Claude Opus 4.6 vs Gemini 3.8 Flash

Claude Opus 4.6
Wins 3 of 6 benchmarks
Gemini 3.8 Flash
$0.93 / task
Wins 0 of 6 benchmarks
Arena Text · creative writing?
Opus 4.61,500
Gemini 3.8 Flashat high1,487
EQ-Bench Longform Creative Writing 1.11?
Opus 4.677.7
Gemini 3.8 Flash76.8
EQ-Bench Creative Writing v3?
Opus 4.61,810.4
Gemini 3.8 Flash1,747.9
Lech Mazur Short-Story?
Opus 4.6—
Gemini 3.8 Flashat high0.1
IFBench (instructions)?
Opus 4.644.6
Gemini 3.8 Flash—
Harvey LAB-AA 1.1?
Opus 4.6—
Gemini 3.8 Flashat high0

Specs

SpecOpus 4.6Gemini 3.8 Flash
Input, per 1M$5!$0.75
Output, per 1M$25!$3.75
Cost per task?—$0.93
Speed, tok/s43—
Context1M1M
WeightsClosedClosed
ReleasedFeb 2026Sep 2026
See images✓✓
Read PDFsPartial✓
Hear audio—✓
Watch video—✓
Call tools✓✓
Force a tool callPartialPartial
Return strict JSON✓✓
Search the web?✓
Run code?✓
Use a computer??

What breaks when you switch

Opus 4.6 → 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 4.6
Nothing known.