Claude Fable 5.5 (Leaked Checkpoint) vs GPT-Image-2.5 (Sunburst)
A direct, empirical evaluation of Claude Fable 5.5 (Leaked Checkpoint) (Anthropic) against GPT-Image-2.5 (Sunburst) (OpenAI).
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.
GPT-Image-2.5 (Sunburst)
Developed by OpenAI · Proprietary Multimodal DiT parameters
High-fidelity typographic rendering, raytracing reflection accuracy, sketch-to-image conditioning, and localized comment inpainting.
| Metric | Claude Fable 5.5 (Leaked Checkpoint) | GPT-Image-2.5 (Sunburst) |
|---|---|---|
| SWE-bench Verified | 84.2% | 62.4% |
| MMLU-Pro | 94.6% | 89.5% |
| MATH-500 | 98.4% | 91.2% |
| Context Window | 1,500,000 tokens | Spatial Vector Token Canvas (1792×1024) |
| Input Pricing (per 1M) | $3.50 | $2.50 |
| Output Pricing (per 1M) | $17.50 | $10.00 |