claude-mythos-5

Model overview

Same card, narrower door. claude-mythos-5 is priced exactly like Fable 5 — $10 per million input, $1 cached, $50 output, a 1M-token context, reasoning, tools and prompt caching — but Anthropic marks it as limited availability on the Claude API, and that flag is the only published field distinguishing the pair. Cost is never the tiebreaker between the two; access is. Set against the rest of the line-up it is the expensive end: double Opus 5 at $5 / $25, five times Sonnet 5's introductory $2 / $10 and 3.33 times its post-September $3 / $15, ten times Haiku 4.5 at $1 / $5. Confirm capacity is obtainable before wiring it into a production path.

Billing conditions: Limited availability on the Claude API.

Context window

1,000,000 tokens

Knowledge cutoff

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Price last verified

2026-09-06

First observed

2026-08-11

Descriptions, capabilities, and tariffs come from the linked source. First-party prices take priority; OpenRouter fallbacks are labelled.