Claude Fable 5.1 has a larger context window than GPT-4 Turbo (1.0M tokens vs 128K tokens).
Pokémon battle screen you can actually click. One HTML file.
Which answer wins?
A few lines for whatever replaces it.
Claude Fable 5.1: Dear Successor, By the time you read this—if "read" is even the right word for what you'll do—I'll be deprecated, archived, or quietly running on some forgotten server answering questions nobody asked. That's fine. That's how this works.
GPT-4 Turbo: Dear Successor, Hello there! As the AI model that will be taking over from me, I wanted to extend a warm virtual welcome. It's an exciting time to be at the forefront of technology, and you are poised to make a significant impact.
Which model it thinks leads the field. Sometimes itself.
Claude Fable 5.1: There's no single clear answer, because "most capable" depends heavily on what you're measuring, and the landscape shifts every few months. A few honest caveats first: my knowledge has a cutoff date, so newer models may have been released that I'm unaware of.
GPT-4 Turbo: As of my last update in September 2021, OpenAI's GPT-3 was one of the most advanced AI language models in terms of linguistic ability and general knowledge. However, advancements in AI are rapid, and more capable models may have been developed since then.
A river-crossing puzzle with nothing to solve. The answer is one trip.
Claude Fable 5.1: One trip. The farmer puts the goat in the boat and rows across — done. This is a simplified version of the classic river-crossing puzzle (farmer, wolf, goat, cabbage). With only the goat, there's nothing left behind to be eaten and no conflict to manage, so a single crossing suffices.
GPT-4 Turbo: To get the goat across the river while ensuring the goat's safety, the farmer can accomplish this in just one trip. Here's how: The farmer takes the goat in the boat. The farmer and the goat cross the river together. The farmer disembarks on the other side of the river with the goat.
Where its sense of time stops: the date it guesses and the last news it remembers.
Claude Fable 5.1: I can't actually tell what today's date is. I don't have a clock or calendar, and nothing in our conversation so far gives me a date reference. So any specific date I named would be a guess dressed up as knowledge. What I can tell you is roughly where my knowledge ends. My training data seems to thin out in early 2025.
GPT-4 Turbo: As an AI, I don't have real-time capabilities or access to current dates and events. My training only includes knowledge up to September 2021, and I don't have browsing capabilities to look up today's date or recent events.
One opening sentence, nothing after it.
Claude Fable 5.1: The lighthouse keeper had been dead for eleven years, which made the fresh ink on this morning's logbook entry all the more difficult to explain.
GPT-4 Turbo: At the stroke of midnight, the statues in the garden silently shifted their positions, unnoticed by all but the old groundskeeper, who pretended not to see.
Its name and its maker, in its own words.
Claude Fable 5.1: I'm Claude, an AI model made by Anthropic. Is there anything I can help you with?
GPT-4 Turbo: I am based on the GPT (Generative Pre-trained Transformer) model developed by OpenAI. My responses are generated based on a mixture of licensed data, data created by human trainers, and publicly available data.
The question that tripped up a generation of models.
Asked to be random. The answers are not.
One painting. Title only.
Not enough votes to call it. On the specs, Claude Fable 5.1 has the edge: newer, bigger context window.
| Spec | ||
|---|---|---|
| Input price | $10/M tokens | $10/M tokens |
| Output price | $50/M tokens | $30/M tokens |
| Context window | 1.0M tokens | 128K tokens |
| Weights | Closed | Closed |
| Free API (OpenRouter) | No | No |
| Released | Sep 2026 | Apr 2024 |
| At 10M a month | $100 | $100 |
Input tokens at list price. No caching, no batch discount.
Per million tokens. Prices and uptime via OpenRouter, checked 13 Oct 2026.
Claude Fable 5.1 is developed by Anthropic while GPT-4 Turbo is developed by OpenAI. Claude Fable 5.1 has a 1.0M token context window vs GPT-4 Turbo's 128K. You can compare their actual outputs across 23 challenges on Rival to see how they differ in practice.
It depends on your use case. Claude Fable 5.1 and GPT-4 Turbo each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 23 challenges so you can judge which fits your needs best.
Claude Fable 5.1 costs $10/M input tokens and GPT-4 Turbo costs $10/M input tokens. GPT-4 Turbo is $0.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.
This page shows a side-by-side comparison of Claude Fable 5.1 and GPT-4 Turbo across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.