Claude Opus 5 vs Gemini 3.8 Flash
Terminal-Bench 4.0 Terminal-Bench 4.0 · source setting 2: Agents use a terminal to complete executable coding, system administration and research tasks in the 4.0 suite
Opus 534.3
Gemini 3.8 Flash19.7
DeepSWE 1.1 DeepSWE 1.1: Agents change repository code to resolve software engineering tasks under the stated DeepSWE edition
Opus 568.9
Gemini 3.8 Flash71
WebDev Arena WebDev Arena: Human pairwise preferences in the stated webdev vote pool
Opus 5 · max1,689
Gemini 3.8 Flash · high1,585
SWE-bench Pro (v2 full) SWE-bench Pro (v2 full): Agents resolve repository issues under the network-locked v2 protocol; full and 51-task Hard results are separate
Opus 5 · xhigh99.4
Gemini 3.8 Flash · high94.9
SWE-bench Pro (v2 hard) SWE-bench Pro (v2 hard): Agents resolve repository issues under the network-locked v2 protocol; full and 51-task Hard results are separate
Opus 5 · xhigh98
Gemini 3.8 Flash · high58.8
SciCode SciCode: Writing code for real scientific computing problems (physics, biology, math)
Opus 551.5
Gemini 3.8 Flash55.1
Terminal-Bench Science 0.1 Terminal-Bench Science 0.1: Agents complete expert-authored research workflows across five scientific domains in a terminal
Opus 5 · max28.6
Gemini 3.8 Flash · high10
FrontierCode 1.1 FrontierCode 1.1: Agents implement changes in real repositories, graded against maintainer-defined requirements
Opus 5—
Gemini 3.8 Flash · high36.4
| Benchmark | Opus 5 | Gemini 3.8 Flash |
|---|---|---|
| Terminal-Bench 4.0 | 34.3 | 19.7 |
| DeepSWE 1.1 | 68.9 | 71 |
| WebDev Arena | 1,689 · max | 1,585 · high |
| SWE-bench Pro (v2 full) | 99.4 · xhigh | 94.9 · high |
| SWE-bench Pro (v2 hard) | 98 · xhigh | 58.8 · high |
| SciCode | 51.5 | 55.1 |
| Terminal-Bench Science 0.1 | 28.6 · max | 10 · high |
| FrontierCode 1.1 | — | 36.4 · 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 | 55 | — |
| 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.