GPT-5.4 Mini vs Muse Spark 1.3
OpenAI · US | Meta · US · Updated June 2026
Quick verdict
Pick GPT-5.4 Mini for free for every chatgpt user or fast, low-cost general tasks. Pick Muse Spark 1.3 for agentic coding with ~20% fewer tool calls and ~25% fewer tokens than muse spark 1.2 or deepswe v1.1 long-horizon software engineering (75.4). On a tight budget at scale, GPT-5.4 Mini is the value pick.
GPT-5.4 Mini (OpenAI) and Muse Spark 1.3 (Meta) are two of the models people most often weigh against each other in 2026. GPT-5.4 Mini is openAI's free, fast workhorse — capable general AI with no subscription needed. Muse Spark 1.3 is meta's September 2, 2026 agentic-coding model update, cutting tool calls and token usage versus Muse Spark 1.2 while its highest-reasoning mode remains gated for safety review. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: GPT-5.4 Mini is about 1.7× cheaper on input ($0.75/$4.5 per 1M tokens vs $1.25/$4.25 per 1M tokens) — modest, but it adds up at steady volume.
- ▸Context window: Muse Spark 1.3 holds 2.5× more — 1M tokens (~1,500 pages) vs 400K (~600 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
- ▸Recency: Muse Spark 1.3 is the newer model by about 6 months (released September 2, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | GPT-5.4 Mini | Muse Spark 1.3 |
|---|---|---|
| Provider | OpenAI (US) | Meta (US) |
| Released | March 17, 2026 | September 2, 2026 |
| Context window | 400K (~600 pages) | 1M tokens (~1,500 pages) |
| Price (in/out) | $0.75/$4.5 per 1M tokens | $1.25/$4.25 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, code | text, image, video |
| SWE-Bench Verified | Not published | Not published |
| MRCR v2 @ 1M | Not published | 98.1% |
Who wins what
Free for every ChatGPT user
GPT-5.4 Mini
OpenAI's free, fast workhorse — capable general AI with no subscription needed — and it runs cheaper at $0.75/$4.5 per 1M tokens.
Fast, low-cost general tasks
GPT-5.4 Mini
At $0.75/$4.5 per 1M tokens it undercuts Muse Spark 1.3 ($1.25/$4.25 per 1M tokens), and that gap compounds at volume.
Subagent capabilities
GPT-5.4 Mini
GPT-5.4 Mini lists subagent capabilities among its strengths; Muse Spark 1.3 does not.
Agentic coding with ~20% fewer tool calls and ~25% fewer tokens than Muse Spark 1.2
Muse Spark 1.3
Its 1M tokens window holds about 2.5× more than GPT-5.4 Mini's 400K in a single prompt.
DeepSWE v1.1 long-horizon software engineering (75.4)
Muse Spark 1.3
Meta's September 2, 2026 agentic-coding model update, cutting tool calls and token usage versus Muse Spark 1.2 while its highest-reasoning mode remains gated for safety review — and it carries the larger 1M tokens context.
Near-perfect long-context retrieval (MRCR v2 512K-1M: 98.1)
Muse Spark 1.3
GPT-5.4 Mini is comparatively weak here — smaller context than flagship models
Lowest cost at scale
GPT-5.4 Mini
At $0.75/$4.5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Muse Spark 1.3
Its 1M tokens window is about 2.5× larger than GPT-5.4 Mini's 400K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ GPT-5.4 Mini
At $0.75/$4.5 per 1M tokens it undercuts Muse Spark 1.3, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Muse Spark 1.3
Larger 1M tokens window fits more in one prompt.
Anyone whose priority is free for every chatgpt user
→ GPT-5.4 Mini
It is specifically built for that.
Anyone whose priority is agentic coding with ~20% fewer tool calls and ~25% fewer tokens than muse spark 1.2
→ Muse Spark 1.3
That is its strongest area.
GPT-5.4 Mini: where it fits
OpenAI's free, fast workhorse — capable general AI with no subscription needed. Released March 17, 2026 by OpenAI, it is built for free for every ChatGPT user, fast, low-cost general tasks, subagent capabilities, and native multimodal reasoning.
Its trade-offs are real: smaller context than flagship models, and not for the hardest reasoning. At $0.75 in / $4.5 out per million tokens, it sits in the budget price band.
Muse Spark 1.3: where it fits
Meta's September 2, 2026 agentic-coding model update, cutting tool calls and token usage versus Muse Spark 1.2 while its highest-reasoning mode remains gated for safety review. Released September 2, 2026 by Meta, it is built for agentic coding with ~20% fewer tool calls and ~25% fewer tokens than Muse Spark 1.2, deepSWE v1.1 long-horizon software engineering (75.4), near-perfect long-context retrieval (MRCR v2 512K-1M: 98.1), and ranks third overall on the Artificial Analysis Intelligence Index (score 61, xhigh variant; the limited-preview max variant scores 62) - behind only Claude Fable 5.1 and Claude Opus 5.
Its trade-offs: strongest 'max' reasoning configuration still gated pending additional safety testing, not yet open-weight, despite Meta roadmapping a future Muse Spark weights release, and no official SWE-bench Verified score published. At $1.25 in / $4.25 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
GPT-5.4 Mini and Muse Spark 1.3 overlap enough that the right pick depends on your specific job. GPT-5.4 Mini costs less per token; Muse Spark 1.3 holds the larger context; and each leads in its own area — GPT-5.4 Mini for free for every chatgpt user, Muse Spark 1.3 for agentic coding with ~20% fewer tool calls and ~25% fewer tokens than muse spark 1.2. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both GPT-5.4 Mini and Muse Spark 1.3 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
See pricingFrequently asked questions
Is GPT-5.4 Mini or Muse Spark 1.3 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, GPT-5.4 Mini leans toward free for every chatgpt user while Muse Spark 1.3 leans toward agentic coding with ~20% fewer tool calls and ~25% fewer tokens than muse spark 1.2, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, GPT-5.4 Mini or Muse Spark 1.3?
GPT-5.4 Mini is cheaper — $0.75/$4.5 per 1M tokens vs $1.25/$4.25 per 1M tokens, roughly 1.7× apart on input.
Which has the bigger context window?
Muse Spark 1.3 — 1M tokens vs 400K, about 2.5× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both GPT-5.4 Mini and Muse Spark 1.3 together?
Yes — a multi-model platform like LumiChats gives you GPT-5.4 Mini, Muse Spark 1.3 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, GPT-5.4 Mini or Muse Spark 1.3?
Muse Spark 1.3 — released September 2, 2026, about 6 months after GPT-5.4 Mini.
Related comparisons
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.