Claude Fable 5.1 vs GPT-5.5 Pro
Benchmark Performance
Available Benchmarks
| Benchmark | Claude Fable 5.1 | GPT-5.5 Pro |
|---|---|---|
| ARC-AGI-1verified-v1-2aa739d957fc · verified_score · leader | 97.50100% of row best · percent · Claude Fable 5.1 (Max) | 96.5099% of row best · percent · GPT-5.5 Pro (High) |
| ARC-AGI-2verified-v2-b5cb5ec6e8c7 · verified_score · leader | 90.00100% of row best · percent · Claude Fable 5.1 (XHigh) | 84.5894% of row best · percent · GPT-5.5 Pro (High) |
| Overall ResultCounted from the protocol-matched rows above | 2 benchmark winsOverall lead | 0 benchmark wins |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Technical Differences
Side-by-Side Facts
| Field | Claude Fable 5.1 | GPT-5.5 Pro |
|---|---|---|
| Developer | Anthropic | OpenAI |
| Family | Claude 5 1 | Gpt 5 5 |
| Model | Claude Fable 5.1 | GPT-5.5 Pro |
| Version | Claude Fable 5.1 | GPT-5.5 Pro |
| Lifecycle | active | active |
| Released | 2026-09-01 | 2026-04-23 |
| Knowledge cutoff | 2026-06-01 | 2025-12-01 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,000K | 1,050K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Anthropic (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, structured_outputs, tools |
15 comparable fields · 9 material differences · Pair passes the primary-source comparison gate
Claude Fable 5.1 Capabilities
GPT-5.5 Pro Capabilities
Internal Comparison Graph
Related Comparisons
| A | Pair | B | Context |
|---|---|---|---|
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Claude Fable 5.1Anthropic | vs |  Kimi-K3Moonshot AI | cross-developer peersimage, text |
 MiniMax-M3MiniMax | vs | Claude Fable 5.1Anthropic | cross-developer peersimage, text |
Claude Fable 5.1Anthropic | vs |  GLM-5.3Z.ai | cross-developer peerstext |
Claude Fable 5.1Anthropic | vs |  Hy4 previewTencent | cross-developer peerstext |
Claude Fable 5.1Anthropic | vs | Seed 2.1 ProByteDance Seed | cross-developer peersimage, text |
Claude Fable 5.1Anthropic | vs |  Mistral Large 3Mistral AI | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Fable 5.1 vs GPT-5.5 Pro FAQs
Is Claude Fable 5.1 or GPT-5.5 Pro better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Fable 5.1 and GPT-5.5 Pro, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Fable 5.1 or GPT-5.5 Pro?+
Claude Fable 5.1 is $10.00 and GPT-5.5 Pro is $30.00 per million tokens, so Claude Fable 5.1 is cheaper on this metric. Claude Fable 5.1 is $50.00 and GPT-5.5 Pro is $180.00 per million tokens, so Claude Fable 5.1 is cheaper on this metric.
Which has a larger context window, Claude Fable 5.1 or GPT-5.5 Pro?+
GPT-5.5 Pro has the larger sourced context window. Claude Fable 5.1 supports 1,000K and GPT-5.5 Pro supports 1,050K.
Which performs better in benchmarks, Claude Fable 5.1 or GPT-5.5 Pro?+
There is no overall benchmark winner: An overall winner requires at least two decisive benchmarks from at least two original publishers.
Can Claude Fable 5.1 or GPT-5.5 Pro be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Fable 5.1 is not marked open weight; GPT-5.5 Pro is not marked open weight.
Can Claude Fable 5.1 and GPT-5.5 Pro understand images?+
Claude Fable 5.1 is documented with image input; GPT-5.5 Pro is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Fable 5.1 or GPT-5.5 Pro?+
Neither has a larger sourced maximum output. Claude Fable 5.1 is 128K and GPT-5.5 Pro is 128K.
Do Claude Fable 5.1 and GPT-5.5 Pro support reasoning and tool use?+
Claude Fable 5.1: reasoning, tool calling, and image input. GPT-5.5 Pro: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Fable 5.1 or GPT-5.5 Pro?+
Claude Fable 5.1 has 1 sourced provider route; GPT-5.5 Pro has 2, so GPT-5.5 Pro has broader tracked availability.
Which offers better value, Claude Fable 5.1 or GPT-5.5 Pro?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.