GPT-5 Mini vs Muse Spark 1.3

The match-up at a glance

This comparison pits two budget models, built for high volumes at a low price against each other: GPT-5 Mini and Muse Spark 1.3, one from OpenAI, the other from Meta. The first dates from August 7, 2025, the second from September 2, 2026.

All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.

Which one is more capable?

On our capability index, GPT-5 Mini scores 62.9 out of 100 and Muse Spark 1.3 82.7. Muse Spark 1.3 leads by 19.8 points.

On the 2 benchmarks reported for both, GPT-5 Mini wins 0 times and Muse Spark 1.3 2:

• OTIS Mock AIME (competition mathematics problems): GPT-5 Mini 86.7%, Muse Spark 1.3 99.2%
• FrontierMath (very hard research-level mathematics): GPT-5 Mini 46.7%, Muse Spark 1.3 74.4%

Which one costs less?

GPT-5 Mini costs $0.25 per million input tokens and $2 per million output tokens; Muse Spark 1.3 costs $0.10 and $0.20.

For a typical agent task (read 20,000 tokens, write 2,000), expect $0.009 with GPT-5 Mini versus $0.002 with Muse Spark 1.3. Muse Spark 1.3 is 3.8 times cheaper, a gap that adds up quickly over 1,000 tasks: $6.6 difference.

Run the numbers with your own volumes in the agent cost calculator.

Under the hood

Muse Spark 1.3 reads more in one go: 1,048,576 tokens of context (roughly 1,573 pages), versus 272,000 for GPT-5 Mini.

Reasoning mode: GPT-5 Mini yes, Muse Spark 1.3 yes. Tool calling: GPT-5 Mini yes, Muse Spark 1.3 yes. Image input: GPT-5 Mini yes, Muse Spark 1.3 yes.

Neither publishes its weights: both are used through an API.

In short

Our reading of the data:

• Choose Muse Spark 1.3 for a higher capability index, a lower cost, a larger context window and a more recent release.

This verdict relies on public figures; it does not replace a trial on your own tasks.