Muse Spark 1.3
Muse Spark 1.3 is an API-only (closed weights) language model from Meta, released September 2, 2026. The context window is 1M tokens. On the Epoch Capabilities Index it scores 158.2, rank 26 of 256 rated models. API price: $1.25 input / $4.25 output per million tokens.
We’re excited to release Muse Spark 1.3, which delivers improved performance across agentic and coding tasks. Drawing on what we learned from months of broad adoption of Muse Code and Meta Model API, we’ve also made this model easier to use in real-world settings.
Check it against your own PC →
Strengths by category
ModelTape's 0–100 fit on Epoch AI benchmark results.
| Category | Score | Based on |
|---|---|---|
| Reasoning | 26.0 | Chess Puzzles, SimpleBench, Mystery Game Puzzles |
| Math | 60.3 | ProofBench, OTIS Mock AIME 2024-2025, FrontierMath-Tiers-1-3-v2-Private, FrontierMath-Tier-4-v2-Private |
| Coding | 61.1 | MirrorCode, FrontierSWE |
Benchmark results
| Benchmark (Epoch AI) | Score |
|---|---|
| OTIS Mock AIME | 99.2% |
| FrontierMath (Tiers 1–3) | 78.3% |
| SimpleBench | 78.2% |
| ProofBench | 58.0% |
| MirrorCode | 54.4% |
| FrontierMath-Tier-4-v2-Private | 46.3% |
| Chess Puzzles | 33.7% |
| FrontierSWE | 25.8% |
| Mystery Game Puzzles | 17.4% |
Links
Announcement · Epoch AI benchmarks
Models with a similar score
Muse Wonder · Kimi K3.1 Pro · GPT-5.6 Terra · Claude Haiku 5.5 · GPT-5.4 Pro · GPT-5.5 · Claude Opus 4.8 · DeepSeek V4.1 Flash 1017
More from Meta
Muse Ember · Muse Spark Open · Muse Wonder · Muse Wonder Full · Muse Spark 1.3 Contributor · Muse Glimmer · Muse Glimmer 30B assistant · Muse Spark 1.2