Claude Fable 5.1 vs GLM-5.3 vs Muse Spark 1.2
Muse Spark 1.2 comes out ahead, 71 to 66 and 63 on our weighted score, and it is the cheaper option too.
AnthropicClaude Fable 5.1
66/100- ECI166.4
- Price$10.00 / $50.00
- Context1M
Z.ai (Zhipu)GLM-5.3
63/100- ECI156.2
- Price$1.40 / $4.40
- Context1M
- Our pick
MetaMuse Spark 1.2
71/100- ECI155.2
- Price$1.25 / $4.25
- Context1.05M
Muse Spark 1.2 is our pick
Muse Spark 1.2 is the better all-round choice, scoring 71/100 against Claude Fable 5.1 (66) and GLM-5.3 (63). It leads on inputs & features. Claude Fable 5.1 wins on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Fable 5.1Capabilities Index (ECI): Claude Fable 5.1 166.4 · GLM-5.3 156.2 · Muse Spark 1.2 155.2
- Lowest priceMuse Spark 1.2Muse Spark 1.2 $2.00 · GLM-5.3 $2.15 · Claude Fable 5.1 $20.00 per 1M tokens (3:1 blend)
- Longest contextMuse Spark 1.2Muse Spark 1.2 1,048,576 · Claude Fable 5.1 1,000,000 · GLM-5.3 1,000,000 tokens
- Widest inputsMuse Spark 1.2Claude Fable 5.1: Text, Images, PDFs · GLM-5.3: Text · Muse Spark 1.2: Text, Images, PDFs, Audio, Video
- Self-hostingGLM-5.3Publishes downloadable weights
| Measure | Weight | Claude Fable 5.1 | GLM-5.3 | Muse Spark 1.2 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 97 | 84 | 83 |
| Price | 25% | 0 | 33 | 34 |
| Inputs & features | 15% | 80 | 45 | 100 |
| Context window | 10% | 60 | 60 | 61 |
| Overall | 100% | 66/100 | 63/100 | 71/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Fable 5.1Anthropic | GLM-5.3Z.ai (Zhipu) | Muse Spark 1.2Meta |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 166.4 (best) | 156.2 | 155.2 |
| ECI rank | #6 of 165 (best) | #33 of 165 | #38 of 165 |
| GPQA DiamondGraduate-level science questions | — | 90.9% | — |
| FrontierMath Tiers 1–3Research-level mathematics | 90.2% (best) | 68.8% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | 91.1% | — |
| SimpleQA VerifiedShort factual questions | 70.8% (best) | 41.0% | 60.3% |
| Price per million tokens | |||
| Input | $10.00 | $1.40 | $1.25 (best) |
| Output | $50.00 | $4.40 | $4.25 (best) |
| Cached input | $0.25 | $0.26 | $0.15 (best) |
| Blended (3:1) | $20.00 | $2.15 | $2.00 (best) |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Anthropic API | Official Z.AI API | Official Meta API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,000,000 tokens | 1,048,576 tokens (best) |
| Max output | 128,000 tokens | 131,072 tokens (best) | 131,072 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | No | Yes |
| PDFs | Yes | No | Yes |
| Audio | No | No | Yes |
| Video | No | No | Yes |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeslow · high · max | Yesminimal · low · medium · high · xhigh |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | claude-fable-5-1 | glm-5.3 | muse-spark-1.2 |
| API providers | 37 | 83 (best) | 18 |
| Released | Sep 1, 2026 | Aug 14, 2026 | Aug 5, 2026 |
| Knowledge cutoff | 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.
- Claude Fable 5.1$200.00
- GLM-5.3$22.80
- Muse Spark 1.2$21.00
Which should you choose?
Which is better: Claude Fable 5.1, GLM-5.3 or Muse Spark 1.2?
Muse Spark 1.2 is the better all-round choice, scoring 71/100 against Claude Fable 5.1 (66) and GLM-5.3 (63). It leads on inputs & features. Claude Fable 5.1 wins on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Fable 5.1, GLM-5.3 or Muse Spark 1.2?
Muse Spark 1.2 is cheaper at $1.25 input / $4.25 output per million tokens (official Meta API price). GLM-5.3 costs $1.40 input / $4.40 output per million tokens (official Z.AI API price); Claude Fable 5.1 costs $10.00 input / $50.00 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 1.2 versus $2.15 for GLM-5.3 (1.1× as much) and $20.00 for Claude Fable 5.1 (10× as much).
Which scores higher on benchmarks?
Claude Fable 5.1 scores higher on the Capabilities Index (ECI): Claude Fable 5.1 166.4 (#6 of 165), GLM-5.3 156.2 (#33 of 165) and Muse Spark 1.2 155.2 (#38 of 165). Their confidence ranges do not overlap (163.6–170.8 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: SimpleQA Verified — Claude Fable 5.1 70.8%, Muse Spark 1.2 60.3%, GLM-5.3 41.0%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Fable 5.1, GLM-5.3 and Muse Spark 1.2 yet, so there is no like-for-like coding score. On overall capability, Claude Fable 5.1 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 1.2 has the largest context window at 1,048,576 tokens, against 1,000,000 for Claude Fable 5.1 and 1,000,000 for GLM-5.3. Maximum output per response: Claude Fable 5.1 up to 128,000, GLM-5.3 up to 131,072, Muse Spark 1.2 up to 131,072 tokens.
Which can read images, PDFs, audio or video?
Claude Fable 5.1 accepts text, images and PDFs; GLM-5.3 accepts text; Muse Spark 1.2 accepts text, images, PDFs, audio and video. Muse Spark 1.2 handles the widest range of inputs.
Are any of these open source?
GLM-5.3 publishes its weights and can be self-hosted; Claude Fable 5.1 and Muse Spark 1.2 is proprietary.
Which is newer?
Claude Fable 5.1 is the newest, released Sep 1, 2026. GLM-5.3 came out Aug 14, 2026; Muse Spark 1.2 came out Aug 5, 2026. Knowledge cutoff: Claude Fable 5.1 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.
