---
title: "Claude Fable 5 and Mythos 5: Pricing, API Costs, and Benchmark Comparison vs Opus 4.8 and GPT-5.5"
url: https://daily.dev/posts/claude-fable-5-and-mythos-5-pricing-api-costs-and-benchmark-comparison-vs-opus-4-8-and-gpt-5-5-nsha8gtxs
source_url: https://www.finout.io/blog/claude-fable-5-mythos-5-pricing-benchmarks
type: article
source: "finout"
published: 2026-06-09T20:34:02.396Z
updated: 2026-06-09T21:17:04.537Z
tags: ["ai", "claude", "gpt"]
reading_time: 10
upvotes: 0
comments: 0
language: en
---

> ## Documentation Index
> Fetch the complete documentation index at: https://daily.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Claude Fable 5 and Mythos 5: Pricing, API Costs, and Benchmark Comparison vs Opus 4.8 and GPT-5.5

**[finout](https://daily.dev/sources/finout)** · 10 min read · 0 upvotes · 0 comments

## Summary

Anthropic has released Claude Fable 5, the publicly accessible version of its Mythos-class model, priced at $10/$50 per million input/output tokens — double Claude Opus 4.8 and double GPT-5.5's input price. Claude Mythos 5 is the same underlying model but without safety classifiers, restricted to approved government and biomedical partners. Fable 5 includes classifier-based fallbacks that reroute sensitive cybersecurity and biology queries to Opus 4.8. On benchmarks, Fable 5 leads with 80.3% on SWE-Bench Pro vs GPT-5.5's 58.6% and Opus 4.8's 69.2%, and shows strong token efficiency on complex reasoning tasks. However, for high-volume, well-defined workloads, Opus 4.8 or Sonnet 4.6 offer better economics. Subscription users get free access through June 22, after which usage credits are required. There is no batch/async pricing tier, giving GPT-5.5 a cost advantage for offline processing at scale.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://www.finout.io/blog/claude-fable-5-mythos-5-pricing-benchmarks>

---

Tags: [#ai](https://daily.dev/tags/ai), [#claude](https://daily.dev/tags/claude), [#gpt](https://daily.dev/tags/gpt)

[View this post on daily.dev](https://daily.dev/posts/claude-fable-5-and-mythos-5-pricing-api-costs-and-benchmark-comparison-vs-opus-4-8-and-gpt-5-5-nsha8gtxs)