Claude Fable 5 vs GPT-5.5
Side-by-side comparison using current list prices and the live leaderboard.
Verdict
Claude Fable 5 is the stronger model; GPT-5.5 is 2x cheaper.
- Claude Fable 5 ranks higher on the LMRank leaderboard (#1 vs #8).
- GPT-5.5 is 2x cheaper per input token ($5.00 vs $10.00 per 1M).
- GPT-5.5 has the larger context window (1.1M vs 1M tokens).
At a Glance
| Attribute | Claude Fable 5 | GPT-5.5 |
|---|---|---|
| Lab | Anthropic | OpenAI |
| Leaderboard rank | #1 | #8 |
| Tags | Long Context Coding Intelligent Reasoning Agentic | Intelligent Reasoning Multimodal |
| Context | 1M tokens | 1.1M tokens |
| Input price | $10.00/1M | $5.00/1M |
| Output price | $50.00/1M | $30.00/1M |
| Input modalities | Image and text | Text |
| Output modalities | Text | Text |
Claude Fable 5: strengths
- #1 Intelligence Index at 64.9
- 1M-token context window
- 95% on SWE-bench Verified
- Strong agentic and coding performance
- Vision and scientific research capable
GPT-5.5: strengths
- Strong general knowledge
- Deep reasoning chain-of-thought
- Reliable structured output
- Broad tool-use capability
- Excellent multilingual support
Claude Fable 5: weaknesses
- Safety fallback reduces capability on sensitive queries
- Access may still be capacity-constrained after the June 2026 suspension
- High cost: $10/$50 per million tokens
- Mandatory 30-day data retention
GPT-5.5: weaknesses
- Creative writing less nuanced than Claude
- High cost for API usage
Claude Fable 5: best for
- Autonomous agentic workflows
- Long-horizon software engineering
- Complex knowledge work and research
- Multi-step tool-use with verifiable chain-of-thought
GPT-5.5: best for
- General purpose tasks
- Tool calling & agents
- Data analysis
- Structured output pipelines