GPT-5.6 vs. Fable 5: Benchmarks Split, Pricing Gap Widens

What happened: OpenAI’s GPT-5.6 (Sol/Terra/Luna) and Anthropic’s Claude Fable 5 went head-to-head in a Decrypt review. GPT-5.6 Sol outperformed on coding and agentic benchmarks (e.g., Coding Agent Index: 80 vs. 77.2), while Fable 5 led on SWE-Bench Pro (80% vs. 64.6%) and creative writing. Pricing is a key differentiator: Fable 5 is roughly twice as expensive as Sol for comparable tasks.

Why it matters: The review underscores that there is no clear "winner" in the current LLM arms race. GPT-5.6 wins on speed, cost, and agentic tasks, while Fable 5 excels in nuanced reasoning and large-repo coding. For users, the choice depends on specific needs and budget, not brand loyalty.

Source: Decrypt