GLM-5.3 vs Muse Spark Open vs Claude Opus 5.5
Too close to call on our weighted score (Claude Opus 5.5 69, Muse Spark Open 68, GLM-5.3 63). The right pick depends on what you value most.
Z.ai (Zhipu)GLM-5.3
63/100- ECI156.2
- Price$1.40 / $4.40
- Context1M
MetaMuse Spark Open
68/100- ECI155.1
- Price$1.25 / $4.25
- Context1.05M
AnthropicClaude Opus 5.5
69/100- ECI168.4
- Price$4.00 / $20.00
- Context1M
Too close to call
It is close. Our weighted score puts them within 1 points (Claude Opus 5.5 69/100, Muse Spark Open 68/100, GLM-5.3 63/100), so choose by what matters most for your work: Claude Opus 5.5 for raw capability, Muse Spark Open on price and Muse Spark Open for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Opus 5.5Capabilities Index (ECI): Claude Opus 5.5 168.4 · GLM-5.3 156.2 · Muse Spark Open 155.1
- Lowest priceMuse Spark OpenMuse Spark Open $2.00 · GLM-5.3 $2.15 · Claude Opus 5.5 $8.00 per 1M tokens (3:1 blend)
- Longest contextMuse Spark OpenMuse Spark Open 1,048,576 · GLM-5.3 1,000,000 · Claude Opus 5.5 1,000,000 tokens
- Widest inputsMuse Spark OpenGLM-5.3: Text · Muse Spark Open: Text, Images, Audio, Video · Claude Opus 5.5: Text, Images, PDFs
- Self-hostingGLM-5.3 and Muse Spark OpenPublishes downloadable weights (Muse Model License)
| Measure | Weight | GLM-5.3 | Muse Spark Open | Claude Opus 5.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 84 | 83 | 99 |
| Price | 25% | 33 | 34 | 7 |
| Inputs & features | 15% | 45 | 80 | 80 |
| Context window | 10% | 60 | 61 | 60 |
| Overall | 100% | 63/100 | 68/100 | 69/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GLM-5.3Z.ai (Zhipu) | Muse Spark OpenMeta | Claude Opus 5.5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 156.2 | 155.1 | 168.4 (best) |
| ECI rank | #33 of 165 | #39 of 165 | #2 of 165 (best) |
| GPQA DiamondGraduate-level science questions | 90.9% (best) | 88.6% | 90.6% |
| FrontierMath Tiers 1–3Research-level mathematics | 68.8% | 69.8% | 91.2% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 91.1% | 98.1% | 100% (best) |
| SimpleQA VerifiedShort factual questions | 41.0% | 56.6% | 72.2% (best) |
| Price per million tokens | |||
| Input | $1.40 | $1.25 (best) | $4.00 |
| Output | $4.40 | $4.25 (best) | $20.00 |
| Cached input | $0.26 | — | $0.20 (best) |
| Blended (3:1) | $2.15 | $2.00 (best) | $8.00 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Z.AI API | Median of 16 providers | Official Anthropic API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,048,576 tokens (best) | 1,000,000 tokens |
| Max output | 131,072 tokens (best) | 131,072 tokens (best) | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | No | Yes | Yes |
| PDFs | No | No | Yes |
| Audio | No | Yes | No |
| Video | No | Yes | No |
| Reasoning | Yeslow · high · max | Yes | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | Yes |
| Availability | |||
| Weights | Open | OpenMuse Model License | Proprietary |
| API model ID | glm-5.3 | — | claude-opus-5-5 |
| API providers | 83 (best) | 16 | 36 |
| Released | Aug 14, 2026 | Oct 15, 2026 | Sep 22, 2026 |
| Knowledge cutoff | — | Jan 4, 2026 | Jun 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GLM-5.3$22.80
- Muse Spark Open$21.00
- Claude Opus 5.5$80.00
Which should you choose?
Which is better: GLM-5.3, Muse Spark Open or Claude Opus 5.5?
It is close. Our weighted score puts them within 1 points (Claude Opus 5.5 69/100, Muse Spark Open 68/100, GLM-5.3 63/100), so choose by what matters most for your work: Claude Opus 5.5 for raw capability, Muse Spark Open on price and Muse Spark Open for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GLM-5.3, Muse Spark Open or Claude Opus 5.5?
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); Claude Opus 5.5 costs $4.00 input / $20.00 output per million tokens (official Anthropic 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 $8.00 for Claude Opus 5.5 (4× as much).
Which scores higher on benchmarks?
Claude Opus 5.5 scores higher on the Capabilities Index (ECI): Claude Opus 5.5 168.4 (#2 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 (165.4–173.0 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — GLM-5.3 90.9%, Claude Opus 5.5 90.6%, Muse Spark Open 88.6%; FrontierMath Tiers 1–3 — Claude Opus 5.5 91.2%, Muse Spark Open 69.8%, GLM-5.3 68.8%; OTIS Mock AIME 2024–2025 — Claude Opus 5.5 100%, Muse Spark Open 98.1%, GLM-5.3 91.1%; SimpleQA Verified — Claude Opus 5.5 72.2%, Muse Spark Open 56.6%, GLM-5.3 41.0%.
Which is better for coding?
There are no published SWE-bench Verified results for GLM-5.3, Muse Spark Open and Claude Opus 5.5 yet, so there is no like-for-like coding score. On overall capability, Claude Opus 5.5 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?
Muse Spark Open has the largest context window at 1,048,576 tokens, against 1,000,000 for GLM-5.3 and 1,000,000 for Claude Opus 5.5. Maximum output per response: GLM-5.3 up to 131,072, Muse Spark Open up to 131,072, Claude Opus 5.5 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
GLM-5.3 accepts text; Muse Spark Open accepts text, images, audio and video; Claude Opus 5.5 accepts text, images and PDFs. Muse Spark Open handles the widest range of inputs.
Are any of these open source?
GLM-5.3 and Muse Spark Open publishes its weights (Muse Model License) and can be self-hosted; Claude Opus 5.5 is proprietary.
Which is newer?
Muse Spark Open is the newest, released Oct 15, 2026. Claude Opus 5.5 came out Sep 22, 2026; GLM-5.3 came out Aug 14, 2026. Knowledge cutoff: Muse Spark Open Jan 4, 2026, Claude Opus 5.5 Jun 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.
