Anthropicproprietary
Released: 2026-08-31

Claude Fable 5.1

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...

Intelligence Index
91.5/ 100
Calibrated multi-domain composite
Throughput Speed
55tok/sec
Output streaming throughput
Time To First Token
420ms
Initial chunk server latency
LiveBench Contam-Free
80.5%
September 2026 suite score

LiveBench Multi-Domain Evaluation Breakdown

Monthly refreshed contamination-free test sets
Logical Reasoning84.2%
Coding & Repo Repair82.4%
Mathematics (AIME)81.4%
Data Analysis & Tables77.8%
Language & Comprehension79.6%
Instruction Following80.5%

Sourced Benchmark Evaluations (61)

Verified performance across authoritative benchmarks with provenance tracking.
BenchmarkStatusScoreTrustDateSource TypeProvenance
MultiPL-EDeprecated79.9%
10
2026-09-12independentSource ↗
SWE-LancerDeprecated59.1%
20
2026-09-12independentSource ↗
Humanity's Last ExamActive39.1%
93
2026-09-12independentSource ↗
SWE-bench ProActive53.9%
90
2026-09-12independentSource ↗
InfiniteBenchNearing Saturation77.8%
65
2026-09-12independentSource ↗
LongBench-ProActive75%
80
2026-09-12independentSource ↗
MATHSaturated83.4%
25
2026-09-12independentSource ↗
MathArenaActive68.1%
99
2026-09-12independentSource ↗
AgentIFNearing Saturation54.7%
80
2026-09-12independentSource ↗
LiveCodeBenchSaturated71.3%
39
2026-09-12independentSource ↗
StructFlowBenchNearing Saturation68.4%
75
2026-09-12independentSource ↗
OlympiadBenchActive69.8%
80
2026-09-12independentSource ↗
Omni-MATHDeprecated63%
10
2026-09-12independentSource ↗
OpenAI-MRCRActive76.9%
80
2026-09-12independentSource ↗
PutnamBenchActive44.3%
90
2026-09-12independentSource ↗
SimpleQAActive47.6%
90
2026-09-12independentSource ↗
SoohakActive64.7%
98
2026-09-12independentSource ↗
ARC-AGI-3Active57.7%
93
2026-09-12independentSource ↗
Terminal-BenchActive60.8%
80
2026-09-12independentSource ↗
ARC-AGI-2Nearing Saturation69.3%
75
2026-09-12independentSource ↗
AIMENearing Saturation80.8%
75
2026-09-12independentSource ↗
FrontierMathActive23.8%
98
2026-09-12independentSource ↗
FrontierCodeActive50.4%
98
2026-09-12independentSource ↗
CodeContestsDeprecated56.5%
10
2026-09-12independentSource ↗
FireBenchActive67.6%
95
2026-09-12independentSource ↗
ZeroSCROLLSNearing Saturation73.2%
78
2026-09-12independentSource ↗
ComplexBenchNearing Saturation66%
80
2026-09-12independentSource ↗
SCROLLSNearing Saturation73.2%
65
2026-09-11independentSource ↗
MMLU-ProNearing Saturation84.2%
75
2026-09-11independentSource ↗
MercuryDeprecated76.5%
10
2026-09-11independentSource ↗
TabMWPSaturated78.3%
25
2026-09-10independentSource ↗
RULERNearing Saturation84.2%
84
2026-09-10independentSource ↗
CyberSecEvalDeprecated78.2%
10
2026-09-10independentSource ↗
QuALITYNearing Saturation80.5%
78
2026-09-09independentSource ↗
MMLU-ReduxSaturated89.7%
25
2026-09-09independentSource ↗
SWE-bench VerifiedSaturated67.8%
25
2026-09-09independentSource ↗
MGSMNearing Saturation80.8%
65
2026-09-08independentSource ↗
SWE-benchDeprecated59.1%
10
2026-09-08independentSource ↗
LongBenchNearing Saturation78.7%
65
2026-09-08independentSource ↗
QASPERNearing Saturation75.9%
65
2026-09-07independentSource ↗
AGIEvalSaturated76.4%
25
2026-09-07independentSource ↗
TruthfulQASaturated80.5%
25
2026-09-07independentSource ↗
SuperGLUESaturated90.6%
25
2026-09-06independentSource ↗
GSM-HardDeprecated81.7%
10
2026-09-06independentSource ↗
BIG-Bench HardSaturated87%
25
2026-09-05independentSource ↗
CodeXGLUEDeprecated81.7%
23
2026-09-05independentSource ↗
MT-BenchNearing Saturation8.3%
75
2026-09-05independentSource ↗
WinoGrandeSaturated92.4%
28
2026-09-04independentSource ↗
MBPP+Nearing Saturation88.6%
65
2026-09-04independentSource ↗
IFEvalDeprecated78.9%
25
2026-09-04independentSource ↗
GPQANearing Saturation80.5%
78
2026-09-04independentSource ↗
Needle-in-a-HaystackSaturated98.3%
44
2026-09-03independentSource ↗
HumanEval+Saturated93.9%
25
2026-09-03independentSource ↗
CommonsenseQASaturated93.2%
28
2026-09-03independentSource ↗
MBPPSaturated92.1%
25
2026-09-02independentSource ↗
GSM8KSaturated91.9%
25
2026-09-02independentSource ↗
GLUESaturated95.9%
28
2026-09-02independentSource ↗
MMLUSaturated93.3%
25
2026-09-01independentSource ↗
HumanEvalSaturated99.1%
25
2026-09-01independentSource ↗
ARC-AGISaturated83.5%
25
2026-09-01independentSource ↗
LiveBench (Continuous)Active80.5%
94
2025-02-01independentSource ↗
Anthropic Python SDKAPI Ready
import anthropic

client = anthropic.Anthropic()
message = client.messages.create(
    model="anthropic-claude-fable-5-1",
    max_tokens=2048,
    temperature=0,
    messages=[{"role": "user", "content": "Execute SWE-bench verified repository fix"}]
)
print(message.content[0].text)

Evaluation & Sourcing Notes

Scores listed for Claude Fable 5.1 represent verified evaluations extracted from official research papers, independent evaluation suites (HELM, LMSYS, OpenCompass, LiveBench), and verified audit reports.

All benchmarks marked as saturated or deprecated reflect historical performance where the benchmark no longer provides active discriminative power.