Claude Fable 5.5 (Leaked Checkpoint) vs DeepSeek-V3

A direct, empirical evaluation of Claude Fable 5.5 (Leaked Checkpoint) (Anthropic) against DeepSeek-V3 (DeepSeek-AI).

Claude Fable 5.5 (Leaked Checkpoint)

Developed by Anthropic · Proprietary Frontier Dynamic Reasoner parameters

Terminal-Bench 4.0 autonomous shell execution (78.5% target), recursive self-critique, and 1.5M-token repository refactoring.

DeepSeek-V3

Developed by DeepSeek-AI · 671B parameters

Cost-effective high-throughput general reasoning and bilingual generation.

Metric Claude Fable 5.5 (Leaked Checkpoint) DeepSeek-V3
SWE-bench Verified 84.2% 49.2%
MMLU-Pro 94.6% 75.9%
MATH-500 98.4% 90.2%
Context Window 1,500,000 tokens 128,000 tokens
Input Pricing (per 1M) $3.50 $0.14
Output Pricing (per 1M) $17.50 $0.28