Muse GlimmervsGPT-5-Codex
Muse Glimmer | GPT-5-Codex | |
|---|---|---|
| Specifications | ||
Parameters | 30B | — |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | — | 39% |
Agentic coding SWE-Bench ProCan the AI fix real bugs in real software? It's handed actual problems from open-source projects and has to write code that genuinely solves them. Higher is better. | 51.2% | — |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 76% | — |
Agentic terminal coding Terminal-Bench 2.1Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? Higher is better. | 51.7% | — |
Multi-step tool use MCP AtlasCan the AI chain together many tools and steps to complete one bigger task, rather than doing just a single thing? Higher is better. | 75.5% | — |
Multidisciplinary reasoning Humanity's Last Exam · no toolsHumanity's Last Exam — extremely hard expert questions across many subjects, written so you can't just look up the answer. “No tools” means the AI answers on its own. Higher is better. | 22% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 83.5% | — |
Agentic computer use OSWorld-VerifiedCan the AI actually operate a computer — clicking, typing, and using real apps — to finish tasks on its own? Higher is better. | 65.9% | — |
Knowledge work GDPval-AA v2economically valuable knowledge work (v2, re-based Elo) | 953 | — |
Chart reasoning CharXiv ReasoningCan the AI read and reason about complex charts and figures, not just text? Higher is better. | 78.8% | — |
Multimodal reasoning MMMU-ProA tougher version of MMMU — college-level questions that mix images, diagrams, and text together. Higher is better. | 74% | — |
| Overview | ||
| Company | Meta | OpenAI |
| Release date | Aug 10 2026 | Sep 15 2025 |
| Access | Open Weight | Proprietary |
Which is better: Muse Glimmer or GPT-5-Codex?
Muse Glimmer and GPT-5-Codex don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GPT-5-Codex shipped 329 days before Muse Glimmer, so benchmark comparisons should account for the intervening progress.
Muse Glimmer is open weight, while GPT-5-Codex is proprietary.
Direct benchmark comparisons are unavailable — Muse Glimmer and GPT-5-Codex don't publish scores on any of the same benchmarks.
Frequently asked questions
Muse Glimmer was released by Meta on Aug 10 2026.
GPT-5-Codex was released by OpenAI on Sep 15 2025.
Muse Glimmer is an open weight model released by Meta. GPT-5-Codex is a proprietary model released by OpenAI.
Other comparisons
Muse GlimmervsClaude Opus 5GPT-5-CodexvsClaude Opus 5Muse GlimmervsGemini 3.7 FlashGPT-5-CodexvsGemini 3.7 FlashMuse GlimmervsGrok 4.6GPT-5-CodexvsGrok 4.6Muse GlimmervsDeepSeek-V4-Pro-0813GPT-5-CodexvsDeepSeek-V4-Pro-0813Muse GlimmervsMistral Medium 3.5GPT-5-CodexvsMistral Medium 3.5Muse GlimmervsKimi K3GPT-5-CodexvsKimi K3