Claude Fable lists at 2× Opus while Gemini 3.1 Flash sits 99.7% below GPT-4

Sources

Quoting Drew Breunig simonwillison.net

Prior to Fable, it felt silly to waste too much time improving your coding harness or context strategies. A new model would arrive at the same price (or cheaper!) and paper over most of your problems. But then Fable landed. It was (and still is!) incredible . But the cost was so high and Opus was good enough (as was 5.6, K3, and even GLM) for most of the code we needed. So we started to think about what work went where. — Drew Breunig , Fable & The End of the Free Lunch Tags: drew-breunig , ant…

References

CloudZero — Claude Mythos pricing breakdown cloudzero.com

Both Fable 5 and Mythos 5 are priced at $10 per million input tokens and $50 per million output tokens, exactly double the rate of Claude Opus 4.8.

Reddit r/claude — ‘Fable 5 is eating my Max 20x plan at 2%/minute’ reddit.com

Users on the $200/month Claude Max plan have documented cases where a single morning of heavy coding consumed 2% of their weekly limit per minute, effectively exhausting their quota in hours.

aimagicx — LLM Pricing Collapse Developer Guide 2026 aimagicx.com

Gemini 3.1 Flash offered a 99.7% price reduction compared to the GPT-4 baseline of 2023… the constraint is no longer the ‘cost of a token,’ but rather the ‘cost of an accepted result.’

Medium — Coding Agent Index 2026 (Wasowski) medium.com

The same model, wrapped in different harnesses, can result in a 32x difference in cost for identical tasks—ranging from $0.07 to over $2.00 per task.

Simon Willison — Cybersecurity as Proof of Work (Apr 2026) simonwillison.net

A system is only as hardened as the volume of tokens its owners spend on discovery compared to what an attacker spends on exploitation.

BenchLM — Claude Mythos 5 leaderboard entry benchlm.ai

BenchLM currently ranks Claude Mythos 5 as #1 of 224 models with a score of 83.0, citing its particular strength in coding.