Claude Mythos 5.1
Last verified September 2, 2026 · Anthropic pricing ↗$10.00/1M input · $50.00/1M output · 1.0M context · Anthropic
Limited access
Not generally available
Claude Mythos 5.1 is not on Anthropic’s open price list. Access is gated to vetted partners or a waitlist, so the rate below is what those customers pay rather than something you can sign up for. It is excluded from the calculator’s default model list and from every ranking.
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Alternatives to Claude Mythos 5.1
Pricing Details
AnthropicSame model as Fable 5.1 with safeguards lifted, launched September 1, 2026. Access restricted to vetted partners via Project Glasswing; Anthropic's pricing table marks it limited availability. Card is identical to Fable 5.1 to the cent, including the 0.025x cache read at $0.25/MTok - these two are the only rows on Anthropic's price list not using the standard 0.1x multiplier. Scores 60.9 on Terminal-Bench 4.0 against Fable 5.1's 55.8 and Mythos 5's 42.0 (Anthropic-reported), so the cheapest cache reads Anthropic sells sit on the model with the highest score and the shortest access list.
Input / 1M tokens
$10
Output / 1M tokens
$50
Context Window
1.0M
Max Output
128K
Price History
Launched at current price on 2026-09-01. No price changes recorded since.
Frequently Asked Questions
Common questions about Claude Mythos 5.1 pricing and usage