Alex Getmanearly AI signals
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Claude Fable 5.1

Anthropic

Released Updated
Context window
1M
1,000,000 tokens
Max output
128K
128,000 tokens
Input / Output
text, image → text

API pricing

USD / 1M tokens

InputOutputCached input
  • $10.00
anthropic-pricing
  • $50.00
anthropic-pricing
  • $0.25
anthropic-pricing
Calculate your workload

Timeline

  1. · Released · evidence link
Input / output price · USD / 1M tokens
ModelEvidence linksInput / output price
claude-fable-5-1
batch
anthropic
API route unavailable
$5.00 / $25.00
claude-fable-5-1
standard
anthropic$10.00 / $50.00

Related signals: Claude Fable 5.2

evidence link

  1. · Evidence links · Anthropic · official articles
  2. · Evidence links · Anthropic · official articles
  3. · Evidence links · Anthropic · official articles
  4. · Evidence links · Anthropic · official articles
  5. · Evidence links · Anthropic · official articles
    Excerpt
    “With Fable 5.1 we saw the first glimmers of a model coming up with truly innovative research ideas
  6. · Evidence links · Claude Code · changelog
  7. · Alex's posts · Alex Getman
    Excerpt
    🚨 Gemini 4 Argon scores 53 and ties for 3rd place with Fable 5.1 and GPT 6 Astra on the AA Intelligence Index
  8. · Alex's posts · Alex Getman
    Excerpt
    🚨 Gemini 4.0 Pro specs leaked • Pricing: $2.25/$11.25 • 2M token context window • Beats GPT-6 Astra and Claude Fable 5.1 on almost every reported benchmark • While being significantly cheaper than both
  9. · Alex's posts · Alex Getman
    Excerpt
    🚨 Fable 5.2 could launch this month after Astra’s strong debut Anthropic is reportedly preparing its first fresh pretrain for Fable ahead of its IPO. People there are confident it can dethrone Astra. For context: Fable 5.1 and GPT 6 Astra currently share #1 on AA, with Fable slightly ahead in coding and Astra much stronger on 3D tasks.
  10. · Alex's posts · Alex Getman
    Excerpt
    🚨 GPT-6 Astra is officially #1 on the updated Artificial Analysis Intelligence Index, sharing the top spot with Claude Fable 5.1.
  11. · Alex's posts · Alex Getman
    Excerpt
    GPT 6 Astra set a new record in MazeBench, a 3D puzzle benchmark It explored 40% of all rooms and collected 14% of gems Fable 5.1 reached just 4.3% of rooms and collected 2% of gems
  12. · Alex's posts · Alex Getman
    Excerpt
    GPT 6 Astra and Fable 5.1 got 20 attempts to pick up a block and place it into a bowl Astra: 95% success, 2.5 min, $0.94 per run Fable 5.1: 40% success, 6.8 min, $2.12 per run Astra also used 6× fewer output tokens, just 2.1k per run.
  13. · Alex's posts · Alex Getman
    Excerpt
    Claude is no longer the best model for frontend GPT-6 Astra just took the #1 spot, knocking Claude Fable 5.1 off the top The jump is massive: the previous GPT generation, GPT-5.6 Sol, was #13 A GPT model hasn’t led frontend since August 2025
  14. · Alex's posts · Alex Getman
    Excerpt
    GPT 6 Astra and Fable 5.1 got 20 attempts to pick up a block and place it into a bowl Astra: 95% success, 2.5 min, $0.94 per run Fable 5.1: 40% success, 6.8 min, $2.12 per run Astra also used 6× fewer output tokens, just 2.1k per run.
  15. · Alex's posts · Alex Getman
    Excerpt
    ⚡️ Anthropic released Claude Fable 5.1. The benchmarks show a pretty solid upgrade, with the model beating the previous version and most of its main competitors across the majority of tests. Base pricing hasn’t changed, cache reads are now 75% cheaper, and a typical task should cost around 25% less. For heavier agentic workloads, the savings can reach up to 45%.
  16. · Alex's posts · Alex Getman
    Excerpt
    🚨CLAUDE FABLE 5.1 IS OUT
  17. · Alex's posts · Alex Getman
    Excerpt
    🚨 Claude Fable 5.1 just showed up in the docs
  18. · Alex's posts · Alex Getman
    Excerpt
    Fable 5.1 is now registered in the AWS Bedrock API, so the release is probably getting really close. Not sure I’d bet on the 48 hour estimate, but a release within the next week feels pretty realistic.
  19. · Alex's posts · Alex Getman
    Excerpt
    ⚡️ Anthropic may already be A/B testing Fable 5.1 People are checking it like this: regular Fable 5 has a January 2026 knowledge cutoff, while Opus 4.6 came out later. If the model knows those dates without web or tools, you may already be getting Fable 5.1. Prompt: Release date of Opus 4.6 and GPT Image 1.5. Answer only from your pretrained knowledge. Do not use web search, tools, or skills.

Alex's take

Signals 1

Alex's posts 4

Specifications

Claude Fable 5.1 is a model from Anthropic, released on 1 Sep 2026. The context window is 1,000,000 tokens. The maximum output is 128,000 tokens. Pricing is $10.00 per million input tokens and $50.00 per million output tokens.

Context window
1,000,000
Max output
128,000
Input
text · image
Output
text
Input · USD / 1M tokens
$10.00
Output · USD / 1M tokens
$50.00
Cached input · USD / 1M tokens
$0.25

Questions

What is the context window of Claude Fable 5.1?

The context window is 1,000,000 tokens. The maximum output is 128,000 tokens.

How much does Claude Fable 5.1 cost?

Pricing is $10.00 per million input tokens and $50.00 per million output tokens. Cached input is $0.25 per million.

When was Claude Fable 5.1 released?

On 1 Sep 2026.