Effort: max · Max, Default Fallback
anthropicReleased Sep 1, 2026
Anthropic: Claude Fable 5.1
Beta controls change effort per message without invalidating the prompt cache and report progress between tool calls.
Source description
Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work: long code refactors, front-end and visual...
Context window1M
Max output128K
Provider endpoints6
Benchmark results19
Agent runs1
Measured performance
All leaderboards ↗Benchmark results
Effort: max · Max, Default Fallback
GDPval-AA ↗2.1
1,754.07Effort: max · Max, Default Fallback
AutomationBench-AA ↗AA Index 4.3.2 collection
59.38%Effort: max · Max, Default Fallback
Effort: max · Max, Default Fallback · Harness unreported
SciCode ↗AA Index 4.3.2 collection
63.08%AA · Under reviewEffort: max · Max, Default Fallback
Humanity’s Last Exam ↗AA Index 4.3.2 collection
59.13%Effort: max · Max, Default Fallback
GDP.pdf ↗AA Index 4.3.2 collection
26.2%Effort: max · Max, Default Fallback
CritPt ↗AA Index 4.3.2 collection
29.71%AA · Under reviewEffort: max · Max, Default Fallback
AA-Omniscience ↗AA Index 4.3.2 collection
43.45Effort: max · Max, Default Fallback
AA-LCR ↗1.1
85.33%Effort: max · Max, Default Fallback
LiveBench Overall ↗2.0 · 2026-10-14 (dataset 2026-09-02)
87.99%Effort: max · single run · equal mean of 7 suites
LiveBench Design ↗2.0 · 2026-10-14 (dataset 2026-09-02)
83.4%Effort: max · single run
LiveBench Research ↗2.0 · 2026-10-14 (dataset 2026-09-02)
82%Effort: max · single run
LiveBench Browser Use ↗2.0 · 2026-10-14 (dataset 2026-09-02)
100%Effort: max · single run
LiveBench Coding ↗2.0 · 2026-10-14 (dataset 2026-09-02)
97.7%Effort: max · single run
LiveBench Agentic ↗2.0 · 2026-10-14 (dataset 2026-09-02)
80.8%Effort: max · single run
LiveBench Data Analysis ↗2.0 · 2026-10-14 (dataset 2026-09-02)
80.3%Effort: max · single run
LiveBench Reasoning ↗2.0 · 2026-10-14 (dataset 2026-09-02)
91.7%Effort: max · single run
Provider measurements
1 configurationSpeed
≈10K input tokens1 requestmedian / 72h
Artificial Analysis · first-party providers · serving endpoint not reported
Anthropic
Claude Fable 5.1 (Max, Default Fallback)
Reasoning max
- Output rate
- 70.5884 tok/s
- Time to first chunk
- 173.575 s
Last checked Source ↗
Methodology 2.2.0 & measurement details
First chunk includes request processing and network time, and may include reasoning.
- Prompt
- long · ≈10,000 input tokens
- Parallel requests
- 1
- Minimum answer
- 1,500 tokens
- Aggregation
- median over 72 hours
- Token counting
- o200k_base
- Benchmark client
- Google Cloud us-central1-a
- Serving endpoint
- Not reported
- Serving region
- Not reported
- Sample size
- Not reported
- Window end
- Not reported
Model + harness
All agent results ↗Agent runs
Terminal-Bench 4.0
claude-code2.1.257
Reasoning effort max
Tested model identity
Fable 5.1anthropic/claude-fable-5-1Pass rate57.88%
95% CI 54.12%–61.64%
n = 330Checked
Access & cost
6 quotesPrices across providers
Your token mix
USD · listed token ratesOpenRouter
Catalog quote- Input
- $10.00
- Output
- $50.00
- Cached input
- $0.25
Experiential
Standard list rate
- Input
- $10.00
- Output
- $50.00
- Cached input
- $0.25
Catalog list rate. Plan allowances and temporary discounts are separate.
- Input
- $10.00
- Output
- $50.00
- Cached input
- $0.25
Cache write $12.5/M tokens · 1h cache write $20/M tokens · Web search $0.01/search
- Input
- $10.00
- Output
- $50.00
- Cached input
- $0.25
Cache write $12.5/M tokens · 1h cache write $20/M tokens · Web search $0.01/search
- Input
- $10.00
- Output
- $50.00
- Cached input
- $0.25
Cache write $12.5/M tokens · 1h cache write $20/M tokens · Web search $0.01/search
- Input
- $10.00
- Output
- $50.00
- Cached input
- $0.25
Cache write $12.5/M tokens · 1h cache write $20/M tokens · Web search $0.01/search
Offers for this model
2 offersExperiential Labs · Discount
2.5% off · Experiential Pro model discounts
Paid Pro plan required, covering the first 2,000 credits of usage each month, then list price.
Checked Source ↗
Experiential Labs · Free access
Daily Astra and Fable promotional tiers
Card and $1 verification required; paid overage can apply.
Checked · Manual checkSource ↗
Model specifications
- Developer
- anthropic
- Modality
- Language
- Context
- 1,000,000 tokens
- Maximum output
- 128,000 tokens
- Weights
- Not reported
- Released
- Sep 1, 2026
- Provider listed
- Sep 1, 2026
- First discovered
- Oct 16, 2026
Exact identities
- openrouter
anthropic/claude-fable-5.1 - experiential
claude-fable-5.1 - artificial-analysis
3e87c73e-a257-495e-9730-367a66229811 - livebench
claude-fable-5.1
Sources
Updated Oct 18, 2026
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