GPT-6.1 Terra vs Muse Spark Open
GPT-6.1 Terra leads Muse Spark Open on coding, 77.4 to 47.3 on the Vibe Coding Index, at about the same output price ($5.00 vs $4.25 per million). Updated October 29, 2026; 27 benchmarks have a result for both.
GPT-6.1 Terra or Muse Spark Open: which to pick
Pick GPT-6.1 Terra for coding: it scores 77.4 on the Vibe Coding Index against 47.3 for Muse Spark Open.
Pick Muse Spark Open for output tokens 1.2x cheaper ($4.25 vs $5.00 per million) and work measured by SciCode or LiveBench research, where it leads.
- Shared results
- 27
- GPT-6.1 Terra only
- 9
- Muse Spark Open only
- 11
- Like-for-like categories
- 5 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
GPT-6.1 Terra
GPT-6.1 Terra scores 77.4 against 47.3.
4 benchmarks behind each score
Intelligence
AA Intelligence Index
No call
Only GPT-6.1 Terra has a AA Intelligence Index result, 51.0.
Directional only
Web design
Design Arena: websites
Muse Spark Open
Muse Spark Open leads, 1306 against 1283.
Same board, both measured
General
Vals Index
GPT-6.1 Terra
GPT-6.1 Terra leads, 60.5% against 48.6%.
Same board, both measured
Long documents
Listed context window
GPT-6.1 Terra
GPT-6.1 Terra takes 1.05M tokens against 1.05M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Muse Spark Open
GPT-6.1 Terra $0.0035, Muse Spark Open $0.0034 per turn.
List prices
At a glance
- Coding index
- GPT-6.1 Terra 77.4 from 4 benchmarks, Muse Spark Open 47.3 from 4 benchmarks.
- Widest category
- Agentic work, 27.4 points apart on average over 7 shared benchmarks.
- Widest single gap
- LiveBench browser: GPT-6.1 Terra 93.1% against Muse Spark Open 26.2%, 66.9 points apart on a 0 to 100 scale.
- Output price
- GPT-6.1 Terra $5.00 against Muse Spark Open $4.25 per million output tokens, 1.2x apart.
- Context window
- GPT-6.1 Terra takes 1.05M tokens, Muse Spark Open 1.05M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | GPT-6.1 Terra | Bars | Muse Spark Open | Ties |
|---|---|---|---|---|
| Coding | 7 | 1 | ||
| Agentic work | 3 | 4 | ||
| Reasoning | 3 | 0 | ||
| Web design | 2 | 3 | ||
| General | 3 | 0 | 1 tie | |
| All shared boards | 18 | 8 | 1 tie |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index71
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench coding | 94.3% | 73.6% | GPT-6.1 Terra |
| LMArena WebDev | 1673 | 1526 | GPT-6.1 Terra |
| Terminal-Bench 4 (Vals AI) | 49.5% | 6.6% | GPT-6.1 Terra |
| Vibe Code Bench (Vals AI) | 84.0% | 76.2% | GPT-6.1 Terra |
| Code migration (Vals AI) | Not measured | 21.2% | Only Muse Spark Open measured |
| SciCode | 55.1% | 58.4% | Muse Spark Open |
| ALE-Bench | 2608.8 | 1590.1 | GPT-6.1 Terra |
| LMArena WebDev: React | 1657 | 1524 | GPT-6.1 Terra |
| LMArena WebDev: HTML | 1719 | 1481 | GPT-6.1 Terra |
| SWE-Bench Pro V2 | Not measured | 95.0% | Only Muse Spark Open measured |
| Neither model has a result on the other 33 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| AA Intelligence Index | 51.0 | Not measured | Only GPT-6.1 Terra measured |
| Epoch Capabilities Index | Not measured | 155.1 | Only Muse Spark Open measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index34
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench research | 73.9% | 80.3% | Muse Spark Open |
| LiveBench browser | 93.1% | 26.2% | GPT-6.1 Terra |
| LiveBench long agentic | 48.6% | 11.7% | GPT-6.1 Terra |
| Finance Agent (Vals AI) | Not measured | 61.3% | Only Muse Spark Open measured |
| Tax Agent Bench (Vals AI) | 15.2% | 26.3% | Muse Spark Open |
| Legal Research Bench (Vals AI) | 26.0% | 38.5% | Muse Spark Open |
| Harvey's Legal Agent Benchmark (Vals AI) | 1.7% | 25.0% | Muse Spark Open |
| Excel Modeling Benchmark (Vals AI) | Not measured | 53.7% | Only Muse Spark Open measured |
| APEX-Agents | 68.3% | 33.4% | GPT-6.1 Terra |
| Neither model has a result on the other 33 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench reasoning | 88.7% | 73.7% | GPT-6.1 Terra |
| GPQA Diamond (Artificial Analysis run) | Not measured | 89.0% | Only Muse Spark Open measured |
| Humanity's Last Exam (Artificial Analysis run) | 46.2% | 43.9% | GPT-6.1 Terra |
| GPQA Diamond (Epoch AI run) | 94.3% | Not measured | Only GPT-6.1 Terra measured |
| ARC-AGI | Not measured | 89.0% | Only Muse Spark Open measured |
| ARC-AGI-2 | Not measured | 57.5% | Only Muse Spark Open measured |
| Mystery game puzzles | 74.0% | Not measured | Only GPT-6.1 Terra measured |
| EBR-bench | 78.1% | Not measured | Only GPT-6.1 Terra measured |
| Humanity's Last Exam (Scale run) | 35.7% | 28.0% | GPT-6.1 Terra |
| Neither model has a result on the other 14 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | Not measured | Only GPT-6.1 Terra measured |
| FrontierMath, tiers 1 to 3 | 90.9% | Not measured | Only GPT-6.1 Terra measured |
| FrontierMath, tier 4 | 92.7% | Not measured | Only GPT-6.1 Terra measured |
| MathArena | Not measured | 33.1% | Only Muse Spark Open measured |
| Neither model has a result on the other 10 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| SimpleQA Verified | 57.3% | Not measured | Only GPT-6.1 Terra measured |
| PRBench Legal | Not measured | 59.8% | Only Muse Spark Open measured |
| Neither model has a result on the other 18 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index23
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| Design Arena: websites | 1283 | 1306 | Muse Spark Open |
| Design Arena: UI components | 1277 | 1338 | Muse Spark Open |
| Design Arena: game dev | 1348 | 1272 | GPT-6.1 Terra |
| Design Arena: all code categories | 1295 | 1301 | Muse Spark Open |
| LiveBench design | 82.3% | 60.3% | GPT-6.1 Terra |
| Neither model has a result on the other 4 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| Vals Index | 60.5% | 48.6% | GPT-6.1 Terra |
| LiveBench data analysis | 82.3% | 60.2% | GPT-6.1 Terra |
| SAGE (Vals AI) | Not measured | 85.8% | Only Muse Spark Open measured |
| Long context reasoning (AA-LCR) | 82.7% | 78.3% | GPT-6.1 Terra |
| Furniture assembly | 79.2% | Not measured | Only GPT-6.1 Terra measured |
| MultiChallenge | 74.2% | 74.2% | Tie |
| Neither model has a result on the other 42 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-6.1 Terra | Muse Spark Open | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Muse Spark Open costs less
Repository review
50K input + 3K output tokens
GPT-6.1 Terra costs less
Agent loop
200K input + 10K output tokens
GPT-6.1 Terra costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | OpenAI GPT-6.1 Terra | Meta Muse Spark Open |
|---|---|---|
| Maker | OpenAI | Meta |
| Weights | No public weights listed | Open weights |
| Released | October 26, 2026 | October 15, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $1.00 | $1.25 |
| Output $/Mtok | $5.00 | $4.25 |
| Coding index | 77.4 | 47.3 |
| Independent measurements behind it | 4 | 4 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-6.1 Terra better than Muse Spark Open for coding?
Pick GPT-6.1 Terra for coding: it scores 77.4 on the Vibe Coding Index against 47.3 for Muse Spark Open. Pick Muse Spark Open for output tokens 1.2x cheaper ($4.25 vs $5.00 per million) and work measured by SciCode or LiveBench research, where it leads.
Which is cheaper, GPT-6.1 Terra or Muse Spark Open?
GPT-6.1 Terra costs $1.00 per million input tokens and $5.00 per million output tokens; Muse Spark Open costs $1.25 and $4.25. Cost per solved task is known for neither of them.
Which has the bigger context window, GPT-6.1 Terra or Muse Spark Open?
GPT-6.1 Terra, with 1.05M tokens against 1.05M.
How many benchmarks is the GPT-6.1 Terra vs Muse Spark Open comparison based on?
27 benchmarks have a result for both models as of October 29, 2026. GPT-6.1 Terra's coding index rests on 4 independent benchmarks and Muse Spark Open's on 4. Where only one model has a result, the page says so instead of naming a winner.