Claude Fable 5 vs GPT-5.5
Pricing, benchmarks, and use case comparison
Quick take
- •Claude Fable 5 leads on 2 of 2 shared benchmarks, including SWE-bench Verified (95.0% vs 82.6%), SWE-bench Pro (80.3% vs 58.6%).
- •GPT-5.5 is 50% cheaper on input tokens, which compounds fast on high-volume or agentic workloads.
- •Claude Fable 5 has a 1M context window vs 1,050,000 tokens (128,000 max output) - better for whole-repo or long-document work.
Specs comparison
| Claude Fable 5 | GPT-5.5 | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Type | Closed source | Closed source |
| Context window | ✓1M | 1,050,000 tokens (128,000 max output) |
| Input / 1M tokens | $10.00 | ✓$5.00 |
| Output / 1M tokens | $50.00 | $30.00 |
| Release date | 2026-06 | 2026-04 |
Benchmarks
| Benchmark | Claude Fable 5 | GPT-5.5 |
|---|---|---|
| SWE-bench Verified | ✓95.0% | 82.6% |
| Terminal-Bench 2.1 | 88.0% | - |
| GPQA Diamond | 92.6% | - |
| SWE-bench Pro | ✓80.3% | 58.6% |
Scores sourced from official provider release posts and independent benchmark aggregators.
Which should you choose?
Choose Claude Fable 5 if...
- →You need the absolute highest capability Anthropic offers for hard tasks
- →You run long, complex autonomous agents where quality compounds over many steps
- →You do frontier-level engineering, research, or analytics and cost is secondary
- →You want maximum accuracy on the toughest coding and reasoning benchmarks
Choose GPT-5.5 if...
- →Complex professional coding, data analysis, and multi-tool agentic workflows
- →Long-document or large-codebase tasks needing a 1M+ context window
- →You want OpenAI's recommended default frontier model for new projects