Head-to-head comparison

Claude Fable 5 vs. Claude Opus 4.8

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

shared result series: 28
distinct benchmarks: 28
latest retrieval: 2026-09-29

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 Claude Opus 4.8
Attribute	Claude Fable 5	Claude Opus 4.8
Provider	Anthropic	Anthropic
Released	Jun 9, 2026	May 2026
Availability	Active	Legacy
Model type	Proprietary	Proprietary
Parameters	Not published	Not published
Architecture	Not published	Not published
Context window	1,000,000 tokens	1,000,000 tokens
Knowledge cutoff	January 2026	January 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 Claude Opus 4.8
Price type	Claude Fable 5	Claude Opus 4.8
API input	$10	$5
API output	$50	$25
Cache read	$1	$0.5
Cache write (5 min.)	$12.5	$6.25
Cache write (1 hr.)	$20	$10
Price verified	09/22/2026 Source	09/22/2026 Source

Claude Fable 5Claude Opus 4.8

API inputUSD per 1M tokens, base tier

Claude Fable 5$10

Claude Opus 4.8$5

API outputUSD per 1M tokens, base tier

Claude Fable 5$50

Claude Opus 4.8$25

Cache readUSD per 1M tokens, base tier

Claude Fable 5$1

Claude Opus 4.8$0.5

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.

No provider tariff for Claude Opus 4.8 is available in the stored OpenRouter snapshot. The official direct price is still shown.

Provider pricing for Claude Fable 5 and Claude Opus 4.8
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	Source10/15/2026
	Anthropic	Via OpenRouteranthropic	Lowest listed price: $10	Lowest listed price: $50	Source10/15/2026
	Azure	Via OpenRouterazure	Lowest listed price: $10	Lowest listed price: $50	Source10/15/2026
	Claude Platform on AWS	Via OpenRouterclaude-on-aws	Lowest listed price: $10	Lowest listed price: $50	Source10/15/2026
	Google	Via OpenRoutergoogle-vertex/europe	$11	$55	Source10/15/2026
	Google	Via OpenRoutergoogle-vertex/global	Lowest listed price: $10	Lowest listed price: $50	Source10/15/2026
Claude Opus 4.8	Anthropic	Direct from developerStandard API	Lowest listed price: $5	Lowest listed price: $25	Source09/22/2026

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

Claude Opus 4.8

Coding: 98.9 / 84.2 (7 benchmark families)

Reasoning: 100 / 99.2 (1 benchmark family)

Knowledge: 100 / 97.9 (1 benchmark family)

Finance: 99.8 / 95.7 (6 benchmark families)

Legal: 100 / 89.3 (3 benchmark families)

Agentic tasks: 100 / 89.3 (1 benchmark family)

Multimodal: 100 / 97 (1 benchmark family)

Productivity: 100 / 96.7 (1 benchmark family)

27 matched rows from 26 benchmark families were considered. The radar shows 8 of 12 comparable categories.

Claude Fable 5Claude Opus 4.8

Code MigrationOverall. Higher is better. No documented setup difference

Claude Fable 555.065 %

Claude Opus 4.847.25 %

CorpFin v2Overall. Higher is better. No documented setup difference

Claude Fable 571.834 %

Claude Opus 4.866.706 %

EMBOverall. Higher is better. No documented setup difference

Claude Fable 573.666 %

Claude Opus 4.869.373 %

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

Claude Fable 539.28% ± 2.8

Claude Opus 4.823.51% ± 2.41

Finance Agent (v2)Overall. Higher is better. No documented setup difference

Claude Fable 556.314 %

Claude Opus 4.853.918 %

GPQA DiamondOverall. Higher is better. No documented setup difference

Claude Fable 593.182 %

Claude Opus 4.892.424 %

Harvey's Legal Agent BenchmarkOverall · Task fully resolved. Higher is better. No documented setup difference

Claude Fable 511.25 %

Claude Opus 4.89.583 %

Legal Research BenchOverall · All-pass. Higher is better. No documented setup difference

Claude Fable 549.519 %

Claude Opus 4.843.75 %

LegalBenchOverall. Higher is better. No documented setup difference

Claude Fable 588.561 %

Claude Opus 4.883.568 %

LiveCodeBench v6Overall. Higher is better. No documented setup difference

Claude Fable 589.778 %

Claude Opus 4.887.819 %

MedCodeOverall. Higher is better. No documented setup difference

Claude Fable 556.07 %

Claude Opus 4.853.217 %

MedScribeOverall. Higher is better. No documented setup difference

Claude Fable 588.522 %

Claude Opus 4.885.755 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for Claude Fable 5 and Claude Opus 4.8
Benchmark and task	Claude Fable 5	Claude Opus 4.8	Source
Code MigrationOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner55.065 %	47.25 %	Vals AI Source details Data as of: 09/27/2026
CorpFin v2Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner71.834 %	66.706 %	Vals AI Source details Data as of: 08/12/2026
EMBOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner73.666 %	69.373 %	Vals AI Source details Data as of: 09/27/2026
EnigmaEvalOverall Test details Test setup not documented as identicalNo direct winnerVersion: open-source release 2026-07-23Metric: pass@1 accuracyScoring: Higher is betterClaude Fable 5: Snapshot: claude-fable-5-high, Reasoning: high, Attempts: pass@1 Claude Opus 4.8: Snapshot: claude-opus-4.8-xhigh, Reasoning: xhigh, Attempts: pass@1Complex multimodal puzzles with exact answer matching and one attempt.	Higher measured value39.28% ± 2.8 95% confidence interval: ±2.8	23.51% ± 2.41 95% confidence interval: ±2.41	Scale AI Source details Data as of: 07/23/2026
Finance Agent (v2)Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner56.314 %	53.918 %	Vals AI Source details Data as of: 09/27/2026
GPQA DiamondOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner93.182 %	92.424 %	Vals AI Source details Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved Test details No documented difference in the test setupVersion: 1Metric: task resolution rateScoring: Higher is better	Winner11.25 %	9.583 %	Vals AI Source details Data as of: 09/27/2026
Legal Research BenchOverall · All-pass Test details No documented difference in the test setupVersion: 1Metric: all-pass rateScoring: Higher is better	Winner49.519 %	43.75 %	Vals AI Source details Data as of: 09/27/2026
LegalBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner88.561 %	83.568 %	Vals AI Source details Data as of: 09/27/2026
LiveCodeBench v6Overall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner89.778 %	87.819 %	Vals AI Source details Data as of: 09/01/2026
MedCodeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner56.07 %	53.217 %	Vals AI Source details Data as of: 09/26/2026
MedScribeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner88.522 %	85.755 %	Vals AI Source details Data as of: 09/26/2026
MMLU-ProOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner91.502 %	89.585 %	Vals AI Source details Data as of: 09/01/2026
MMMU-ProOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner89.306 %	86.59 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	68.919 %	Winner69.912 %	Vals AI Source details Data as of: 09/01/2026
ProgramBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner2 %	1 %	Vals AI Source details Data as of: 09/27/2026
Public Benefits Bench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better	Winner70.433 %	68.133 %	Vals AI Source details Data as of: 09/27/2026
SAGEOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	51.89 %	Winner54.788 %	Vals AI Source details Data as of: 09/26/2026
SWE-bench VerifiedOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner95 %	88.6 %	Vals AI Source details Data as of: 09/01/2026
SWE-Marathon v1.0Binary resolution, pass@1 Test details No documented difference in the test setupVersion: v1.0 leaderboardMetric: binary resolution pass@1Scoring: Higher is betterSettings: Agent: Claude Code20 multi-hour tasks. The named coding agent is part of every result row.	24 % Two refusals and three unavailable provider-ban trials were counted as zero.	Winner26 %	SWE-Marathon Source details Data as of: 06/05/2026
Tax Agent BenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner69.822 %	64.906 %	Vals AI Source details Data as of: 09/27/2026
TaxEval v2Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner76.942 %	75.634 %	Vals AI Source details Data as of: 09/01/2026
Terminal-Bench 2.1Overall Test details No documented difference in the test setupVersion: 2.1Metric: accuracyScoring: Higher is better	Winner80.524 %	71.91 %	Vals AI Source details Data as of: 09/27/2026
Terminal-Bench 4.0Overall Test details No documented difference in the test setupVersion: 4.0Metric: accuracyScoring: Higher is better	Winner22.727 %	16.162 %	Vals AI Source details Data as of: 09/27/2026
Terminal-Bench ScienceOverall Test details No documented difference in the test setupVersion: 0.1Metric: accuracyScoring: Higher is better	Winner12.857 %	10 %	Vals AI Source details Data as of: 09/27/2026
Vals IndexOverall Test details No documented difference in the test setupVersion: 2Metric: weighted index scoreScoring: Higher is better	Winner66.036 %	60.908 %	Vals AI Source details Data as of: 09/27/2026
Vals Multimodal IndexOverall Test details No documented difference in the test setupVersion: 1.2Metric: weighted index scoreScoring: Higher is better	Winner74.154 %	70.889 %	Vals AI Source details Data as of: 08/11/2026
Vibe Code Bench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands	Winner90.352 %	82.725 %	Vals AI Source details Data as of: 09/27/2026
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

Claude Opus 4.8

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.

Claude Opus 4.8

Reasoning (requested): high

Current attempt

Run date: Oct 1, 2026
API provider: openrouter
Requested API model: anthropic/claude-opus-4.8
API model reported in response: anthropic/claude-opus-4.8
Reasoning setting: high
Pinned endpoint: Anthropic | anthropic/claude-4.8-opus-20260528
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: 18 s

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

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 Claude Opus 4.8 with other leading models using the same data and benchmark logic.

View the complete LLM comparison

Claude Fable 5 vs. Claude Opus 4.8

Change model selection

General specifications

API pricing compared

Shared benchmarks

Capability profile from matched benchmarks

Our tests

SVG short test

Claude Fable 5

Claude Opus 4.8

Pelican on a bicycle

Winning one benchmark is not an overall verdict

Related LLM comparisons