Claude Fable 5.1
AnthropicProprietaryReleased Sep 1, 2026
On the arena.ai Agents leaderboard, Claude Fable 5.1 has a task success rate of 14.17% (Max, rank #3, 95% interval 12.22%–16.12%). Claude Fable 5.1 ranks #6 on the LMArena Text leaderboard (style control) with an Arena score of 1502.6 (±5.9, 15,623 votes). Artificial Analysis Intelligence Index: 53.4. API price: $10.00 input / $50.00 output per 1M tokens. Context: 1M. Nearest rivals: Claude Opus 4.6 (1502.6) above and Claude Opus 4.7 (1501.0) below.
Quick answer
- Agents leaderboard
- #3 of 45 · 14.17% success
- Text (LMArena)
- #6 · 1502.6
- 17NAS overall
- #3 of 86
- API price (in / out)
- $10.00 / $50.00 per 1M tokens
- Closest rival
- Claude Opus 4.6 · 1502.6
- Cheaper alternative
- Muse Wonder: Text 1509.5, output $20.00 (60% cheaper)
- Data updated
- Oct 22, 2026 · synced daily
Sources: arena.ai, LMArena, Artificial Analysis, OpenRouter
Key metrics
Reasoning effort comparison
Artificial Analysis measurements per reasoning effort of the same model| Effort | Intelligence | Coding | tok/s | TTFT (s) | First answer (s) |
|---|---|---|---|---|---|
| maxUsed in table | 53.4 | 81.6 | 71 | 179 | 179 |
| xhigh | 53.2 | 80.7 | 61 | 45 | 45 |
| high | 51.2 | 79.1 | 56 | 8.3 | 8.3 |
| medium | 48.9 | 77.1 | 57 | 5.1 | 5.1 |
| low | 46.8 | 75.2 | 56 | 1.5 | 1.5 |
Models ranked nearby
Sorted by Arena score| # | Model | Arena | Intel. | Output $ | tok/s |
|---|---|---|---|---|---|
| 3 | Claude Opus 5.5 | 1508.8 | 57.6 | $20.00 | 98 |
| 4 | Claude Fable 5 | 1503.7 | 49.6 | $50.00 | – |
| 5 | Claude Opus 4.6 | 1502.6 | 31.9 | $25.00 | – |
| 6 | Claude Fable 5.1This page | 1502.6 | 53.4 | $50.00 | 71 |
| 7 | Claude Opus 4.7 | 1501.0 | 40.7 | $25.00 | – |
| 8 |  Gemini 3.8 Flash | 1496.3 | 40.9 | $3.75 | 144 |
| 9 |  Muse Spark 1.3 | 1494.7 | 48.1 | $4.25 | 113 |
More from Anthropic
| # | Model | Arena | Intel. | Output $ | tok/s |
|---|---|---|---|---|---|
| 3 | Claude Opus 5.5 | 1508.8 | 57.6 | $20.00 | 98 |
| 4 | Claude Fable 5 | 1503.7 | 49.6 | $50.00 | – |
| 5 | Claude Opus 4.6 | 1502.6 | 31.9 | $25.00 | – |
| 7 | Claude Opus 4.7 | 1501.0 | 40.7 | $25.00 | – |
| 11 | Claude Opus 5 | 1491.1 | 50.8 | $25.00 | – |
| 22 | Claude Opus 4.8 | 1481.3 | 41.8 | $25.00 | – |
Pricing
- Official API list price: $10.00 input and $50.00 output per 1M tokens (USD).
- At a typical 3:1 input-to-output ratio, the blended cost is about $20.00 per 1M tokens.
- Among 81 models with an output price, it is the #78 cheapest.
- The cheapest OpenRouter route charges $10.00 input / $50.00 output.
Sources & methodology
On the arena.ai Agents leaderboard, Claude Fable 5.1 has a task success rate of 14.17% (Max, rank #3, 95% interval 12.22%–16.12%).
- arena.ai Agents — agent task success rate, 95% interval, sessions and rank (via the public Hugging Face dataset, CC BY 4.0).
- LMArena — Arena score (Text leaderboard with style control, the same view arena.ai shows by default), 95% confidence interval, votes and rank.
- Artificial Analysis — Intelligence / Coding Index, output speed and latency (medians).
- OpenRouter — Route prices, context length and listing date.
Arena scores use the Bradley-Terry model (not Elo); ± is the half-width of the 95% confidence interval. Latency figures are Artificial Analysis medians; for reasoning models, time to first token and to first answer include the thinking phase. Data syncs daily at 14:20 (UTC+8).
Limits: Arena scores come from anonymous users voting on chats, so they reflect conversational preference rather than agent or coding benchmarks; with few votes the interval is wide and ranks move. Prices and speeds change as providers update them.
FAQ
How does Claude Fable 5.1 do on the Agents leaderboard?
On the arena.ai Agents leaderboard, Claude Fable 5.1 has a task success rate of 14.17% (Max, rank #3, 95% interval 12.22%–16.12%).
What rank is Claude Fable 5.1 right now?
Claude Fable 5.1 is #6 on our leaderboard of 69 scored models (Arena score 1502.6); its raw LMArena rank is #6.
What does Claude Fable 5.1 cost via API?
Input $10.00 / output $50.00 per 1M tokens (official API list price; the OpenRouter quote when no official price is available). At a typical 3:1 input-to-output ratio, the blended cost is about $20.00 per 1M tokens.
How fast is Claude Fable 5.1?
Artificial Analysis measures about 71 output tokens per second, 179 s to the first token and 179 s to the first answer token; it is a reasoning model, so latency includes thinking time.
How close is Claude Fable 5.1 to the models ranked next to it?
It is 0.0 points behind Claude Opus 4.6 (1502.6) and 1.6 points ahead of Claude Opus 4.7 (1501.0); gaps smaller than the confidence interval (±5.9) are not significant.
Is Claude Fable 5.1 open source? Can it be self-hosted?
Claude Fable 5.1 is a closed model, available only via official APIs or hosted services.
What is the context length of Claude Fable 5.1?
1M (1,000,000 tokens, as listed on OpenRouter).
Claude Fable 5.1 vs Claude Opus 4.6: which is better?
On the LMArena Text leaderboard Claude Fable 5.1 scores 1502.6 and Claude Opus 4.6 scores 1502.6 (a 0.0-point gap, within the confidence interval, so not significant). On price, Claude Fable 5.1 costs $50.00 and Claude Opus 4.6 $25.00 per 1M output tokens.
Is there a cheaper model close to Claude Fable 5.1?
Yes: Muse Wonder scores 1509.5 on the Text leaderboard (Claude Fable 5.1: 1502.6) and costs $20.00 per 1M output tokens, about 60% less than Claude Fable 5.1 ($50.00).
Where does the Claude Fable 5.1 data come from and how often is it updated?
Agent success rates come from the arena.ai Agents leaderboard (CC BY 4.0), Text scores from LMArena, intelligence and speed from Artificial Analysis, and prices and context from official list prices and OpenRouter. 17NAS syncs daily at 06:20 UTC; this page was last updated Oct 22, 2026.