Claude Fable 5 vs GPT-5.6 Sol
Side-by-side comparison using current list prices and the live leaderboard.
Claude Fable 5 is the stronger model; GPT-5.6 Sol is 5x cheaper.
- Claude Fable 5 ranks higher on the LMRank leaderboard (#1 vs #4).
- GPT-5.6 Sol is 5x cheaper per input token ($2.00 vs $10.00 per 1M).
- GPT-5.6 Sol has the larger context window (1.1M vs 1M tokens).
At a Glance
| Attribute | Claude Fable 5 | GPT-5.6 Sol |
|---|---|---|
| Lab | Anthropic | OpenAI |
| Leaderboard rank | #1 | #4 |
| Tags | Long Context Coding Intelligent Reasoning Agentic | Long Context Coding Intelligent Reasoning Agentic |
| Context | 1M tokens | 1.1M tokens |
| Input price | $10.00/1M | $2.00/1M |
| Output price | $50.00/1M | $10.00/1M |
| 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-5.6 Sol: strengths
- Terminal-Bench 2.1 SOTA (91.9% in Ultra mode)
- Ultra multi-agent mode coordinates parallel sub-agents for complex tasks
- 1.05M-token context for long-horizon agentic work
- Max reasoning-effort control for deeper single-pass reasoning
- New predictable prompt-caching with explicit cache controls
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-5.6 Sol: weaknesses
- Highest GPT-5.6 price at $5/$30 per 1M tokens
- Ultra mode multiplies token spend via parallel sub-agents
- Limited preview access at launch; GA rolling out
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-5.6 Sol: best for
- Frontier agentic coding and tool use
- Long-horizon automation and research
- Deep reasoning and hard multi-step problems
Claude Fable 5 vs GPT-5.6 Sol
GPT-5.6 Sol and Claude Fable 5 are both aimed at long-horizon, agentic work, but they emphasize different trade-offs. Sol is the cheaper option on the current list prices and offers a slightly larger 1.05M-token context window, plus explicit max-reasoning and multi-agent controls. Fable 5 costs more, but its current profile leads on the Intelligence Index and SWE-bench Verified, with strong autonomous software-engineering and research positioning. Choose Sol when controllable reasoning, coordinated sub-agents, and lower token cost matter most; choose Fable 5 when frontier coding and complex knowledge-work performance justify the premium.