Muse Spark Open vs GPT-6 Astra vs GLM-5.3
Too close to call on our weighted score (GPT-6 Astra 68, Muse Spark Open 68, GLM-5.3 63). The right pick depends on what you value most.
MetaMuse Spark Open
68/100- ECI155.1
- Price$1.25 / $4.25
- Context1.05M
OpenAIGPT-6 Astra
68/100- ECI169.1
- Price$10.00 / $50.00
- Context1.05M
Z.ai (Zhipu)GLM-5.3
63/100- ECI156.2
- Price$1.40 / $4.40
- Context1M
Too close to call
It is close. Our weighted score puts them within a point (GPT-6 Astra 68/100, Muse Spark Open 68/100, GLM-5.3 63/100), so choose by what matters most for your work: GPT-6 Astra for raw capability and Muse Spark Open on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-6 AstraCapabilities Index (ECI): GPT-6 Astra 169.1 · GLM-5.3 156.2 · Muse Spark Open 155.1
- Lowest priceMuse Spark OpenMuse Spark Open $2.00 · GLM-5.3 $2.15 · GPT-6 Astra $20.00 per 1M tokens (3:1 blend)
- Longest contextGPT-6 Astra and Muse Spark OpenGPT-6 Astra 1,050,000 · Muse Spark Open 1,048,576 · GLM-5.3 1,000,000 tokens
- Widest inputsMuse Spark OpenMuse Spark Open: Text, Images, Audio, Video · GPT-6 Astra: Text, Images, PDFs · GLM-5.3: Text
- Self-hostingMuse Spark Open and GLM-5.3Publishes downloadable weights (Muse Model License)
| Measure | Weight | Muse Spark Open | GPT-6 Astra | GLM-5.3 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 83 | 100 | 84 |
| Price | 25% | 34 | 0 | 33 |
| Inputs & features | 15% | 80 | 80 | 45 |
| Context window | 10% | 61 | 61 | 60 |
| Overall | 100% | 68/100 | 68/100 | 63/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Muse Spark OpenMeta | GPT-6 AstraOpenAI | GLM-5.3Z.ai (Zhipu) |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 155.1 | 169.1 (best) | 156.2 |
| ECI rank | #39 of 165 | #1 of 165 (best) | #33 of 165 |
| GPQA DiamondGraduate-level science questions | 88.6% | 95.8% (best) | 90.9% |
| FrontierMath Tiers 1–3Research-level mathematics | 69.8% | 93.7% (best) | 68.8% |
| OTIS Mock AIME 2024–2025Competition mathematics | 98.1% | 100% (best) | 91.1% |
| SimpleQA VerifiedShort factual questions | 56.6% | 75.6% (best) | 41.0% |
| Price per million tokens | |||
| Input | $1.25 (best) | $10.00 | $1.40 |
| Output | $4.25 (best) | $50.00 | $4.40 |
| Cached input | — | $1.00 | $0.26 (best) |
| Blended (3:1) | $2.00 (best) | $20.00 | $2.15 |
| Long-context rate | Same rate | Over 272K: $20.00 / $75.00 | Same rate |
| Price source | Median of 16 providers | Official OpenAI API | Official Z.AI API |
| Limits | |||
| Context window | 1,048,576 tokens | 1,050,000 tokens (best) | 1,000,000 tokens |
| Max output | 131,072 tokens (best) | 128,000 tokens | 131,072 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | No |
| PDFs | No | Yes | No |
| Audio | Yes | No | No |
| Video | Yes | No | No |
| Reasoning | Yes | Yeslow · medium · high · xhigh · max | Yeslow · high · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | No | Yes | Yes |
| Availability | |||
| Weights | OpenMuse Model License | Proprietary | Open |
| API model ID | — | gpt-6-astra | glm-5.3 |
| API providers | 16 | 37 | 83 (best) |
| Released | Oct 15, 2026 | Sep 4, 2026 | Aug 14, 2026 |
| Knowledge cutoff | Jan 4, 2026 | Apr 30, 2026 | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Muse Spark Open$21.00
- GPT-6 Astra$200.00
- GLM-5.3$22.80
Which should you choose?
Which is better: Muse Spark Open, GPT-6 Astra or GLM-5.3?
It is close. Our weighted score puts them within a point (GPT-6 Astra 68/100, Muse Spark Open 68/100, GLM-5.3 63/100), so choose by what matters most for your work: GPT-6 Astra for raw capability and Muse Spark Open on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Muse Spark Open, GPT-6 Astra or GLM-5.3?
Muse Spark Open is cheaper at $1.25 input / $4.25 output per million tokens (median across 16 API providers). GLM-5.3 costs $1.40 input / $4.40 output per million tokens (official Z.AI API price); GPT-6 Astra costs $10.00 input / $50.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $2.00 per million tokens for Muse Spark Open versus $2.15 for GLM-5.3 (1.1× as much) and $20.00 for GPT-6 Astra (10× as much).
Which scores higher on benchmarks?
GPT-6 Astra scores higher on the Capabilities Index (ECI): GPT-6 Astra 169.1 (#1 of 165), GLM-5.3 156.2 (#33 of 165) and Muse Spark Open 155.1 (#39 of 165). Their confidence ranges do not overlap (165.9–174.3 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — GPT-6 Astra 95.8%, GLM-5.3 90.9%, Muse Spark Open 88.6%; FrontierMath Tiers 1–3 — GPT-6 Astra 93.7%, Muse Spark Open 69.8%, GLM-5.3 68.8%; OTIS Mock AIME 2024–2025 — GPT-6 Astra 100%, Muse Spark Open 98.1%, GLM-5.3 91.1%; SimpleQA Verified — GPT-6 Astra 75.6%, Muse Spark Open 56.6%, GLM-5.3 41.0%.
Which is better for coding?
There are no published SWE-bench Verified results for Muse Spark Open, GPT-6 Astra and GLM-5.3 yet, so there is no like-for-like coding score. On overall capability, GPT-6 Astra leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
GPT-6 Astra and Muse Spark Open have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for GLM-5.3. Maximum output per response: Muse Spark Open up to 131,072, GPT-6 Astra up to 128,000, GLM-5.3 up to 131,072 tokens.
Which can read images, PDFs, audio or video?
Muse Spark Open accepts text, images, audio and video; GPT-6 Astra accepts text, images and PDFs; GLM-5.3 accepts text. Muse Spark Open handles the widest range of inputs.
Are any of these open source?
Muse Spark Open and GLM-5.3 publishes its weights (Muse Model License) and can be self-hosted; GPT-6 Astra is proprietary.
Which is newer?
Muse Spark Open is the newest, released Oct 15, 2026. GPT-6 Astra came out Sep 4, 2026; GLM-5.3 came out Aug 14, 2026. Knowledge cutoff: Muse Spark Open Jan 4, 2026, GPT-6 Astra Apr 30, 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
