Model comparison

Claude Fable 5.1 vs Seed 2.0 Pro

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 43.2 on the Noometry Index. Seed 2.0 Pro costs 18× less per token, which makes it the better buy when Claude Fable 5.1's lead doesn't matter for your workload.

Last verified . 19 shared benchmarks.

Claude Fable 5.1 Anthropic

69.0

Rank #2 Confirmed

Seed 2.0 Pro ByteDance Seed

43.2

Rank #96 Confirmed

Summary

  • They share 19 benchmarks with published results for both. Claude Fable 5.1 scores higher in 9 categories and Seed 2.0 Pro in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Fable 5.1 leads 76.7 to 24.1.
  • The biggest single-benchmark swing is NYT Connections (extended): 90% for Claude Fable 5.1 and 28.4% for Seed 2.0 Pro.
  • Seed 2.0 Pro is cheaper at $0.50 / $3 per million input/output tokens, against $10 / $50 for Claude Fable 5.1.
  • Claude Fable 5.1 accepts more context: 1M tokens versus 256K.

Side by side

Claude Fable 5.1 and Seed 2.0 Pro specifications
Claude Fable 5.1Seed 2.0 Pro
ProviderAnthropicByteDance Seed
Noometry Index69.043.2
Released2026-09-012026-02-14
WeightsProprietaryProprietary
Context window1M256K
Max output128K128K
Input $ / M tokens$10$0.50
Output $ / M tokens$50$3
Results tracked5220

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Category by category

Coding Claude Fable 5.1 leads

Claude Fable 5.1: 74.7 (#1), Seed 2.0 Pro: 43.5 (#86)

Coding benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
LMArena Coding15281472
FrontierCode50.9%—
CursorBench51.8%—
LMArena WebDev1744—
FrontierSWE56.3%—
SciCode63.1%—
GSO88.2%—
WeirdML92.9%—
MirrorCode73.3%—
ALE-Bench2,143—

Agentic & Tool Use Not comparable

Claude Fable 5.1: 50.7 (#5), Seed 2.0 Pro: —

Agentic & Tool Use benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
APEX-Agents68.6%—
Remote Labor Index17.9%—
GDP.pdf29.6%—
Vending-Bench 25,422—

Reasoning Claude Fable 5.1 leads

Claude Fable 5.1: 76.7 (#7), Seed 2.0 Pro: 24.1 (#165)

Reasoning benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
NYT Connections (extended)90%28.4%
LMArena Hard Prompts15261453
ARC-AGI-290%—
ARC-AGI-197.5%—
CritPt31.1%—
Chess Puzzles47%—
Thematic Generalization—57.1%
EBR-Bench57.1%—
Mystery Game Puzzles58%—
DTBench97.6%—
LMCA65.5%—
Epoch Capabilities Index164.7—

Math Claude Fable 5.1 leads

Claude Fable 5.1: 89.6 (#4), Seed 2.0 Pro: 39.3 (#108)

Math benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
LMArena Math15251439
FrontierMath (Tiers 1-3)90.2%—
FrontierMath Tier 487.8%—
OTIS Mock AIME 2024-2025100%—
ProofBench100%—
FrontierMath Erdős0%—

Knowledge Claude Fable 5.1 leads

Claude Fable 5.1: 69.6 (#6), Seed 2.0 Pro: 40.2 (#122)

Knowledge benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
LMArena Expert15351440
Humanity's Last Exam46.5%—
SimpleQA Verified70.8%—

Multimodal Claude Fable 5.1 leads

Claude Fable 5.1: 53.9 (#4), Seed 2.0 Pro: 41.5 (#35)

Multimodal benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
LMArena Vision13181274
Blueprint-Bench 241.9%—
Furniture Assembly70%—
LMArena Document1513—

Multilingual Claude Fable 5.1 leads

Claude Fable 5.1: 59.1 (#3), Seed 2.0 Pro: 54.5 (#39)

Multilingual benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
LMArena Non-English15071441
LMArena Chinese15861489
LMArena French15251471
LMArena German15001442
LMArena Japanese15431408
LMArena Korean15341411
LMArena Russian15211449
LMArena Spanish15161460

Instruction Following Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#6), Seed 2.0 Pro: 74.5 (#91)

Instruction Following benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
LMArena Instruction Following15171414

Long Context Claude Fable 5.1 leads

Claude Fable 5.1: 46.7 (#20), Seed 2.0 Pro: 43.6 (#90)

Long Context benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
LMArena Longer Query15221428

Writing & Preference Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#2), Seed 2.0 Pro: 62.9 (#69)

Writing & Preference benchmarks
BenchmarkClaude Fable 5.1Seed 2.0 Pro
LMArena Text15101448
LMArena Creative Writing15071406
LMArena Multi-Turn14921441
EQ-Bench Creative Writing2162—

Frequently asked questions

Is Claude Fable 5.1 better than Seed 2.0 Pro?

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 43.2 on the Noometry Index. Seed 2.0 Pro costs 18× less per token, which makes it the better buy when Claude Fable 5.1's lead doesn't matter for your workload.

Which is cheaper, Claude Fable 5.1 or Seed 2.0 Pro?

Seed 2.0 Pro is cheaper. It lists at $0.50 per million input tokens and $3 per million output tokens; Claude Fable 5.1 lists at $10 and $50.

Is Claude Fable 5.1 or Seed 2.0 Pro better for coding?

Claude Fable 5.1 scores higher on coding benchmarks: 74.7 versus 43.5 in the Noometry coding category.

Which has the bigger context window?

Claude Fable 5.1 does, with 1M tokens against 256K.

How many benchmarks do Claude Fable 5.1 and Seed 2.0 Pro share?

19 benchmarks have published results for both models. Claude Fable 5.1 has 52 scored results on Noometry and Seed 2.0 Pro has 20.

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