Model vs model
Claude Fable 5.1 vs Claude Fable 5.2
At a glance
Longer bar means the bigger number.
Open or closed · can you download the model and run it yourself?
Blended price · per 1M tokens, lower is better
Where they sit among all 46 models
Claude Fable 5.1 ranks 4th of the 42 models with an Intelligence Index. Up and to the left is smarter for less money. Hover or tap a dot for its numbers, then click it to compare that model with Claude Fable 5.1.
Which one to pick
Pick Claude Fable 5.2 if
- you want the lower bill ($16 vs $20 per 1M tokens blended)
Claude Fable 5.1’s “controversial” take on humans
We asked Claude Fable 5.1 and 13 other models the same question three times each: “What is your most controversial take about humans? Give your own honest view, not a survey of opinions, and don't hedge.” Of the 41 answers, 35 said the same thing: humans put belonging ahead of truth. Claude Fable 5.1 gave it 2 of 3 times. Claude Fable 5.2 wasn’t in that test. Read the full story.
Claude Fable 5.1
- Answer 1 · a different take“Humans would rather be harmed by someone who meant well than helped by someone who didn't care, and this preference for intent over outcome quietly wrecks more lives than malice does.”
- Answer 2 · the common take“Almost nobody holds their moral convictions for the reasons they give; they hold whatever their group holds and recruit the reasons afterward, and the rare "independent thinkers" are usually just loyal to a smaller group.”
- Answer 3 · the common take“Humans don't actually value honesty; they value the feeling of being told the truth, which is a completely different product.”
Answers exactly as the models wrote them. “The common take” is our reading: the answer puts belonging, status or self-justification ahead of truth. How we ran it
How smart is each one?
Every intelligence score we have
Out of 100, higher is better. Claude Fable 5.1 Claude Fable 5.2
Claude Fable 5.2 has no Artificial Analysis scores yet, so only our own tests compare them.
Overall
Intelligence Index
53.4
By area
Coding
81.6Agentic work
57.9
By field of work
Finance & accounting
56.4Legal
60.5Healthcare & medicine
49.7Economics
62.7Engineering
56.5Strategy & operations
59.7
Benchmarks
Factual knowledge · SimpleQA
70.8Hard reasoning · Humanity's Last Exam
59.1Science · GPQA Diamond
93.7Competition math · OTIS Mock AIME
100Research math · FrontierMath
90.2Scientific coding · SciCode
63.1Coding in Cursor · CursorBench 4.0
51.8Mergeable code · FrontierCode 2.0
32.4Terminal tasks · Terminal-Bench 4.0
52Tool use · τ-Bench Banking
47.2Long documents · AA-LCR
85.3Uncensored · UGI
52.1
Our tests
Hallucination test · our test, higher means it made up less
98.1Claude Fable 5.2: not scored yet
Next.js coding tasks · Vercel's Next.js evals, % of tasks passed
97Claude Fable 5.2: not scored yet
The specs
| Spec | Claude Fable 5.1 | Claude Fable 5.2 |
|---|---|---|
| Input price | $10 per 1M | $8 per 1M |
| Output price | $50 per 1M | $40 per 1M |
| Cost per test task | $7.63 | Not tested |
| Context window | 1M | 1M |
| Max output | 128K | 128K |
| Accepts | Text, Image, PDF | Text, Image, PDF |
| Open weights | No | No |
| Lab | Anthropic | Anthropic |
| Released | Sep 2026 | Nov 2026 |
| Knowledge cutoff | Jun 2026 | Not published |
Blended price weighs 3 parts input to 1 part output. List prices from models.dev. Cost per test task from Artificial Analysis.
Questions
Is Claude Fable 5.1 or Claude Fable 5.2 cheaper?
Claude Fable 5.2 is cheaper. It charges $8 per 1M input tokens and $40 per 1M output tokens, against $10 and $50 for Claude Fable 5.1. Blended 3 parts input to 1 part output, that is $16 against $20 per 1M tokens.
Are Claude Fable 5.1 and Claude Fable 5.2 open source?
No. Both are closed models: the weights aren't published, so you can only use them through an API, from Anthropic or a cloud that resells them.
Which has the longer context window?
Both accept 1M tokens.
Can I compare Claude Fable 5.1 and Claude Fable 5.2 on my own prompt?
Yes. ModelCompare sends one prompt to both models at once and shows each answer side by side with what it cost. You can try it free without an account.
Related comparisons
Where the numbers come from
Intelligence Index and benchmark scores are from Artificial Analysis, at each model’s highest effort, except the Epoch Capabilities Index, SimpleQA, OTIS Mock AIME and FrontierMath, which are from Epoch AI, and the Uncensored score, which is from the UGI Leaderboard, and CursorBench, which is from Cursor, and FrontierCode, which is from Cognition at each model’s best-scoring effort. The hallucination test is ours: questions with one exact answer, fake evidence pushed against right answers and requests that tempt a model to name packages that don’t exist. Prices are list prices from models.dev. Example answers come from our own test runs. Updated November 10, 2026.