Claude Fable 5.1 vs DeepSeek V5 (Leaked Staging)

A direct, empirical evaluation of Claude Fable 5.1 (Anthropic) against DeepSeek V5 (Leaked Staging) (DeepSeek AI).

Claude Fable 5.1

Developed by Anthropic · Proprietary Frontier parameters

Full-repository software refactoring, agentic tool workflows, formal verification, and 1.5M-token needle retrieval.

DeepSeek V5 (Leaked Staging)

Developed by DeepSeek AI · 1.8 Trillion (Sparse MoE) parameters

Autonomous coding agents scoring 81.4% on SWE-bench Verified, zero-telemetry self-hosting, sub-cent 1M-token processing, and formal mathematical proofs.

Metric Claude Fable 5.1 DeepSeek V5 (Leaked Staging)
SWE-bench Verified 82.8% 81.4%
MMLU-Pro 92.4% 87.5%
MATH-500 97.9% 96.8%
Context Window 1,500,000 tokens 1,000,000 tokens
Input Pricing (per 1M) $12.00 $0.12
Output Pricing (per 1M) $60.00 $0.48