Claude Fable 5 vs Gemini 3.8 Flash
| Benchmark | Fable 5 | Gemini 3.8 Flash |
|---|---|---|
| MMMU-Pro (vision) | — | 84.2 |
| Chartography | 34.8 | 40.9 · high |
| GDP.pdf · AA all-pass | 24 | 22.8 |
| Arena Vision · overall | 1,324.9 · high | 1,315.4 · high |
| Arena Document · overall | 1,496.1 | — |
Specs
| Spec | Fable 5 | Gemini 3.8 Flash |
|---|---|---|
| Input, per 1M | $10 | !$0.75 |
| Output, per 1M | $50 | !$3.75 |
| Cost per task? | $8.75 | $0.93 |
| Speed, tok/s | 67 | — |
| Context | 1M | 1M |
| Weights | Closed | Closed |
| Released | Jun 2026 | Sep 2026 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | ✓ |
| Hear audio | — | ✓ |
| Watch video | — | ✓ |
| Call tools | ✓ | ✓ |
| Force a tool call | Partial | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ✓ |
| Run code | ? | ✓ |
| Use a computer | ? | ? |
What breaks when you switch
Fable 5 → Gemini 3.8 Flash
Sampling parameters are ignored›
temperature, top_p and top_k are ignored now and will cause HTTP 400 in future generations; remove them from requests.
No minimal thinking level›
The minimal thinking level returns an error; avoid minimal.
Gemini 3.8 Flash → Fable 5
Nothing known.