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Muse Spark 1.3 vs Claude Fable 5.1
Claude Fable 5.1 scores higher than Muse Spark 1.3 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, Muse Spark 1.3 is at 59.9 and Claude Fable 5.1 at 86.8 (out of 100). On each maker's API, Muse Spark 1.3 costs $1.25 / $4.25 per 1M tokens (input / output) and Claude Fable 5.1 $10 / $50.
Scores as published by each board; table composed November 12, 2026.
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Leaderboard by leaderboard
| Board | Muse Spark 1.3 | Claude Fable 5.1 | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,655.1 | 1,742.1 | Claude Fable 5.1 |
| LiveBench global average (0-100) | 68.6 | 84 | Claude Fable 5.1 |
| SimpleBench AVG@5 % (private set) | 81.8 | 86.6 | Claude Fable 5.1 |
| Epoch AI Epoch Capabilities Index (ECI) · many benchmarks on one scale | 158.2 | 167 | Claude Fable 5.1 |
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, Muse Spark 1.3 is at 76.2 (#10 of 47) and Claude Fable 5.1 at 88.1 (#5). Claude Fable 5.1 scores higher on all 3 coding boards that rate both.
| Coding board | Muse Spark 1.3 | Claude Fable 5.1 |
|---|---|---|
| LMArena · Coding | 1,507.9 | 1,527 |
| LiveBench · Coding | 84.4 | 89.7 |
| Vals Vibe Code Bench | 85.9 | 90.3 |
Muse Spark 1.3 at a glance
- Developer
- Meta
- Status
- Live since September 2, 2026
- API price
- $1.25 input / $4.25 output per 1M tokens · Meta, muse-spark-1.3
- Context window
- 1.05M tokens
Live — Sep 2 · $1.25/$4.25 per 1M and 1M ctx, identical to 1.2 · Meta: ~20% fewer tool calls, ~25% fewer tokens vs 1.2 · open weights on the roadmap, undated · the open-weights Spark shipped Oct 15 as Muse Spark Open (its own entry).
Muse Spark 1.3 is out — same price as 1.2, and the radar called it in 61 seconds
2026-09-03 · Meta released Muse Spark 1.3 today. Its own words: "We're excited to release Muse Spark 1.3, which delivers improved performance across agentic and coding tasks." The numbers Meta gives are efficiency, not capability: ~20% fewer tool calls and ~25% fewer tokens than 1.2 on coding work, fewer interaction turns, less…
Claude Fable 5.1 at a glance
- Developer
- Anthropic
- Status
- Live since September 1, 2026
- API price
- $10 input / $50 output per 1M tokens · Anthropic, claude-fable-5-1
- Context window
- 1M tokens
Live - sticker price held at $10/$50, but cache reads cut 75% to $0.25 = ~25% cheaper typical, up to ~45% agentic · 1M ctx · effort low-max.
Claude Fable 5.1 is live — the sticker price never moved, and the cache read fell 75%
2026-09-01 · Claude Fable 5.1 shipped today, alongside Claude Mythos 5.1. Our radar detected it at 17:52:22 UTC and confirmed it on the next sweep 60 seconds later.
Fable 5.1's August window has closed — the market now prices September at 78%, and one claim in the leak can't be checked at all
2026-08-20 · A claim going round today says Fable 5.1 is in pre-release testing, targeted at September, and running inside Anthropic's own products under the Fable 5 name. One part of that is checkable, one part is checkable and slipping, and one part is — by construction — invisible to anything we can measure.
Muse Spark 1.3 vs Claude Fable 5.1: quick answers
Which is better, Muse Spark 1.3 or Claude Fable 5.1?
It depends on what you measure. Claude Fable 5.1 scores higher than Muse Spark 1.3 on all 4 public leaderboards that rate both. Claude Fable 5.1'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, Muse Spark 1.3 is at 59.9 and Claude Fable 5.1 at 86.8 (out of 100).
Which is newer, Muse Spark 1.3 or Claude Fable 5.1?
Muse Spark 1.3. It went live on September 2, 2026, 1 day after Claude Fable 5.1 (September 1, 2026).
Which is cheaper, Muse Spark 1.3 or Claude Fable 5.1?
Muse Spark 1.3 is cheaper on both input and output. On each vendor's own API, Muse Spark 1.3 is $1.25 input / $4.25 output per million tokens and Claude Fable 5.1 is $10 input / $50 output per million tokens. Prices as published in the models.dev catalog, as of 2026-11-12.
Which has the bigger context window, Muse Spark 1.3 or Claude Fable 5.1?
Muse Spark 1.3, at 1.05M tokens against Claude Fable 5.1's 1M, as each vendor lists it.
How do Muse Spark 1.3 and Claude Fable 5.1 compare for coding?
On the ArtificialWatch coding index, Muse Spark 1.3 is at 76.2 (#10 of 47) and Claude Fable 5.1 at 88.1 (#5). Claude Fable 5.1 scores higher on all 3 coding boards that rate both.
Who makes Muse Spark 1.3 and Claude Fable 5.1?
Muse Spark 1.3 is from Meta; Claude Fable 5.1 is from Anthropic.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed November 12, 2026). Boards measure different things, so raw scores are only comparable within a row.
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Also: the bench index · API pricing · what a workload costs on each · the wire