Head-to-head comparison

Claude Fable 5 vs. Gemini 3.8 Flash

Compare published benchmark results from matching versions and cohorts, API pricing, and technical specifications. Any documented test setup differences remain visible.

shared result series: 229
distinct benchmarks: 28
latest retrieval: 2026-10-15

First modelSecond model

Specifications

General specifications

Release date, availability, context window, architecture, and published parameter counts at a glance. Undisclosed details remain marked as unavailable.

Specifications for Claude Fable 5 and Gemini 3.8 Flash
Attribute	Claude Fable 5	Gemini 3.8 Flash
Provider	Anthropic	Google
Released	Jun 9, 2026	Sep 2, 2026
Availability	Active	Active
Model type	Proprietary	Proprietary
Parameters	Not published	Not published
Architecture	Not published	Not published
Context window	1,000,000 tokens	1,048,576 tokens
Knowledge cutoff	January 2026	March 2026
Technical sources	Model, Context, Knowledge cutoff	Model, Knowledge cutoff

Pricing

API pricing compared

The table compares official standard API rates per 1M tokens, including published cache pricing. Batch, fast, priority, regional surcharges, tool calls, and cloud platform pricing are excluded.

API pricing for Claude Fable 5 and Gemini 3.8 Flash
Price type	Claude Fable 5	Gemini 3.8 Flash
API input	$10	$0.75
API output	$50	$3.75
Cache read	$1	$0.075
Cache write (5 min.)	$12.5	Not listed
Cache write (1 hr.)	$20	Not listed
Price verified	09/22/2026 Source	09/22/2026 Source

Claude Fable 5Gemini 3.8 Flash

API inputUSD per 1M tokens, base tier

Claude Fable 5$10

Gemini 3.8 Flash$0.75

API outputUSD per 1M tokens, base tier

Claude Fable 5$50

Gemini 3.8 Flash$3.75

Cache readUSD per 1M tokens, base tier

Claude Fable 5$1

Gemini 3.8 Flash$0.075

Key to the marks:better valuebetter, but not conclusivetie

Pricing by provider

Direct developer pricing and provider endpoint tariffs routed through OpenRouter are listed separately. Prices are in USD per 1M tokens. Context-dependent direct tiers plus regional, Flex, Priority, and other OpenRouter tariffs remain individually identifiable.

Provider pricing for Claude Fable 5 and Gemini 3.8 Flash
Model	Provider	Purchase route and tariff	Input per 1M tokens	Output per 1M tokens	Source
Claude Fable 5	Anthropic	Direct from developerStandard API	Lowest listed price: $10	Lowest listed price: $50	Source09/22/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock	Lowest listed price: $10	Lowest listed price: $50	Source10/17/2026
	Anthropic	Via OpenRouteranthropic	Lowest listed price: $10	Lowest listed price: $50	Source10/17/2026
	Azure	Via OpenRouterazure	Lowest listed price: $10	Lowest listed price: $50	Source10/17/2026
	Claude Platform on AWS	Via OpenRouterclaude-on-aws	Lowest listed price: $10	Lowest listed price: $50	Source10/17/2026
	Google	Via OpenRoutergoogle-vertex/europe	$11	$55	Source10/17/2026
	Google	Via OpenRoutergoogle-vertex/global	Lowest listed price: $10	Lowest listed price: $50	Source10/17/2026
Gemini 3.8 Flash	Google	Direct from developerStandard API	$0.75	$3.75	Source09/22/2026
	Google	Via OpenRoutergoogle-vertex/us	$0.825	$4.125	Source10/17/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio	$0.75	$3.75	Source10/17/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio/flex	Lowest listed price: $0.375	Lowest listed price: $1.875	Source10/17/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio/priority	$1.35	$6.75	Source10/17/2026

Performance

Shared benchmarks

Only published results with the same benchmark version, task, metric, and comparison cohort are paired. Different reasoning levels, agents, harnesses, or output limits appear directly in the table.

Capability profile from matched benchmarks

Each axis averages directly matched benchmark families. A value of 100 means the stronger value within this pair, not a universal quality score.

Claude Fable 5

Gemini 3.8 Flash

Coding: 100 / 98.1 (2 benchmark families)

Reasoning: 100 / 98.8 (1 benchmark family)

Mathematics: 100 / 99.6 (1 benchmark family)

Knowledge: 100 / 99.2 (1 benchmark family)

Finance: 100 / 98.6 (1 benchmark family)

Legal: 100 / 98.7 (1 benchmark family)

Multimodal: 99.7 / 98.6 (1 benchmark family)

Health: 99.9 / 100 (1 benchmark family)

41 matched rows from 3 benchmark families were considered. The radar shows 8 of 9 comparable categories.

Claude Fable 5Gemini 3.8 Flash

Code MigrationOverall. Higher is better. Test setup not documented as identical

Claude Fable 555.065 %

Gemini 3.8 Flash36.546 %

EMBOverall. Higher is better. Test setup not documented as identical

Claude Fable 573.666 %

Gemini 3.8 Flash72.196 %

Finance Agent (v2)Overall. Higher is better. Test setup not documented as identical

Claude Fable 556.314 %

Gemini 3.8 Flash61.435 %

GPQA DiamondOverall. Higher is better. Test setup not documented as identical

Claude Fable 593.182 %

Gemini 3.8 Flash94.444 %

Harvey's Legal Agent BenchmarkOverall · Task fully resolved. Higher is better. Test setup not documented as identical

Claude Fable 511.25 %

Gemini 3.8 Flash10 %

Legal Research BenchOverall · All-pass. Higher is better. Test setup not documented as identical

Claude Fable 549.519 %

Gemini 3.8 Flash38.942 %

LegalBenchOverall. Higher is better. Test setup not documented as identical

Claude Fable 588.561 %

Gemini 3.8 Flash86.993 %

LiveCodeBench v6Overall. Higher is better. Test setup not documented as identical

Claude Fable 589.778 %

Gemini 3.8 Flash89.484 %

LMArena Code Arena WebDevOverall. Higher is better. No documented setup difference

Claude Fable 51,623.828

Gemini 3.8 Flash1,584.77

LMArena Text, Style ControlOverall. Higher is better. No documented setup difference

Claude Fable 51,503.377

Gemini 3.8 Flash1,496.319

LMArena Vision, Style ControlOverall. Higher is better. No documented setup difference

Claude Fable 51,307.966

Gemini 3.8 Flash1,289.129

MedCodeOverall. Higher is better. Test setup not documented as identical

Claude Fable 556.07 %

Gemini 3.8 Flash48.135 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for Claude Fable 5 and Gemini 3.8 Flash
Benchmark and task	Claude Fable 5	Gemini 3.8 Flash	Source
Code MigrationOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value55.065 %	36.546 %	Vals AI Source details Data as of: 10/12/2026
EMBOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value73.666 %	72.196 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	56.314 %	Higher measured value61.435 %	Vals AI Source details Data as of: 10/12/2026
GPQA DiamondOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	93.182 %	Higher measured value94.444 %	Vals AI Source details Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: task resolution rateScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value11.25 %	10 %	Vals AI Source details Data as of: 10/12/2026
Legal Research BenchOverall · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value49.519 %	38.942 %	Vals AI Source details Data as of: 10/12/2026
LegalBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value88.561 %	86.993 %	Vals AI Source details Data as of: 10/13/2026
LiveCodeBench v6Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value89.778 %	89.484 %	Vals AI Source details Data as of: 09/01/2026
LMArena Code Arena WebDevOverall Test details No documented difference in the test setupVersion: webdevMetric: WebDev Arena Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Code Arena WebDev Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Code Arena WebDevClaude Fable 5: Arena rating from 15,295 published pairwise votes.Gemini 3.8 Flash: Arena rating from 10,077 published pairwise votes.	Winner1,623.828 95% confidence interval: ±6.238The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,584.77 95% confidence interval: ±7.59The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Text, Style ControlOverall Test details No documented difference in the test setupNo clear leadVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Text, style control Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Text, style controlClaude Fable 5: Arena rating from 41,439 published pairwise votes.Gemini 3.8 Flash: Arena rating from 35,670 published pairwise votes.	No clear lead1,503.377 95% confidence interval: ±4.304The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,496.319 95% confidence interval: ±4.654The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Vision, Style ControlOverall Test details No documented difference in the test setupVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Vision, style control Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Vision, style controlClaude Fable 5: Arena rating from 14,175 published pairwise votes.Gemini 3.8 Flash: Arena rating from 3,792 published pairwise votes.	Winner1,307.966 95% confidence interval: ±7.156The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,289.129 95% confidence interval: ±10.62The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
MedCodeOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 30,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value56.07 %	48.135 %	Vals AI Source details Data as of: 10/13/2026
MedScribeOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 30,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value88.522 %	84.496 %	Vals AI Source details Data as of: 10/13/2026
MMLU-ProOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value91.502 %	90.221 %	Vals AI Source details Data as of: 09/01/2026
MMMU-ProOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value89.306 %	89.075 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value68.919 %	65.342 %	Vals AI Source details Data as of: 09/01/2026
ProgramBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully resolved rateScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value2 %	1 %	Vals AI Source details Data as of: 10/12/2026
ProofBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value95 %	48 %	Vals AI Source details Data as of: 10/12/2026
Public Benefits Bench v1.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value70.433 %	65.291 %	Vals AI Source details Data as of: 10/12/2026
SAGEOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 30,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 30,000 tokens	Higher measured value51.89 %	35.064 %	Vals AI Source details Data as of: 10/08/2026
SWE-bench VerifiedOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value95 %	80 %	Vals AI Source details Data as of: 09/01/2026
Tax Agent BenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value38.281 %	32.124 %	Vals AI Source details Data as of: 10/12/2026
TaxEval v2Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value76.942 %	74.448 %	Vals AI Source details Data as of: 09/01/2026
Terminal-Bench 2.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	80.524 %	Higher measured value81.273 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0Overall Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value41.414 %	19.697 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceOverall Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 65,536 tokens	Higher measured value15.714 %	8.571 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexOverall Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: weighted index scoreScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value61.388 %	54.887 %	Vals AI Source details Data as of: 10/13/2026
Vibe Code Bench v1.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Harness: OpenHands, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Harness: OpenHands, Temperature: 1, Output limit: 65,536 tokens	Higher measured value90.352 %	78.651 %	Vals AI Source details Data as of: 10/12/2026
Code MigrationCLI Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value60.087 %	25.871 %	Vals AI Source details Data as of: 10/12/2026
EMBComps Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	70.785 %	Higher measured value76.435 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Adjustments Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	51.092 %	Higher measured value54.828 %	Vals AI Source details Data as of: 10/12/2026
GPQA DiamondFew-Shot CoT Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	92.929 %	Higher measured value94.949 %	Vals AI Source details Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkAntitrust Competition · Criteria passed Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: criteria pass rateScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value92.035 %	87.681 %	Vals AI Source details Data as of: 10/12/2026
Legal Research BenchAdministrative / Regulatory · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value57.576 %	46.97 %	Vals AI Source details Data as of: 10/12/2026
LegalBenchConclusion Tasks Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value91.775 %	90.691 %	Vals AI Source details Data as of: 10/13/2026
LiveCodeBench v6Easy Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	98.758 %	Higher measured value99.068 %	Vals AI Source details Data as of: 09/01/2026
LMArena Code Arena WebDevImage to webdev Test details No documented difference in the test setupVersion: webdevMetric: WebDev Arena Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Code Arena WebDev Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Code Arena WebDevClaude Fable 5: Arena rating from 5,457 published pairwise votes.Gemini 3.8 Flash: Arena rating from 2,015 published pairwise votes.	Winner1,622.483 95% confidence interval: ±9.201The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,593.067 95% confidence interval: ±13.862The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
LMArena Text, Style ControlBusiness, management and finance Test details No documented difference in the test setupVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Text, style control Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Text, style controlClaude Fable 5: Arena rating from 8,265 published pairwise votes.Gemini 3.8 Flash: Arena rating from 6,520 published pairwise votes.	Winner1,501.237 95% confidence interval: ±7.279The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,479.887 95% confidence interval: ±8.136The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Vision, Style ControlChinese Test details No documented difference in the test setupNo clear leadVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Vision, style control Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Vision, style controlClaude Fable 5: Arena rating from 765 published pairwise votes.Gemini 3.8 Flash: Arena rating from 182 published pairwise votes.	1,355.183 95% confidence interval: ±23.131The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	No clear lead1,379.729 95% confidence interval: ±43.521The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
MMLU-ProBiology Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	93.584 %	Higher measured value94.979 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxNumerical Extraction Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value76.709 %	70.588 %	Vals AI Source details Data as of: 09/01/2026
ProgramBenchAlmost Resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: almost-resolved rateScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value33 %	14 %	Vals AI Source details Data as of: 10/12/2026
SAGEAutomata Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 30,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 30,000 tokens	Higher measured value39.682 %	33.334 %	Vals AI Source details Data as of: 10/08/2026
SWE-bench Verified<15 min fix Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value95.876 %	89.691 %	Vals AI Source details Data as of: 09/01/2026
Tax Agent BenchControversy & Precedence Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value13.333 %	6.667 %	Vals AI Source details Data as of: 10/12/2026
TaxEval v2Correctness Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value65.822 %	62.469 %	Vals AI Source details Data as of: 09/01/2026
Terminal-Bench 2.1Easy Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	No direct winner100 %	No direct winner100 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0Hardware Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value40 %	26.667 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceEarth Sciences Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 65,536 tokens	Higher measured value25 %	0 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexCode Migration Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: benchmark scoreScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value54.635 %	31.558 %	Vals AI Source details Data as of: 10/13/2026
Code MigrationCOBOL Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	40 %	Higher measured value68.571 %	Vals AI Source details Data as of: 10/12/2026
EMBDataroom Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	85.362 %	Higher measured value86.218 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)All-Pass Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	45.694 %	Higher measured value49.694 %	Vals AI Source details Data as of: 10/12/2026
GPQA DiamondZero-Shot CoT Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	93.434 %	Higher measured value93.939 %	Vals AI Source details Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkAntitrust Competition · Task fully resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: task resolution rateScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	No direct winner0 %	No direct winner0 %	Vals AI Source details Data as of: 10/12/2026
Legal Research BenchAdministrative / Regulatory · Weighted partial credit Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: weighted partial-credit scoreScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value90.224 %	87.613 %	Vals AI Source details Data as of: 10/12/2026
LegalBenchInterpretation Tasks Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value86.863 %	84.589 %	Vals AI Source details Data as of: 10/13/2026
LiveCodeBench v6Hard Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value79.714 %	78 %	Vals AI Source details Data as of: 09/01/2026
LMArena Code Arena WebDevWebdev Test details No documented difference in the test setupVersion: webdevMetric: WebDev Arena Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Code Arena WebDev Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Code Arena WebDevClaude Fable 5: Arena rating from 15,295 published pairwise votes.Gemini 3.8 Flash: Arena rating from 10,077 published pairwise votes.	Winner1,623.828 95% confidence interval: ±6.238The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,584.77 95% confidence interval: ±7.59The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Text, Style ControlChinese Test details No documented difference in the test setupNo clear leadVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Text, style control Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Text, style controlClaude Fable 5: Arena rating from 3,073 published pairwise votes.Gemini 3.8 Flash: Arena rating from 2,903 published pairwise votes.	No clear lead1,554.631 95% confidence interval: ±11.32The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,532.833 95% confidence interval: ±11.757The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Vision, Style ControlCreative writing vision Test details No documented difference in the test setupVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Harness: Arena Vision, style control Gemini 3.8 Flash: Snapshot: gemini-3.8-flash-high, Reasoning: high, Harness: Arena Vision, style controlClaude Fable 5: Arena rating from 1,115 published pairwise votes.Gemini 3.8 Flash: Arena rating from 363 published pairwise votes.	Winner1,320.194 95% confidence interval: ±18.881The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,263.378 95% confidence interval: ±32.508The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
MMLU-ProBusiness Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	93.156 %	Higher measured value93.79 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxSemantic Extraction Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value61.129 %	60.095 %	Vals AI Source details Data as of: 09/01/2026
ProgramBenchFully Resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully resolved rateScoring: Higher is betterClaude Fable 5: Compute: max, Temperature: 1, Output limit: 128,000 tokens Gemini 3.8 Flash: Reasoning: high, Temperature: 1, Output limit: 65,536 tokens	Higher measured value2 %	1 %	Vals AI Source details Data as of: 10/12/2026
Key to the marks:better valuebetter, but not conclusivetie

Our model tests

Our tests

SVG short test

One SVG prompt and fixed output settings. Captures are shown only with 0 reported reasoning tokens or documented lack of reasoning controls. Identical test conditions do not make the models' internal compute identical.

Shared test round: 4ae5d8eeb9a9

Claude Fable 5

Unavailable in this round

Gemini 3.8 Flash

Unavailable in this round

Earlier tests

Pelican on a bicycle

A community classic for free-form SVG drawing.

Claude Fable 5

Reasoning (requested): high

Current attempt

Run date: Sep 7, 2026
API provider: openrouter
Requested API model: anthropic/claude-fable-5
API model reported in response: anthropic/claude-fable-5
Reasoning setting: high
Pinned endpoint: Anthropic | anthropic/claude-5-fable-20260609
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Passed, not a quality rating
Response time: 53.1 s

Visually reviewed. This individual test does not establish overall model quality.

Gemini 3.8 Flash

The response reached the token limit. No complete recording is available.

Reasoning (requested): high

Current attempt

Run date: Oct 5, 2026
API provider: openrouter
Requested API model: google/gemini-3.8-flash
API model reported in response: google/gemini-3.8-flash
Reasoning setting: high
Pinned endpoint: Google AI Studio | google/gemini-3.8-flash-20260902
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Failed
Response time: 40.2 s

Not yet visually reviewed. A successful recording does not confirm correct physics or full compliance with the prompt.

Earlier attempts (3)

Oct 2, 2026API request failedReasoning setting: high
Oct 1, 2026API request failedReasoning setting: high
Sep 7, 2026API request failedReasoning setting: high

Prompt and test conditions

Generate an SVG of a pelican riding a bicycle

Token limit including reasoning: 8,192 tokens

Task origin (Simon Willison)

How to read this comparison

Winning one benchmark is not an overall verdict

Your workload, budget, and required context length matter most. A coding benchmark says little about visual understanding or agent performance.

The standard price table uses direct developer rates. The provider comparison labels OpenRouter endpoints, regions, and special tariffs separately.

Every result links to its measurement source and retrieval date. Labels distinguish vendor reports, official benchmark leaderboards, and independent evaluations. Disputed or archived results are excluded.

More matchups

Compare Claude Fable 5 and Gemini 3.8 Flash with other leading models using the same data and benchmark logic.

View the complete LLM comparison

Claude Fable 5 vs. Gemini 3.8 Flash

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General specifications

API pricing compared

Shared benchmarks

Capability profile from matched benchmarks

Our tests

SVG short test

Claude Fable 5

Gemini 3.8 Flash

Pelican on a bicycle

Winning one benchmark is not an overall verdict

Related LLM comparisons