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GPT-5 Codex vs Muse Spark Open

Muse Spark Open leads the LLM Stats Score 45.3 to 26.5.

OpenAI · Meta · Updated for 2026

Which is better?

Muse Spark Open leads the overall LLM Stats Score 45.3 to 26.5, ranking #42 overall.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose GPT-5 Codex

  • you are already invested in the OpenAI ecosystem

Choose Muse Spark Open

  • overall performance matters — it scores 45.3 and ranks #42 on LLM Stats
  • your work emphasizes reasoning — it leads those capability indexes
  • you want the most recent training data — it shipped Oct 2026
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

GPT-5 Codex
OpenAI
Muse Spark Open
Meta
Core performance indexes
LLM Stats Score
26.5
#170
45.3
#42
Reasoning
26.4
#169
45.7
#35
Coding
19.3
#122
33.5
#40
Cost, coverage & limits
Benchmark wins
—
—
Input price
— / M
$1.25 / M
Output price
— / M
$4.25 / M
Context window
—
1,048,576

Individual benchmarks

1 reported for GPT-5 Codex · 17 for Muse Spark Open

No common benchmarks found

GPT-5 Codex and Muse Spark Opendon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Muse Spark Open specifies input context (1,048,576 tokens). Only Muse Spark Open specifies output context (1,048,576 tokens).

OpenAI
GPT-5 Codex
Input- tokens
Output- tokens
Meta
Muse Spark Open
Input1,048,576 tokens
Output1,048,576 tokens
Sat Oct 24 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Muse Spark Open supports multimodal inputs, whereas GPT-5 Codex does not.

Muse Spark Open can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-5 Codex

Text
Images
Audio
Video

Muse Spark Open

Text
Images
Audio
Video

License

Usage and distribution terms

GPT-5 Codex is licensed under a proprietary license, while Muse Spark Open uses Muse Model License.

License differences may affect how you can use these models in commercial or open-source projects.

GPT-5 Codex

Proprietary

Closed source

Muse Spark Open

Muse Model License

Open weights

Release Timeline

When each model was launched

GPT-5 Codex was released on 2025-09-15, while Muse Spark Open was released on 2026-10-15.

Muse Spark Open is 13 months newer than GPT-5 Codex.

GPT-5 Codex

Sep 15, 2025

1.1 years ago

Muse Spark Open

Oct 15, 2026

4 days ago

1.1yr newer

Knowledge Cutoff

When training data ends

GPT-5 Codex has a documented knowledge cutoff of 2024-09-30, while Muse Spark Open's cutoff date is not specified.

We can confirm GPT-5 Codex's training data extends to 2024-09-30, but cannot make a direct comparison without Muse Spark Open's cutoff date.

GPT-5 Codex

Sep 2024

Muse Spark Open

—

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against GPT-5 Codex and Muse Spark Open side-by-side, then vote on the output you prefer.

GPT-5 Codex
✓ Preferred
Muse Spark Open
Open in Playground

FAQ

Common questions about GPT-5 Codex vs Muse Spark Open.

Which is better, GPT-5 Codex or Muse Spark Open?

Muse Spark Open leads the LLM Stats Score 45.3 to 26.5. GPT-5 Codex is made by OpenAI and Muse Spark Open is made by Meta. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does GPT-5 Codex compare to Muse Spark Open in benchmarks?

GPT-5 Codex scores SWE-Bench Verified: 74.5%. Muse Spark Open scores MCP Atlas: 89.2%, GPQA: 89.0%, OSWorld-Verified: 80.4%, BabyVision: 80.2%, Terminal-Bench 2.1: 76.4%.

What are the context window sizes for GPT-5 Codex and Muse Spark Open?

GPT-5 Codex supports an unknown number of tokens and Muse Spark Open supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-5 Codex and Muse Spark Open?

Key differences include LLM Stats Score (26.5 vs 45.3), multimodal support (no vs yes), licensing (Proprietary vs Muse Model License). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5 Codex and Muse Spark Open?

GPT-5 Codex is developed by OpenAI and Muse Spark Open is developed by Meta.

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