AI Model Release Tracker - Timeline of Major AI Models from 2022-2026

Muse Spark vs GPT-5.5

Meta
Muse Spark
OpenAI
GPT-5.5
Overview
CompanyMetaOpenAI
Release dateApr 8 2026Apr 23 2026
AccessProprietaryProprietary
Specifications
Context window
1.05M
Benchmarks
Nonsense detection
BullshitBench v2
47%
Agentic coding
SWE-Bench Pro
55%
58.6%Best
Coding
SWE-Bench Verified
77.4%
Multilingual coding
SWE-Bench Multilingual
77.8%
Agentic coding
CursorBench v3.1
64.3%
Agentic coding
DeepSWE 1.1
10%
Agentic coding
DeepSWE 1.0
64.3%
Agentic terminal coding
Terminal-Bench 2.1
67.3%
78.2%Best
Agentic terminal coding
Terminal-Bench 2.0
82.7%
Software engineering
Expert-SWE (Internal)
73.1%
Multi-step tool use
MCP Atlas
82.2%Best
75.3%
Professional tool use
JobBench
17%
Personal tool use
Toolathlon-Verified
49.4%
General tool use
Toolathlon
55.6%
Web browsing
BrowseComp
84.4%
Cybersecurity
CyberGym
81.8%
Multidisciplinary reasoning
Humanity's Last Exam · no tools
41.4%
Multidisciplinary reasoning
Humanity's Last Exam · with tools
50.4%
52.2%Best
Abstract reasoning
ARC-AGI-2
42.5%
84.6%Best
Advanced math
FrontierMath · Tier 1–3
51.7%
Advanced math
FrontierMath · Tier 4
35.4%
Science
GPQA Diamond
89.5%
93.6%Best
Agentic computer use
OSWorld-Verified
53.3%
78.7%Best
Agentic financial analysis
Finance Agent v2
51.8%
Agentic legal work
Harvey's Legal Agent Benchmark
3.75%
Tax questions
TaxEval v2
74.98%
Medical admin work
MedScribe
86.87%
Knowledge work
GDPval-AA
1769
Knowledge work
GDPval-AA v2
1494
Knowledge work
GDPval (win/tie rate)
84.9%
Chart reasoning
CharXiv Reasoning
88.9%Best
84.1%
Visual reasoning
BabyVision
39.9%
Multimodal reasoning
MMMU-Pro
81.2%
Multimodal
MMMU
80.4%
Spatial reasoning
Blueprint-Bench 2
36.2%
Long context
MRCR v2 (8-needle) · 128k average
94.8%
Community preference
Arena Elo (Text)
1488Best
1481
Community preference (code)
Arena Elo (Code)
1502
Timeline
Release gapMuse Spark shipped 15 days before GPT-5.5

Which is better: Muse Spark or GPT-5.5?

GPT-5.5 leads Muse Spark on 6 of the 9 benchmarks they both report. Muse Spark shipped 15 days before GPT-5.5, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

On SWE-Bench Pro, GPT-5.5 leads at 58.6% vs Muse Spark at 55%. On Terminal-Bench 2.1, GPT-5.5 leads at 78.2% vs Muse Spark at 67.3%. On MCP Atlas, Muse Spark leads at 82.2% vs GPT-5.5 at 75.3%. On Humanity's Last Exam · with tools, GPT-5.5 leads at 52.2% vs Muse Spark at 50.4%. On ARC-AGI-2, GPT-5.5 leads at 84.6% vs Muse Spark at 42.5%. On GPQA Diamond, GPT-5.5 leads at 93.6% vs Muse Spark at 89.5%. On OSWorld-Verified, GPT-5.5 leads at 78.7% vs Muse Spark at 53.3%. On CharXiv Reasoning, Muse Spark leads at 88.9% vs GPT-5.5 at 84.1%. On Arena Elo (Text), Muse Spark leads at 1488 vs GPT-5.5 at 1481.

Frequently asked questions

Muse Spark was released by Meta on Apr 8 2026.

GPT-5.5 was released by OpenAI on Apr 23 2026.

GPT-5.5 leads on SWE-Bench Pro — Muse Spark 55% vs GPT-5.5 58.6%.

GPT-5.5 leads on Humanity's Last Exam · with tools — Muse Spark 50.4% vs GPT-5.5 52.2%.

Other comparisons