Pick GPT-5.4 for strong general-purpose default or coding and software engineering. 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, Muse Spark 1.3 is the value pick.
GPT-5.4 (OpenAI) and Muse Spark 1.3 (Meta) are two of the models people most often weigh against each other in 2026. GPT-5.4 is openAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5. 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. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Price: Muse Spark 1.3 is about 2× cheaper on input ($1.25/$4.25 per 1M tokens vs $2.5/$15 per 1M tokens) — meaningful once you are processing millions of tokens a month.
Context window: both advertise 1M (~1,500 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
Recency: Muse Spark 1.3 is the newer model by about 6 months (released September 2, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
GPT-5.4
Muse Spark 1.3
Provider
OpenAI (US)
Meta (US)
Released
March 5, 2026
September 2, 2026
Context window
1M (~1,500 pages)
1M tokens (~1,500 pages)
Price (in/out)
$2.5/$15 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
Strong general-purpose default: GPT-5.4 — Muse Spark 1.3 is comparatively weak here — strongest 'max' reasoning configuration still gated pending additional safety testing
Coding and software engineering: GPT-5.4 — GPT-5.4 lists coding and software engineering among its strengths; Muse Spark 1.3 does not.
Document understanding and tool use: GPT-5.4 — GPT-5.4 lists document understanding and tool use 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 — 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 runs cheaper at $1.25/$4.25 per 1M tokens.
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 is the newer of the two.
Near-perfect long-context retrieval (MRCR v2 512K-1M: 98.1): Muse Spark 1.3 — Muse Spark 1.3 lists near-perfect long-context retrieval (MRCR v2 512K-1M: 98.1) among its strengths; GPT-5.4 does not.
Lowest cost at scale: Muse Spark 1.3 — At $1.25/$4.25 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Which should you pick?
A cost-sensitive startup shipping high volume: Muse Spark 1.3 — At $1.25/$4.25 per 1M tokens it undercuts GPT-5.4, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is strong general-purpose default: GPT-5.4 — 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: where it fits
OpenAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5. Released March 5, 2026 by OpenAI, it is built for strong general-purpose default, coding and software engineering, document understanding and tool use, and 1M context with good token efficiency.
Its trade-offs are real: topped by GPT-5.5 on the hardest tasks, and pricier than open-weight rivals. At $2.5 in / $15 out per million tokens, it sits in the mid 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 and Muse Spark 1.3 overlap enough that the right pick depends on your specific job. Muse Spark 1.3 costs less per token; and each leads in its own area — GPT-5.4 for strong general-purpose default, 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.
Frequently asked questions
Is GPT-5.4 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 leans toward strong general-purpose default 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 or Muse Spark 1.3?
Muse Spark 1.3 is cheaper — $2.5/$15 per 1M tokens vs $1.25/$4.25 per 1M tokens, roughly 2× apart on input.
Which has the bigger context window?
Both advertise 1M (~1,500 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both GPT-5.4 and Muse Spark 1.3 together?
Yes — a multi-model platform like LumiChats gives you GPT-5.4, 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 or Muse Spark 1.3?
Muse Spark 1.3 — released September 2, 2026, about 6 months after GPT-5.4.
GPT-5.4 vs Muse Spark 1.3
OpenAI · US | Meta · US · Updated June 2026
Quick verdict
Pick GPT-5.4 for strong general-purpose default or coding and software engineering. 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, Muse Spark 1.3 is the value pick.
GPT-5.4 (OpenAI) and Muse Spark 1.3 (Meta) are two of the models people most often weigh against each other in 2026. GPT-5.4 is openAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5. 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. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences at a glance
▸Price: Muse Spark 1.3 is about 2× cheaper on input ($1.25/$4.25 per 1M tokens vs $2.5/$15 per 1M tokens) — meaningful once you are processing millions of tokens a month.
▸Context window: both advertise 1M (~1,500 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
▸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
Muse Spark 1.3
Provider
OpenAI (US)
Meta (US)
Released
March 5, 2026
September 2, 2026
Context window
1M (~1,500 pages)
1M tokens (~1,500 pages)
Price (in/out)
$2.5/$15 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
Strong general-purpose default
GPT-5.4
Muse Spark 1.3 is comparatively weak here — strongest 'max' reasoning configuration still gated pending additional safety testing
Coding and software engineering
GPT-5.4
GPT-5.4 lists coding and software engineering among its strengths; Muse Spark 1.3 does not.
Document understanding and tool use
GPT-5.4
GPT-5.4 lists document understanding and tool use 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
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 runs cheaper at $1.25/$4.25 per 1M tokens.
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 is the newer of the two.
Muse Spark 1.3 lists near-perfect long-context retrieval (MRCR v2 512K-1M: 98.1) among its strengths; GPT-5.4 does not.
Lowest cost at scale
Muse Spark 1.3
At $1.25/$4.25 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Muse Spark 1.3
At $1.25/$4.25 per 1M tokens it undercuts GPT-5.4, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is strong general-purpose default
→ GPT-5.4
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: where it fits
OpenAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5. Released March 5, 2026 by OpenAI, it is built for strong general-purpose default, coding and software engineering, document understanding and tool use, and 1M context with good token efficiency.
Its trade-offs are real: topped by GPT-5.5 on the hardest tasks, and pricier than open-weight rivals. At $2.5 in / $15 out per million tokens, it sits in the mid 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 and Muse Spark 1.3 overlap enough that the right pick depends on your specific job. Muse Spark 1.3 costs less per token; and each leads in its own area — GPT-5.4 for strong general-purpose default, 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 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.
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 leans toward strong general-purpose default 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 or Muse Spark 1.3?
Muse Spark 1.3 is cheaper — $2.5/$15 per 1M tokens vs $1.25/$4.25 per 1M tokens, roughly 2× apart on input.
Which has the bigger context window?
Both advertise 1M (~1,500 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both GPT-5.4 and Muse Spark 1.3 together?
Yes — a multi-model platform like LumiChats gives you GPT-5.4, 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 or Muse Spark 1.3?
Muse Spark 1.3 — released September 2, 2026, about 6 months after GPT-5.4.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.