safety profileClaude Fable 5 wins
Fable 5's safeguards block specific high-risk cyber responses, which is the right default for nearly all production use.
Advanced security workClaude Mythos 5 wins
Mythos 5 lifts safeguards for vetted partners doing vulnerability discovery and containment research.
PriceTie
Both are priced identically at $10/$50 per 1M tokens.
Which should you pick?
Pick Claude Fable 5 if…
You want the most capable model you can actually access today
You need standard, production-safe behavior with high-risk responses blocked
You don't have — or don't need — vetted-partner access
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.
The case for each model
What each one is genuinely good at, where it falls down, and when we would steer you away from it.
Our overall pick in this comparison. It is the closer match to Claude Mythos 5 on price, context and speed than the headline numbers suggest.
Anthropic's new Mythos-class flagship and the most capable coding model anyone can use — 80.3% SWE-Bench Pro, an 11-point jump over Opus 4.8. 1M context, 128K output, native parallel subagents. Released June 9, 2026.
Input
$10.00/1M
Output
$50.00/1M
Context
1M tokens
Speed
Deliberate
What people actually use it for
Autonomous agents that plan, write, run, and debug across an entire codebase with minimal supervision
Whole-repo refactors and PR review where accuracy outranks latency or cost
80.3% SWE-Bench Pro — the new #1, up from Opus 4.8's 69.2% and GPT-5.5's 58.6%
1932 on GDPval-AA, ahead of Opus 4.8 (1890) and GPT-5.5 (1769)
1M-token context at standard pricing, 128K max output per request
Mythos-class capability released for general use with new cyber-risk safeguards
Where it falls down
Priced at $10/$50 per 1M tokens — double Opus 4.8 ($5/$25)
Deliberate pace; not for latency-sensitive interactive apps
Standard-use safeguards block some high-risk security workloads (use Mythos 5 with partner access)
Skip it if
You are latency- or cost-sensitive, or your tasks don't need frontier-level reasoning — Opus 4.8 at half the price is plenty.
Our verdict
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.
The runner-up here, but not by a wide margin. It is the closer match to Claude Fable 5 on price, context and speed than the headline numbers suggest.
Anthropic's most powerful frontier model — the same underlying model as Fable 5 with safeguards lifted in some areas, restricted to vetted enterprise and research partners. The capability ceiling of mid-2026.
Input
$10.00/1M
Output
$50.00/1M
Context
1M tokens
Speed
Deliberate
What people actually use it for
Multi-step cybersecurity workflows: vulnerability discovery, exploit reasoning, and containment analysis
High-stakes autonomous engineering where the safety-tuned Fable 5 is too constrained
Frontier research programs running under Anthropic's vetted-partner access controls
Where it wins
80.3% SWE-Bench Pro — tied with Fable 5 as the highest public coding score of any model
Safeguards lifted in some areas for advanced security and research workloads
Excels at complex, multi-step cybersecurity tasks under partner access
Same 1M-token context and 1932 GDPval-AA score as Fable 5
Where it falls down
Not generally available — limited to vetted partners after Project Glasswing's private preview
Most teams should use Fable 5, which is the same model with standard safeguards
Premium $10/$50 pricing and a deliberate, high-latency profile
Skip it 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.
Our verdict
The most capable model Anthropic has ever shipped — but access is gated to vetted partners because its safeguards are lifted in high-risk areas. For everyone else, Fable 5 is the same model at the same price with standard safety controls. Choose Mythos 5 only if you have partner access and need its security ceiling.
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.