Head-to-head comparison

Claude Opus 4.8 vs. Muse Spark 1.3

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

shared result series: 197
distinct benchmarks: 13
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 Opus 4.8 and Muse Spark 1.3
Attribute	Claude Opus 4.8	Muse Spark 1.3
Provider	Anthropic	Meta
Released	May 2026	Sep 2, 2026
Availability	Legacy	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	Not published
Technical sources	Model, Knowledge cutoff	Model, Context

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 Opus 4.8 and Muse Spark 1.3
Price type	Claude Opus 4.8	Muse Spark 1.3
API input	$5	$1.25
API output	$25	$4.25
Cache read	$0.5	$0.15
Cache write (5 min.)	$6.25	Not listed
Cache write (1 hr.)	$10	Not listed
Price verified	09/22/2026 Source	10/17/2026 Source

Claude Opus 4.8Muse Spark 1.3

API inputUSD per 1M tokens, base tier

Claude Opus 4.8$5

Muse Spark 1.3$1.25

API outputUSD per 1M tokens, base tier

Claude Opus 4.8$25

Muse Spark 1.3$4.25

Cache readUSD per 1M tokens, base tier

Claude Opus 4.8$0.5

Muse Spark 1.3$0.15

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 Opus 4.8 and Muse Spark 1.3
Model	Provider	Purchase route and tariff	Input per 1M tokens	Output per 1M tokens	Source
Claude Opus 4.8	Anthropic	Direct from developerStandard API	Lowest listed price: $5	Lowest listed price: $25	Source09/22/2026
Muse Spark 1.3	Meta	Via OpenRoutermeta	Lowest listed price: $1.25	Lowest listed price: $4.25	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.

Not enough directly matched categories for a reliable radar

Only 0 of at least 5 categories have comparable, direct model measurements. The benchmark tables below show the available evidence without filling missing axes.

Claude Opus 4.8Muse Spark 1.3

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

Claude Opus 4.847.25 %

Muse Spark 1.327.58 %

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

Claude Opus 4.869.373 %

Muse Spark 1.362.712 %

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

Claude Opus 4.853.918 %

Muse Spark 1.358.901 %

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

Claude Opus 4.89.583 %

Muse Spark 1.322.917 %

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

Claude Opus 4.843.75 %

Muse Spark 1.340.865 %

LMArena Text, Style ControlOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.81,474.25

Muse Spark 1.31,494.213

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

Claude Opus 4.81 %

Muse Spark 1.30.5 %

Tax Agent BenchOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.829.999 %

Muse Spark 1.335.974 %

Terminal-Bench 2.1Overall. Higher is better. Test setup not documented as identical

Claude Opus 4.871.91 %

Muse Spark 1.372.285 %

Terminal-Bench 4.0Overall. Higher is better. Test setup not documented as identical

Claude Opus 4.823.232 %

Muse Spark 1.310.606 %

Terminal-Bench ScienceOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.84.286 %

Muse Spark 1.34.286 %

Vals IndexOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.855.1 %

Muse Spark 1.353.197 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for Claude Opus 4.8 and Muse Spark 1.3
Benchmark and task	Claude Opus 4.8	Muse Spark 1.3	Source
Code MigrationOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value47.25 %	27.58 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value69.373 %	62.712 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	53.918 %	Higher measured value58.901 %	Vals AI Source details Data as of: 10/12/2026
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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	9.583 %	Higher measured value22.917 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value43.75 %	40.865 %	Vals AI Source details Data as of: 10/12/2026
LMArena Text, Style ControlOverall Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8, Harness: Arena Text, style control Muse Spark 1.3: Snapshot: muse-spark-1.3-max, Reasoning: max, Harness: Arena Text, style controlClaude Opus 4.8: Arena rating from 65,181 published pairwise votes.Muse Spark 1.3: Arena rating from 16,731 published pairwise votes.	1,474.25 95% confidence interval: ±3.848The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	Higher measured value1,494.213 95% confidence interval: ±5.665The 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
ProgramBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully resolved rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value1 %	0.5 %	Vals AI Source details Data as of: 10/12/2026
Tax Agent BenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	29.999 %	Higher measured value35.974 %	Vals AI Source details Data as of: 10/12/2026
Terminal-Bench 2.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	71.91 %	Higher measured value72.285 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value23.232 %	10.606 %	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 Opus 4.8: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 131,072 tokens	No direct winner4.286 %	No direct winner4.286 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value55.1 %	53.197 %	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 Opus 4.8: Compute: max, Harness: OpenHands, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Harness: OpenHands, Temperature: 1, Output limit: 131,072 tokens	82.725 %	Higher measured value82.859 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value40.143 %	13.916 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value72.797 %	64.798 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	48.387 %	Higher measured value52.818 %	Vals AI Source details Data as of: 10/12/2026
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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	87.319 %	Higher measured value96.377 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	43.939 %	Higher measured value51.515 %	Vals AI Source details Data as of: 10/12/2026
LMArena Text, Style ControlOverall Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8-high, Reasoning: high, Harness: Arena Text, style control Muse Spark 1.3: Snapshot: muse-spark-1.3-max, Reasoning: max, Harness: Arena Text, style controlClaude Opus 4.8: Arena rating from 64,112 published pairwise votes.Muse Spark 1.3: Arena rating from 16,731 published pairwise votes.	1,481.505 95% confidence interval: ±3.87The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	Higher measured value1,494.213 95% confidence interval: ±5.665The 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
ProgramBenchAlmost Resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: almost-resolved rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value15.5 %	13 %	Vals AI Source details Data as of: 10/12/2026
Tax Agent BenchControversy & Precedence Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	13.133 %	Higher measured value14.667 %	Vals AI Source details Data as of: 10/12/2026
Terminal-Bench 2.1Easy Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value100 %	75 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value26.667 %	0 %	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 Opus 4.8: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 131,072 tokens	No direct winner0 %	No direct winner0 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value46.942 %	42.192 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	No direct winner68.571 %	No direct winner68.571 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value85.948 %	84.191 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	43.517 %	Higher measured value48.737 %	Vals AI Source details Data as of: 10/12/2026
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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	0 %	Higher measured value20 %	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 Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value87.365 %	85.884 %	Vals AI Source details Data as of: 10/12/2026
LMArena Text, Style ControlBusiness, management and finance Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8, Harness: Arena Text, style control Muse Spark 1.3: Snapshot: muse-spark-1.3-max, Reasoning: max, Harness: Arena Text, style controlClaude Opus 4.8: Arena rating from 12,774 published pairwise votes.Muse Spark 1.3: Arena rating from 3,041 published pairwise votes.	1,486.06 95% confidence interval: ±6.336The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	Higher measured value1,503.61 95% confidence interval: ±11.102The 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
ProgramBenchFully Resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully resolved rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value1 %	0.5 %	Vals AI Source details Data as of: 10/12/2026
Tax Agent BenchControversy & Precedence Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	58.743 %	Higher measured value60.859 %	Vals AI Source details Data as of: 10/12/2026
Terminal-Bench 2.1Hard Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	60 %	Higher measured value61.111 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0Media Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	No direct winner0 %	No direct winner0 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceEngineering Sciences Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 131,072 tokens	No direct winner0 %	No direct winner0 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexEMB Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: benchmark scoreScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value69.373 %	62.712 %	Vals AI Source details Data as of: 10/13/2026
Code MigrationCode Quality Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: mean reviewer code-quality ratingScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value4.7 / 5	4.02 / 5	Vals AI Source details Data as of: 10/12/2026
EMBDCF Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value66.334 %	55.697 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Comparables Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	44.853 %	Higher measured value47.167 %	Vals AI Source details Data as of: 10/12/2026
Harvey's Legal Agent BenchmarkArbitration International Dispute Resolution · Criteria passed Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: criteria pass rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	88.172 %	Higher measured value93.907 %	Vals AI Source details Data as of: 10/12/2026
Legal Research BenchBusiness & Commercial · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value41.86 %	32.558 %	Vals AI Source details Data as of: 10/12/2026
LMArena Text, Style ControlBusiness, management and finance Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8-high, Reasoning: high, Harness: Arena Text, style control Muse Spark 1.3: Snapshot: muse-spark-1.3-max, Reasoning: max, Harness: Arena Text, style controlClaude Opus 4.8: Arena rating from 12,740 published pairwise votes.Muse Spark 1.3: Arena rating from 3,041 published pairwise votes.	1,488.783 95% confidence interval: ±6.374The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	Higher measured value1,503.61 95% confidence interval: ±11.102The 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
ProgramBenchRaw Pass Rate Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: raw test pass rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value71.945 %	71.722 %	Vals AI Source details Data as of: 10/12/2026
Tax Agent BenchCurrent & Temporal Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	46.524 %	Higher measured value49.769 %	Vals AI Source details Data as of: 10/12/2026
Terminal-Bench 2.1Medium Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	76.364 %	Higher measured value78.182 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0ML Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value27.273 %	21.212 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceLife Sciences Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 131,072 tokens	0 %	Higher measured value15.789 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexFinance Agent v2 Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: benchmark scoreScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	53.918 %	Higher measured value58.901 %	Vals AI Source details Data as of: 10/13/2026
EMBLBO Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	54.384 %	Higher measured value56.579 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Disclosure Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	65.706 %	Higher measured value66.693 %	Vals AI Source details Data as of: 10/12/2026
Harvey's Legal Agent BenchmarkArbitration International Dispute Resolution · Task fully resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: task resolution rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	No direct winner0 %	No direct winner0 %	Vals AI Source details Data as of: 10/12/2026
Legal Research BenchBusiness & Commercial · Weighted partial credit Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: weighted partial-credit scoreScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	86.112 %	Higher measured value88.24 %	Vals AI Source details Data as of: 10/12/2026
LMArena Text, Style ControlChinese Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8, Harness: Arena Text, style control Muse Spark 1.3: Snapshot: muse-spark-1.3-max, Reasoning: max, Harness: Arena Text, style controlClaude Opus 4.8: Arena rating from 4,392 published pairwise votes.Muse Spark 1.3: Arena rating from 1,298 published pairwise votes.	1,524.693 95% confidence interval: ±9.624The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	Higher measured value1,529.417 95% confidence interval: ±16.859The 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
Tax Agent BenchCurrent & Temporal Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value76.033 %	73.142 %	Vals AI Source details Data as of: 10/12/2026
Terminal-Bench 4.0Operations Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value11.111 %	7.407 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceMathematical Sciences Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 131,072 tokens	Higher measured value5.882 %	0 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexHLAB Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: benchmark scoreScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	9.583 %	Higher measured value22.917 %	Vals AI Source details Data as of: 10/13/2026
EMBM&A Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value80.091 %	64.366 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Earnings Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	72.07 %	Higher measured value77.088 %	Vals AI Source details Data as of: 10/12/2026
Harvey's Legal Agent BenchmarkBanking Finance · Criteria passed Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: criteria pass rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	87.732 %	Higher measured value94.052 %	Vals AI Source details Data as of: 10/12/2026
Legal Research BenchCivil Litigation · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	Higher measured value51.852 %	40.741 %	Vals AI Source details Data as of: 10/12/2026
LMArena Text, Style ControlChinese Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8-high, Reasoning: high, Harness: Arena Text, style control Muse Spark 1.3: Snapshot: muse-spark-1.3-max, Reasoning: max, Harness: Arena Text, style controlClaude Opus 4.8: Arena rating from 4,354 published pairwise votes.Muse Spark 1.3: Arena rating from 1,298 published pairwise votes.	1,526.02 95% confidence interval: ±9.629The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	Higher measured value1,529.417 95% confidence interval: ±16.859The 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
Tax Agent BenchFact-Pattern Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens Muse Spark 1.3: Reasoning: xhigh, Temperature: 1, Output limit: 131,072 tokens	25.581 %	Higher measured value45.814 %	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 Opus 4.8

Unavailable in this round

Muse Spark 1.3

Unavailable in this round

Earlier tests

Pelican on a bicycle

A community classic for free-form SVG drawing.

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.

Muse Spark 1.3

Reasoning (requested): high

Current attempt

Run date: Oct 2, 2026
API provider: openrouter
Requested API model: meta/muse-spark-1.3
API model reported in response: meta/muse-spark-1.3
Reasoning setting: high
Pinned endpoint: Meta | meta/muse-spark-1.3-20260902
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: 87.9 s

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

Earlier attempts (2)

Oct 1, 2026Output withheld for safetyReasoning 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 Opus 4.8 and Muse Spark 1.3 with other leading models using the same data and benchmark logic.

View the complete LLM comparison

Claude Opus 4.8 vs. Muse Spark 1.3

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General specifications

API pricing compared

Shared benchmarks

Capability profile from matched benchmarks

Our tests

SVG short test

Claude Opus 4.8

Muse Spark 1.3

Pelican on a bicycle

Winning one benchmark is not an overall verdict

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