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Claude Fable 5.2 vs Claude Opus 5.5
Claude Fable 5.2 scores higher than Claude Opus 5.5 on all 4 public leaderboards that rate both. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Claude Fable 5.2 is at 100 and Claude Opus 5.5 at 92.9 (out of 100).
Scores as published by each board; table composed November 9, 2026.
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Leaderboard by leaderboard
| Board | Claude Fable 5.2 | Claude Opus 5.5 | Higher |
|---|---|---|---|
| LiveBench global average (0-100) | 84.9 | 83.4 | Claude Fable 5.2 |
| LLM Stats LLM Stats Score · composite (0-100), their rendered top 15 | 61.6 | 59.2 | Claude Fable 5.2 |
| Vals AI Vals Index accuracy % · weighted finance + coding tasks | 71.3 | 70.1 | Claude Fable 5.2 |
| Epoch AI Epoch Capabilities Index (ECI) · many benchmarks on one scale | 174.2 | 168.7 | Claude Fable 5.2 |
Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.
For coding
On the ArtificialWatch coding index, Claude Fable 5.2 is at 82.7 (#8 of 47) and Claude Opus 5.5 at 89.8 (#3). Claude Fable 5.2 scores higher on 1 of the 2 coding boards that rate both and Claude Opus 5.5 on 1.
| Coding board | Claude Fable 5.2 | Claude Opus 5.5 |
|---|---|---|
| LiveBench · Coding | 79.2 | 87.1 |
| Vals Vibe Code Bench | 93.8 | 90.3 |
Claude Fable 5.2 at a glance
- Developer
- Anthropic
- Status
- Live since November 9, 2026
Live — Nov 9 · Anthropic's upgrade of Fable; Mythos 5.2 is the same underlying model without certain cyber and biology safeguards · claude-fable-5-2 on the Claude API, AWS, Google Cloud and Microsoft Azure · $8 / $40 per 1M (Fable 5.1 was $10 / $50); optional fast mode, up to 2.5x faster, $16 / $80 · 1M ctx, 128K max output, adaptive thinking always on, default effort high on the API and medium in Claude apps, reliable knowledge cutoff Jun 2026 (Anthropic's models overview) · Anthropic's own figures: output up to 30% faster than Fable 5.1; FrontierCode 2.0 45.3% at High (Opus 5.5 best 45.5%) for about half the cost per task, 49.1% at Xhigh; BenchCAD 2.1 83.5 (Opus 5.5 65.3); RoboDojo Sim 64.9% (GPT-6 Astra 29.8%) · Artificial Analysis Intelligence Index (read Nov 9 19:55 UTC): Fable 5.2 (Max) 65, ranked first · launch week: eligible paid plans get 1-3 Fable resets, and Pro and standard Team seats can spend up to 50% of weekly usage on Fable · AWS's public price list carried it from 18:09:52 UTC; our sweep first saw claude-fable-5-2 at 18:52:10 UTC and fired at 18:53:06, 4 min 53 s before @claudeai's post · Epoch Capabilities Index (eci_scores.csv, updated Nov 9, read 21:52 UTC): 174.24 (CI 170.12-178.79), ranked first of 255, ahead of GPT-6 Astra 169.16; Fable 5.1 167.04.
Claude Fable 5.2 takes #1 on Epoch's Capabilities Index at 174, five points clear of GPT-6 Astra
2026-11-09 · Claude Fable 5.2 is the new #1 on the Epoch Capabilities Index (ECI), Epoch AI's composite of more than 50 benchmarks. Epoch's public score file, updated November 9, puts it at 174.2, five points ahead of GPT-6 Astra at 169.2. It scores 255 models.
Anthropic releases Claude Fable 5.2 and Mythos 5.2 at $8 / $40, 20% below 5.1, and Artificial Analysis ranks Fable 5.2 first at 65
2026-11-09 · Anthropic released Claude Fable 5.2 and Claude Mythos 5.2 on November 9. Fable 5.2 is available now to everyone on the Claude API as claude-fable-5-2, and on Amazon Web Services, Google Cloud and Microsoft Azure.
Claude Opus 5.5 at a glance
- Developer
- Anthropic
- Status
- Live since September 22, 2026
- API price
- $4 input / $20 output per 1M tokens · Anthropic, claude-opus-5-5
- Context window
- 1M tokens
Live — Sep 22 · $4/$20 per MTok, down from Opus 5 at $5/$25 · 1M ctx / 128K out · adaptive thinking always on, default effort medium · cache reads 5% of base input · Anthropic now says start here for most workloads, and Opus 5 is legacy · fast mode (speed: 'fast', up to 2.5x the output tokens per second by Anthropic's figure) at $8 / $40 per MTok, double standard, left research preview Oct 15 with no waitlist, access request or beta header; on the Claude API and on Claude in Microsoft Foundry (Azure-hosted), not on Bedrock, Google Cloud, Claude Platform on AWS, the Batch API or Priority Tier; @ClaudeDevs says Google Cloud is coming soon (Anthropic's fast mode docs, read Oct 16).
AI models go live a median of 4 months after their knowledge ends: Claude Opus 5.5 knows up to June 2026, Gemini 4 Argon only to March
2026-11-06 · Of the 22 live AI models whose labs publish a knowledge cutoff, the median went live 4 months after its training data ends, by ArtificialWatch's count. The latest published cutoff we found is June 2026, for Anthropic's four current Claude models and OpenAI's GPT-6.1 Terra.
SemiAnalysis launches GDPx: Opus 5.5 leads at 12%, Gemini 4 Carbon close behind
2026-11-02 · SemiAnalysis released GDPx on November 2, a new agentic benchmark of 206 tasks across 11 domains, and the best model it tested scores 12%. Claude Opus 5.5 leads at 12.0, Gemini 4 Carbon is second at 10.9 and GPT-6 Astra third at 9.6. We read the leaderboard directly at gdpx.semianalysis.com.
Claude Fable 5.2 vs Claude Opus 5.5: quick answers
Which is better, Claude Fable 5.2 or Claude Opus 5.5?
It depends on what you measure. Claude Fable 5.2 scores higher than Claude Opus 5.5 on all 4 public leaderboards that rate both. Claude Fable 5.2's widest lead is on LiveBench. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Claude Fable 5.2 is at 100 and Claude Opus 5.5 at 92.9 (out of 100).
Which is newer, Claude Fable 5.2 or Claude Opus 5.5?
Claude Fable 5.2. It went live on November 9, 2026, 48 days after Claude Opus 5.5 (September 22, 2026).
How do Claude Fable 5.2 and Claude Opus 5.5 compare for coding?
On the ArtificialWatch coding index, Claude Fable 5.2 is at 82.7 (#8 of 47) and Claude Opus 5.5 at 89.8 (#3). Claude Fable 5.2 scores higher on 1 of the 2 coding boards that rate both and Claude Opus 5.5 on 1.
Who makes Claude Fable 5.2 and Claude Opus 5.5?
Both are from Anthropic.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed November 9, 2026). Boards measure different things, so raw scores are only comparable within a row.
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