AI model comparison
Claude Fable 5.1 vs Claude Fable 5
Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.
Anthropic
Claude Fable 5.1
Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work: long code refactors, front-end and visual
- Input / 1M
- $10
- Output / 1M
- $50
- Context
- 1M
Anthropic
Claude Fable 5
Claude Fable 5 is a Mythos-class model from Anthropic, built for autonomous knowledge work and coding.
- Input / 1M
- $10
- Output / 1M
- $50
- Context
- 1M
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
Tie
Same price for a typical chat
Higher intelligence score
Claude Fable 5.1
53.4 vs 49.6 on Artificial Analysis
Larger context window
Tie
1M vs 1M tokens
Newer release
Claude Fable 5.1
Released September 1, 2026
Benchmarks
Benchmark scores
Independent scores from Artificial Analysis. Higher is better.
Intelligence index
Claude Fable 5.153.4Claude Fable 549.6Coding index
Claude Fable 5.181.6Claude Fable 576.5Agentic index
Claude Fable 5.157.9Claude Fable 550.7Pricing
Claude Fable 5.1 vs Claude Fable 5 API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | Claude Fable 5.1 | Claude Fable 5 |
|---|---|---|
| Input tokensPer 1M tokens | $10 | $10 |
| Output tokensPer 1M tokens | $50 | $50 |
| Cached input (read)Per 1M tokens | $0.25 | $1 |
| Cache writePer 1M tokens | $12.50 | $12.50 |
| Web searchPer request | $0.01 | $0.01 |
What it costs in practice
Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.
Chat message
2K in, 500 out
Claude Fable 5.1$45Claude Fable 5$45Coding task
30K in, 4K out
Claude Fable 5.1$500$207.50 cachedClaude Fable 5$500$230 cachedLong document summary
150K in, 2K out
Claude Fable 5.1$1600$137.50 cachedClaude Fable 5$1600$250 cachedSpecs
Context window and capabilities
How much each model can read, how much it can write, and what it accepts as input.
| Metric | Claude Fable 5.1 | Claude Fable 5 |
|---|---|---|
| Context window | 1M tokens | 1M tokens |
| Max output | 128K tokens | 128K tokens |
| Input types | File, Image, Text | File, Image, Text |
| Output types | Text | Text |
| Reasoning effort levels | Max, Extra high, High, Medium, Low | Max, Extra high, High, Medium, Low |
| Default reasoning effort | High | High |
| Release date | September 1, 2026 | June 9, 2026 |
Features
Supported features
API features available for each model.
| Metric | Claude Fable 5.1 | Claude Fable 5 |
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Supported |
| Temperature | Not supported | Not supported |
| Stop sequences | Supported | Supported |
| Deterministic seed | Not supported | Not supported |
| Verbosity control | Supported | Supported |
Keep exploring
More on these models
Other head-to-heads, the full model page, and the alternatives list for each model.
Claude Fable 5.1View full model details- Claude Fable 5.1 vs Claude Opus 5.5
- Claude Fable 5.1 vs Claude Sonnet 5.5
- Claude Fable 5.1 vs GPT-6 Astra
- Claude Fable 5.1 vs GPT-6.1 Sol
- Claude Fable 5.1 vs Claude Opus 5
- Claude Fable 5.1 vs Muse Spark 1.3
- Claude Fable 5.1 vs GPT-6 Sol
- Claude Fable 5.1 vs GPT-5.6 Sol
- Claude Fable 5.1 vs Kimi K3
- Claude Fable 5.1 vs GLM 5.3 Flash
- Claude Fable 5.1 vs Claude Opus 4.8
- Claude Fable 5.1 vs DeepSeek V4.1 Flash
- Claude Fable 5.1 vs GPT-6 Luna
- Claude Fable 5.1 vs MiMo-V2.6-Flash
- Claude Fable 5.1 vs DeepSeek V4 Flash 0731
- Claude Fable 5.1 vs Hy4 preview
Claude Fable 5View full model details- Claude Fable 5 vs Claude Opus 5.5
- Claude Fable 5 vs Claude Sonnet 5.5
- Claude Fable 5 vs GPT-6 Astra
- Claude Fable 5 vs GPT-6.1 Sol
- Claude Fable 5 vs Claude Opus 5
- Claude Fable 5 vs Muse Spark 1.3
- Claude Fable 5 vs GPT-6 Sol
- Claude Fable 5 vs GPT-5.6 Sol
- Claude Fable 5 vs Kimi K3
- Claude Fable 5 vs Claude Opus 4.8
Our take
Claude Fable 5.1 scores higher on the Artificial Analysis Intelligence Index (53.4 vs 49.6). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.
FAQ
Frequently asked questions
Is Claude Fable 5.1 or Claude Fable 5 cheaper?
Claude Fable 5.1 and Claude Fable 5 cost the same for a typical chat (2K input tokens and 500 output tokens). Claude Fable 5.1 costs $10 per 1M input tokens and $50 per 1M output tokens, and Claude Fable 5 costs $10 per 1M input tokens and $50 per 1M output tokens.
Which has a bigger context window, Claude Fable 5.1 or Claude Fable 5?
Claude Fable 5.1 supports up to 1M tokens of context, compared with 1M for Claude Fable 5.
Is Claude Fable 5.1 smarter than Claude Fable 5?
On the Artificial Analysis Intelligence Index, Claude Fable 5.1 scores 53.4 and Claude Fable 5 scores 49.6, putting Claude Fable 5.1 ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.
Can I use Claude Fable 5.1 and Claude Fable 5 at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Claude Fable 5.1 and Claude Fable 5 answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to Claude Fable 5.1 and Claude Fable 5 at the same time. Compare the answers side by side and keep the best one.