Claude Opus 5 vs Gemini 3.8 Flash
Harvey LAB-AA 1.1?
Opus 5—
Gemini 3.8 Flashat high0
| Benchmark | Opus 5 | Gemini 3.8 Flash |
|---|---|---|
| Arena Text · creative writing | 1,471 · max | 1,487 · high |
| EQ-Bench Longform Creative Writing 1.11 | 86.3 | 76.8 |
| EQ-Bench Creative Writing v3 | 2,133.5 | 1,747.9 |
| Lech Mazur Short-Story | 3.7 · xhigh | 0.1 · high |
| Harvey LAB-AA 1.1 | — | 0 · high |
Specs
| Spec | Opus 5 | Gemini 3.8 Flash |
|---|---|---|
| Input, per 1M | $5 | !$0.75 |
| Output, per 1M | $25 | !$3.75 |
| Cost per task? | $2.19 | $0.93 |
| Speed, tok/s | 51 | — |
| Context | 1M | 1M |
| Weights | Closed | Closed |
| Released | Jul 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
Opus 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 → Opus 5
Nothing known.