Post by @claudedevs@bird.makeup

Fable 5.1 is now live in Claude Code and the Claude Platform.

It's priced the same as Fable 5, with 75% cheaper API cache reads. It gets a lot further into a long task before it needs your input, is better at telling you when it's stuck, and its writing style is more natural.
https://bird.makeup/users/claudeai/statuses/2094848572143407483

claudeai@bird.makeup

@claudeai@bird.makeup yesterday

We’re introducing Claude Fable 5.1 and Claude Mythos 5.1.

They're the world’s most advanced models for coding and knowledge work.

3 Replies

4 Boosts

ClaudeDevs

@claudedevs@bird.makeup yesterday

It’s ahead of both Fable 5 and Opus 5 across our agentic coding and computer use evals.

On Terminal-Bench 4.0 in Claude Code, Fable 5.1 scores 55.8%. Fable 5 scores 42%, and Opus 5 scores 52.3% on the same setup.

ClaudeDevs

@claudedevs@bird.makeup yesterday

Our biggest goal with this upgrade was to deliver increased intelligence while making the model safely accessible. So we’ve taken steps to manage costs while improving safety measures.

ClaudeDevs

@claudedevs@bird.makeup yesterday

To lower costs, we’ve kept pricing the same as Fable 5 while lowering the price of cache reads on usage-based billing. Cache reads on Fable 5.1 are $0.25/MTok, down from $1/MTok on Fable 5.

For builders on the Claude Platform with long horizon workloads, a prompt cache-optimized integration will see significant savings.

In Claude Code, cache reads count at a reduced rate toward subscription usage, which remains unchanged. Long sessions billed at API rates can net out 25%-45% cheaper.