Muse Spark vs GPT-5.4 vs Claude vs Gemini: Full 2026 Comparison (Benchmarks & Verdict)
Meta launched Muse Spark on April 8, 2026 — and it changes the frontier AI landscape in one specific way: it is free. GPT-5.4 Thinking costs $200/month for Pro access. Gemini 3.1 Pro sits behind a Google One AI Premium subscription. Muse Spark, for now, is completely free to use. But is it actually competitive? After reviewing every benchmark published at launch, here is the honest verdict: Muse Spark wins on health AI and token efficiency, but trails GPT-5.4 and Gemini by a significant margin on coding, abstract reasoning, and agentic tasks.
What Is Meta Muse Spark?
Muse Spark is the first model from Meta Superintelligence Labs (MSL) — Meta's new AI research unit built around Scale AI's Alexandr Wang, who joined in a deal that cost Meta over $14 billion. It is the first proprietary (non-open-source) model Meta has ever shipped. Llama 4 Maverick was open-source. Muse Spark is not — at least not yet. Meta says it hopes to open-source future versions.
The model is natively multimodal: it accepts voice, text, and image inputs, though it produces text-only output. It powers Meta AI across the Meta ecosystem — the standalone Meta AI app, Facebook, Instagram, WhatsApp, Messenger, and Ray-Ban Meta AI glasses — rolling out over the next several weeks.
Three interaction modes ship at launch: Instant (fast, direct answers), Thinking (pauses to reason before responding), and Contemplating (orchestrates multiple parallel reasoning agents for the hardest tasks). Contemplating mode is genuinely novel — no other major model ships this as a native feature today.
Benchmark Comparison: Muse Spark vs GPT-5.4 vs Claude Sonnet 4.6 vs Gemini 3.1 Pro
| Benchmark | Muse Spark | GPT-5.4 Thinking | Gemini 3.1 Pro | Claude Sonnet 4.6 |
|---|---|---|---|---|
| AI Intelligence Index v4.0 | 52 | 57 | 57 | 53 |
| HealthBench Hard | 42.8 | 40.1 | 20.6 | 14.8 |
| ARC-AGI-2 (Abstract Reasoning) | 42.5 | 76.1 | 76.5 | N/A |
| Terminal-Bench 2.0 (Coding) | 59.0 | 75.1 | 68.5 | N/A |
| GDPval-AA (Agentic Tasks, ELO) | 1,444 | 1,672 | N/A | 1,607 |
| Output Tokens (full eval) | 58M | 120M | 58M | 157M |
| Cost to use | Free | $200/mo (Pro) | Subscription | Subscription |
The numbers tell a clear story. Muse Spark is not the best frontier model overall — it scores 52 on the Intelligence Index versus 57 for both GPT-5.4 and Gemini 3.1 Pro. But it leads on health AI by a 2x+ margin, matches Gemini on token efficiency, and is completely free. For developers and users in health, medical, and wellness use cases, Muse Spark is the current state-of-the-art.
Where Muse Spark Wins
1. Health and Medical AI — By a Wide Margin
42.8 on HealthBench Hard is a landmark score. GPT-5.4 hits 40.1. Gemini 3.1 Pro gets 20.6. Claude Sonnet 4.6 scores 14.8. Muse Spark is not slightly better — it is categorically better for health-adjacent tasks. If you are building a medical AI product, Muse Spark should be your first API call once public access opens.
