Claude Fable 5.1 vs Gemini 3.8 Flash vs Muse Spark 1.3
Too close to call on our weighted score (Gemini 3.8 Flash 75, Muse Spark 1.3 73, Claude Fable 5.1 66). The right pick depends on what you value most.
AnthropicClaude Fable 5.1
66/100- ECI164.8
- Price$10.00 / $50.00
- Context1M
GoogleGemini 3.8 Flash
75/100- ECI156.9
- Price$0.75 / $3.75
- Context1.05M
MetaMuse Spark 1.3
73/100- ECI156.9
- Price$1.25 / $4.25
- Context1.05M
Too close to call
It is close. Our weighted score puts them within 2 points (Gemini 3.8 Flash 75/100, Muse Spark 1.3 73/100, Claude Fable 5.1 66/100), so choose by what matters most for your work: Claude Fable 5.1 for raw capability and Gemini 3.8 Flash on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Fable 5.1Capabilities Index (ECI): Claude Fable 5.1 164.8 · Gemini 3.8 Flash 156.9 · Muse Spark 1.3 156.9
- Lowest priceGemini 3.8 FlashGemini 3.8 Flash $1.50 · Muse Spark 1.3 $2.00 · Claude Fable 5.1 $20.00 per 1M tokens (3:1 blend)
- Longest contextGemini 3.8 Flash and Muse Spark 1.3Gemini 3.8 Flash 1,048,576 · Muse Spark 1.3 1,048,576 · Claude Fable 5.1 1,000,000 tokens
- Widest inputsGemini 3.8 Flash and Muse Spark 1.3Claude Fable 5.1: Text, Images, PDFs · Gemini 3.8 Flash: Text, Images, PDFs, Audio, Video · Muse Spark 1.3: Text, Images, PDFs, Audio, Video
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Claude Fable 5.1 | Gemini 3.8 Flash | Muse Spark 1.3 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 97 | 87 | 87 |
| Price | 25% | 0 | 42 | 36 |
| Inputs & features | 15% | 80 | 100 | 100 |
| Context window | 10% | 60 | 61 | 61 |
| Overall | 100% | 66/100 | 75/100 | 73/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Fable 5.1Anthropic | Gemini 3.8 FlashGoogle | Muse Spark 1.3Meta |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 164.8 (best) | 156.9 | 156.9 |
| ECI rank | #4 of 148 (best) | #15 of 148 | #17 of 148 |
| GPQA DiamondGraduate-level science questions | — | 95.4% | — |
| FrontierMath Tiers 1–3Research-level mathematics | 90.2% (best) | 68.4% | 74.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | 98.9% | 99.2% |
| SimpleQA VerifiedShort factual questions | 70.8% (best) | 69.7% | — |
| Price per million tokens | |||
| Input | $10.00 | $0.75 (best) | $1.25 |
| Output | $50.00 | $3.75 (best) | $4.25 |
| Cached input | $0.25 | $0.075 (best) | $0.15 |
| Blended (3:1) | $20.00 | $1.50 (best) | $2.00 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Anthropic API | Official Google API | Official Meta API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,048,576 tokens (best) | 1,048,576 tokens (best) |
| Max output | 128,000 tokens | 65,536 tokens | 131,072 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | No | Yes | Yes |
| Video | No | Yes | Yes |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeslow · medium · high | Yesminimal · low · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | claude-fable-5-1 | gemini-3.8-flash | muse-spark-1.3 |
| API providers | 29 (best) | 21 | 12 |
| Released | Sep 1, 2026 | Sep 2, 2026 | Sep 2, 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
- Gemini 3.8 Flash$15.00
- Muse Spark 1.3$21.00
Which should you choose?
Which is better: Claude Fable 5.1, Gemini 3.8 Flash or Muse Spark 1.3?
It is close. Our weighted score puts them within 2 points (Gemini 3.8 Flash 75/100, Muse Spark 1.3 73/100, Claude Fable 5.1 66/100), so choose by what matters most for your work: Claude Fable 5.1 for raw capability and Gemini 3.8 Flash on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Fable 5.1, Gemini 3.8 Flash or Muse Spark 1.3?
Gemini 3.8 Flash is cheaper at $0.75 input / $3.75 output per million tokens (official Google API price). Muse Spark 1.3 costs $1.25 input / $4.25 output per million tokens (official Meta 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 $1.50 per million tokens for Gemini 3.8 Flash versus $2.00 for Muse Spark 1.3 (1.3× as much) and $20.00 for Claude Fable 5.1 (13× as much).
Which scores higher on benchmarks?
Claude Fable 5.1 scores higher on the Capabilities Index (ECI): Claude Fable 5.1 164.8 (#4 of 148), Gemini 3.8 Flash 156.9 (#15 of 148) and Muse Spark 1.3 156.9 (#17 of 148). Their confidence ranges do not overlap (161.8–169.1 vs 154.6–160.4), so the gap is a real one. On individual benchmarks: FrontierMath Tiers 1–3 — Claude Fable 5.1 90.2%, Muse Spark 1.3 74.4%, Gemini 3.8 Flash 68.4%; OTIS Mock AIME 2024–2025 — Claude Fable 5.1 100%, Muse Spark 1.3 99.2%, Gemini 3.8 Flash 98.9%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Fable 5.1, Gemini 3.8 Flash and Muse Spark 1.3 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?
Gemini 3.8 Flash and Muse Spark 1.3 have the largest context windows (1,048,576 and 1,048,576 tokens), against 1,000,000 for Claude Fable 5.1. Maximum output per response: Claude Fable 5.1 up to 128,000, Gemini 3.8 Flash up to 65,536, Muse Spark 1.3 up to 131,072 tokens.
Which can read images, PDFs, audio or video?
Claude Fable 5.1 accepts text, images and PDFs; Gemini 3.8 Flash accepts text, images, PDFs, audio and video; Muse Spark 1.3 accepts text, images, PDFs, audio and video. Gemini 3.8 Flash handles the widest range of inputs.
Are any of these open source?
No. Claude Fable 5.1, Gemini 3.8 Flash and Muse Spark 1.3 are proprietary and only available through APIs and apps.
Which is newer?
Gemini 3.8 Flash is the newest, released Sep 2, 2026. Muse Spark 1.3 came out Sep 2, 2026; Claude Fable 5.1 came out Sep 1, 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 Oct 4, 2026.
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